The aspects of the disclosed embodiments relate generally to far field wireless power transmission (WPT) and, more particularly to wireless power delivery to energy depleted apparatus in a wireless power transfer network (WPTN).
In far-field WPT, to increase the power delivery and communication range, high gain antennas and beam-forming techniques are desired for long range wireless power transfer. However, for increased gain the wireless power transmitter has to know where the wireless power receiver is, or has to find the best direction to send energy to it.
Typically, the wireless power receiver apparatus to be powered can initiate a communication by its own, or it is located within the transmitter's field of view (FOV). If the wireless power receiver apparatus does not have an energy source or is not located within the wireless power transmitter's FOV due to the use of high gain antennas, detection becomes more challenging.
Backscatter signaling can be useful as a feedback mechanism in wireless power transfer systems and ultra-low power receivers. However, backscatter signaling generates a clock and/or data modulation signal within the wireless power receiver. The use of a processing unit to generate such signal uses a certain amount of power and can introduce additional delay to the scanning/detection of battery-less power receivers due to the initialization of protocols, overheads and possible signal sampling.
Thus, there is a need for improved apparatus and methods that can efficiently identify, locate and provide wireless electrical power to energy depleted wireless power receiver apparatus in a WPTN. Accordingly, it would be desirable to provide methods and apparatuses that address at least some of the problems described above.
The aspects of the disclosed embodiments are directed to a wireless power transfer system that allows the fast detection and delivery of wireless power by focusing the energy from a high gain beam-forming/beam-shaping antenna towards a battery-less wireless power receiver apparatus or a wireless power receiver apparatus with a depleted battery. This and other objectives are solved by the subject matter of the independent claims. Further advantageous embodiments can be found in the dependent claims.
According to a first aspect, the above and further objectives and advantages are obtained by a wireless power transfer system. In one embodiment, the wireless power transfer system includes a wireless power transmitter apparatus configured to transmit a query power signal (fQPS) and a wireless power receiver apparatus in an energy depleted state that is configured to transmit a backscatter signal (fBS) in response to receipt of fQPS. The wireless power transmitter apparatus is configured to detect fBS from the wireless power receiver apparatus, determine from the detected fBS if a wireless power delivery requirement of the wireless power receiver apparatus is met, and deliver wireless power to the wireless power receiver apparatus if the wireless power delivery requirement is met. The aspects of the disclosed embodiments enable the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the wireless power transmitter apparatus is configured to switch to a continuous wave (CW) mode to deliver power to the wireless power receiver apparatus. The wireless power receiver apparatus cooperates with the wireless power transmitter apparatus in order to be detectable and to allow the wireless power transmitter to find the best direction to transmit the radio frequency (RF) energy.
In a possible implementation form the wireless power transmitter apparatus is configured to transmit a backscatter carrier signal (fBC). The aspects of the disclosed embodiments enable the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the fQPS includes a power signal (fWPT) and a query modulation signal component (fn). The frequency of oscillation is related with the input RF power enabling the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the fBS comprises an fBC modulated by an fn of the fQPS. The frequency of oscillation is related with the input RF power enabling the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the fQPS is a pulse modulated signal with a specific pulse period. The frequency of oscillation is related with the input RF power enabling the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the wireless power transmitter apparatus is configured to transmit the fQPS in a plurality of directions (Dm). The aspects of the disclosed embodiments do not need to try every beam direction and there is no need for processing, which allows for speeding up the detection time and power delivery.
In a possible implementation form the wireless power transmitter apparatus is configured to transmit the fQPS in a plurality of sub-directions (Dm, k). The aspects of the disclosed embodiments do not need to try every beam direction and there is no need for processing, which allows for speeding up the detection time and power delivery.
In a possible implementation form the wireless power transmitter apparatus is configured to transmit the fQPS in one direction of the Dm or Dm, k at a time. The wireless power receiver device can be detected and the best direction to transmit the energy can be known even if the wireless power system is within a highly multipath environment or at non-line-of-sight conditions.
