Controlling wireless power transfer systems

Description

BACKGROUND

Wireless power transfer systems operate over a wide range of coupling factors k, load conditions, and environmental conditions. Variations in these parameters affect the efficiencies of wireless power transfer systems. Wireless power transfer systems can include impedance matching networks to improve power transfer capability and efficiency. Obtaining good performance in a wireless power transfer system over such a wide range of conditions is challenging for traditional impedance matching networks.

SUMMARY

In general, the disclosure features wireless power transmission control systems that synchronously tune a wireless power transmitter and receiver to adapt to changing system, parameters, environmental parameters, or both. The wireless power transmission control systems described herein can be used in a variety of contexts, including implantable devices, cell phone and other mobile computing device chargers, and chargers for electric vehicles.

In a first aspect, the disclosure features a wireless energy transmitter that has a transmitter-impedance matching network (IMN). The transmitter is configured to perform operations including performing a first comparison between a characteristic of a power of the transmitter and a target power. Adjusting, based on the first comparison, a reactance of the transmitter-IMN to adjust the power of the transmitter. Transmitting power data that indicates the power of the transmitter to a wireless energy receiver.

In a second aspect, the disclosure features a wireless energy receiver that has a receiver-IMN. The receiver is configured to perform operations including determining an efficiency of a wireless energy transfer system at a second time based on power data from a wireless energy transmitter. Performing a second comparison between the efficiency at the second time and an efficiency of the wireless energy transfer system at a first time, the first time being prior to the second time. Adjusting, based on the second comparison, a reactance of the receiver-IMN.

In a third aspect, the disclosure features a wireless energy transfer system that includes an energy transmitter, and an energy receiver. The transmitter has a transmitter-IMN. The transmitter is configured to perform operations including performing a first comparison between a characteristic of a power of the transmitter and a target power. Adjusting, based on the first comparison, a reactance of the transmitter-IMN to adjust the power of the transmitter. The receiver has a receiver-IMN. The receiver is configured to perform operations including determining an efficiency of the wireless energy transfer system at a second time based on power data from the transmitter. Performing a second comparison between the efficiency at the second time and an efficiency of the wireless energy transfer system at a first time, the first time being prior to the second time. Adjusting, based on the second comparison, a reactance of the receiver-IMN.

The first aspect and the second aspect can operate together in a system such as the system of the third aspect. Furthermore, these and the fourth through sevenths aspects can each optionally include one or more of the following features.

In some implementations, adjusting the reactance of the receiver-IMN includes adjusting the reactance of the receiver-IMN by a variable reactance adjustment value.

In some implementations, the first comparison and adjustment to the reactance of the transmitter-IMN occur iteratively until the characteristic of the power is within a threshold value of the target power.

In some implementations, adjusting the reactance of the receiver-IMN includes, in response to the efficiency at the second time being less than the efficiency at the first time, negating a reactance adjustment value. Adjusting the reactance of the receiver-IMN includes adjusting the reactance of the receiver-IMN by the negated reactance adjustment value.

In some implementations, adjusting the reactance of the transmitter-IMN includes, in response to the power being less than the target power, adjusting the reactance of the transmitter-IMN by a first reactance adjustment value. In response to the power being greater than the target power, adjusting the reactance of the transmitter-IMN by a second, different reactance adjustment value.

In some implementations, the first reactance adjustment value is equal in magnitude and opposite in sign to the second reactance adjustment value

In some implementations, the first comparison is between a power factor of the power of the transmitter and a target power factor. The operations of the transmitter can include a third comparison between a magnitude of the power and a target power magnitude, wherein the third comparison follows the first comparison, and adjusting, based on the third comparison, a bus voltage of the transmitter to adjust the power of the transmitter.

In some implementations, the power factor is represented by a phase relationship between a transmitter voltage and a transmitter current.

In some implementations, the first comparison and adjustment of the reactance of the transmitter-IMN based on the first comparison occur iteratively until the power factor of the power is within a threshold value of the target power factor.

In some implementations, the steps of performing the first comparison and adjusting the reactance of the transmitter-IMN are iterated at a faster rate than the steps of performing the third comparison and adjusting the bus voltage.

In some implementations, the transmitter is an electric vehicle charger and wherein the receiver is a coupled to a power system of an electric vehicle.

In some implementations, the operations of the transmitter include shutting down the wireless energy transfer system by reducing the target power to zero.

In some implementations, the operations of the transmitter include shutting down a power inverter in the transmitter.

In some implementations, the operations of the transmitter include starting up the transmitter by adjusting the reactance of the transmitter-IMN to a maximum value.

In some implementations, the operations of the transmitter include starting up the transmitter by adjusting a frequency of an inverter to a target frequency.

In some implementations, the operations of the receiver include starting up the receiver by adjusting the reactance of the receiver-IMN to a minimum value.

In some implementations, the operations of the receiver include starting up the receiver by adjusting the reactance of the receiver-IMN from a maximum value to a minimum value.

In some implementations, the transmitter-IMN includes a tunable reactive element electrically connected between an inverter and at least one fixed reactive element, and adjusting the reactance of the transmitter-IMN includes adjusting the tunable reactive element.

In some implementations, the receiver-IMN includes a tunable reactive element electrically connected between a rectifier and at least one fixed reactive element, and adjusting the reactance of the receiver-IMN includes adjusting the tunable reactive element.

In some implementations, determining the efficiency of the wireless energy transfer system includes receiving power data from the transmitter, determining an output power of the receiver, and calculating the efficiency of the wireless energy transfer system based on the power data from the transmitter and the output power of the receiver.

In some implementations, the operations of the transmitter include performing a plurality of checks that can include a check of a magnitude of the power, a check of a power factor of the power, and a check of a frequency of an inverter in the transmitter, and in response to the plurality checks, selectively adjusting the frequency of the inverter to adjust the power of the transmitter.

In some implementations, the operations of the transmitter include performing a plurality of checks that can include a check of a magnitude of the power and a check of a phase shift of an inverter of the transmitter, in response to the plurality checks, selectively adjusting the phase shift of the inverter to adjust the power of the transmitter.

In some implementations, the operations of the transmitter include, before adjusting the bus voltage, verifying that the bus voltage is greater than a minimum bus voltage.

In some implementations, the first comparison is between a power factor of the power of the transmitter and a target power factor. The operations of the transmitter can include performing a third comparison between a magnitude of the power and a target power magnitude, adjusting, based on the third comparison, the reactance of the transmitter-IMN to reduce the power of the transmitter.

In some implementations, the first comparison is between a power factor of the power of the transmitter and a target power factor. The operations of the transmitter can include performing a third comparison between a magnitude of the power and a target power magnitude, and adjusting, based on the third comparison, a frequency of an inverter of the transmitter to reduce the power of the transmitter.

In some implementations, the first comparison is between a power factor of the power of the transmitter and a target power factor. The operations of the can include performing a third comparison between a magnitude of the power and a target power magnitude, and adjusting, based on the third comparison, a phase shift of an inverter of the transmitter to reduce the power of the transmitter.

In some implementations, the transmitter includes an inductive coil coupled to at least portion of the transmitter-impedance matching network to form a transmitter resonator.

In some implementations, the receiver includes an inductive coil coupled to at least portion of the receiver-impedance matching network to form a receiver resonator.

In a fourth aspect, the disclosure features the subject matter described in this specification can be embodied in methods that include the actions of tuning, by a wireless energy transmitter, a transmitter-IMN of the wireless energy transmitter to achieve a target transmitter power characteristic. Sending, by the wireless energy transmitter, power data that indicates the power of the transmitter to a wireless energy receiver. Tuning, by the wireless energy receiver and based on the power data, the receiver-IMN to improve an efficiency of the wireless energy transfer system.

In a fifth aspect, the disclosure features a wireless energy transmitter that has a transmitter-IMN. The transmitter is configured to perform operations including tuning the transmitter-IMN to achieve a target transmitter power characteristic and sending power data that indicates the power of the transmitter to a wireless energy receiver.

In a sixth aspect, the disclosure features a features a wireless energy receiver that has a receiver-IMN. The receiver is configured to perform operations including tuning the receiver-IMN to improve an efficiency of the wireless energy transfer system based on power data received from a wireless energy transmitter.

In a seventh aspect, the disclosure features a wireless energy transfer system that includes an energy transmitter, and an energy receiver. The transmitter is configured to perform operations including tuning the transmitter-IMN to achieve a target transmitter power characteristic and sending power data that indicates the power of the transmitter to the wireless energy receiver. The receiver has a receiver-IMN. The receiver is configured to perform operations including tuning the receiver-IMN to improve an efficiency of the wireless energy transfer system based on power data received from the wireless energy transmitter.

The fifth aspect and the sixth aspect can operate together in a system such as the system of the seventh aspect. Furthermore, these and the first through third aspects can each optionally include one or more of the following features.

In some implementations, the target transmitter power characteristic is a target power factor and the target transmitter power characteristic is a target power factor.

In some implementations, the power factor is represented by a phase difference between a transmitter voltage and a transmitter current, and the target power factor is a target phase difference.

In some implementations, the operations include adjusting, by the transmitter, an inverter bus voltage to achieve a target power magnitude.

In some implementations, the operations include performing a safety check prior to adjusting the transmitter-IMN. In some implementations, the safety check is an over-voltage check or an over-current check.

In some implementations, the operations include performing, by the transmitter, a plurality of checks that can include a check of a magnitude of a transmitter power, a check of a transmitter power factor, and a check of a frequency of an inverter in the transmitter; and in response to the plurality checks, selectively adjusting the frequency of the inverter to adjust the power of the transmitter.

In some implementations, the operations include performing a plurality of checks that can include a check of a magnitude of a transmitter power and a check of a phase shift of an inverter of the transmitter; and in response to the plurality checks, selectively adjusting the phase shift of the inverter to adjust the power of the transmitter.

In some implementations, the transmitter is an electric vehicle charger and the receiver is a coupled to a power system of an electric vehicle.

In some implementations, the operations include adjusting, while starting up the transmitter, the reactance of the transmitter-IMN to a maximum value.

In some implementations, the operations include adjusting, while starting up the receiver, the reactance of the receiver-IMN to a minimum value.

In some implementations, the transmitter includes an inductive coil coupled to at least portion of the transmitter-impedance matching network to form a transmitter resonator.

In some implementations, the receiver includes an inductive coil coupled to at least portion of the receiver-impedance matching network to form a receiver resonator.

In an eighth aspect, the disclosure features a wireless power transmission system without bus voltage control configured to implement a control loop for tuning power transmission, where the control loop includes: a first sub-loop to control output power of a transmitter of the wireless power transmission system, and a second sub-loop to tune a combined reactance of an inductor and a capacitor that couple a tank circuit to a rectifier in a receiver of the wireless power transmission system, where the second sub-loop tunes the combined reactance by monitoring efficiency of wireless power transmission. Furthermore, this and other implementations can each optionally include one or more of the following features.

In some implementations, the second sub-loop employs a perturb-and-observe strategy to improve efficiency based on a previous point by tuning the combined reactance of an inductor and a capacitor that couple a tank circuit to a rectifier in a receiver of the wireless power transmission system.

In some implementations, the second sub-loop is dependent on a power comparison where output power is compared to target power at a start of the control loop.

In some implementations, the second sub-loop operates at the rate of communication, for example, 40 Hz.

In some implementations, the control loop is characterized by:

$P_{inv} = \frac{\frac{8}{π^{2}} V_{bus}^{2}}{R_{inv}^{2} + X_{inv}^{2}} R_{inv}$

where P_invis power out of an inverter of the transmitter of the wireless power transmission system, V_busis bus voltage, R_invis resistance seen by the inverter, and X_invis reactance seen by the inverter, and where the tuning occurs at X_inv=the combined reactance of the inductor and the capacitor.

In some implementations, the first sub-loop is a local loop that does not communicate with another part of the wireless power transmission system.

In some implementations, the first sub-loop is faster than the second sub-loop where the first sub-loop is on order of 1 to 10 kHz.

In some implementations, the control loop includes preparing inputs, including: setting transmitter reactance to a maximum value, setting receiver reactance to a minimum value, and where the efficiency of wireless power transmission at time zero=0 and receiver reactance is to be changed by a constant or variable value.

In some implementations, the control loop starts by comparing output power to target power. In some implementations, if the output power equals the target power within a tolerance, then: efficiency is measured at a time n, the efficiency at time n is compared to efficiency at a previous time n−1, if the efficiency at time n is greater than the efficiency at the previous time n−1, then a change in receiver reactance is added to the receiver reactance and the output power is compared to the target power; whereas if efficiency at time n is equal to or less than the efficiency at the previous time n−1, then a change in receiver reactance is negated, the negated change is added to the receiver reactance, and the output power is compared to the target power.

In some implementations, if the output power does not equal the target power within a tolerance, then: it is determined whether the output power is less than the target power, if the output power is less than the target power, then a change in transmitter reactance is set to −δ, the change in transmitter reactance is added to the transmitter reactance, and the output power is compared to the target power; if the output power is greater than the target power, then the change in transmitter reactance is set to δ, the change in transmitter reactance is added to the transmitter reactance, and the output power is compared to the target power.

In a ninth aspect, the disclosure features a wireless power transmission system with bus voltage control configured to implement a control loop for tuning power transmission, where the control loop includes: a first sub-loop to control phase as defined: φ=arctan(X_inverter/R_inverter), a second sub-loop to control output power, and a third sub-loop to tune a combined reactance of an inductor and a capacitor that couple a tank circuit to a rectifier in a receiver of the wireless power transmission system by monitoring efficiency. Furthermore, this and other implementations can each optionally include one or more of the following features.

In some implementations, the third sub-loop employs a perturb-and-observe strategy to improve efficiency based on a previous point by tuning the combined reactance of an inductor and a capacitor.

In some implementations, the third sub-loop is dependent on a power comparison and thus on the second sub-loop.

In some implementations, the third sub-loop operates at a rate of communication, for example, 40 Hz (speed of WiFi).

In some implementations, the control loop can be characterized by:

$P_{inv} = \frac{\frac{8}{π^{2}} V_{bus}^{2}}{R_{inv}^{2} + X_{inv}^{2}} R_{inv}$

where P_invis power output from an inverter of the transmitter of the wireless power transmission system, V_busis bus voltage, R_invis resistance seen by the inverter, and X_invis the reactance seen by the inverter, and where tuning occurs at both V_busand X3=X_inv.

In some implementations, the first sub-loop is adjusted first, the second sub-loop is then adjusted, and the third sub-loop is then adjusted.

In some implementations, the first sub-loop runs on the order of 1 to 10 kHz.

In some implementations, the first sub-loop is a local loop and does not communicate with another part of the wireless power transmission system.

In some implementations, the second sub-loop is a local loop and does not communicate with another part of the wireless power transmission system.

In some implementations, the second sub-loop runs on the order of 1 to 10 kHz.

In some implementations, the control loop includes preparing inputs, including: setting transmitter reactance to a maximum value, setting receiver reactance to a minimum value, where the efficiency of wireless power transmission at time zero=0, the receiver reactance is to be increased, the transmitter reactance is to be increased, the bus voltage is to be increased, and phase is to be increased.

In some implementations, the control loop includes: comparing a phase measured at the inverter to a target phase, and if the phase measured at the inverter equals the target phase, then output power is compared to target power.

In some implementations, the third sub-loop occurs if the output power equals the target power and includes: measuring efficiency at a time n, comparing efficiency at the time n to efficiency at a previous time n−1, if the efficiency at the time n is greater than the efficiency at the previous time n−1 then receiver reactance is incremented; whereas if the efficiency at the time n is less than or equal to the efficiency at the previous time n−1, then change in the receiver reactance is negated and the negated value is added to the receiver reactance.

In some implementations, the second sub-loop occurs if the output power does not equal the target power and includes: if the output power is less than the target power, increasing the bus voltage, and if the output power is greater than the target power, reducing the bus voltage.

In some implementations, the first sub-loop occurs if a phase measured at inverter is not equal to a target phase and includes: if the phase measured at inverter is greater than a target phase, comparing receiver reactance to a minimum receiver reactance and if the receiver reactance equals the minimum receiver reactance, then comparing the output power to the target power; whereas if the receiver reactance does not equal the minimum receiver reactance, decreasing the transmitter reactance; and if the phase measured at the inverter is less than the target phase, then comparing the receiver reactance to a maximum receiver reactance and if the receiver reactance equals maximum receiver reactance then comparing the output power to the target power whereas if the receiver reactance does not equal the maximum receiver reactance then increasing the transmitter reactance.

Particular implementations of the subject matter described in this specification can be implemented so as to realize one or more of the following advantages. Implementations may improve the efficiency of operating wireless power transfer systems. Implementations may improve the dependability of wireless power transfer systems. Implementations may improve robustness of wireless power transfer systems to operate over many conditions. Implementations may improve ability to achieve higher levels of power transfer over many conditions.

Embodiments of the devices, circuits, and systems disclosed can also include any of the other features disclosed herein, including features disclosed in combination with different embodiments, and in any combination as appropriate.

The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will be apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B depict diagrams of an exemplary wireless power transmission system.

FIGS. 2A-2D depict plots related to the effects of receiver X3 tuning in an exemplary wireless power transmission system.

FIG. 3 depicts a flowchart of an exemplary control process for operating a wireless power transmission system.

FIG. 4 depicts a flowchart of another exemplary control process for operating a wireless power transmission system.

FIGS. 5A-5C depict more detailed flowcharts of exemplary control processes for operating control loop for tuning a wireless power transmission system.

FIG. 6A depicts a flowchart of an exemplary startup process for a wireless power transmission control system.

FIG. 6B depicts a flowchart of an exemplary shutdown process for a wireless power transmission control system.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

Wireless energy transfer systems described herein can be implemented using a wide variety of resonators and resonant objects. As those skilled in the art will recognize, important considerations for resonator-based power transfer include resonator quality factor and resonator coupling. Extensive discussion of such issues, e.g., coupled mode theory (CMT), coupling coefficients and factors, quality factors (also referred to as Q-factors), and impedance matching is provided, for example, in U.S. patent application Ser. No. 13/428,142, published on Jul. 19, 2012 as US 2012/0184338, in U.S. patent application Ser. No. 13/567,893, published on Feb. 7, 2013 as US 2013/0033118, and in U.S. patent application Ser. No. 14/059,094, published on Apr. 24, 2014 as US 2014/0111019. The entire contents of each of these applications are incorporated by reference herein.

In some applications such as wireless power transfer, impedances seen by the wireless power supply source and device may vary dynamically. In such applications, impedance matching between a device resonator coil and a load, and a source resonator coil and the power supply, may be required to prevent unnecessary energy losses and excess heat. The impedance experienced by a resonator coil may be dynamic, in which case, a dynamic impedance matching network can be provided to match the varying impedance to improve the performance of the system. In the case of the power supply in a wireless power system, the impedances seen by the power supply may be highly variable because of changes in the load receiving power (e.g., battery or battery charging circuitry) and changes in the coupling between the source and device (caused, for example, by changes in the relative position of the source and device resonators). Similarly, the impedance experienced by the device resonator may also change dynamically because of changes in the load receiving power. In addition, the desired impedance matching for the device resonator may be different for different coupling conditions and/or power supply conditions. Accordingly, power transfer systems transferring and/or receiving power via highly resonant wireless power transfer, for example, may be required to configure or modify impedance matching networks to maintain efficient power transfer. Implementations of the present disclosure provide startup, shutdown, and steady state operation processes that allow for efficient operation over the entire range of conditions encountered in highly-resonant wireless power transfer systems (HRWPT) system such as high-power vehicle charging systems, for example.

FIGS. 1A and 1B depict diagrams of an exemplary a wireless power transfer system 100. Referring first to FIG. 1A, the system 100 includes a wireless power transmitter 102 and a wireless power receiver 104. A wirelessly powered or wirelessly charged device 112 is coupled to receiver 104. Wirelessly powered or wirelessly charged devices 112 can include, for example, high-power devices such as electric vehicles or electronic devices such as laptops, smartphones, tablets, and other mobile electronic devices that are commonly placed on desktops, tabletops, bar tops, and other types of surfaces.

For purposes of illustration, wireless power transfer system 100 will be discussed in the context of a wireless charging system for an electric vehicle. For example, system 100 can be a HRWPT system which is required to operate over a wide range of coupling factors k, load conditions (such as a battery voltage), and environmental conditions that detune the inductances of the resonators (e.g., due to spatial variations and interfering objects). Furthermore, in order to perform wireless charging of electric vehicles, system 100 may be required to operate with high voltages (e.g., between 360V and 800V) and high currents (e.g., between 26 A and 40 A) to achieve a suitable range of power (e.g., 0 to 3.7 kW, 0 to 7.7 kW, 0 to 11 kW, or 0 to 22 kW).

Wireless power transmitter 102 converts power from an external power source (e.g., power grid or generator) to electromagnetic energy which is transmitted between resonators 108T and 108R to wireless power receiver 104. Receiver 104 converts the oscillating energy received by resonator 108R to an appropriate form for use by device 112 (e.g., charging an electric vehicle battery). More specifically, the receiver power and control circuitry 110 can convert AC voltage and current from resonator 108R to DC power within appropriate voltage and current parameters for device 112.

The transmitter power and control circuitry 106 can include circuits and components to isolate the source electronics from the power supply, so that any reflected power or signals are not coupled out through the source input terminals. The source power and control circuitry 106 can drive the source resonator 108S with alternating current, such as with a frequency greater than 10 kHz and less than 100 MHz (e.g., 85 kHz). The source power and control circuitry 106 can include, for example, power factor correction (PFC) circuitry, a transmitter controller, impedance matching circuitry, a power inverter, a DC-to-DC converter, an AC-to-DC converter, a power amplifier, or any combination thereof.

The receiver power and control circuitry 110 can be designed to transform alternating current power from the receiver resonator 108R to stable direct current power suitable for powering or charging one or more devices 112. For example, the receiver power and control circuitry 110 can be designed to transform an alternating current power at one frequency (e.g., 85 kHz) from resonator 108R to alternating current power at a different frequency suitable for powering or charging one or more devices 112. The receiver power and control circuitry 110 can include, for example, a receiver controller, impedance matching circuitry, rectification circuitry, voltage limiting circuitry, current limiting circuitry, AC-to-DC converter circuitry, DC-to-DC converter circuitry, DC-to-AC circuitry, AC-to-AC converter circuitry, and battery charge control circuitry.

Transmitter 102 and receiver 104 can have tuning capabilities, for example, dynamic impedance matching circuits, that allow adjustment of operating points to compensate for changing environmental conditions, perturbations, and loading conditions that can affect the operation of the source and device resonators and the efficiency of the energy transfer. The tuning capability can be controlled automatically, and may be performed continuously, periodically, intermittently or at scheduled times or intervals. In some implementations, tuning is performed synchronously between the transmitter 102 and the receiver 104 as described in more detail below.

FIG. 1B shows the power and control circuitry 106 and 110 of transmitter 102 and receiver 104 in more detail. Referring to both FIGS. 1A and 1B, transmitter 102 includes an inverter 122 powering a transmitter impedance matching network (IMN) 124 and a controller 125 that controls the operation of inverter 122 and tunes transmitter IMN 124. Transmitter IMN 124 is coupled to resonator coil 108T. Receiver 104 includes a receiver IMN 126 coupled to resonator 108R, a rectifier 128 and a controller 129 that can tune the receiver IMN 126. In operation, inverter 122 provides power through transmitter IMN 124 to resonator 108T. Resonator 108T couples oscillating electromagnetic energy to resonator 108R, with a coupling constant k. The energy received by resonator 108R is transferred through receiver IMN 126 to rectifier 108 which converts the energy into an appropriate form for use by device 112.

Transmitter controller 125 and receiver controller 129 can be implemented as processors or microcontrollers. In some implementations, transmitter controller 125 and receiver controller 129 can be implemented as ASIC or FPGA controllers. Transmitter controller 125 and receiver controller 129 need not be implemented in the same form. For example, transmitter controller 125 can be implemented as a microcontroller and receiver controller 129 can be implemented as an ASIC controller.

Transmitter 102 also includes a plurality of sensors such as voltage, current, and power sensors to measure transmitter operating parameters. Transmitter controller 125 can use measurements from the sensors to control the operation of the transmitter 102 and to tune the transmitter IMN 124. Transmitter operating parameters measured by the sensors can include, but is not limited to, inverter bus voltage (V_bus), transmitter input power, inverter AC voltage (V_AC), inverter AC current (I_AC), transmitter power factor (pf), and other voltages and currents as needed for safety checks. In some implementations, the transmitter input power is measured at an AC input to a transmitter PFC circuit. In some implementations, the transmitter input power is measured as an inverter power (P_in), as shown in FIG. 1B. In some implementations, the inverter power (P_in) is measured at the DC input of inverter 122. In some implementations, inverter power (P_in) is measured at the AC output of inverter 122. Transmitter power factor can be measured as the phase difference (φ) between the inverter AC voltage (V_AC) and inverter AC current (I_AC), where the power factor is the cosine of the phase difference (φ). In some implementations, the phase difference (φ) can be used as a proxy for power factor. That is, transmitter controller 125 can perform operations based on the phase difference (φ) instead of calculating an actual power factor value. In some implementations, transmitter power factor (pf) can be calculated based on equivalent resistance and reactance values as seen at the output of the inverter. For example, the phase difference (φ) can be represented by:

φ=arctan(X_inverter/R_inverter).

Receiver 104 also includes a plurality of sensors such as voltage, current, and power sensors to measure receiver operating parameters. Receiver controller 129 can use measurements from the sensors to control the operation of the receiver 104 and to tune the receiver IMN 126. Receiver operating parameters measured by the sensors can include, but is not limited to, receiver output power (P_out), rectifier AC voltage, rectifier AC current, rectifier DC voltage, rectifier DC current, and other voltages and currents as needed for safety checks.

Transmitter IMN 124 and receiver IMN 126 can each include a plurality of fixed and variable impedance matching components such as resistors, capacitors, inductors, or combinations thereof. Variable impedance components can be tunable reactive impedance components including, but not limited to, PWM-switched capacitors, radio frequency (RF) controlled capacitors whose effective capacitance at RF is controlled by a DC bias field, temperature-controlled capacitors, PWM-switched inductors, DC controlled inductors whose effective inductance is controlled by a bias DC field (e.g., a saturable core), temperature-controlled inductors, arrays of reactive elements switched in and out of the circuit by switches, or a combination thereof.

In the illustrated example, transmitter IMN 124 includes series capacitor 132, parallel capacitor 134, and the combination of capacitor 136 and inductor 138 at the output of inverter 122. Capacitor 136 is a variable capacitor and can include one or more variable capacitors. A resistive component of the transistor resonator coil 108T is represented by resistor 140.

Receiver IMN 126 includes series capacitor 144, parallel capacitor 146, and the combination of capacitor 148 and inductor 150 at the input to rectifier 128. Capacitor 148 is a variable capacitor and can include one or more variable capacitors. A resistive component of the receiver resonator coil 108R is represented by resistor 152.

IMNs 124 and 126 can have a wide range of circuit implementations with various components having impedances to meet the needs of a particular application. For example, U.S. Pat. No. 8,461,719 to Kesler et al., which is incorporated herein by reference in its entirety, discloses a variety of tunable impedance network configurations, such as in FIGS. 28a-37b. In some implementations, each of the components shown in FIG. 1B may represent networks or groups of components.

Each of the IMNs 124 and 126 include three reactances: series reactance X1 (e.g., capacitor 132 or 144), parallel reactance X2 (e.g., capacitor 134 or 146), and inverter output/rectifier input reactance X3 (combined reactance of inductor 138 or 150 with capacitor 136 or 148, respectively). The reactances X1-X3 of receiver IMN 126 mirror the corresponding reactances X1-X3 of transmitter IMN 124. Although reactance X3 is the only reactance illustrated as including a tunable reactance component, namely, capacitors 136 and 148, in other implementations, reactances X1 and X2 can include tunable reactance components in addition to or in place of the tunable reactance component in reactance X3. In other words, IMNs 124 and 126 can be tuned by tuning any one or more of reactances X1-X3. In some implementations, components that make up reactances X1 and X3 can be balanced.

While any of reactances X1, X2, X3, or combinations thereof can be tuned, in some implementations, it can be advantageous to tune reactance X3. For example, by tuning reactance X3, it may be possible to reduce system complexity and cost if tuning a single component in IMN is sufficient. By tuning reactance X3, the current through the X3 elements can be significantly lower than that through the tank circuit formed by X1, X2, and the resonator coil. This lower current may make implementation of tunable components more cost-effective by, for example, reducing current ratings that may be required for such components. Additionally, lower currents may reduce losses by tuning elements at X3.

In some implementations, tunable reactive elements (e.g., PWM controlled capacitors) can inject harmonic noise into a HRWPT system. To help with EMI compliance, may be preferable to keep this harmonic noise away from the main HRWPT resonator coils (e.g., 108T and 108R). Higher-harmonics injected by a tunable element at X3 may be more suppressed than those that can be generated by the inverter and rectifier and may be significantly suppressed by the rest of the HRWPT circuit before reaching the resonator coil 108T or 108R.

In some implementations with tunable elements at X3 (e.g., PWM controlled capacitors), the tunable element dissipates the least amount of power (theoretically zero) when the overall efficiency of the rest of the system is lowest, and the highest amount of power when the overall efficiency of the rest of system is highest. This has the desirable effect of optimizing the minimum and average efficiencies of the system while only slightly affecting the maximum efficiency. However, tuning elements at X1 or X2 can have the opposite, less desirable, effect.

Fixed reactances of X1 and X2, and the base reactance value of X3 can be selected to achieve the results shown in FIGS. 2A-2D and discussed below. For example, values for X1 and X2 can be determined by: 1) Determining the maximum range of reactive tuning that can be achieved based on the maximum current that flows through the circuit branches containing X3 and the current and voltage ratings of the components used in the implementation of the tunable reactive elements. For example, one may conclude that a single-stage reactive element can affect 20Ω of reactive tuning. 2) Optimizing, for the receiver-side IMN, X1, X2, and the base value of X3 so as to optimize the coil-to-coil efficiency over the range of relative positions of the resonators (and of load conditions) and/or ensure that the amount of power dissipated in the resonators stays below a specified limit based on the range of reactive determined in step 1. 3) Optimizing, for the transmitter-side IMN, X1, X2, and the base value of X3 so as to present a desirable effective impedance to the inverter (e.g., sufficiently inductive to achieve zero-voltage-switching in a Class D inverter, but not too inductive that there's excessive reactive current, and with a magnitude that falls within the range of bus voltages that can be practically achieved).

FIGS. 2A-2D illustrate plots related to the effects of tuning receiver X3. FIG. 2A shows source (transmitter) resonator power losses (in W per kW to the load) as a function of quality factor ratio Q_d^U/Q_d^L, where Q_d^Uis the quality factor of the unloaded device (receiver) resonator and Q_d^Uis the quality factor of the loaded device loaded device resonator (loading includes the loading of the remaining device circuitry and load) and figure of merit F_oM=U=k√{square root over (Q_sQ_d)}. FIG. 2A illustrates that figure of merit plays a dominate role in losses at the transmitter resonator.

FIG. 2B shows device resonator power losses (in W per kW to the load) as a function of quality factor ratio Q_d^U/Q_d^Lwhere Q is the quality factor of the unloaded device resonator and Q_d^Lis the quality factor of the loaded device resonator (loading includes the remaining device circuitry and load) and figure of merit F_oM=U=k√{square root over (Q_sQ_d)}. FIG. 2B illustrates that quality factor ratio plays a dominate role in losses at the receiver resonator.

FIG. 2C shows device figure of merit U_dat an operating frequency of 84 kHz as a function of the change in reactance dX (in ohms) at position X3 and load resistance R_L(in ohms). Figure of merit U_dis defined through:

$\frac{R_{L, eq}}{R_{d}} = \sqrt{1 + U_{d}^{2}}$

where R_L,eqis the loaded equivalent series resistance (ESR) (due to device electronics, such as the rectifier, and battery) of the device resonator and R_dis the unloaded ESR of the device resonator. When U_dis set to equal figure of merit U of the system, then the coil-to-coil efficiency can be maximized.

FIG. 2D shows phase ψ (in degrees) at an operating frequency of 84 kHz as a function of the change in reactance (in ohms) and load resistance (in ohms). Phase ψ is defined by:

$ψ = \arctan (\frac{Δ X_{L}}{R_{L, eq}})$

where ΔX_Lis the residual reactance of the loaded device resonator at the operating frequency. A phase ψ=0 means the loaded device resonator is at resonance.

The trapezoidal dotted outline 202 in FIGS. 2C and 2D shows an operating range for a wireless power transfer receiver. Outline 202 in FIG. 2D shows a range of R_Lthat would be seen for a wireless power transmission system operating at 11 kW output. For example, for R_L=10Ω, there is a significant ability to tune X3, as shown in FIG. 2C by range of dX at R_L=10Ω, while maintaining near resonance (or avoiding detuning the resonator), as shown in FIG. 2D by the proximity of ψ=0 curve to R_L=10Ω.

Referring again to FIG. 1B, controllers 125 and 129 can synchronously tune the IMNs 124 and 126, respectively, to maintain system 100 operations within desired operating ranges such as outline 202. In the illustrated implementations, controllers 125 and 129 perform the processes described below to synchronously tune reactance X3 of the transmitter and receiver IMNs 124 and 126 in order to safely and efficiently transfer power to a device 112 such as an electric vehicle. In order to synchronously control the IMNs 124 and 126, transmitter 102 and receiver 104 can communicate control data between each other. For example, controllers 125 and 129 can include wireless communication interfaces to conduct electronic communications in an out-of-band communications channel. Communications between controllers 125 and 129 can include, but are not limited to, RF communications (e.g., WiFI, Bluetooth, Zigbee), optical communication, infrared communications, ultrasonic communications, or a combination thereof.

For example, as described in more detail below in reference to FIGS. 3-5C, controller 125 can tune transmitter IMN 124 to achieve a target power characteristics of transmitter 102, while controller 129 can tune receiver IMN 126 to achieve a target system efficiency. Transmitter controller 125 adjusts IMN 124 to achieve and maintain target power characteristics of the transmitter 102. Transmitter controller 125 sends input power data to receiver controller 129. Receiver controller 129 measures output power of the receiver 104 and, together with the input power data, calculates the efficiency of the system 100. Receiver controller 129 tunes the receiver IMN 126 to maximize the system efficiency. For example, receiver controller 129 can determine appropriate adjustments to receiver IMN 126 based on comparing a calculated efficiency values at two different times.

In some implementations, transmitter controller 125 operates at a faster rate than receiver controller 129. That is, transmitter controller 125 can tune the transmitter IMN 124 at a faster rate than receiver controller 129 can tune the receiver IMN 126. For example, receiver controller 129 may only be permitted to tune receiver IMN 126 as fast as it receives new input power data from transmitter controller 125.

FIG. 3 depicts a flowchart of an exemplary control process 300 for operating a wireless power transmission system. In some examples, the example process 300 can be provided as computer-executable instructions executed using one or more processing devices (e.g., processors or microcontrollers) or computing devices. In some examples, the process 300 may be executed by hardwired electrical circuitry, for example, as an ASIC or an FPGA controller.

Portions of process 300 are be performed by a wireless power transmitter 102 (e.g., transmitter controller 125) and portions of process 300 are performed by a wireless power receiver 104 (e.g., receiver controller 129). Process 300 includes two control loops 303 and 305. Loop 303 is performed by a transmitter 102 to tune a transmitter IMN 124 by adjusting reactance X3 to control the transmitter power. In some implementations, loop 303 is a local loop that does not require communication with other devices (e.g., receiver 104) to be performed. In some implementations, loop 303 is executed by a transmitter at between 1-10 kHz. Loop 303 can be characterized by:

$P_{in} = \frac{\frac{8}{π^{2}} V_{bus}^{2}}{R_{inv}^{2} + X_{inv}^{2}} R_{inv}$

where P_inis the power of the inverter, V_busis the DC bus voltage of the inverter 122, R_invis the effective resistance as seen by the inverter, and X_invis the effective reactance as seen by the inverter.

Loop 305 is performed by a receiver 104 to tune a receiver IMN 126 based on system efficiency. For example, loop 305 can employ a “perturb-and-observe” strategy to improve efficiency by adjusting reactance X3 of a receiver IMN 126 to continually improve efficiency over consecutive iterations. Loop 305 depends on input power data from transmitter 102 to calculate system efficiency at each iteration. In some implementations, loop 305 operates at the rate of communication between transmitter 102 and receiver 104, for example, 40 Hz.

Block 302 lists the inputs and initial conditions for process 300 which include a variable transmitter reactance X_tx(e.g., X3 of transmitter IMN 124), set to a maximum reactance value X_tx,max; a variable receiver reactance Xrx (e.g., X3 of receiver IMN 126), set to a minimum reactance value X_rx,min; a system efficiency η, initially set to zero; a transmitter reactance step size ΔX_tx, set to an adjustment value of 6; and a receiver reactance step size ΔX_rx, set to an adjustment value of ε. In some implementations, the reactance step sizes ΔX_txand ΔX_rxare constant values. In some implementations, the reactance step sizes ΔX_txand ΔX_rxcan be variable. For example, controller 125 or controller 129 can increase or decrease the magnitude of the respective step sizes dynamically during process 300.