In a possible implementation form the wireless power transmitter apparatus is configured to record a direction associated with a detected fBS based on the Dm of the corresponding transmitted fQPS. The wireless power receiver device cooperates with the wireless power transmitter device in order to be detectable and to allow the wireless power transmitter device to find the best direction to transmit the RF energy.
In a possible implementation form the fBS transmitted by the wireless power receiver apparatus is a signal modulated by an fn of the fQPS. The frequency of oscillation is related with the input RF power enabling the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the wireless power transmitter apparatus is configured to determine from the fn that the pre-determined amount of RF power is being delivered to the wireless power receiver apparatus. The frequency of oscillation is related with the input RF power enabling the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the wireless power transmitter apparatus includes a backscatter apparatus configured to transmit an fBC when the wireless power transmitter apparatus transmits the fQPS and to detect the fBS transmitted by the wireless power receiver apparatus. The fBC is transmitted whenever the wireless power transmitter apparatus wants to listen to a wireless power receiver apparatus.
In a possible implementation form the fBC can be transmitted simultaneously with the fn. The fBC is transmitted whenever the wireless power transmitter apparatus wants to listen to a wireless power receiver apparatus.
In a possible implementation form the wireless power receiver apparatus is configured to transmit the fBS when an RF power of the fQPS received by the wireless power receiver apparatus exceeds a pre-determined power threshold. The fBS is generated when the wireless power receiver apparatus is receiving a certain amount of RF power, which can be less than the RF power required to operate the receiver.
In a possible implementation form the wireless power receiver apparatus has a plurality of query power signal receiver paths, where individual ones of the plurality of query power signal receiver paths are associated with a different pre-determined power threshold. The wireless power receiver apparatus is configured to transmit the fBS when a received power associated with the fQPS exceeds a pre-determined power threshold of one of the plurality of query power signal receiver paths. The aspects of the disclosed embodiments provide a single path for each fQPS and each path has its own power threshold.
In a possible implementation form the wireless power transmitter apparatus is further configured, when the pre-determined received amount of power is less than the required amount of power to transmit a next query power signal (fQPSn+1), the fQPSn+1 associated with a received RF power that is higher than an RF power of the fQPS. The aspects of the disclosed embodiments can iteratively query for a higher amount of RF power delivered until the power delivery requirements of the wireless power receiver are met.
In a possible implementation form the wireless power transmitter apparatus is further configured to determine the Dm associated with the fBS and transmit the fQPSn+1 in Dk,m associated with the Dm. The aspects of the disclosed embodiments enable a fast focus of the beam direction for wireless power delivery.
In a possible implementation form when the wireless power transmitter apparatus does not detect the fBS, the wireless power transmitter apparatus is further configured to change a beam pattern (Pk) with a beam width (φk) and gain (gk) associated with the fQPS to a next beam pattern (Pk+1) with a next beam width (φk+1) and next gain (gk+1), where the φk+1 of the Pk+1 is narrower than the φk of the Pk and the next gain (gk+1) is greater than the gk; and transmit the fQPS with the φk+1 and gk+1. When the wireless power transmitter does not detect the fBS this can trigger the use of the fQPS with a new beam pattern of narrower width and higher gain. To overcome propagation path loss, the beam width is traded for antenna gain.
In a possible implementation form the wireless power transmitter apparatus is further configured to iteratively narrow the φk+1 of the Pk+1 until the fBS detected by the wireless power transmitter apparatus indicates that the required amount of power is being delivered to the wireless power receiver apparatus. Narrowing the beam width will increase the antenna gain.
In a possible implementation form the wireless power receiver apparatus includes a switching apparatus (T1) configured to modulate the fBC to generate the fBS. An input sensitivity of the T1 is less than an input power threshold required to power on the wireless power receiver apparatus. The aspects of the disclosed embodiments enable the generation of the backscatter signal even when the wireless power receiver is not receiving enough RF power to be operational.