Process 300 starts at step 304. At step 306 the power of the transmitter 102 is measured. Transmitter controller 125 measures the input power P_in, and, at step 306, compares the input power P_into a target power level P_target. If P_inequals P_targetthe process 300 proceeds to step 308 of loop 305. If P_indoes not equal P_target, process 300 proceeds to step 316 of loop 303. In some implementations or some operation modes, the target power level is set by the transmitter 102. In some implementations or some operation modes, the target power level is set by the receiver 104. For example, when in steady-state operations (e.g., normal operations apart from startup or shutdown sequences), system 100 can operate as a demand based system. For example, receiver 104 can request power levels from the transmitter 102. Transmitter controller 125 can calculate a target input power level based on the demanded power level from the receiver 104. For example, transmitter controller 125 can convert the demanded power to a target input power level that would be required to transmit the demanded power level by accounting for expected losses in the transmitter (e.g., IMN losses and inverter losses).

Referring first to the transmitter-side loop, loop 303, if the input power of the transmitter (e.g., the inverter power) is not equal to the target power, at step 316 transmitter controller 125 compares the input power to the target power level to determine whether the input power is less than the target power level. If P_inis less than P_target, then, at step 318, transmitter controller 125 sets the transmitter reactance step size ΔX_tx, to a negative adjustment value to decrease the variable transmitter reactance X_txin step 320. If P_inis not less than P_target, then, at step 322, transmitter controller 125 sets the transmitter reactance step size ΔX_tx, to a positive adjustment value to increase the variable transmitter reactance X_txin step 320. In some implementations, the magnitude of the reactance adjustment value δ can be varied. For example, if the difference between P_inand P_targetis large, for example, greater than a coarse adjustment threshold value, then the transmitter controller 125 can increase the magnitude of the reactance adjustment value δ. Correspondingly, if the difference between P_inand P_targetis small, for example, less than a fine adjustment threshold value, then the transmitter controller 125 can decrease the magnitude of the reactance adjustment value δ. After the variable transmitter reactance X_txis adjusted in step 320, loop 303 returns to step 306, where the input power is again compared to the target power level.

Referring to the receiver-side loop, loop 305, if the input power of the transmitter is equal to the target power, at step 308, the receiver controller 129 measures the efficiency of the system 100. For example, when P_inis equal to P_target, the transmitter can send data indicating the measured value of P_into the receiver 104. (It should be noted that measured transmitter power can be represented by a floating point number and, thus, may not exactly equal the target power, but may be equivalent within a predetermined tolerance.) Receiver controller 129 measures the output power of the receiver, and calculates the system efficiency η(n) at time n based on the received transmitter power data and the measured receiver output power value.

At step 310, receiver controller 129 compares the system efficiency calculated at time n, to the system efficiency calculated at a previous time n−1. If the efficiency at time n is greater than the efficiency at time n−1, then, at step 312, the variable receiver reactance X_rxis adjusted by the receiver reactance step size ΔX_rx. For example, the change in receiver reactance ΔX_rxis added to the variable receiver reactance X_rx. If the efficiency at time n is not greater than the efficiency at time n−1, then, at step 314, receiver controller 129 changes the sign of the receiver reactance step size ΔX_rxbefore adjusting the variable receiver reactance X_rxat step 312. For example, the value of the change in receiver reactance ε can be negated. For example, the direction of adjustments for the variable receiver reactance X_rxis swapped when the efficiency is no longer increasing between subsequent iterations of loop 305. As illustrated in by loop 305, direction of adjustments for the variable receiver reactance X_rxwill then be retained in subsequent iterations of loop 305 until efficiency decreases again, thereby, maintaining a near-maximum system efficiency.

In some implementations, the magnitude of the reactance adjustment value ε can be varied. For example, if the efficiency at time n is less than a coarse adjustment threshold value (e.g., soon after system startup), then the receiver controller 129 can increase the magnitude of the reactance adjustment value E. Correspondingly, if the efficiency at time n is near an estimated maximum value for example, within a fine adjustment threshold of the estimated maximum value, then the receiver controller 129 can decrease the magnitude of the reactance adjustment value ε.

FIG. 4 depicts a flowchart of an exemplary control process 400 for operating a wireless power transmission system. In some examples, the example process 400 can be provided as computer-executable instructions executed using one or more processing devices (e.g., processors or microcontrollers) or computing devices. In some examples, the process 400 may be executed by hardwired electrical circuitry, for example, as an ASIC or an FPGA controller.

Process 400 is similar to process 300, but includes control of inverter bus voltage V_busto adjust transmitter power P_in, and measurements of and the use of inverter power factor (e.g., inverter AC voltage V_ACand inverter AC current I_ACphase difference φ) to tune the transmitter IMN 124.

Portions of process 400 are be performed by a wireless power transmitter 102 (e.g., transmitter controller 125) and portions of process 400 are performed by a wireless power receiver 104 (e.g., receiver controller 129). Process 400 includes three control loops 401, 403, and 405. Loops 401 and 403 are performed by a transmitter 102 to tune a transmitter IMN 124 and to control the transmitter power. Loop 401 is a phase loop that tunes the transmitter IMN 124 by adjusting reactance X3 to achieve a target phase φ relationship between the inverter AC output voltage and inverter AC output current (e.g., inverter power factor), hereinafter referred to as “inverter output phase φ_inv” and “target inverter output phase φ_target.” Loop 403 is a power control loop that controls and maintains the transmitter power magnitude P_inat or near the target power P_targetby adjusting the inverter bus voltage V_bus. In some implementations, loops 401 and 403 are local loops that do not require communication with other devices (e.g., receiver 104) to be performed. In some implementations, loops 401 and 403 are executed by a transmitter at between 1-10 kHz. Loops 401 and 403 can be characterized by:

Loop 405 is performed by a receiver 104 to tune a receiver IMN 126 based on system efficiency. Loop 405 is similar to loop 305 of process 300. For example, loop 405 can employ a “perturb-and-observe” strategy to improve efficiency by adjusting reactance X3 of a receiver IMN 126 to continually improve efficiency over consecutive iterations. Loop 405 depends on input power data from transmitter 102 to calculate system efficiency at each iteration. In some implementations, loop 405 operates at the rate of communication between transmitter 102 and receiver 104, for example, 40 Hz.

Block 402 lists the inputs and initial conditions for process 400 which include a variable transmitter reactance X_tx(e.g., X3 of transmitter IMN 124), set to a maximum reactance value X_tx,max; a variable receiver reactance X_rx(e.g., X3 of receiver IMN 126), set to a minimum reactance value X_rx,min; a system efficiency η, initially set to zero; a transmitter reactance step size ΔX_tx, set to an adjustment value greater than zero; a receiver reactance step size ΔX_rx, set to an adjustment value greater than zero; and a bus voltage step size ΔV_busset to an adjustment value greater than zero. In some implementations, the reactance step sizes ΔX_txand ΔX_rxand bus voltage step size ΔV_busare constant values. In some implementations, the reactance step sizes ΔX_txand ΔX_rxand bus voltage step size ΔV_buscan be variable. For example, controller 125 or controller 129 can increase or decrease the magnitude of the respective step sizes dynamically during process 400.

Process 400 starts at step 404. At step 406, transmitter controller 125 measures the inverter output phase φ_inv, and compares the measured inverter output phase φ_invto a target inverter output phase φ_target. If φ_invequals φ_targetthe process 400 proceeds to step 408 of loop 403. If φ_invdoes not equal φ_targetthe process 400 proceeds to step 424 of loop 401. In some implementations, φ_targetis slightly greater than 0 so the inverter still sees a slightly inductive load.

Referring first to phase loop, loop 401, if the inverter output phase is not equal to the target inverter output phase, at step 406 transmitter controller 125 compares the inverter output phase to the target inverter output phase, at step 424, to determine whether the inverter output phase is greater than the target inverter output phase. If φ_invis greater than φ_target, then, at step 426, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a minimum value X_tx,min. If the variable transmitter reactance X_txis already at a minimum value X_tx,min, then loop 401 proceeds to step 408 with no adjustment to the variable transmitter reactance X_tx. If the variable transmitter reactance X_txis not at a minimum value X_tx,min, then, at step 332, transmitter controller 125 decrements the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 401 reverts back to step 406 to reevaluate the inverter output phase.

If, at step 424, φ_invis not greater than φ_target, then, at step 430, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a maximum value X_tx,max. If the variable transmitter reactance X_txis already at a maximum value X_tx,max, then loop 401 proceeds to step 408 with no adjustment to the variable transmitter reactance X_tx. If the variable transmitter reactance X_txis not at a maximum value X_tx,max, then, at step 420, transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 401 reverts back to step 406 to reevaluate the inverter output phase.

Referring to the power loop, loop 403, at step 408 transmitter controller 125 measures the input power P_in, and compares the measured input power P_into a target power level P_target. If P_inequals P_targetthe process 400 reverts to step 406 of loop 401. In addition, transmitter controller 125 can send data indicating the measured value of P_into the receiver 104. If P_indoes not equal P_target, process 400 proceeds to step 418. In some implementations or some operation modes, the target power level is set by the transmitter 102. In some implementations or some operation modes, the target power level is set by the receiver 104. For example, when in steady-state operations (e.g., normal operations apart from startup or shutdown sequences), system 100 can operate as a demand based system. For example, receiver 104 can request power levels from the transmitter 102. Transmitter controller 125 can calculate a target input power level based on the demanded power level from the receiver 104. For example, transmitter controller 125 can convert the demanded power to a target input power level that would be required to transmit the demanded power level by accounting for expected losses in the transmitter (e.g., IMN losses and inverter losses).

If the power of the transmitter is not equal to the target power, at step 418 transmitter controller 125 compares the input power to the target power level to determine whether the input power is less than the target power level. If P_inis less than P_target, then, at step 420, transmitter controller 125 increments the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 403 reverts back to step 408 to reevaluate the power of the transmitter. If P_inis not less than P_target, then, at step 422, transmitter controller 125 decrements the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 403 reverts back to step 408 to reevaluate the power of the transmitter.

In some implementations, the magnitude of the transmitter reactance step size ΔX_txcan be varied. For example, if the difference between φ_invand φ_targetis large, for example, greater than a coarse adjustment threshold value, then the transmitter controller 125 can increase the transmitter reactance step size ΔX_tx. Correspondingly, if the difference between φ_invand φ_targetis small, for example, less than a fine adjustment threshold value, then the transmitter controller 125 can decrease the magnitude of the transmitter reactance step size ΔX_tx.

In some implementations, the magnitude of the bus voltage step size ΔV_buscan be varied. For example, if the difference between P_inand P_targetis large, for example, greater than a coarse adjustment threshold value, then the transmitter controller 125 can increase the bus voltage step size ΔV_bus. Correspondingly, if the difference between P_inand P_targetis small, for example, less than a fine adjustment threshold value, then the transmitter controller 125 can decrease the magnitude of the bus voltage step size ΔV_bus.

Referring to the receiver-side loop, loop 405, at step 409 receiver 104 receives transmitter power data. For example, when P_inis equal to P_targetat step 408, the transmitter 102 can send data indicating the measured value of P_into the receiver 104. At step 410, the receiver controller 129 measures the efficiency of the system 100. Receiver controller 129 measures the output power of the receiver 104, and calculates the system efficiency η(n) at time n based on the received transmitter power data and the measured receiver output power value.

At step 412, receiver controller 129 compares the system efficiency calculated at time n, to the system efficiency calculated at a previous time n−1. If the efficiency at time n is greater than the efficiency at time n−1, then, at step 414, the variable receiver reactance X_rxis adjusted by the receiver reactance step size ΔX_rx. For example, the change in receiver reactance ΔX_rxis added to the variable receiver reactance X_rx. If the efficiency at time n is not greater than the efficiency at time n−1, then, at step 416, receiver controller 129 changes the sign of the receiver reactance step size ΔX_rxbefore adjusting the variable receiver reactance X_rxat step 414. For example, the value of the receiver reactance step size ΔX_rxcan be negated. For example, the direction of adjustments for the variable receiver reactance X_rxis swapped when the efficiency is no longer increasing between subsequent iterations of loop 405. As illustrated in by loop 405, direction of adjustments for the variable receiver reactance X_rxwill then be retained in subsequent iterations of loop 405 until efficiency decreases again, thereby, maintaining a near-maximum system efficiency.

In some implementations, the magnitude of the receiver reactance step size ΔX_rxcan be varied. For example, if the efficiency at time n is less than a coarse adjustment threshold value (e.g., soon after system startup), then the receiver controller 129 can increase the magnitude of the receiver reactance step size ΔX_rx. Correspondingly, if the efficiency at time n is near an estimated maximum value for example, within a fine adjustment threshold of the estimated maximum value, then the receiver controller 129 can decrease the magnitude of the receiver reactance step size ΔX_rx.

FIGS. 5A-5C depicts a flowchart of an exemplary control processes 500a, 500b, and 500c for operating a wireless power transmission system. In some examples, the processes 500a, 500b, and 500c can be provided as computer-executable instructions executed using one or more processing devices (e.g., processors or microcontrollers) or computing devices. In some examples, the processes 500a, 500b, and 500c may be executed by hardwired electrical circuitry, for example, as an ASIC or an FPGA controller. Processes 500a, 500b, and 500c are related to processes 300 and 400, but include additional steps that evaluate and control additional system parameters to operate a wireless power transmission system.

Referring to FIG. 5A, process 500a includes portions that are be performed by a wireless power transmitter 102 (e.g., transmitter controller 125) and portions that are performed by a wireless power receiver 104 (e.g., receiver controller 129). Process 500a includes three control loops 501a, 503a, and 505. Loops 501a and 503a are performed by a transmitter 102 to tune a transmitter IMN 124 and to control the transmitter power. Loop 501a is a phase loop that tunes the transmitter IMN 124 by adjusting reactance X3 to achieve a target inverter output phase φ_target. Loop 501a also includes safety checks to ensure that current, voltage, or other device limitations are not exceeded. Loop 503a is a power control loop that controls and maintains the transmitter power magnitude P_inat or near the target power P_targetby adjusting the inverter bus voltage V_bus. Loop 503a also incorporates adjustments to inverter frequency f_invto control transmitter power. In some implementations, loops 501a and 503a are local loops that do not require communication with other devices (e.g., receiver 104) to be performed. In some implementations, loops 501a and 503a are executed by a transmitter at between 1-10 kHz.

Loop 505 is performed by a receiver 104 to tune a receiver IMN 126 based on system efficiency. Loop 505 is the same as loop 405 of process 400 the operation of which is described above.

Block 502 lists the inputs and initial conditions for process 500a which include a variable transmitter reactance X_tx(e.g., X3 of transmitter IMN 124), set to a maximum reactance value X_tx,max; a variable receiver reactance X_rx(e.g., X3 of receiver IMN 126), set to a minimum reactance value X_rx,min; an inverter frequency f_invset to a maximum frequency f_inv,max; a system efficiency η, initially set to zero; a transmitter reactance step size ΔX_tx, set to an adjustment value greater than zero; a receiver reactance step size ΔX_rx, set to an adjustment value greater than zero; an inverter frequency step size Δf_invset to an adjustment value greater than zero; and a bus voltage step size ΔV_busset to an adjustment value greater than zero. In some implementations, the reactance step sizes ΔX_txand ΔX_rx, bus voltage step size ΔV_bus, and inverter frequency step size Δf_invare constant values. In some implementations, the reactance step sizes ΔX_txand ΔX_rx, bus voltage step size ΔV_bus, and inverter frequency step size Δf_invcan be variable. For example, controller 125 or controller 129 can increase or decrease the magnitude of the respective step sizes dynamically during process 500a.

Process 500a starts at step 504. At step 506, transmitter controller 125 performs several checks while tuning the inverter frequency in step 508. Transmitter controller 125 compares the measured input power P_into a target power level P_target, the measured inverter output phase φ_invto an inverter output phase limit φ_limit(e.g., 45 degrees), and the inverter frequency f_invto the minimum inverter frequency f_inv,min. When all of the comparisons in step 506 are true, then transmitter controller 125 decrements the inverter frequency f_invby inverter frequency step size Δf_invat step 508. If any of the comparisons are false, the process 500a proceeds to step 510 of loop 501a.

Referring to phase loop, loop 501a, if the inverter output phase is not equal to the target inverter output phase, at step 510 transmitter controller 125 compares the inverter output phase to the target inverter output phase, at step 536, to determine whether the inverter output phase is greater than the target inverter output phase. If φ_invis greater than φ_target, then, at step 538, transmitter controller 125 performs several additional checks. At step 538, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a minimum value X_tx,min; whether P_inis greater than P_target, or whether a safety check has failed. The safety check can be, for example, an over voltage or over current check. If any of the checks are true, then loop 501a proceeds to an additional safety check at step 540. The safety check at step 540 can be the same safety check as performed at step 538, for example, to determine whether the safety check at step 538 was the check that caused the transmitter controller 125 to proceed to step 540. If so, then transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501a reverts back to step 506. If not, then loop 501a proceeds to step 512 of loop 503a to adjust the transmitter power. If all of the checks at step 538 are false, then transmitter controller 125 decrements the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501a reverts back to step 506.

Referring back to step 536, if φ_invis not greater than φ_target, then, at step 546, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a maximum value X_tx,max. If the variable transmitter reactance X_txis already at a maximum value X_tx,max, then loop 501a issue a fault condition 548. If the variable transmitter reactance X_txis not at a maximum value X_tx,max, then, at step 550, transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501a reverts back to step 506.

Referring to the power loop, loop 503a, at step 512 transmitter controller 125 measures the input power P_in, and compares the measured input power P_into a target power level P_target. If P_inequals P_targetthe process 500a reverts to step 506. In addition, transmitter controller 125 can send data indicating the measured value of P_into the receiver 104. If P_indoes not equal P_targetprocess 500a proceeds to step 522. At step 522, transmitter controller 125 compares the input power to the target power level to determine whether the input power is greater than the target power level. If P_inis not greater than P_target, then, at step 534, transmitter controller 125 increments the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 503a reverts back to step 506. If P_inis greater than P_target, then, at step 524, transmitter controller 125 checks the bus voltage. If the bus voltage V_busis greater than a minimum bus voltage V_bus,min, then, at step 532, transmitter controller 125 decrements the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 503a reverts back to step 506.