According to a second aspect, the above and further objectives and advantages are obtained by a wireless power transmitter apparatus. In one embodiment, the wireless power transmitter apparatus is configured to transmit an fQPS; detect an fBS sent from a wireless power receiver apparatus; determine from the detected fBS if a wireless power delivery requirement of the wireless power receiver apparatus is met; and deliver wireless power to the wireless power receiver apparatus if the wireless power delivery requirement is met. The aspects of the disclosed embodiments enable the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form, the wireless power transmitter apparatus is configured to transmit an fBC when the fQPS is being transmitted. The wireless power transmitter apparatus can transmit the fBC when it wants to listen to a wireless power receiver apparatus.
According to a third aspect, the above and further objectives and advantages are obtained by a wireless power receiver apparatus. In one embodiment, the wireless power receiver apparatus is configured to receive an fQPS and transmit an fBS when an RF power of the fQPS received by the wireless power receiver apparatus exceeds a pre-determined power threshold. The aspects of the disclosed embodiments enable the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form the wireless power receiver apparatus forms the fBS by modulating a received fBC with an fn of the fQPS. The frequency of oscillation is related with the input RF power enabling the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
According to a fourth aspect, the above and further objectives and advantages are obtained by a method. In one embodiment the method includes transmitting an fQPS from a wireless power transmitter apparatus, detecting an fBS sent from a wireless power receiver apparatus in an energy depleted state responsive to the fQPS, determining from the fBS if a wireless power delivery requirement of the wireless power receiver is met, and delivering wireless power to the wireless power receiver apparatus when the wireless power delivery requirement is met. The aspects of the disclosed embodiments enable the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power.
In a possible implementation form, when the fBS is not detected, the method further comprises changing a Pk associated with the fQPS to a Pk+1, wherein an φk+1 of the Pk+1 is narrower than an φk of the Pk and a gk+1 is greater than a gk, and transmitting the fQPS with the Pk+1. The aspects of the disclosed embodiments enable fast detection and delivery of wireless power to a wireless power receiver device by focusing the RF energy from a high gain beam-forming/beam-shaping antenna towards the battery-less wireless power receiver device or wireless power receiver device with a depleted battery.
In a possible implementation form, when the pre-determined amount of delivered power is less than the required amount of power, the method further includes transmitting an fQPSn+1, the fQPSn+1 associated with a received RF power that is higher than an RF power of the fQPS. The aspects of the disclosed embodiments enable fast detection and delivery of wireless power to a wireless power receiver device by focusing the RF energy from a high gain beam-forming/beam-shaping antenna towards the battery-less wireless power receiver device or wireless power receiver device with a depleted battery.
In a possible implementation form the wireless power transmitter apparatus is a high-gain beam shaping antenna. The aspects of the disclosed embodiments enable fast detection and delivery of wireless power to a wireless power receiver device by focusing the RF energy from a high gain beam-forming/beam-shaping antenna towards the battery-less wireless power receiver device or wireless power receiver device with a depleted battery.
In a possible implementation form the wireless power receiver apparatus is in an energy depleted state. The aspects of the disclosed embodiments enable fast detection and delivery of wireless power to a wireless power receiver device by focusing the RF energy from a high gain beam-forming/beam-shaping antenna towards the battery-less wireless power receiver device or wireless power receiver device with a depleted battery.
According to a fifth aspect, the above and further objectives and advantages are obtained by a non-transitory computer readable medium having stored thereon program instructions. The program instructions, when executed by a processor, are configured to cause the processor to perform the method according to any one or more of the possible implementation forms described herein.
These and other aspects, implementation forms, and advantages of the exemplary embodiments will become apparent from the embodiments described herein considered in conjunction with the accompanying drawings. It is to be understood, however, that the description and drawings are designed solely for purposes of illustration and not as a definition of the limits of the disclosure, for which reference should be made to the appended claims. Additional aspects and advantages of the disclosure will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. Moreover, the aspects and advantages of the disclosure may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The following portion of the disclosure is explained in more detail with reference to the example embodiments shown in the drawings, in which:
Referring to
As shown in
As illustrated in
In this example, the wireless power receiver apparatus 200 is in an energy depleted state, generally meaning that the wireless power receiver apparatus 200 does not have enough stored energy to initiate communication with the wireless power transmitter apparatus 100. If the wireless power receiver apparatus 200 can “answer” with the fBS, that generally indicates that the wireless power receiver apparatus 200 is receiving at least a certain amount of RF power. This certain amount of RF power may be less than the power used to operate the wireless power receiver apparatus 200.
In one embodiment, the wireless power transmitter apparatus 100 is configured to detect the fBS from the wireless power receiver apparatus 200, determine from the detected fBS if a wireless power delivery requirement of the wireless power receiver apparatus 200 is met, and deliver wireless power to the wireless power receiver apparatus 200 if the wireless power delivery requirement is met.
In a typical wireless power transfer system, the use of high gain antennas to deliver wireless power generally uses some kind of localization and/or feedback technique in order to focus the narrow beam toward the wireless power receiver and minimize the transmission losses by choosing the best transmission technique. However, these techniques generally include the receiver apparatus being powered on to initiate communication and detection.
Where backscatter signaling is used, such backscatter signaling generates a clock and/or data modulation signal within the wireless power receiver. This signal is usually generated with a processing unit, such as a microcontroller or a voltage controlled oscillator (VCO). The use of a processing unit to generate the modulation signal uses a certain amount of power and can introduce additional delay to the scanning/detection of battery-less power receivers due to the initialization of protocols, overheads and possible signal sampling.
The aspects of the disclosed embodiments enable the detection of targets, such as battery-less wireless power receiver apparatus, or wireless power receiver apparatus that cannot initiate signaling to request wireless power. The wireless power receiver apparatus 200 of the disclosed embodiments can be detected and the best direction to transmit the RF energy can be determined even if the wireless power receiver apparatus 200 is within a highly multipath environment or non-line-of-sight conditions. The wireless power receiver apparatus cooperates 200 with the wireless power transmitter apparatus 100 in order to be detectable and to allow the wireless power transmitter apparatus 100 to find the best direction to transmit the energy.
In the example of
Each fQPS is generally configured to “ask” the wireless power receiver apparatus 200 if it is collecting, at least, a certain predefined amount of power. The wireless power receiver apparatus 200 is configured to answer the fQPS from the wireless power transmitter apparatus 100 through backscatter signaling. The aspects of the disclosed embodiments use backscatter signaling but without generating a backscatter modulation signal within the wireless power receiver apparatus 200, thus providing a low cost and simple solution.
The backscatter transmitter 104 is configured to transmit an fBC. The fBC is used whenever the wireless power transmitter apparatus 100 wants to “listen” for a wireless power receiver apparatus 200.
The backscatter reader 106 is generally configured to listen for the feedback provided by the wireless power receiver apparatus 200. As described herein, the feedback is generally in the form of the fBS. In one embodiment, the fBS generally comprises the fBC, modulated by an fn of the fQPS.
The wireless power transfer system 10 of the disclosed embodiments is configured to operate with two different frequencies. As used herein, fWPT refers to the carrier frequency used for wireless power transfer. The frequency fBC refers to the carrier frequency transmitted by the backscatter transmitter 104 and used for feedback through backscatter signaling. The aspects of the disclosed embodiments generally use distinct carrier frequencies for successful operation.
In one embodiment, the backscatter module 102 is configured to continuously transmit a CW fBC through the backscatter module transmitter 104. The fBS is generally configured to “illuminate” the whole FOV of the wireless power transmitter apparatus 100. Typically, low gain antennas are employed to transmit the fBC.
In one embodiment, the wireless power receiver apparatus 200 shown in
In the example of
S1 is configured by a data/clock modulation signal 210. The load terminations Z1 and Z2 may be a matched load and a pure reactive load for amplitude-shift keying (ASK) modulation, or pure reactive loads with 180 degrees of phase shift for binary phase-shift keying (BPSK) modulation. The aspects of the disclosed embodiments can include other modulations, which can be generated by adding additional termination loads, such as for example M-ary phase-shift keying (M-PSK) and quadrature phase-shift keying (QPSK).