If, at step 524, the bus voltage V_busis at a minimum bus voltage V_bus,min, then the transmitter controller 125 reduces the transmitter power by adjusting either the variable transmitter reactance X_txor the inverter frequency fin. At step 526, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a maximum value X_tx,max. If the variable transmitter reactance X_txis not at a maximum value X_tx,max, then, at step 530, transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501 reverts back to step 506. If the variable transmitter reactance X_txis already at a maximum value X_tx,max, then the transmitter controller 125 checks whether the inverter frequency f_invis less than a maximum inverter frequency f_inv,maxat step 527. If the inverter frequency f_invis already at a maximum value f_inv,max, then loop 503a reverts to step 506 with no adjustments to the bus voltage V_bus, the variable transmitter reactance X_tx, or the inverter frequency f_inv. If the inverter frequency f_invis not already at a maximum value f_inv,max, then, at step 528, transmitter controller 125 increments the inverter frequency f_invby the frequency step size Δf_inv, and loop 503a reverts back to step 506.

Referring to FIG. 5B, process 500b differs from process 500a by monitoring and controlling inverter phase shift θ_invinstead of inverter frequency f_inv. For example, in some implementations, inverter power can be controlled by adjusting the internal phase shift θ_invbetween bridge circuits in the inverter. In such implementations, a phase shift θ_invof zero degrees may produce a minimum (e.g., zero) inverter power, and a phase shift θ_invof 180 degrees may produce a maximum inverter power for a given bus voltage V_bus. More specifically, in process 500b steps 560, 562, 564, 566, and 568 replace steps 502, 506, 508, 527, and 528 of process 500a, respectively.

Process 500b includes portions that are be performed by a wireless power transmitter 102 (e.g., transmitter controller 125) and portions that are performed by a wireless power receiver 104 (e.g., receiver controller 129). Process 500b includes three control loops 501b, 503b, and 505. Loops 501b and 503b are performed by a transmitter 102 to tune a transmitter IMN 124 and to control the transmitter power. Loop 501b is a phase loop that tunes the transmitter IMN 124 by adjusting reactance X3 to achieve a target inverter output phase φ_target. Loop 501b also includes safety checks to ensure that current, voltage, or other device limitations are not exceeded. Loop 503b is a power control loop that controls and maintains the transmitter power magnitude P_inat or near the target power P_targetby adjusting the inverter bus voltage V_bus. Loop 503b also incorporates adjustments to inverter phase shift θ_invto control transmitter power. In some implementations, loops 501b and 503b are local loops that do not require communication with other devices (e.g., receiver 104) to be performed. In some implementations, loops 501b and 503b are executed by a transmitter at between 1-10 kHz.

Block 560 lists the inputs and initial conditions for process 500b which include a variable transmitter reactance X_tx(e.g., X3 of transmitter IMN 124), set to a maximum reactance value X_tx,max; a variable receiver reactance X_rx(e.g., X3 of receiver IMN 126), set to a minimum reactance value X_rx,min; an inverter phase shift θ_inv, set to a minimum phase shift θ_inv,min; a system efficiency η, initially set to zero; a transmitter reactance step size ΔX_tx, set to an adjustment value greater than zero; a receiver reactance step size Δθ_rx, set to an adjustment value greater than zero; an inverter phase shift step size Δθ_invset to an adjustment value greater than zero; and a bus voltage step size ΔV_busset to an adjustment value greater than zero. In some implementations, the reactance step sizes ΔX_txand ΔX_rx, bus voltage step size ΔV_bus, and inverter phase shift step size Δθ_invare constant values. In some implementations, the reactance step sizes ΔX_txand ΔX_rx, bus voltage step size ΔV_bus, and inverter phase shift step size Δθ_invcan be variable. For example, controller 125 or controller 129 can increase or decrease the magnitude of the respective step sizes dynamically during process 500b.

Process 500b starts at step 504. At step 562, transmitter controller 125 performs several checks while tuning the inverter phase shift in step 564. Transmitter controller 125 compares the measured input power P_into a target power level P_targetand the inverter phase shift θ_invto a phase shift limit θ_limit(e.g., 180 degrees). When all of the comparisons in step 564 are true, then transmitter controller 125 increments the inverter phase shift θ_invby inverter phase shift step size Δθ_invat step 564. If any of the comparisons are false, at step 582, transmitter controller 125 checks whether the inverter phase shift θ_invis less than the phase shift limit θ_limit. If so, process 500b proceeds to step 566. If not, process 500b proceeds to step 510 of loop 501b.

Referring to phase loop, loop 501b, if the inverter output phase is not equal to the target inverter output phase, at step 510 transmitter controller 125 compares the inverter output phase to the target inverter output phase, at step 536, to determine whether the inverter output phase is greater than the target inverter output phase. If φ_invis greater than φ_target, then, at step 538, transmitter controller 125 performs several additional checks. At step 538, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a minimum value X_tx,min; whether P_inis greater than P_target, or whether a safety check has failed. The safety check can be, for example, an over voltage or over current check. If any of the checks are true, then loop 501b proceeds to an additional safety check at step 540. The safety check at step 540 can be the same safety check as performed at step 538, for example, to determine whether the safety check at step 538 was the check that caused the transmitter controller 125 to proceed to step 540. If so, then transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501b reverts back to step 562. If not, then loop 501b proceeds to step 512 of loop 503b to adjust the transmitter power. If all of the checks at step 538 are false, then transmitter controller 125 decrements the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501b reverts back to step 562.

Referring back to step 536, if φ_invis not greater than φ_target, then, at step 546, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a maximum value X_tx,max. If the variable transmitter reactance X_txis already at a maximum value X_tx,max, then loop 501b issue a fault condition 548. If the variable transmitter reactance X_txis not at a maximum value X_tx,max, then, at step 550, transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501b reverts back to step 562.

Referring to the power loop, loop 503b, at step 512 transmitter controller 125 measures the input power P_in, and compares the measured input power P_into a target power level P_target. If P_inequals P_targetthe process 500b reverts to step 562. In addition, transmitter controller 125 can send data indicating the measured value of P_into the receiver 104. If P_indoes not equal P_target, process 500b proceeds to step 522. At step 522, transmitter controller 125 compares the input power to the target power level to determine whether the input power is greater than the target power level. If P_inis not greater than P_target, then, at step 534, transmitter controller 125 increments the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 503b reverts back to step 562. If P_inis greater than P_target, then, at step 524, transmitter controller 125 checks the bus voltage. If the bus voltage V_busis greater than a minimum bus voltage V_bus,min, then, at step 532, transmitter controller 125 decrements the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 503b reverts back to step 562.

If, at step 524, the bus voltage V_busis at a minimum bus voltage V_bus,min, then the transmitter controller 125 reduces the transmitter power by adjusting either the variable transmitter reactance X_txor the inverter phase shift θ_inv. At step 526, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a maximum value X_tx,max. If the variable transmitter reactance X_txis not at a maximum value X_tx,max, then, at step 530, transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501b reverts back to step 562. If the variable transmitter reactance X_txis already at a maximum value X_tx,max, then the transmitter controller 125 checks whether the inverter phase shift θ_invis greater than a minimum inverter phase shift θ_inv,minat step 566. If the inverter phase shift θ_invis already at a minimum value θ_inv,min, then loop 503b reverts to step 562 with no adjustments to the bus voltage V_bus, the variable transmitter reactance X_tx, or the inverter phase shift θ_inv. If the inverter phase shift θ_invis not already at a minimum value θ_inv,min, then, at step 568, transmitter controller 125 decrements the inverter phase shift θ_invby the phase shift step size Δθ_inv, and loop 503b reverts back to step 562.

Referring to FIG. 5C, process 500c combines aspects of processes 500a and 500b. Process 500c includes portions that are be performed by a wireless power transmitter 102 (e.g., transmitter controller 125) and portions that are performed by a wireless power receiver 104 (e.g., receiver controller 129). Process 500c includes three control loops 501c, 503c, and 505. Loops 501c and 503c are performed by a transmitter 102 to tune a transmitter IMN 124 and to control the transmitter power. Loop 501c is a phase loop that tunes the transmitter IMN 124 by adjusting reactance X3 to achieve a target inverter output phase φ_target. Loop 501b also includes safety checks to ensure that current, voltage, or other device limitations are not exceeded. Loop 503c is a power control loop that controls and maintains the transmitter power magnitude P_inat or near the target power P_targetby adjusting the inverter bus voltage V_bus. Loop 503c also incorporates adjustments to both inverter frequency f_invand inverter phase shift θ_invto control transmitter power. In some implementations, loops 501c and 503c are local loops that do not require communication with other devices (e.g., receiver 104) to be performed. In some implementations, loops 501c and 503c are executed by a transmitter at between 1-10 kHz.

Block 580 represents the inputs and initial conditions for process 500c which include a variable transmitter reactance X_tx(e.g., X3 of transmitter IMN 124), set to a maximum reactance value X_tx,max; a variable receiver reactance X_rx(e.g., X3 of receiver IMN 126), set to a minimum reactance value X_rx,min; an inverter frequency f_inv, set to a maximum frequency f_inv,max; an inverter phase shift θ_inv, set to a minimum phase shift θ_inv,min; a system efficiency η, initially set to zero; a transmitter reactance step size ΔX_tx, set to an adjustment value greater than zero; a receiver reactance step size ΔX_rx, set to an adjustment value greater than zero; an inverter frequency step size Δf_invset to an adjustment value greater than zero; an inverter phase shift step size Δθ_invset to an adjustment value greater than zero; and a bus voltage step size ΔV_busset to an adjustment value greater than zero. In some implementations, the reactance step sizes ΔX_txand ΔX_rx, bus voltage step size ΔV_bus, inverter frequency step size Δf_inv, and inverter phase shift step size Δθ_invare constant values. In some implementations, the reactance step sizes ΔX_txand ΔX_rx, bus voltage step size ΔV_bus, inverter frequency step size Δf_inv, and inverter phase shift step size Δθ_invcan be variable. For example, controller 125 or controller 129 can increase or decrease the magnitude of the respective step sizes dynamically during process 500c.

Process 500c starts at step 504. At step 562, transmitter controller 125 performs several checks while tuning the inverter phase shift in step 564. Transmitter controller 125 compares the measured input power P_into a target power level P_targetand the inverter phase shift θ_invto a phase shift limit θ_limit(e.g., 180 degrees). When all of the comparisons in step 564 are true, then transmitter controller 125 increments the inverter phase shift θ_invby inverter phase shift step size Δθ_invat step 564. If any of the comparisons are false, at step 582, transmitter controller 125 checks whether the inverter phase shift θ_invis less than the phase shift limit θ_limit. If so, process 500c proceeds to step 566. If not, process 500c proceeds to step 506.

At step 506, transmitter controller 125 performs several checks while tuning the inverter frequency in step 508. Transmitter controller 125 compares the measured input power P_into a target power level P_target, the measured inverter output phase φ_invto an inverter output phase limit φ_limit(e.g., 45 degrees), and the inverter frequency f_invto the minimum inverter frequency f_inv,min. When all of the comparisons in step 506 are true, then transmitter controller 125 decrements the inverter frequency f_invby inverter frequency step size Δf_invat step 508. If any of the comparisons are false, the process 500a proceeds to step 510 of loop 501c.

Referring to phase loop, loop 501c, if the inverter output phase is not equal to the target inverter output phase, at step 510 transmitter controller 125 compares the inverter output phase to the target inverter output phase, at step 536, to determine whether the inverter output phase is greater than the target inverter output phase. If φ_invis greater than φ_target, then, at step 538, transmitter controller 125 performs several additional checks. At step 538, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a minimum value X_tx,min; whether P_inis greater than P_target, or whether a safety check has failed. The safety check can be, for example, an over voltage or over current check. If any of the checks are true, then loop 501c proceeds to an additional safety check at step 540. The safety check at step 540 can be the same safety check as performed at step 538, for example, to determine whether the safety check at step 538 was the check that caused the transmitter controller 125 to proceed to step 540. If so, then transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501c reverts back to step 562. If not, then loop 501c proceeds to step 512 of loop 503c to adjust the transmitter power. If all of the checks at step 538 are false, then transmitter controller 125 decrements the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501c reverts back to step 562.

Referring back to step 536, if φ_invis not greater than φ_target, then, at step 546, transmitter controller 125 checks whether the variable transmitter reactance X_txis already at a maximum value X_tx,max. If the variable transmitter reactance X_txis already at a maximum value X_tx,max, then loop 501c issue a fault condition 548. If the variable transmitter reactance X_txis not at a maximum value X_tx,max, then, at step 550, transmitter controller 125 increments the variable transmitter reactance X_txby the transmitter reactance step size ΔX_tx, and loop 501c reverts back to step 562.

Referring to the power loop, loop 503b, at step 512 transmitter controller 125 measures the input power P_in, and compares the measured input power P_into a target power level P_target. If P_inequals P_targetthe process 500c reverts to step 562. In addition, transmitter controller 125 can send data indicating the measured value of P_into the receiver 104. If P_indoes not equal P_targetprocess 500c proceeds to step 522. At step 522, transmitter controller 125 compares the input power to the target power level to determine whether the input power is greater than the target power level. If P_inis not greater than P_target, then, at step 534, transmitter controller 125 increments the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 503c reverts back to step 562. If P_inis greater than P_target, then, at step 524, transmitter controller 125 checks the bus voltage. If the bus voltage V_busis greater than a minimum bus voltage V_bus,min, then, at step 532, transmitter controller 125 decrements the inverter bus voltage V_busby the bus voltage step size ΔV_bus, and loop 503c reverts back to step 562.

If the variable transmitter reactance X_txis already at a maximum value X_tx,max, then the transmitter controller 125 checks whether the inverter frequency f_invis less than a maximum inverter frequency f_inv,maxat step 527. If the inverter frequency f_invis not already at a maximum value f_inv,max, then, at step 528, transmitter controller 125 increments the inverter frequency f_invby the frequency step size Δf_inv, and loop 503c reverts back to step 562. If the inverter frequency f_invis already at a maximum value f_inv,max, then the transmitter controller 125 checks whether the inverter phase shift θ_invis greater than a minimum inverter phase shift θ_inv,minat step 566. If the inverter phase shift θ_invis already at a minimum value θ_inv,min, then loop 503c reverts to step 562 with no adjustments to the bus voltage V_bus, the variable transmitter reactance X_tx, or the inverter phase shift θ_inv. If the inverter phase shift θ_invis not already at a minimum value θ_inv,min, then, at step 568, transmitter controller 125 decrements the inverter phase shift φ_invby the phase shift step size Δθ_inv, and loop 503c reverts back to step 562.

In some implementations, the magnitude of the inverter frequency step size Δf_inv, can be varied. For example, if the difference between P_inand P_target, in step 506, is large, for example, greater than a coarse adjustment threshold value, then the transmitter controller 125 can increase the inverter frequency step size Δf_inv. Correspondingly, if the difference between P_inand P_targetis small, for example, less than a fine adjustment threshold value, then the transmitter controller 125 can decrease the magnitude of inverter frequency step size Δf_inv.

In some implementations, the magnitude of the inverter phase shift step size Δθ_invcan be varied. For example, if the difference between P_inand P_target, in step 562, is large, for example, greater than a coarse adjustment threshold value, then the transmitter controller 125 can increase the inverter phase shift step size Δθ_inv. Correspondingly, if the difference between P_inand P_targetis small, for example, less than a fine adjustment threshold value, then the transmitter controller 125 can decrease the magnitude of inverter phase shift step size Δθ_inv.

The following table (Table 1) shows experimental measurements of output voltage and efficiency (Eff.) for variations between relative positions of a wireless power transmitter and receiver for charging an electric vehicle operating according to processes described herein. Position X is the position of the receiver resonator coil relative to the transmitter resonator coil along the X-axis, where the X-axis runs along a width of the vehicle (e.g., driver door to passenger door), and where X=0 is the center of transmitter resonator coil. Position Y is the position of the receiver resonator coil relative to the transmitter resonator coil along the Y-axis, where the Y-axis runs along a length of the vehicle (e.g., front of the vehicle to the rear of the vehicle), and where Y=0 is the center of the transmitter resonator coil. Position Z is the separation distance between the receiver resonator coil and the transmitter resonator coil along the vertical Z-axis.

TABLE 1

Z (mm)
X (mm)
Y (mm)
Vout (V)
Eff (%)

160
0
0
280
94.01

160
0
0
350
94.46

160
0
0
420
94.42

160
100
75
280
94.03

160
100
75
350
94.32

160
100
75
420
93.84

160
150
75
280
93.74

160
150
75
350
94.08

160
150
75
420
93.56

190
0
0
280
94.14

190
0
0
350
94.50

190
0
0
420
94.19

190
100
75
280
93.81

190
100
75
350
93.75

190
100
75
420
93.11

190
150
75
280
93.10

190
150
75
350
93.10

190
150
75
420
91.86

220
0
0
280
93.97

220
0
0
350
94.03

220
0
0
420
93.27

220
100
75
280
92.82

220
100
75
350
92.52

FIG. 6A depicts a flowchart of an exemplary startup process 600 for a wireless power transmission control system. In some examples, the process 600 can be provided as computer-executable instructions executed using one or more processing devices (e.g., processors or microcontrollers) or computing devices. In some examples, the process 600 may be executed by hardwired electrical circuitry, for example, as an ASIC or an FPGA controller. Some portions of process 600 can be performed by a wireless power transmitter 102 (e.g., transmitter controller 125) and some portions of process 600 can be performed by a wireless power receiver 104 (e.g., receiver controller 129).

Block 602 lists the inputs and initial conditions for the system startup process 600 which include a power factor correction (PFC) stage of a transmitter set to OFF; an inverter pulse width modulation (PWM) set to OFF; an inverter frequency f_invset to a maximum frequency f_inv,max; a variable transmitter reactance X_tx(e.g., X3 of transmitter IMN 124) set to a maximum reactance value X_tx,max; and a variable receiver reactance X_rx(e.g., X3 of receiver IMN 126) set to a maximum reactance value X_rx,max. The startup process 600 begins at step 604, the PFC is turned ON and bus voltage V_busis brought to minimum bus voltage V_bus,min. At step 606, the inverter PWMs are turned ON. At step 608, variable receiver reactance X_rxis adjusted to minimum receiver reactance X_rx,min. At step 610, inverter frequency f_invis adjusted to target inverter frequency f_inv,target. At step 612, the system begins steady state operations, e.g., according to one of processes 300, 400, 500a, 500b, or 500c.

FIG. 6A depicts a flowchart of an exemplary shutdown process 601 for a wireless power transmission control system m. In some examples, the process 601 can be provided as computer-executable instructions executed using one or more processing devices (e.g., processors or microcontrollers) or computing devices. In some examples, the process 601 may be executed by hardwired electrical circuitry, for example, as an ASIC or an FPGA controller. Some portions of process 601 can be performed by a wireless power transmitter 102 (e.g., transmitter controller 125) and some portions of process 601 can be performed by a wireless power receiver 104 (e.g., receiver controller 129).