S1 can be any suitable type of switching apparatus. Examples include, but are not limited to, a transistor or a diode. The backscatter module 204 is configured to modulate and transmit the fBC back to the wireless power transmitter apparatus 100 based on predefined conditions.
The clock and/or data modulation signal 210 shown in
The backscatter reader 106 of the backscatter apparatus 102 shown in
Although a bi-static backscatter configuration is shown in the example of
As described further herein, the aspects of the disclosed embodiments rely on beam-forming/beam-shaping antennas and backscatter communications in a wireless power transfer system 10 that can detect and focus wireless power towards a wireless power receiver apparatus 200 in an energy depleted state. These wireless power receiver apparatus 200 are generally disposed or otherwise positioned within the range of high gain wireless power transmitting antenna systems 112 of the wireless power transmitter apparatus 100.
In one embodiment, the wireless power transmitter apparatus 100 is a high gain antenna array 112 with beam-forming and/or beam-shaping capabilities. The wireless power transmitter apparatus 100 may produce Px for the fQPS with different φk and gk, as well as transmit the fQPS in several directions. The wireless power transmitter apparatus 100 is configured to trade its maximum gain for a larger beam-width.
In one embodiment, the wireless power transmitter apparatus 100 can include a processor(s) or processing unit 108. The processing unit 108 can be a microcontroller, digital signal processor (DSP) or field-programmable gate array (FPGA), for example. The processing unit or processor 108 is configured to provide the control signals for setting the phase and/or amplitude of the fQPS that is fed to each element of the antenna 112 of the wireless power transmitter apparatus 100. One or more of the phase and amplitude of the fQPS described herein can be adjusted to a form an φk with a specific beam-width and with a maximum RF power intensity towards specific Dm or Dm,k. This is also known as beam-forming or beam-shaping.
When the Pk is shaped, the maximum gain can decrease. In one embodiment, a look-up table of phases and/or amplitudes is stored within a memory 110 or other suitable storage medium of the processing unit 108. This look-up table can be accessed to identify the control signals that are applied to generate certain Pk. For example, in one embodiment, the look-up table should contain the control signals that are used to generate the Pk that cover several segments of the total FOV of the wireless power transmitter 100 as is described herein. Examples of such Pk with different φk are shown in
In one embodiment, the wireless power transmitter 100 will include or be communicatively connected to the memory or storage apparatus 110. The memory 110 is generally configured to store or maintain information or data related to the wireless power transmitter apparatus 100 and the wireless power receiver apparatus 200. In addition to the phase, amplitude and control signals described above, the information stored in the memory 110 could also include, but is not limited to, a capability of each wireless power transmitter apparatus 100, a number and type of antennas, a number of supported beam directions, per unit power delivery capabilities, a type of the wireless power receiver apparatus 200, a type of battery, remaining charging time, priority and receiver identifier.
Referring to the example of
In pulsed operation, the fWPT is mixed, via mixer 304, with a low frequency oscillator such as one of f1, f2, . . . fN. In one embodiment, the low frequency oscillator f1, f2, . . . fN is in the megahertz (MHz) range. A single VCO may be used to generate the low frequency signals f1, f2, . . . fN, also referred to herein as “query modulation signal component fn” for descriptive purposes only.
This mixing will produce an ON/OFF wireless fQPS, with fn, which will be used to detect and to query the wireless power receiver apparatus 200. Based on the response, or lack of response by the wireless power receiver apparatus 200 to the fQPS, the wireless power transmitter apparatus 100 shall be guided until it delivers the required power to the wireless power receiver apparatus 200. As used herein, the term “required power” generally refers to an amount of received RF power that is needed for the wireless power receiver apparatus 200 to operate.
The fn of the fQPS is generally configured to “ask” the wireless power receiver 200 if it is collecting, at least, a certain predefined amount of power. The amount of RF power associated with the fn is known by the wireless power transmitter apparatus 100. For example, in one embodiment, the amount of RF power associated with a specific fn is stored in the memory 110.
In one embodiment, instead of an up-conversion architecture, a switch S2, or other similar apparatus may be used to switch ON/OFF the fWPT generated by the VCO at the frequencies f1, f2, . . . fN, effectively creating pulse modulation. In one embodiment, an additional pulse shaping block may be added to smooth out the pulsed waveform and to decrease the out-of-band spectrum emission.
In one embodiment, the processing unit 108 of the wireless power transmitter apparatus 100 is configured to control the CW operation, pulsed operation and the pulse period by sending a control signal 306 to the switch S2. As further described herein, the processing unit 108 can also be configured to control which φk should be used at any given time instant. The CW or pulsed power signal, generally referred to herein as “query power signal fQPS” can then be amplified via an amplifier 308 to a transmission power level and delivered to the transmitting antenna array 112 of the wireless power transmitter apparatus 100.
The pulsed wireless fQPSn transmitted by the wireless power transmitter apparatus 100 as shown in
As is shown in this example, an RF-DC converter 402 is configured to convert the collected RF energy of the fQPS at fWPT to usable DC energy. A low-pass filter 404 is added to the output of the RF-DC converter 402 to filter out the fundamental frequency fWPT of the fQPS and the harmonics generated by the rectifying process. The low-pass filter 404 is configured to allow DC and the low frequency modulations f1, f2 . . . fN of the fQPS to pass through, where fN<<1/RC<<fWPT.
As shown in the example of
In one embodiment, the wireless power receiver apparatus 200 also comprises a switch S3. One side of S3 is coupled or otherwise connected to the output of the RF-DC converter 402. The other side of S3 is coupled or otherwise connected to a bank of filters 414.
As illustrated in the example of
In one embodiment, the S3 can be configured to be in the closed and connected state when the wireless power receiver apparatus 200 is in the energy depleted state. When S3 is closed the low frequency components (<1/RC) produced by the RF-DC converter 402 are communicated to the bank of filters 414.
When in the energy depleted state, the wireless power receiver apparatus 200 has no energy to initiate a request for wireless charging. In one embodiment, S3 can be a relay with a “closed” default state. S3 can be set to “open” by an external control signal provided by a microcontroller or directly from the battery 410, if any.
As illustrated in the example of
The filters in the filter bank 414 are matched to the frequency of the low frequency oscillators f1, f2 . . . fN of the wireless power transmitter apparatus of
In one embodiment, the wireless power receiver apparatus 200 does not include S3. In this example, a straight connection is provided between the output Vout of the RF-DC converter 402 and the filter bank 414. When there is such a direct connection, the wireless power receiver apparatus 200 may provide a response to the fQPS from the wireless power transmitter apparatus 100 through the backscatter link even if when the wireless power receiver apparatus 200 does not use wireless power.
The wireless power transmitter apparatus 100 of
As shown in the example of
In one embodiment, the attenuation of different ones of the blocks in the attenuation block 416 can vary. For example, an attenuation value of Attenuation 1 can be less than the attenuation value of Attenuation 2, which is less than the attenuation value of Attention N. In alternate embodiments, the blocks of the attenuation block 416 can have any suitable values.
Referring again to
T1 is generally configured to switch between OFF and ON or ON and OFF based on a control input. In one embodiment, T1 is a transistor. In alternate embodiments, T1 can be any suitable switching apparatus.
As described further herein, when S3 is in the closed state, the aspects of the disclosed embodiments provide for the fn component of the fQPS to turn T1 ON and OFF. This switching will add ON/OFF modulation to the fBC that is received from the wireless power transmitter apparatus 100 at a frequency that is equal to the frequency of fn, or the respective low frequency oscillator signal f1, f2 . . . fN, portion of the fQPS.
To activate the switching of T1, the peak-to-peak voltage of the fn portion of the fQPS must be large enough, after attenuation by the corresponding block in attenuation block 416, to surpass the threshold of T1. When the peak-to-peak voltage of fn is large enough, the fn will effectively switch ON/OFF T1, modulating the received fBC at one of the low frequency oscillators f1 to fN.