Shutdown process 601 begins, at step 612, with the system in steady state operation, e.g., according to one of processes 300, 400, 500a, 500b, or 500c. At step 614, variable receiver reactance X_rxis brought to minimum receiver reactance X_rx,min. At step 616, variable transmitter reactance X_txis brought to maximum transmitter reactance X_tx,max, and at step 618, bus voltage V_busis brought to minimum bus voltage V_bus,min. In some implementations, steps 616 and 618 can be performed directly by a transmitter. In some implementations, steps 616 and 618 can be performed indirectly. For example, steps 616 and 618 will be performed automatically as part of the steady state operations of processes 500a, 500b, and 500c (steps 524, 532, 526, and 530) simply be adjusting the target power P_targetto a shutdown value P_shutdownat step 615. For example, P_shutdowncan be zero or near zero. As P_targetis decreased, the variable transmitter reactance X_txis brought to maximum transmitter reactance X_tx,maxand bus voltage V_busis brought to minimum bus voltage V_bus,minby the steady state transmitter operations process. At step 620, the PFC is turned OFF and V_busis brought to 0 V. At step 622, the inverter PWMs are turned off. In some implementations, the wireless communication between the receiver and transmitter may be remain on or be turned off after power transmission is secured.

While the disclosed techniques have been described in connection with certain preferred embodiments, other embodiments will be understood by one of ordinary skill in the art and are intended to fall within the scope of this disclosure. For example, designs, methods, configurations of components, etc. related to transmitting wireless power have been described above along with various specific applications and examples thereof. Those skilled in the art will appreciate where the designs, components, configurations or components described herein can be used in combination, or interchangeably, and that the above description does not limit such interchangeability or combination of components to only that which is described herein.

For illustrative purposes, the foregoing description focuses on the use of devices, components, and methods in high power wireless power transfer applications, e.g., power transfer for charging electric vehicles.

More generally, however, it should be understood that devices that can receive power using the devices, components, and methods disclosed herein can include a wide range of electrical devices, and are not limited to those devices described for illustrative purposes herein. In general, any portable electronic device, such as a cell phone, keyboard, mouse, radio, camera, mobile handset, headset, watch, headphones, dongles, multifunction cards, food and drink accessories, and the like, and any workspace electronic devices such as printers, clocks, lamps, headphones, external drives, projectors, digital photo frames, additional displays, and the like, can receive power wirelessly using the devices, components, and methods disclosed herein. Furthermore, any electrical device, such as electric or hybrid vehicles, motorized wheel chairs, scooters, power tools, and the like, can receive power wirelessly using the devices, components, and methods disclosed herein. In addition, the devices, components, and methods disclosed herein may be used for applications outside of wireless power transfer.

In this disclosure, certain circuit or system components such as capacitors, inductors, resistors, are referred to as circuit “components” or “elements.” The disclosure also refers to series and parallel combinations of these components or elements as elements, networks, topologies, circuits, and the like. More generally, however, where a single component or a specific network of components is described herein, it should be understood that alternative embodiments may include networks for elements, alternative networks, and/or the like.

As used herein, the equalities and inequalities when referring to comparisons between transmitter or receiver operating parameters is not intended to require exact equivalence of values, but instead refers to an equivalence of values that are within a threshold or a tolerance of one another. For example, measured values such as powers, voltages, currents, and phases can be represented and stored as floating point numbers. As such, exact equivalence may be unlikely deepening on the precision of the measurements. Therefore, equivalence between such numbers and target values refers to equivalence within a threshold range, for example, equivalence within a tolerance of ±1%, ±2%, ±5%, or ±10% of the target value. Similarly, inequalities may require a measured value to be greater or less than a target value by an additional ±1%, ±2%, ±5%, or ±10% of the target value.

As used herein, the term “coupled” when referring to circuit or system components is used to describe an appropriate, wired or wireless, direct or indirect, connection between one or more components through which information or signals can be passed from one component to another.

As used herein, the term “direct connection” or “directly connected,” refers to a direct connection between two elements where the elements are connected with no intervening active elements between them. The term “electrically connected” or “electrical connection,” refers to an electrical connection between two elements where the elements are connected such that the elements have a common potential. In addition, a connection between a first component and a terminal of a second component means that there is a path between the first component and the terminal that does not pass through the second component.

Implementations of the subject matter and the operations described in this specification can be realized in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Implementations of the subject matter described in this specification can be realized using one or more computer programs, i.e., one or more modules of computer program instructions, encoded on computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal; a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium can also be, or be included in, one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices).

The operations described in this specification can be implemented as operations performed by a data processing apparatus on data stored on one or more computer-readable storage devices or received from other sources.

The term “data processing apparatus” encompasses all kinds of apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, a system on a chip, or multiple ones, or combinations, of the foregoing. The apparatus can include special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). The apparatus can also include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of them. The apparatus and execution environment can realize various different computing model infrastructures, such as web services, distributed computing and grid computing infrastructures.

A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform actions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer can include a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a wireless power transmitter or receiver or a wirelessly charged or powered device such as a vehicle, a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, or a Global Positioning System (GPS) receiver, to name just a few. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any implementation of the present disclosure or of what may be claimed, but rather as descriptions of features specific to example implementations. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. A method of operating a wireless energy transfer system comprising: tuning, by a wireless energy transmitter, a transmitter impedance matching network (IMN) of the wireless energy transmitter to achieve a target transmitter power characteristic;sending, by the wireless energy transmitter to a wireless energy receiver, power data that indicates a value of a power level of the wireless energy transmitter;tuning, by the wireless energy receiver and based on the power data, a receiver-IMN to improve an efficiency of the wireless energy transfer system.
2. The method of claim 1, wherein the target transmitter power characteristic is a target power factor.
3. The method of claim 2, wherein a power factor is represented by a phase difference between a transmitter voltage and a transmitter current, and wherein the target power factor is a target phase difference.
4. The method of claim 1, further comprising adjusting an inverter bus voltage to achieve a target power magnitude.
5. The method of claim 1, further comprising performing a safety check prior to adjusting the transmitter-IMN.
6. The method of claim 5, wherein the safety check is an over-voltage check or an over-current check.
7. The method of claim 1, further comprising: performing, by the wireless energy transmitter, a plurality of checks comprising a check of a magnitude of a transmitter power, a check of a transmitter power factor, and a check of a frequency of an inverter in the wireless energy transmitter; andin response to the plurality checks, selectively adjusting the frequency of the inverter to adjust the power of the wireless energy transmitter.
8. The method of claim 1, further comprising: performing a plurality of checks comprising a check of a magnitude of a transmitter power and a check of a phase shift of an inverter of the wireless energy transmitter; andin response to the plurality of checks, selectively adjusting the phase shift of the inverter to adjust the power of the wireless energy transmitter.
9. The method of claim 1, wherein the wireless energy transmitter is an electric vehicle charger and wherein the wireless energy receiver is coupled to a power system of an electric vehicle.
10. The method of claim 1, further comprising adjusting, while starting up the wireless energy transmitter, a reactance of the transmitter-IMN to a maximum value.
11. The method of claim 1, further comprising adjusting, while starting up the wireless energy receiver, a reactance of the receiver-IMN to a minimum value.
12. The method of claim 2, wherein a magnitude of a step size for adjustments to the transmitter IMN is based on a difference between a measured power factor and the target power factor.
13. The method of claim 4, wherein a magnitude of a step size for adjustments to the inverter bus voltage is based on a difference between a measured power magnitude and the target power magnitude.
14. The method of claim 1, further comprising: performing at least one check comprising testing an operational limit of the wireless energy transmitter; andin response to the at least one check, selectively adjusting a phase shift of an inverter to adjust the power of the wireless energy transmitter.
15. The method of claim 8, wherein a magnitude of the phase shift of the inverter is based on a difference between a measured power characteristic and the target transmitter power characteristic.
16. The method of claim 1, further comprising adjusting, while starting up the wireless energy transmitter, a phase shift of an inverter to a predefined value.
17. The method of claim 16, wherein the predefined value is a maximum value.
18. The method of claim 1, further comprising: calculating, by the wireless energy receiver and using the power data from the wireless energy transmitter, the efficiency of the wireless energy transfer system.
19. A wireless power transmitter for a wireless energy transfer system, the wireless power transmitter comprising: a source resonator; andtransmitter power and control circuitry coupled with the source resonator to drive the source resonator with alternating current, the transmitter power and control circuitry comprising a transmitter impedance matching network (IMN), and the transmitter power and control circuitry being configured to tune the transmitter-IMN to achieve a target transmitter power characteristic, andsend, to a wireless energy receiver, power data that indicates a value of a power level of the wireless power transmitter, thereby causing the wireless power receiver to tune, based on the power data, a receiver-IMN to improve an efficiency of the wireless energy transfer system.
20. The wireless power transmitter of claim 19, comprising one or more non-transitory computer readable storage media storing first instructions, wherein the transmitter power and control circuitry is configured to tune the transmitter-IMN and send the power data responsive to execution of the first instructions using one or more first processing devices, and the wireless power receiver is configured to tune the receiver-IMN responsive to execution of second instructions using one or more second processing devices.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to U.S. patent application Ser. No. 15/422,554, filed on Feb. 2, 2017, which claims priority to U.S. Provisional Patent Application Nos. 62/290,325, filed on Feb. 2, 2016, and 62/379,618 filed on Aug. 25, 2016, the entire contents of which are incorporated herein by reference.

US Referenced Citations (720)