In the example of
The generated fBS will be the fBC modulated by fn. This modulated signal, also referred to as the backscatter signal fBS, is then sent back to the wireless power transmitter apparatus 100, where it can be detected by the backscatter reader 104 of
The time used by the feedback mechanism shown in
Referring again to
In one embodiment, a peak detector 322 is used to detect the presence of the frequency components of the fn, the low frequency oscillator signals f1, f2 . . . fN. The peak detector 322 can be configured to generate a “high” DC voltage if a frequency component corresponding to the frequency component of the low frequency oscillator signals f1, f2 . . . fN is detected and a “low” DC voltage if no frequency component is detected. The output signal 324 from the peak detector 322 is then routed to the processing unit 108 to trigger an action, such as to set a new Pk or a generate a new fQPSn+1.
The fn of the fQPS can be understood as a question to the wireless power receiver apparatus 200 as to whether the wireless power receiver apparatus 200 is receiving, at least, a certain predefined amount of RF power. The detection of fBS by the backscatter reader 104 of
There are N possible fQPS with N modulations f1, f2 . . . fN and N RF power thresholds. In the examples generally described herein, the received RF power associated with fPQS2 is greater than the received RF power associated with fPQS1. Similarly, the received RF power associated with fPQSn+1 is greater that the received RF power associated with fQPSn.
Also, the attenuation of attenuation block Attenuation 2 of
When the wireless power transmitter apparatus 100 is operated in CW mode, meaning it is transmitting wireless power to the wireless power receiver apparatus 200, there is no modulation frequency applied to T1. The CW mode will only be set after the wireless power transmitter apparatus 100 is able to detect that the wireless power receiver apparatus 200 is receiving the required power to remain operational. During CW mode, the backscatter module 204 of the wireless power receiver apparatus 200 is free for other purposes, such as further signaling or information transfer. Using the backscatter module 204 of the wireless power receiver apparatus 200 for communications can reduce the energy consumption of the wireless power receiver apparatus 200. For example, instead of the wireless power receiver apparatus 200 using a typical power hungry dedicated communication module, such as WI-FI™, BLUETOOTH™ or ZIGBEE™, for communications, the wireless power receiver apparatus 200 may use the backscatter module 204.
In one embodiment, referring again to
The voltage produced by an RF-DC converter depends on the input RF power. The higher the input RF power, the higher will be the voltage produced and the DC power. This behavior is represented in the graph of
In the example of
Generally, the first pulsed signal, referred to herein as signal f1, is used for detection purposes. If the signal f1 is backscattered by the wireless power receiver 200 as described above, this indicates that the wireless power receiver apparatus 200 was detected and it is collecting at least x dBm of RF power. The signal f1 is generally associated with or is configured to provide a minimum input RF power (x dBm) to surpass the voltage threshold level of T1. The minimum input RF power that triggers such detection at f1 is largely dependent on the type of RF-DC converter and its sensitivity. In one embodiment information about the signal f1 and the power associated with signal f1 can be stored in the memory 110 shown in
Similarly, the next signal f2 is configured to query the wireless power receiver apparatus 200 to determine whether it is receiving at least y dBm of RF power. The signal f3 is configured to determine whether the wireless power receiver apparatus 200 is receiving at least z dBm. Generally, the RF power level of signal f2 will be greater than the RF power level of signal f1, and the RF power level of signal f3 will be higher than the RF power level of signal f2.