Number	Name	Date	Kind
645576	Tesla	Mar 1900	A
649621	Tesla	May 1900	A
787412	Tesla	Apr 1905	A
1119732	Tesla	Dec 1914	A
2133494	Waters	Oct 1938	A
3517350	Beaver	Jun 1970	A
3535543	Dailey	Oct 1970	A
3780425	Penn et al.	Dec 1973	A
3871176	Schukei	Mar 1975	A
4088999	Fletcher et al.	May 1978	A
4095998	Hanson	Jun 1978	A
4180795	Matsuda et al.	Dec 1979	A
4280129	Wells	Jul 1981	A
4450431	Hochstein	May 1984	A
4588978	Allen	May 1986	A
5027709	Slagle	Jul 1991	A
5033295	Schmid et al.	Jul 1991	A
5034658	Hiering et al.	Jul 1991	A
5053774	Schuermann et al.	Oct 1991	A
5070293	Ishii et al.	Dec 1991	A
5118997	El-Hamamsy	Jun 1992	A
5216402	Carosa	Jun 1993	A
5229652	Hough	Jul 1993	A
5287112	Schuermann	Feb 1994	A
5341083	Klontz et al.	Aug 1994	A
5367242	Hulman	Nov 1994	A
5374930	Schuermann	Dec 1994	A
5408209	Tanzer et al.	Apr 1995	A
5437057	Richley et al.	Jul 1995	A
5455467	Young et al.	Oct 1995	A
5493691	Barrett	Feb 1996	A
5522856	Reineman	Jun 1996	A
5528113	Boys et al.	Jun 1996	A
5541604	Meier	Jul 1996	A
5550452	Shirai et al.	Aug 1996	A
5565763	Arrendale et al.	Oct 1996	A
5630835	Brownlee	May 1997	A
5697956	Bornzin	Dec 1997	A
5703461	Minoshima et al.	Dec 1997	A
5703573	Fujimoto et al.	Dec 1997	A
5710413	King et al.	Jan 1998	A
5742471	Barbee, Jr. et al.	Apr 1998	A
5821728	Sshwind	Oct 1998	A
5821731	Kuki et al.	Oct 1998	A
5864323	Berthon	Jan 1999	A
5898579	Boys et al.	Apr 1999	A
5903134	Takeuchi	May 1999	A
5923544	Urano	Jul 1999	A
5940509	Jovanovich et al.	Aug 1999	A
5957956	Kroll et al.	Sep 1999	A
5959245	Moe et al.	Sep 1999	A
5986895	Stewart et al.	Nov 1999	A
5993996	Firsich	Nov 1999	A
5999308	Nelson et al.	Dec 1999	A
6012659	Nakazawa et al.	Jan 2000	A
6047214	Mueller et al.	Apr 2000	A
6066163	John	May 2000	A
6067473	Greeninger et al.	May 2000	A
6108579	Snell et al.	Aug 2000	A
6127799	Krishnan	Oct 2000	A
6176433	Uesaka et al.	Jan 2001	B1
6184651	Fernandez et al.	Feb 2001	B1
6207887	Bass et al.	Mar 2001	B1
6232841	Bartlett et al.	May 2001	B1
6238387	Miller, III	May 2001	B1
6252762	Amatucci	Jun 2001	B1
6436299	Baarman et al.	Aug 2002	B1
6450946	Forsell	Sep 2002	B1
6452465	Brown et al.	Sep 2002	B1
6459218	Boys et al.	Oct 2002	B2
6473028	Luc	Oct 2002	B1
6483202	Boys	Nov 2002	B1
6515878	Meins et al.	Feb 2003	B1
6535133	Gohara	Mar 2003	B2
6561975	Pool et al.	May 2003	B1
6563425	Nicholson et al.	May 2003	B2
6597076	Scheible et al.	Jul 2003	B2
6609023	Fischell et al.	Aug 2003	B1
6631072	Paul et al.	Oct 2003	B1
6650227	Bradin	Nov 2003	B1
6664770	Bartels	Dec 2003	B1
6673250	Kuennen et al.	Jan 2004	B2
6683256	Kao	Jan 2004	B2
6696647	Ono et al.	Feb 2004	B2
6703921	Wuidart et al.	Mar 2004	B1
6731071	Baarman	May 2004	B2
6749119	Scheible et al.	Jun 2004	B2
6772011	Dolgin	Aug 2004	B2
6798716	Charych	Sep 2004	B1
6803744	Sabo	Oct 2004	B1
6806649	Mollema et al.	Oct 2004	B2
6812645	Baarman	Nov 2004	B2
6825620	Kuennen et al.	Nov 2004	B2
6831417	Baarman	Dec 2004	B2
6839035	Addonisio et al.	Jan 2005	B1
6844702	Giannopoulos et al.	Jan 2005	B2
6856291	Mickle et al.	Feb 2005	B2
6858970	Malkin et al.	Feb 2005	B2
6906495	Cheng et al.	Jun 2005	B2
6917163	Baarman	Jul 2005	B2
6917431	Soljacic et al.	Jul 2005	B2
6937130	Scheible et al.	Aug 2005	B2
6960968	Odendaal et al.	Nov 2005	B2
6961619	Casey	Nov 2005	B2
6967462	Landis	Nov 2005	B1
6975198	Baarman	Dec 2005	B2
6988026	Breed et al.	Jan 2006	B2
7027311	Vanderelli et al.	Apr 2006	B2
7035076	Stevenson	Apr 2006	B1
7042196	Ka-Lai et al.	May 2006	B2
7069064	Govorgian et al.	Jun 2006	B2
7084605	Mickle et al.	Aug 2006	B2
7116200	Baarman et al.	Oct 2006	B2
7118240	Baarman et al.	Oct 2006	B2
7126450	Baarman et al.	Oct 2006	B2
7127293	MacDonald	Oct 2006	B2
7132918	Baarman et al.	Nov 2006	B2
7147604	Allen et al.	Dec 2006	B1
7180248	Kuennen et al.	Feb 2007	B2
7191007	Desai et al.	Mar 2007	B2
7193418	Freytag	Mar 2007	B2
D541322	Garrett et al.	Apr 2007	S
7212414	Baarman	May 2007	B2
7233137	Nakamura et al.	Jun 2007	B2
D545855	Garrett et al.	Jul 2007	S
7239110	Cheng et al.	Jul 2007	B2
7248017	Cheng et al.	Jul 2007	B2
7251527	Lyden	Jul 2007	B2
7288918	DiStefano	Oct 2007	B2
7340304	MacDonald	Mar 2008	B2
7375492	Calhoon et al.	May 2008	B2
7375493	Calhoon et al.	May 2008	B2
7378817	Calhoon et al.	May 2008	B2
7382636	Baarman et al.	Jun 2008	B2
7385357	Kuennen et al.	Jun 2008	B2
7443135	Cho	Oct 2008	B2
7462951	Baarman	Dec 2008	B1
7466213	Lobl et al.	Dec 2008	B2
7471062	Bruning	Dec 2008	B2
7474058	Baarman	Jan 2009	B2
7492247	Schmidt et al.	Feb 2009	B2
7514818	Abe et al.	Apr 2009	B2
7518267	Baarman	Apr 2009	B2
7521890	Lee et al.	Apr 2009	B2
7525283	Cheng et al.	Apr 2009	B2
7545337	Guenther	Jun 2009	B2
7554316	Stevens et al.	Jun 2009	B2
7599743	Hassler, Jr. et al.	Oct 2009	B2
7615936	Baarman et al.	Nov 2009	B2
7639514	Baarman	Dec 2009	B2
7741734	Joannopoulos et al.	Jun 2010	B2
7795708	Katti	Sep 2010	B2
7825543	Karalis et al.	Nov 2010	B2
7825544	Jansen et al.	Nov 2010	B2
7835417	Heideman et al.	Nov 2010	B2
7843288	Lee et al.	Nov 2010	B2
7844306	Shearer et al.	Nov 2010	B2
7863859	Soar	Jan 2011	B2
7880337	Farkas	Feb 2011	B2
7884697	Wei et al.	Feb 2011	B2
7885050	Lee	Feb 2011	B2
7919886	Tanaka	Apr 2011	B2
7923870	Jin	Apr 2011	B2
7932798	Tolle et al.	Apr 2011	B2
7948209	Jung	May 2011	B2
7952322	Partovi et al.	May 2011	B2
7963941	Wilk	Jun 2011	B2
7969045	Schmidt et al.	Jun 2011	B2
7994880	Chen et al.	Aug 2011	B2
7999506	Hollar et al.	Aug 2011	B1
8022576	Joannopoulos et al.	Sep 2011	B2
8035255	Kurs et al.	Oct 2011	B2
8076800	Joannopoulos et al.	Dec 2011	B2
8076801	Karalis et al.	Dec 2011	B2
8084889	Joannopoulos et al.	Dec 2011	B2
8097983	Karalis et al.	Jan 2012	B2
8106539	Schatz et al.	Jan 2012	B2
8115448	John	Feb 2012	B2
8131378	Greenberg et al.	Mar 2012	B2
8178995	Amano et al.	May 2012	B2
8193769	Azancot et al.	Jun 2012	B2
8212414	Howard et al.	Jul 2012	B2
8260200	Shimizu et al.	Sep 2012	B2
8304935	Karalis et al.	Nov 2012	B2
8324759	Karalis et al.	Dec 2012	B2
8334620	Park et al.	Dec 2012	B2
8362651	Hamam et al.	Jan 2013	B2
8395282	Joannopoulos et al.	Mar 2013	B2
8395283	Joannopoulos et al.	Mar 2013	B2
8400017	Kurs et al.	Mar 2013	B2
8400018	Joannopoulos et al.	Mar 2013	B2
8400019	Joannopoulos et al.	Mar 2013	B2
8400020	Joannopoulos et al.	Mar 2013	B2
8400021	Joannopoulos et al.	Mar 2013	B2
8400022	Joannopoulos et al.	Mar 2013	B2
8400023	Joannopoulos et al.	Mar 2013	B2
8400024	Joannopoulos et al.	Mar 2013	B2
8410636	Kurs et al.	Apr 2013	B2
8441154	Karalis et al.	May 2013	B2
8457547	Meskens	Jun 2013	B2
8457656	Perkins et al.	Jun 2013	B2
8461719	Kesler et al.	Jun 2013	B2
8461720	Kurs et al.	Jun 2013	B2
8461721	Karalis et al.	Jun 2013	B2
8461722	Kurs et al.	Jun 2013	B2
8461817	Martin et al.	Jun 2013	B2
8466583	Karalis et al.	Jun 2013	B2
8471410	Karalis et al.	Jun 2013	B2
8476788	Karalis et al.	Jul 2013	B2
8482157	Cook et al.	Jul 2013	B2
8482158	Kurs et al.	Jul 2013	B2
8487480	Kesler et al.	Jul 2013	B1
8497601	Hall et al.	Jul 2013	B2
8552592	Schatz et al.	Oct 2013	B2
8569914	Karalis et al.	Oct 2013	B2
8587153	Schatz et al.	Nov 2013	B2
8587155	Giler et al.	Nov 2013	B2
8598743	Hall et al.	Dec 2013	B2
8618696	Karalis et al.	Dec 2013	B2
8629578	Kurs et al.	Jan 2014	B2
8643326	Campanella et al.	Feb 2014	B2
9124125	Leabman et al.	Sep 2015	B2
20020032471	Loftin et al.	Mar 2002	A1
20020105343	Scheible et al.	Aug 2002	A1
20020118004	Scheible et al.	Aug 2002	A1
20020130642	Ettes et al.	Sep 2002	A1
20020167294	Odaohhara	Nov 2002	A1
20030038641	Scheible	Feb 2003	A1
20030062794	Scheible et al.	Apr 2003	A1
20030062980	Scheible et al.	Apr 2003	A1
20030071034	Thompson et al.	Apr 2003	A1
20030124050	Yadav et al.	Jul 2003	A1
20030126948	Yadav et al.	Jul 2003	A1
20030160590	Schaefer et al.	Aug 2003	A1
20030199778	Mickle et al.	Oct 2003	A1
20030214255	Baarman et al.	Nov 2003	A1
20040000974	Odenaal et al.	Jan 2004	A1
20040026998	Henriott et al.	Feb 2004	A1
20040100338	Clark	May 2004	A1
20040113847	Qi et al.	Jun 2004	A1
20040130425	Dayan et al.	Jul 2004	A1
20040130915	Baarman	Jul 2004	A1
20040130916	Baarman	Jul 2004	A1
20040142733	Parise	Jul 2004	A1
20040150934	Baarman	Aug 2004	A1
20040189246	Bulai et al.	Sep 2004	A1
20040201361	Koh et al.	Oct 2004	A1
20040222751	Mollema et al.	Nov 2004	A1
20040227057	Tuominen et al.	Nov 2004	A1
20040232845	Baarman	Nov 2004	A1
20040233043	Yazawa et al.	Nov 2004	A1
20040267501	Freed et al.	Dec 2004	A1
20050007067	Baarman et al.	Jan 2005	A1
20050021134	Opie	Jan 2005	A1
20050027192	Govari et al.	Feb 2005	A1
20050033382	Single	Feb 2005	A1
20050085873	Gord et al.	Apr 2005	A1
20050093475	Kuennen et al.	May 2005	A1
20050104064	Hegarty et al.	May 2005	A1
20050104453	Vanderelli et al.	May 2005	A1
20050116650	Baarman	Jun 2005	A1
20050116683	Cheng et al.	Jun 2005	A1
20050122058	Baarman et al.	Jun 2005	A1
20050122059	Baarman et al.	Jun 2005	A1
20050125093	Kikuchi et al.	Jun 2005	A1
20050127849	Baarman et al.	Jun 2005	A1
20050127850	Baarman et al.	Jun 2005	A1
20050127866	Hamilton et al.	Jun 2005	A1
20050135122	Cheng et al.	Jun 2005	A1
20050140482	Cheng et al.	Jun 2005	A1
20050151511	Chary	Jul 2005	A1
20050156560	Shimaoka et al.	Jul 2005	A1
20050189945	Reiderman	Sep 2005	A1
20050194926	DiStefano	Sep 2005	A1
20050253152	Klimov et al.	Nov 2005	A1
20050288739	Hassler, Jr. et al.	Dec 2005	A1
20050288740	Hassler, Jr. et al.	Dec 2005	A1
20050288741	Hassler, Jr. et al.	Dec 2005	A1
20050288742	Giordano et al.	Dec 2005	A1
20060001509	Gibbs	Jan 2006	A1
20060010902	Trinh et al.	Jan 2006	A1
20060022636	Xian et al.	Feb 2006	A1
20060053296	Busboom et al.	Mar 2006	A1
20060061323	Cheng et al.	Mar 2006	A1
20060066443	Hall	Mar 2006	A1
20060090956	Peshkovskiy et al.	May 2006	A1
20060132045	Baarman	Jun 2006	A1
20060164866	Vanderelli et al.	Jul 2006	A1
20060181242	Freed et al.	Aug 2006	A1
20060184209	John et al.	Aug 2006	A1
20060184210	Singhal et al.	Aug 2006	A1
20060185809	Elfrink et al.	Aug 2006	A1
20060199620	Greene et al.	Sep 2006	A1
20060202665	Hsu	Sep 2006	A1
20060205381	Beart et al.	Sep 2006	A1
20060214626	Nilson et al.	Sep 2006	A1
20060219448	Grieve et al.	Oct 2006	A1
20060238365	Vecchione et al.	Oct 2006	A1
20060270440	Shearer et al.	Nov 2006	A1
20060281435	Shearer et al.	Dec 2006	A1
20070010295	Greene et al.	Jan 2007	A1
20070013483	Stewart	Jan 2007	A1
20070016089	Fischell et al.	Jan 2007	A1
20070021140	Keyes, IV et al.	Jan 2007	A1
20070024246	Flaugher	Feb 2007	A1
20070064406	Beart	Mar 2007	A1
20070069687	Suzuki	Mar 2007	A1
20070096875	Waterhouse et al.	May 2007	A1
20070105429	Kohl et al.	May 2007	A1
20070117596	Greene et al.	May 2007	A1
20070126650	Guenther	Jun 2007	A1
20070145830	Lee et al.	Jun 2007	A1
20070164839	Naito	Jul 2007	A1
20070171681	Baarman	Jul 2007	A1
20070176840	Pristas et al.	Aug 2007	A1
20070178945	Cook et al.	Aug 2007	A1
20070182367	Partovi	Aug 2007	A1
20070208263	John et al.	Sep 2007	A1
20070222542	Joannopoulos et al.	Sep 2007	A1
20070257636	Phillips et al.	Nov 2007	A1
20070267918	Gyland	Nov 2007	A1
20070276538	Kjellsson et al.	Nov 2007	A1
20080012569	Hall et al.	Jan 2008	A1
20080014897	Cook et al.	Jan 2008	A1
20080030415	Homan et al.	Feb 2008	A1
20080036588	Iverson et al.	Feb 2008	A1
20080047727	Sexton et al.	Feb 2008	A1
20080051854	Bulkes et al.	Feb 2008	A1
20080067874	Tseng	Mar 2008	A1
20080132909	Jascob et al.	Jun 2008	A1
20080154331	John et al.	Jun 2008	A1
20080176521	Singh et al.	Jul 2008	A1
20080191638	Kuennen et al.	Aug 2008	A1
20080197710	Kreitz	Aug 2008	A1
20080197802	Onishi et al.	Aug 2008	A1
20080211320	Cook et al.	Sep 2008	A1
20080238364	Weber et al.	Oct 2008	A1
20080255901	Carroll et al.	Oct 2008	A1
20080265684	Farkas	Oct 2008	A1
20080266748	Lee	Oct 2008	A1
20080272860	Pance	Nov 2008	A1
20080273242	Woodgate et al.	Nov 2008	A1
20080278264	Karalis et al.	Nov 2008	A1
20080291277	Jacobsen et al.	Nov 2008	A1
20080300657	Stultz	Dec 2008	A1
20080300660	John	Dec 2008	A1
20090010028	Baarmen et al.	Jan 2009	A1
20090015075	Cook et al.	Jan 2009	A1
20090033280	Choi et al.	Feb 2009	A1
20090033564	Cook et al.	Feb 2009	A1
20090038623	Farbarik et al.	Feb 2009	A1
20090045772	Cook et al.	Feb 2009	A1
20090051224	Cook et al.	Feb 2009	A1
20090058189	Cook et al.	Mar 2009	A1
20090058361	John	Mar 2009	A1
20090067198	Graham et al.	Mar 2009	A1
20090072627	Cook et al.	Mar 2009	A1
20090072628	Cook et al.	Mar 2009	A1
20090072629	Cook et al.	Mar 2009	A1
20090072782	Randall	Mar 2009	A1
20090079268	Cook et al.	Mar 2009	A1
20090079387	Jin et al.	Mar 2009	A1
20090085408	Bruhn	Apr 2009	A1
20090085706	Baarman et al.	Apr 2009	A1
20090096413	Patovi et al.	Apr 2009	A1
20090102292	Cook et al.	Apr 2009	A1
20090108679	Porwal	Apr 2009	A1
20090108997	Patterson et al.	Apr 2009	A1
20090115628	Dicks et al.	May 2009	A1
20090127937	Widmer et al.	May 2009	A1
20090134712	Cook et al.	May 2009	A1
20090146892	Shimizu et al.	Jun 2009	A1
20090153273	Chen	Jun 2009	A1
20090160261	Elo	Jun 2009	A1
20090161078	Wu et al.	Jun 2009	A1
20090167449	Cook et al.	Jul 2009	A1
20090174263	Baarman et al.	Jul 2009	A1
20090179502	Cook et al.	Jul 2009	A1
20090188396	Hofmann et al.	Jul 2009	A1
20090189458	Kawasaki	Jul 2009	A1
20090195332	Joannopoulos et al.	Aug 2009	A1
20090195333	Joannopoulos et al.	Aug 2009	A1
20090212636	Cook et al.	Aug 2009	A1
20090213028	Cook et al.	Aug 2009	A1
20090218884	Soar	Sep 2009	A1
20090224608	Cook et al.	Sep 2009	A1
20090224609	Cook et al.	Sep 2009	A1
20090224723	Tanabe	Sep 2009	A1
20090224856	Karalis et al.	Sep 2009	A1
20090230777	Baarman et al.	Sep 2009	A1
20090237194	Waffenschmidt et al.	Sep 2009	A1
20090243394	Levine	Oct 2009	A1
20090243397	Cook et al.	Oct 2009	A1
20090251008	Sugaya	Oct 2009	A1
20090261778	Kook	Oct 2009	A1
20090267558	Jung	Oct 2009	A1
20090267709	Joannopoulos et al.	Oct 2009	A1
20090267710	Joannopoulos et al.	Oct 2009	A1
20090271047	Wakamatsu	Oct 2009	A1
20090271048	Wakamatsu	Oct 2009	A1
20090273242	Cook	Nov 2009	A1
20090273318	Rondoni et al.	Nov 2009	A1
20090281678	Wakamatsu	Nov 2009	A1
20090284082	Mohammadian	Nov 2009	A1
20090284083	Karalis et al.	Nov 2009	A1
20090284218	Mohammadian et al.	Nov 2009	A1
20090284220	Toncich et al.	Nov 2009	A1
20090284227	Mohammadian et al.	Nov 2009	A1
20090284245	Kirby et al.	Nov 2009	A1
20090284369	Toncich et al.	Nov 2009	A1
20090286470	Mohammadian et al.	Nov 2009	A1
20090286475	Toncich et al.	Nov 2009	A1
20090286476	Toncich et al.	Nov 2009	A1
20090289595	Chen et al.	Nov 2009	A1
20090299918	Cook et al.	Dec 2009	A1
20090308933	Osada	Dec 2009	A1
20090322158	Stevens et al.	Dec 2009	A1
20090322280	Kamijo et al.	Dec 2009	A1
20100015918	Liu et al.	Jan 2010	A1
20100017249	Fincham et al.	Jan 2010	A1
20100033021	Bennett	Feb 2010	A1
20100034238	Bennett	Feb 2010	A1
20100036773	Bennett	Feb 2010	A1
20100038970	Cook et al.	Feb 2010	A1
20100045114	Sample et al.	Feb 2010	A1
20100052431	Mita	Mar 2010	A1
20100052811	Smith et al.	Mar 2010	A1
20100060077	Paulus et al.	Mar 2010	A1
20100065352	Ichikawa	Mar 2010	A1
20100066349	Lin et al.	Mar 2010	A1
20100076524	Forsberg et al.	Mar 2010	A1
20100081379	Cooper et al.	Apr 2010	A1
20100094381	Kim et al.	Apr 2010	A1
20100096934	Joannopoulos et al.	Apr 2010	A1
20100102639	Joannopoulos et al.	Apr 2010	A1
20100102640	Joannopoulos et al.	Apr 2010	A1
20100102641	Joannopoulos et al.	Apr 2010	A1
20100104031	Lacour	Apr 2010	A1
20100109443	Cook et al.	May 2010	A1
20100109445	Kurs et al.	May 2010	A1
20100109604	Boys et al.	May 2010	A1
20100115474	Takada et al.	May 2010	A1
20100117454	Cook et al.	May 2010	A1
20100117455	Joannopoulos et al.	May 2010	A1
20100117456	Karalis et al.	May 2010	A1
20100117596	Cook et al.	May 2010	A1
20100123353	Joannopoulos et al.	May 2010	A1
20100123354	Joannopoulos et al.	May 2010	A1
20100123355	Joannopoulos et al.	May 2010	A1
20100123452	Amano et al.	May 2010	A1
20100123530	Park et al.	May 2010	A1
20100127573	Joannopoulos et al.	May 2010	A1
20100127574	Joannopoulos et al.	May 2010	A1
20100127575	Joannopoulos et al.	May 2010	A1
20100127660	Cook et al.	May 2010	A1
20100133918	Joannopoulos et al.	Jun 2010	A1
20100133919	Joannopoulos et al.	Jun 2010	A1
20100133920	Joannopoulos et al.	Jun 2010	A1
20100141042	Kesler et al.	Jun 2010	A1
20100148589	Hamam et al.	Jun 2010	A1
20100148723	Cook et al.	Jun 2010	A1
20100151808	Toncich et al.	Jun 2010	A1
20100156346	Takada et al.	Jun 2010	A1
20100156355	Bauerle et al.	Jun 2010	A1
20100156570	Hong et al.	Jun 2010	A1
20100164295	Ichikawa et al.	Jul 2010	A1
20100164296	Kurs	Jul 2010	A1
20100164297	Kurs et al.	Jul 2010	A1
20100164298	Karalis et al.	Jul 2010	A1
20100171368	Schatz et al.	Jul 2010	A1
20100171370	Karalis et al.	Jul 2010	A1
20100179384	Hoeg et al.	Jul 2010	A1
20100181843	Schatz et al.	Jul 2010	A1
20100181844	Karalis et al.	Jul 2010	A1
20100181845	Fiorello et al.	Jul 2010	A1
20100181961	Novak et al.	Jul 2010	A1
20100181964	Huggins et al.	Jul 2010	A1
20100184371	Cook et al.	Jul 2010	A1
20100187911	Joannopoulos et al.	Jul 2010	A1
20100187913	Smith et al.	Jul 2010	A1
20100188183	Shpiro	Jul 2010	A1
20100190435	Cook et al.	Jul 2010	A1
20100190436	Cook et al.	Jul 2010	A1
20100194206	Burdo et al.	Aug 2010	A1
20100194207	Graham	Aug 2010	A1
20100194334	Kirby et al.	Aug 2010	A1
20100194335	Kirby et al.	Aug 2010	A1
20100201189	Kirby et al.	Aug 2010	A1
20100201201	Mobarhan et al.	Aug 2010	A1
20100201202	Kirby et al.	Aug 2010	A1
20100201203	Schatz et al.	Aug 2010	A1
20100201204	Sakoda et al.	Aug 2010	A1
20100201205	Karalis et al.	Aug 2010	A1
20100201310	Vorenkamp et al.	Aug 2010	A1
20100201312	Kirby et al.	Aug 2010	A1
20100201313	Vorenkamp et al.	Aug 2010	A1
20100201316	Takada et al.	Aug 2010	A1
20100201513	Vorenkamp et al.	Aug 2010	A1
20100207458	Joannopoulos et al.	Aug 2010	A1
20100210233	Cook et al.	Aug 2010	A1
20100213770	Kikuchi	Aug 2010	A1
20100213895	Keating et al.	Aug 2010	A1
20100217553	Von Novak et al.	Aug 2010	A1
20100219694	Kurs et al.	Sep 2010	A1
20100219695	Komiyanria et al.	Sep 2010	A1
20100219696	Kojima	Sep 2010	A1
20100222010	Ozaki et al.	Sep 2010	A1
20100225175	Karalis et al.	Sep 2010	A1
20100225270	Jacobs et al.	Sep 2010	A1
20100225271	Oyobe et al.	Sep 2010	A1
20100225272	Kirby et al.	Sep 2010	A1
20100231053	Karalis et al.	Sep 2010	A1
20100231163	Mashinsky	Sep 2010	A1
20100231340	Fiorello et al.	Sep 2010	A1
20100234922	Forsell	Sep 2010	A1
20100235006	Brown	Sep 2010	A1
20100237706	Karalis et al.	Sep 2010	A1
20100237707	Karalis et al.	Sep 2010	A1
20100237708	Karalis et al.	Sep 2010	A1
20100237709	Hall et al.	Sep 2010	A1
20100244576	Hillan et al.	Sep 2010	A1
20100244577	Shimokawa	Sep 2010	A1
20100244578	Yoshikawa	Sep 2010	A1
20100244579	Sogabe et al.	Sep 2010	A1
20100244580	Uchida et al.	Sep 2010	A1
20100244581	Uchida	Sep 2010	A1
20100244582	Yoshikawa	Sep 2010	A1
20100244583	Shimokawa	Sep 2010	A1
20100244767	Turner et al.	Sep 2010	A1
20100244839	Yoshikawa	Sep 2010	A1
20100248622	Kirby et al.	Sep 2010	A1
20100253152	Karalis et al.	Oct 2010	A1
20100253281	Li	Oct 2010	A1
20100256481	Mareci et al.	Oct 2010	A1
20100256831	Abramo et al.	Oct 2010	A1
20100259108	Giler et al.	Oct 2010	A1
20100259109	Sato	Oct 2010	A1
20100259110	Kurs et al.	Oct 2010	A1
20100264745	Karalis et al.	Oct 2010	A1
20100264746	Kazama et al.	Oct 2010	A1
20100264747	Hall et al.	Oct 2010	A1
20100276995	Marzetta et al.	Nov 2010	A1
20100277003	Von Novak et al.	Nov 2010	A1
20100277004	Suzuki et al.	Nov 2010	A1
20100277005	Karalis et al.	Nov 2010	A1
20100277120	Cook et al.	Nov 2010	A1
20100277121	Hall et al.	Nov 2010	A1
20100289341	Ozaki et al.	Nov 2010	A1
20100289449	Elo	Nov 2010	A1
20100295505	Jung et al.	Nov 2010	A1
20100295506	Ichikawa	Nov 2010	A1
20100308939	Kurs	Dec 2010	A1
20100314946	Budde et al.	Dec 2010	A1
20100327660	Karalis et al.	Dec 2010	A1
20100327661	Karalis et al.	Dec 2010	A1
20100328044	Waffenschmidt et al.	Dec 2010	A1
20110004269	Strother et al.	Jan 2011	A1
20110012431	Karalis et al.	Jan 2011	A1
20110018361	Karalis et al.	Jan 2011	A1
20110025131	Karalis et al.	Feb 2011	A1
20110031928	Soar	Feb 2011	A1
20110043046	Joannopoulos et al.	Feb 2011	A1
20110043047	Karalis et al.	Feb 2011	A1
20110043048	Karalis et al.	Feb 2011	A1
20110043049	Karalis et al.	Feb 2011	A1
20110049995	Hashiguchi	Mar 2011	A1
20110049996	Karalis et al.	Mar 2011	A1
20110049998	Karalis et al.	Mar 2011	A1
20110074218	Karalis et al.	Mar 2011	A1
20110074346	Hall et al.	Mar 2011	A1
20110074347	Karalis et al.	Mar 2011	A1
20110089895	Karalis et al.	Apr 2011	A1
20110095618	Schatz et al.	Apr 2011	A1
20110115303	Baarman et al.	May 2011	A1
20110115431	Dunworth et al.	May 2011	A1
20110121920	Kurs et al.	May 2011	A1
20110127843	Karaoguz et al.	Jun 2011	A1
20110128015	Dorairaj et al.	Jun 2011	A1
20110140544	Karalis et al.	Jun 2011	A1
20110148219	Karalis et al.	Jun 2011	A1
20110162895	Karalis et al.	Jul 2011	A1
20110169339	Karalis et al.	Jul 2011	A1
20110181122	Karalis et al.	Jul 2011	A1
20110193416	Campanella et al.	Aug 2011	A1
20110193419	Karalis et al.	Aug 2011	A1
20110198939	Karalis et al.	Aug 2011	A1
20110215086	Yeh	Sep 2011	A1
20110221278	Karalis et al.	Sep 2011	A1
20110227528	Karalis et al.	Sep 2011	A1
20110227530	Karalis et al.	Sep 2011	A1
20110241618	Karalis et al.	Oct 2011	A1
20110248573	Kanno et al.	Oct 2011	A1
20110254377	Wildmer et al.	Oct 2011	A1
20110254503	Widmer et al.	Oct 2011	A1
20110266878	Cook et al.	Nov 2011	A9
20110278943	Eckhoff et al.	Nov 2011	A1
20120001492	Cook et al.	Jan 2012	A9
20120001593	DiGuardo	Jan 2012	A1
20120007435	Sada et al.	Jan 2012	A1
20120007441	John et al.	Jan 2012	A1
20120025602	Boys et al.	Feb 2012	A1
20120032522	Schatz et al.	Feb 2012	A1
20120038525	Monsalve Carcelen et al.	Feb 2012	A1
20120062345	Kurs et al.	Mar 2012	A1
20120068549	Karalis et al.	Mar 2012	A1
20120086284	Campanella et al.	Apr 2012	A1
20120086867	Kesler et al.	Apr 2012	A1
20120091794	Campanella et al.	Apr 2012	A1
20120091795	Fiorello et al.	Apr 2012	A1
20120091796	Kesler et al.	Apr 2012	A1
20120091797	Kesler et al.	Apr 2012	A1
20120091819	Kulikowski et al.	Apr 2012	A1
20120091820	Campanella et al.	Apr 2012	A1
20120091949	Campanella et al.	Apr 2012	A1
20120091950	Campanella et al.	Apr 2012	A1
20120098350	Campanella et al.	Apr 2012	A1
20120112531	Kesler et al.	May 2012	A1
20120112532	Kesler et al.	May 2012	A1
20120112534	Kesler et al.	May 2012	A1
20120112535	Karalis et al.	May 2012	A1
20120112536	Karalis et al.	May 2012	A1
20120112538	Kesler et al.	May 2012	A1
20120112691	Kurs et al.	May 2012	A1
20120119569	Karalis et al.	May 2012	A1
20120119575	Kurs et al.	May 2012	A1
20120119576	Kesler et al.	May 2012	A1
20120119698	Karalis et al.	May 2012	A1
20120139355	Ganem et al.	Jun 2012	A1
20120146575	Armstrong et al.	Jun 2012	A1
20120153732	Kurs et al.	Jun 2012	A1
20120153733	Schatz et al.	Jun 2012	A1
20120153734	Kurs et al.	Jun 2012	A1
20120153735	Karalis et al.	Jun 2012	A1
20120153736	Karalis et al.	Jun 2012	A1
20120153737	Karalis et al.	Jun 2012	A1
20120153738	Karalis et al.	Jun 2012	A1
20120153893	Schatz et al.	Jun 2012	A1
20120184338	Kesler et al.	Jul 2012	A1
20120206096	John	Aug 2012	A1
20120223573	Schatz et al.	Sep 2012	A1
20120223709	Schillak	Sep 2012	A1
20120228952	Hall et al.	Sep 2012	A1
20120228953	Kesler et al.	Sep 2012	A1
20120228954	Kesler et al.	Sep 2012	A1
20120235500	Ganem et al.	Sep 2012	A1
20120235501	Kesler et al.	Sep 2012	A1
20120235502	Kesler et al.	Sep 2012	A1
20120235503	Kesler et al.	Sep 2012	A1
20120235504	Kesler et al.	Sep 2012	A1
20120235505	Schatz et al.	Sep 2012	A1
20120235566	Karalis et al.	Sep 2012	A1
20120235567	Karalis et al.	Sep 2012	A1
20120235633	Kesler et al.	Sep 2012	A1
20120235634	Hall et al.	Sep 2012	A1
20120239117	Kesler et al.	Sep 2012	A1
20120242159	Lou et al.	Sep 2012	A1
20120242225	Karalis et al.	Sep 2012	A1
20120242283	Kim	Sep 2012	A1
20120248884	Karalis et al.	Oct 2012	A1
20120248886	Kesler et al.	Oct 2012	A1
20120248887	Kesler et al.	Oct 2012	A1
20120248888	Kesler et al.	Oct 2012	A1
20120248981	Karalis et al.	Oct 2012	A1
20120256494	Kesler et al.	Oct 2012	A1
20120267960	Low et al.	Oct 2012	A1
20120280765	Kurs et al.	Nov 2012	A1
20120299540	Perry	Nov 2012	A1
20120313449	Kurs et al.	Dec 2012	A1
20120313742	Kurs et al.	Dec 2012	A1
20120326660	Lu et al.	Dec 2012	A1
20130007949	Kurs et al.	Jan 2013	A1
20130020878	Karalis et al.	Jan 2013	A1
20130033118	Karalis et al.	Feb 2013	A1
20130038402	Karalis et al.	Feb 2013	A1
20130043735	Low et al.	Feb 2013	A1
20130057364	Kesler et al.	Mar 2013	A1
20130062966	Verghese et al.	Mar 2013	A1
20130069441	Verghese et al.	Mar 2013	A1
20130069753	Kurs et al.	Mar 2013	A1
20130099587	Lou et al.	Apr 2013	A1
20130154383	Kasturi et al.	Jun 2013	A1
20130154389	Kurs et al.	Jun 2013	A1
20130159956	Verghese et al.	Jun 2013	A1
20130175874	Lou et al.	Jul 2013	A1
20130175875	Kurs et al.	Jul 2013	A1
20130200716	Kesler et al.	Aug 2013	A1
20130200721	Kurs et al.	Aug 2013	A1
20130221744	Hall et al.	Aug 2013	A1
20130278073	Kurs et al.	Oct 2013	A1
20130278074	Kurs et al.	Oct 2013	A1
20130278075	Kurs et al.	Oct 2013	A1
20130300353	Kurs et al.	Nov 2013	A1
20130307349	Hall et al.	Nov 2013	A1
20130320773	Schatz et al.	Dec 2013	A1
20130331042	See	Dec 2013	A1
20130334892	Hall et al.	Dec 2013	A1
20140002012	McCauley et al.	Jan 2014	A1
20140055098	Lee	Feb 2014	A1
20140062551	Bhaumik et al.	Mar 2014	A1
20140070764	Keeling	Mar 2014	A1
20140084858	Kim et al.	Mar 2014	A1
20140141584	Kim et al.	May 2014	A1
20140265615	Kim	Sep 2014	A1
20140292090	Cordeior et al.	Oct 2014	A1
20140333258	Matsukura et al.	Nov 2014	A1
20140372780	Murai et al.	Dec 2014	A1
20150051750	Kurs et al.	Feb 2015	A1
20150333799	Perry	Nov 2015	A1
20150333800	Perry	Nov 2015	A1
20150349538	Agostinelli et al.	Dec 2015	A1
20150372493	Sankar	Dec 2015	A1
20160065005	Won	Mar 2016	A1
20160268813	Reynolds	Sep 2016	A1
20170047786	Park	Feb 2017	A1
20170066336	Okamoto	Mar 2017	A1
20170098991	Takahashi	Apr 2017	A1
20170126049	Pan	May 2017	A1
20170141584	DeVaul	May 2017	A1
20170187250	Cha	Jun 2017	A1
20170222466	Sankar	Aug 2017	A1

Foreign Referenced Citations (117)

Number	Date	Country
142352	Aug 1912	CA
102239633	Nov 2011	CN
102439669	May 2012	CN
103329397	Sep 2013	CN
103855928	Jun 2014	CN
38 24 972	Jan 1989	DE
100 29147	Dec 2001	DE
200 16 655	Mar 2002	DE
102 21 484	Nov 2003	DE
103 04 584	Aug 2004	DE
10 2005 036290	Feb 2007	DE
10 2006 044057	Apr 2008	DE
1 335 477	Aug 2003	EP
1 521 206	Apr 2005	EP
1 524 010	Apr 2005	EP
2 357 716	Aug 2011	EP
02-097005	Apr 1990	JP
4-265875	Sep 1992	JP
6-341410	Dec 1994	JP
9-182323	Jul 1997	JP
9-298847	Nov 1997	JP
10-164837	Jun 1998	JP
11-75329	Mar 1999	JP
11-188113	Jul 1999	JP
2001-309580	Nov 2001	JP
2002-010535	Jan 2002	JP
2003-179526	Jun 2003	JP
2004-166459	Jun 2004	JP
2004-201458	Jul 2004	JP
2004-229144	Aug 2004	JP
2005-57444	Mar 2005	JP
2005-149238	Jun 2005	JP
2006-074848	Mar 2006	JP
2007-505480	Mar 2007	JP
2007-266892	Oct 2007	JP
2007-537637	Dec 2007	JP
2008-508842	Mar 2008	JP
2008-206231	Sep 2008	JP
2008-206327	Sep 2008	JP
2011-072074	Apr 2011	JP
2012-504387	Feb 2012	JP
2013-074685	Apr 2013	JP
2013-543718	Dec 2013	JP
2014-003849	Jan 2014	JP
2014-017893	Jan 2014	JP
2014-110662	Jun 2014	JP
2014-241698	Dec 2014	JP
10-2007-0017804	Feb 2007	KR
10-2008-0007635	Jan 2008	KR
10-2009-0122072	Nov 2009	KR
10-2011-0050920	May 2011	KR
112842	Jul 2005	SG
WO 9217929	Oct 1992	WO
WO 9323908	Nov 1993	WO
WO 9428560	Dec 1994	WO
WO 9511545	Apr 1995	WO
WO 9602970	Feb 1996	WO
WO 9850993	Nov 1998	WO
WO 0077910	Dec 2000	WO
WO 03092329	Nov 2003	WO
WO 03096361	Nov 2003	WO
WO 03096512	Nov 2003	WO
WO 2004015885	Feb 2004	WO
WO 2004038888	May 2004	WO
WO 2004055654	Jul 2004	WO
WO 2004073150	Aug 2004	WO
WO 2004073166	Aug 2004	WO
WO 2004073176	Aug 2004	WO
WO 2004073177	Aug 2004	WO
WO 2004112216	Dec 2004	WO
WO 2005024865	Mar 2005	WO
WO 2005060068	Jun 2005	WO
WO 2005109597	Nov 2005	WO
WO 2005109598	Nov 2005	WO
WO 2006011769	Feb 2006	WO
WO 2007008646	Jan 2007	WO
WO 2007020583	Feb 2007	WO
WO 2007042952	Apr 2007	WO
WO 2007084716	Jul 2007	WO
WO 2007084717	Jul 2007	WO
WO 2008109489	Sep 2008	WO
WO 2008118178	Oct 2008	WO
WO 2009009559	Jan 2009	WO
WO 2009018568	Feb 2009	WO
WO 2009023155	Feb 2009	WO
WO 2009023646	Feb 2009	WO
WO 2009033043	Mar 2009	WO
WO 2009062438	May 2009	WO
WO 2009070730	Jun 2009	WO
WO 2009126963	Oct 2009	WO
WO 2009140506	Nov 2009	WO
WO 2009149464	Dec 2009	WO
WO 2009155000	Dec 2009	WO
WO 2010030977	Mar 2010	WO
WO 2010036980	Apr 2010	WO
WO 2010039967	Apr 2010	WO
WO 2010090538	Aug 2010	WO
WO 2010090539	Aug 2010	WO
WO 2010093997	Aug 2010	WO
WO 2010104569	Sep 2010	WO
WO 2011061388	May 2011	WO
WO 2011061821	May 2011	WO
WO 2011062827	May 2011	WO
WO 2011112795	Sep 2011	WO
WO 2012037279	Mar 2012	WO
WO 2012170278	Dec 2012	WO
WO 2013013235	Jan 2013	WO
WO 2013020138	Feb 2013	WO
WO 2013036947	Mar 2013	WO
WO 2013048034	Apr 2013	WO
WO 2013059441	Apr 2013	WO
WO 2013067484	May 2013	WO
WO 2013113017	Aug 2013	WO
WO 2013142840	Sep 2013	WO
WO 2014004843	Jan 2014	WO
WO 2015128941	Sep 2015	WO
WO 2015159962	Oct 2015	WO

Non-Patent Literature Citations (121)

Entry
European Search Report for European Application No. 17 15 4475 dated Jun. 8, 2017 (7 pages).
“Intel CTO Says Gap between Humans, Machines Will Close by 2050”, Intel News Release, (See intel.com/.../20080821comp.htm?iid=S . . .) (Printed Nov. 6, 2009).
“Physics Update, Unwired Energy”, Physics Today, pp. 26, (Jan. 2007) (See http://arxiv.org/abs/physics/0611063.).
“In pictures: A year in technology”, BBC News, (Dec. 28, 2007).
“Next Little Thing 2010 Electricity without wires”, CNN Money (See money.cnn.com/galleries/2009/smallbusiness/0911/gallery.next_little_thing_2010.smb/) (dated Nov. 30, 2009).
Abe et al. “A Noncontact Charger Using a Resonant Converter with Parallel Capacitor of the Secondary Coil”. IEEE, 36(2):444-451, Mar./Apr. 2000.
Ahmadian, M. et al., “Miniature Transmitter for Implantable Micro Systems”, Proceedings of the 25th Annual International Conference of the IEEE EMBS Cancun, Mexico, pp. 3028-3031 (Sep. 17-21, 2003).
Aoki, T. et al., “Observation of strong coupling between one atom and a monolithic microresonator”, Nature, vol. 443:671-674 (2006).
Apneseth et al. “Introducing wireless proximity switches” ABB Review Apr. 2002.
Aristeidis Karalis et al., “Efficient Wireless non-radiative mid-range energy transfer”, Annals of Physics, vol. 323, pp. 34-48 (2008)
Baker et al., “Feedback Analysis and Design of RF Power Links for Low-Power Bionic Systems,” IEEE Transactions on Biomedical Circuits and Systems, vol. 1(1):28-38 (Mar. 2007).
Balanis, C.A., “Antenna Theory: Analysis and Design,” 3rd Edition, Sections 4.2, 4.3, 5.2, 5.3 (Wiley, New Jersey, 2005).
Berardelli, P., “Outlets Are Out”, ScienceNOW Daily News, Science Now, http://sciencenow.sciencemag.org/ cgi/content/full/2006/1114/2, (Nov. 14, 2006) 2 pages.
Biever, C., “Evanescent coupling could power gadgets wirelessly”, NewScientistsTech.com, http://www. newscientisttech.com/article.ns?id=dn1 0575&print=true, (Nov. 15, 2006) 2 pages.
Borenstein, S., “Man tries wirelessly boosting batteries”, (The Associated Press), USA Today, (Nov. 16, 2006) 1 page.
Borenstein, S., “Man tries wirelessly boosting batteries”, AP Science Writer, Boston.com, (See http://www.boston.com/business/technology/articles/2006/11/15/man_tries_wirelessly_b . . . ) (Nov. 15, 2006).
Boyle, A., “Electro-nirvana? Not so fast”, MSNBC, http:/lcosmiclog.msnbc.msn.com/_news/2007/06/08/4350760- electro-nirvana-not-so-fast, (Jun. 8, 2007) 1 page.
Budhia, M. et al., “A New IPT Magnetic Coupler for Electric Vehicle Charging Systems”, IECON 2010—36th Annual Conference on IEEE Industrial Electronics Society, Glendale, AZ, pp. 2487-2492 (Nov. 7-10, 2010).
Budhia, M. et al., “Development and evaluation of single sided flux couplers for contactless electric vehicle charging”, 2011 IEEE Energy Conversion Congress and Exposition (ECCE), Phoenix, AZ, pp. 614-621 (Sep. 17-22, 2011).
Budhia, M. et al.,“Development of a Single-Sided Flux Magnetic Coupler for Electric Vehicle IPT”, IEEE Transactions on Industrial Electronics, vol. 60:318-328 (Jan. 2013).
Bulkeley, W. M., “MIT Scientists Pave the Way for Wireless Battery Charging”, The Wall Street Journal (See http://online.wsj.com/article/SB118123955549228045.html?mod=googlenews_wsj), (Jun. 8, 2007) 2 pages.
Burri et al., “Invention Description”, (Feb. 5, 2008).
Cass, S., “Air Power—Wireless data connections are common—now scientists are working on wireless power”, Sponsored by IEEE Spectrum, http://spectrum.ieee.org/computing/hardware/air-power, (Nov. 2006) 2 pages.
Castelvecchi, Davide, “The Power of Induction—Cutting the last cord could resonate with our increasingly gadget dependent lives”, Science News Online, vol. 172, No. 3, Jul. 21, 2007, 6 pages.
Chang, A., “Recharging the Wireless Way—Even physicists forget to recharge their cell phones sometimes.”, PC Magazine, ABC News Internet Ventures, (Dec. 12, 2006) 1 page.
Chinaview, , “Scientists light bulb with ‘wireless electricity’”,www.Chinaview.cn, http://news.xinhuanet.com/english/2007-06/08/content_6215681.htm,Jun. 2007,1 page.
Cooks, G., “The vision of an MIT physicist: Getting rid of pesky rechargers”, Boston.com, (Dec. 11, 2006) 1 page.
Derbyshire, D., “The end of the plug? Scientists invent wireless device that beams electricity through your home”, Daily Mail, http://www.dailymail.co.uk/pages/live/articles/technology/technology.html?in_article_id=4 . . . ), (Jun. 7, 2007) 3 pages.
Eisenberg, Anne, “Automatic Recharging, From a Distance”, The New York Times, (see www.nytimes.com/2012/03/11/business/built-in-wireless-chargeing-for-electronic-devices.html?_r=0) (published on Mar. 10, 2012).
Esser et al., “A New Approach to Power Supplies for Robots”, IEEE, vol. 27(5):872-875, (Sep./Oct. 1991).
Fan, Shanhui et al., “Rate-Equation Analysis of Output Efficiency and Modulation Rate of Photomic-Crystal Light-Emitting Diodes”, IEEE Journal of Quantum Electronics, vol. 36(10):1123-1130 (Oct. 2000).
Fenske et al., “Dielectric Materials at Microwave Frequencies”, Applied Microwave & Wireless, pp. 92-100 (2000).
Fernandez, C. et al., “A simple dc-dc converter for the power supply of a cochlear implant”, IEEE, pp. 1965-1970 (2003).
Ferris, David, “How Wireless Charging Will Make Life Simpler (And Greener)”, Forbes (See forbes.com/sites/davidferris/2012/07/24/how-wireless-charging-will-make-life-simpler-and-greener/print/) (dated Jul. 24, 2012).
Fildes, J., “Physics Promises Wireless Power”, (Science and Technology Reporter), BBC News, (Nov. 15, 2006) 3 pages.
Fildes, J., “The technology with impact 2007”, BBC News, (Dec. 27, 2007) 3 pages.
Fildes, J., “Wireless energy promise powers up”, BBC News, http://news.bbc.co.uk/2/hi/technology/6725955.stm, (Jun. 7, 2007) 3 pages.
Finkenzeller, Klaus, “RFID Handbook—Fundamentals and Applications in Contactless Smart Cards”, Nikkan Kohgyo-sya, Kanno Taihei, first version, pp. 32-37, 253 (Aug. 21, 2001).
Finkenzeller, Klaus, “RFID Handbook (2nd Edition)”, The Nikkan Kogyo Shimbun, Ltd., pp. 19, 20, 38, 39, 43, 44, 62, 63, 67, 68, 87, 88, 291, 292 (Published on May 31, 2004).
Freedman, D.H., “Power on a Chip”, MIT Technology Review, (Nov. 2004).
Gary Peterson, “MIT WiTricity Not So Original After All”, Feed Line No. 9, (See http://www.tfcbooks.com/articles/witricity.htm) printed Nov. 12, 2009.
Geyi, Wen, “A Method for the Evaluation of Small Antenna Q”, IEEE Transactions on Antennas and Propagation, vol. 51(8):2124-2129 (Aug. 2003).
Hadley, F., “Goodbye Wires—MIT Team Experimentally Demonstrates Wireless Power Transfer, Potentially Useful for Power Laptops, Cell-Phones Without Cords”, Massachusetts Institute of Technology, Institute for Soldier D Nanotechnologies, http://web.mit.edu/newsoffice/2007/wireless-0607.html, (Jun. 7, 2007) 3 pages.
Haus, H.A., “Waves and Fields in Optoelectronics,” Chapter 7 “Coupling of Modes—Reasonators and Couplers” (Prentice-Hall, New Jersey, 1984).
Heikkinen et al., “Performance and Efficiency of Planar Rectennas for Short-Range Wireless Power Transfer at 2.45 GHz”, Microwave and Optical Technology Letters, vol. 31(2):86-91, (Oct. 20, 2001).
Highfield, R., “Wireless revolution could spell end of plugs”,(Science Editor), Telegraph.co.uk, http://www. telegraph.co.uk/news/main.jhtml?xml=/news/2007/06/07/nwireless1 07.xml, (Jun. 7, 2007) 3 pages.
Hirai et al., “Integral Motor with Driver and Wireless Transmission of Power and Information for Autonomous Subspindle Drive”, IEEE, vol. 15(1):13-20, (Jan. 2000).
Hirai et al., “Practical Study on Wireless Transmission of Power and Information for Autonomous Decentralized Manufacturing System”, IEEE, vol. 46(2):349-359, Apr. 1999.
Hirai et al., “Study on Intelligent Battery Charging Using Inductive Transmission of Power and Information”, IEEE, vol. 15(2):335-345, (Mar. 2000).
Hirai et al., “Wireless Transmission of Power and Information and Information for Cableless Linear Motor Drive”, IEEE, vol. 15(1):21-27, (Jan. 2000).
Hirayama, M., “Splashpower—World Leaders in Wireless Power”, PowerPoint presentation, Splashpower Japan, (Sep. 3, 2007) 30 pages.
Ho, S. L. et al., “A Comparative Study Between Novel Witricity and Traditional Inductive Magnetic Coupling in Wireless Charging”, IEEE Transactions on Magnetics, vol. 47(5):1522-1525 (May 2011).
Infotech Online, “Recharging gadgets without cables”, infotech.indiatimes.com, (Nov. 17, 2006) 1 page.
Jackson, J. D., “Classical Electrodynamics”, 3rd Edition, Wiley, New York, 1999, pp. 201-203.
Jackson, J.D., “Classical Electrodynamics,” 3rd Edition, Sections 1.11, 5.5, 5.17, 6.9, 8.1, 8.8, 9.2, 9.3 (Wiley, New York, 1999).
Jacob, M. V. et al., “Lithium Tantalate—A High Permittivity Dielectric Material for Microwave Communication Systems”, Proceedings of IEEE TENCON—Poster Papers, pp. 1362-1366, 2003.
Karalis, Aristeidis, “Electricity Unplugged”, Feature: Wireless Energy Physics World, physicsworld.com, pp. 23-25 (Feb. 2009).
Kawamura et al., “Wireless Transmission of Power and Information Through One High-Frequency Resonant AC Link Inverter for Robot Manipulator Applications”, IEEE, vol. 32(3):503-508, (May/Jun. 1996).
Kurs, A. et al., “Wireless Power Transfer via Strongly Coupled Magnetic Resonances”, Science vol. 317, pp. 83-86 (Jul. 6, 2007).
Kurs, A. et al., “Simultaneous mid-range power transfer to multiple devices”, Applied Physics Letters, vol. 96, No. 044102 (2010).
Kurs, A. et al.,“Optimized design of a low-resistance electrical conductor for the multimegahertz range”, Applied Physics Letters, vol. 98:172504-172504-3 (Apr. 2011).
Lamb, Gregory M. ,“Look Ma—no wires!—Electricity broadcast through the air may someday run your home”,The Christian Science Monitor,http://www.csmonitor.com/2006/1116/p14s01-stct.html,Nov. 15, 2006,2 pages.
Lee, “Antenna Circuit Design for RFID Applications,” Microchip Technology Inc., AN710, 50 pages (2003).
Lee, “RFID Coil Design,” Microchip Technology Inc., AN678, 21 pages (1998).
Liang et al., “Silicon waveguide two-photon absorption detector at 1.5 μm wavelength for autocorrelation measurements,” Applied Physics Letters, 81(7):1323-1325 (Aug. 12, 2002).
Markoff, J. ,“Intel Moves to Free Gadgets of Their Recharging Cords”, The New York Times—nytimes.com, Aug. 21, 2008, 2 pages.
Median, A. et al. “Design of class E amplifier with nonlinear and linear shunt capacitances for any duty cycle”, IEEE Trans. Microwave Theor. Tech., vol. 55, No. 3, pp. 484-492, (2007).
Microchip Technology Inc., “microID 13.56 MHz Design Guide—MCRF355/360 Reader Reference Design,” 24 pages (2001).
Minkel, J R. ,“Wireless Energy Lights Bulb from Seven Feet Away—Physicists vow to cut the cord between your laptop battery and the wall socket—with just a simple loop of wire”,Scientific American,http://www.scientificamerican.com/article.cfm?id=wireless-energy-lights-bulb-from-seven-feet-away,Jun. 7, 2007,1 page.
Minkel, J R. ,“Wireless Energy Transfer May Power Devices at a Distance”,Scientific American,Nov. 14, 2006,1 page.
Morgan, J., “Lab report: Pull the plug for a positive charge”, The Herald, Web Issue 2680, (Nov. 16, 2006) 3 pages.
Moskvitch, Katia, “Wireless charging—the future for electric cars?”, BBC News Technology (See www.bbc.co.uldnews/technology-14183409) (dated Jul. 21, 2011).
O'Brien et al., “Analysis of Wireless Power Supplies for Industrial Automation Systems”, IEEE, pp. 367-372 (Nov. 2-6, 2003).
O'Brien et al., “Design of Large Air-Gap Transformers for Wireless Power Supplies”, IEEE, pp. 1557-1562 (Jun. 15-19, 2003).
Pendry, J. B., “A Chiral Route to Negative Refraction”, Science, vol. 306:1353-1355 (2004).
Physics Today, “Unwired energy questions asked answered”, Sep. 2007, pp. 16-17.
Powercast LLC. “White Paper” Powercast simply wire free, 2003.
PR News Wire, “The Big Story for CES 2007: The public debut of eCoupled Intelligent Wireless Power”, Press Release, Fulton Innovation LLC, Las Vegas, NV, (Dec. 27, 2006) 3 pages.
Press Release, “The world's first sheet-type wireless power transmission system: Will a socket be replaced by e-wall?”,Public Relations Office, School of Engineering, University of Tokyo, Japan,Dec. 12, 2006,4 pages.
PressTV, “Wireless power transfer possible”, http://edition.presstv.ir/detail/12754.html, Jun. 11, 2007, 1 page.
Reidy, C. (Globe Staff), “MIT discovery could unplug your iPod forever”, Boston.com, http://www.boston.com/ business/ticker/2007/06/mit_discovery_c.html, (Jun. 7, 2007) 3 pages.
Risen, C., “Wireless Energy”, The New York Times, (Dec. 9, 2007) 1 page.
Sakamoto et al., “A Novel Circuit for Non-Contact Charging Through Electro-Magnetic Coupling”, IEEE, pp. 168-174 (1992).
Scheible, G. et al., “Novel Wireless Power Supply System for Wireless Communication Devices in Industrial Automation Systems”, IEEE, pp. 1358-1363, (Nov. 5-8, 2002).
Schneider, D. “A Critical Look at Wireless Power”, IEEE Spectrum, pp. 35-39 (May 2010).
Schneider, David, “Electrons Unplugged. Wireless power at a distance is still far away”, IEEE Spectrum, pp. 35-39 (May 2010).
Schuder, J. C. et al., “An Inductively Coupled RF System for the Transmission of 1 kW of Power Through the Skin”, IEEE Transactions on Bio-Medical Engineering, vol. BME-18, No. 4, pp. 265-273 (Jul. 1971).
Schuder, J. C., “Powering an Artificial Heart: Birth of the Inductively Coupled-Radio Frequency System in 1960”, Artificial Organs, vol. 26:909-915 (2002).
Schuder, J.C. et al., “Energy Transport Into the Closed Chest From a Set of Very-Large Mutually Orthogonal Coils”, Communication Electronics, vol. 64:527-534 (Jan. 1963).
Schutz, J. et al., “Load Adaptive Medium Frequency Resonant Power Supply”, IEEE, pp. 282-287 (Nov. 2002).
Sekitani et al. “A large-area wireless power-transmission sheet using printed organic transistors and plastic MEMS switches” www.nature.com/naturematerials. Published online Apr. 29, 2007.
Sekitani et al., “A large-area flexible wireless power transmission sheet using printed plastic MEMS switches and organic field-effect transistors”, IEDM '06, International Electron Devices Meeting, (Dec. 11-13, 2006) 4 pages.
Sekiya, H. et al., “FM/PWM control scheme in class DE inverter”, IEEE Trans. Circuits Syst. I, vol. 51(7) (Jul. 2004).
Senge, M., “MIT's wireless electricity for mobile phones”, Vanguard, http://www.vanguardngr.com/articles/2002/features/gsm/gsm211062007.htm, (Jun. 11, 2007) 1 page.
Sensiper, S., “Electromagnetic wave propogation on helical conductors”, Technical Report No. 194 (based on PhD Thesis), Massachusetts Institute of Technology, (May 16, 1951) 126 pages.
Soljacic, M. , “Wireless Non-Radiative Energy Transfer—PowerPoint presentation”. Massachusetts Institute of Technology, (Oct. 6, 2005).
Soljacic, M. et al., “Wireless Energy Transfer Can Potentially Recharge Laptops Cell Phones Without Cords”, (Nov. 14, 2006) 3 pages.
Soljacic, M. et al., “Photonic-crystal slow-light enhancement of nonlinear phase sensitivity”, J. Opt. Soc. Am B, vol. 19, No. 9, pp. 2052-2059 (Sep. 2002).
Soljacic, M., “Wireless nonradiative energy transfer”, Visions of Discovery New Light on Physics, Cosmology, and Consciousness, Cambridge University Press, New York, NY pp. 530-542 (2011).
Someya, Takao. “The world's first sheet-type wireless power transmission system”. University of Tokyo, (Dec. 12, 2006).
Staelin, David H. et al., Electromagnetic Waves, Chapters 2, 3, 4, and 8, pp. 46-176 and 336-405 (Prentice Hall Upper Saddle River, New Jersey 1998).
Stark III, Joseph C., “Wireless Power Transmission Utilizing a Phased Array of Tesla Coils”, Master Thesis, Massachusetts Institute of Technology (2004).
Stewart, W., “The Power to Set you Free”, Science, vol. 317:55-56 (Jul. 6, 2007).
Tang, S.C. et al., “Evaluation of the Shielding Effects on Printed-Circuit-Board Transformers Using Ferrite Plates and Copper Sheets”, IEEE Transactions on Power Electronics, vol. 17:1080-1088 (Nov. 2002).
Tesla, Nikola, “High Frequency Oscillators for Electro-Therapeutic and Other Purposes”, Proceedings of the IEEE, vol. 87:1282-1292 (Jul. 1999).
Tesla, Nikola, “High Frequency Oscillators for Electro-Therapeutic and Other Purposes”, The Electrical Engineer, vol. XXVI, No. 50 (Nov. 17, 1898).
Texas Instruments, “HF Antenna Design Notes—Technical Application Report,” Literature No. 11-08-26-003, 47 pages (Sep. 2003).
Thomsen et al., “Ultrahigh speed all-optical demultiplexing based on two-photon absorption in a laser diode,” Electronics Letters, 34(19):1871-1872 (Sep. 17, 1998).
UPM Rafsec, “Tutorial overview of inductively coupled RFID Systems,” 7 pages (May 2003).
Valtchev et al. “Efficient Resonant Inductive Coupling Energy Transfer Using New Magnetic and Design Criteria”. IEEE, pp. 1293-1298, 2005.
Vandevoorde et al., “Wireless energy transfer for stand-alone systems: a comparison between low and high power applicability”, Sensors and Actuators, vol. 92:305-311 (2001).
Vilkomerson, David et al., “Implantable Doppler System for Self-Monitoring Vascular Grafts”, IEEE Ultrasonics Symposium, pp. 461-465 (2004).
Villeneuve, Pierre R. et al., “Microcavities in photonic crystals: Mode symmetry, tunability, and coupling efficiency”, Physical Review B, vol. 54:7837-7842 (Sep. 15, 1996).
Yariv, Amnon et al., “Coupled-resonator optical waveguide: a proposal and analysis”, Optics Letters, vol. 24(11):711-713 (Jun. 1, 1999).
Yates, David C. et al., “Optimal Transmission Frequency for Ultralow-Power Short-Range Radio Links”, IEEE Transactions on Circuits and Systems—1, Regular Papers, vol. 51:1405-1413 (Jul. 2004).
Yoshihiro Konishi, Microwave Electronic Circuit Technology, Chapter 4, pp. 145-197 (Marcel Dekker, Inc., New York, NY 1998).
Ziaie, Babak et al., “A Low-Power Miniature Transmitter Using a Low-Loss Silicon Platform for Biotelemetry”, Proceedings—19th International Conference IEEE/EMBS, pp. 2221-2224, (Oct. 30-Nov. 2, 1997) 4 pages.
Zierhofer, Clemens M. et al., “High-Efficiency Coupling-Insensitive Transcutaneous Power and Data Transmission via an Inductive Link”, IEEE Transactions on Biomedical Engineering, vol. 37, No. 7, pp. 716-722 (Jul. 1990).
International Search Report and Written Opinion of the International Searching Authority for International Application No. PCT/US2017/016119 dated Apr. 18, 2017 (18 pages).
Extended European Search Report for European Patent Application No. EP 18 20 5934 dated Feb. 14, 2019.
Transmittal of International Preliminary Report on Patentability for International Application No. PCT/US2017/016119 dated Aug. 16, 2018 (14 pages)

Related Publications (1)

	Number	Date	Country
	20170222484 A1	Aug 2017	US

Provisional Applications (2)

	Number	Date	Country
	62290325	Feb 2016	US
	62379618	Aug 2016	US

Continuations (1)

	Number	Date	Country
Parent	15422554	Feb 2017	US
Child	15423649		US

Controlling wireless power transfer systems

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

Field of Search

US

CPC

International Classifications

Abstract