Referring again to
Based on the received power of the signal f1, f2 or f3, the wireless power receiver apparatus 200 will or will not reflect back, or otherwise send to the wireless power transmitter apparatus 100 the fBC modulated by the respective frequency f1, f2 or f3, referred to as fBS. The transmission or absence of transmission of fBS shall be understood as a “yes” or a “no” to the question “Are you receiving, at least, a certain predefined amount of RF power?” The input RF power level at which the backscatter signaling will occur at f1, f2 or f3 can be defined by adjusting the value of their corresponding resistors at the attenuator block 416 shown in
Every attenuation 1-N in the attenuation block 416 (or input RF power threshold) can be set independently. The input RF power required to backscatter a signal at f1 and f2 is much lower than the one required to keep the wireless power receiver apparatus 200 fully functional. The aspects of the disclosed embodiments can provide feedback to the wireless power transmitter apparatus 100 even if the received power is not enough to fully turn the wireless power receiver ON, including a processing unit and/or a dedicated communication module such as WI-FI™, BLUETOOTH™, or ZIGBEE™.
The aspects of the disclosed embodiments enable a fast focus of the required amount of energy towards a wireless power receiver apparatus 200 located within the FOV of the wireless power transmitter 100. Referring again to
To transmit wireless power to a wireless power receiver 200 located far away, Pk with the narrowest φk (highest gk and highest power delivered) are used. The aspects of the disclosed embodiments allow the wireless power transmitter apparatus 100 to select one of the 64 possible beam directions without trying them all, based on the feedback provided by the wireless power receiver apparatus 200 to the fQPSn.
As shown in the example of
The gain g1, g2, g3 associated with respective beam patterns P1, P2 and P3 is also different. Generally, the larger the φk of the Pk, the lower the Gk, also described as the power that the wireless power transmitter apparatus 100 can deliver through a specific direction. In this example, g1<g2<g3. The Pk with largest beam-width will have a broader coverage area, but less power delivered, generally per unit area. It is assumed that by using a larger beam pattern, the wireless power transmitter apparatus 100 can deliver at least x dBm of RF power to any wireless power receiver apparatus 200 located within its range.
In one embodiment, the largest beam pattern, such as beam pattern φ1 of
Referring to
In this example, the beam patterns with the largest beam-width, namely φ1, are configured to cover approximately ¼ of the total FOV, or use four beam directions to cover the entire FOV. The beam patterns P2 are configured to cover approximately 1/16 of the total FOV. The beam patterns P3 in this example are configured to cover approximately 1/64 of the total FOV. Thus, to cover the entire FOV, beam pattern P1 uses four beam directions, beam pattern P2 16 beam directions, and beam pattern P3 64 beam directions. In alternate embodiments, any suitable technique to achieve different beam-width (covered area) and different gain (power delivered) may be used.
In one embodiment, the beam pattern P1 can be used for initial detection purposes. The beam pattern P1 in the example of
In one embodiment, the beam patterns P1, P2 and P3 can also be used for actual wireless power transfer if the target wireless power receiver apparatus 200 is close enough to the wireless power transmitter apparatus 100. In the example of
In one embodiment, a direction from which an fBS is transmitted can be determined. For example, the signal f1 is transmitted from the wireless power transmitter apparatus 100 in one direction at a time. If an fBC modulated by signal f1 is transmitted back and detected (also referred to herein as a “response” or backscatter signal fBS), the direction associated with the particular transmission of signal f1 can be identified. In alternate embodiments, any suitable manner of determining a direction from which an fBS modulated by a particular signal f1 is transmitted can be used.
In one embodiment, the direction(s) from which a response(s) is received is verified and stored in the memory 108. Then, while still using the beam pattern P1 with the same beam width, the wireless power transmitter apparatus 100 switches to the signal f2. The wireless power transmitter apparatus 100 is configured to transmit the signal f2 using beam pattern P1 in the direction from which the response to signal f1 was received. If the target wireless power receiver apparatus 200 is within a predetermined range of the wireless power transmitter apparatus 100, the response to the signal f2 may occur from specific direction that can be identified.
If a response to signal f2 is received, fBC modulated by f2, the wireless power transmitter 100 is configured to switch to the signal f3 while still using the beam pattern φ1. The wireless power transmitter 100 will transmit the query power signal f3 in the direction from which the response to query signal f2 was received, which is stored in the memory. If a response to the query signal f3 occurs, it means that there is a direction from which the beam pattern P1 can be used to deliver sufficient power to keep the wireless power receiver 200 operating in a fully functional manner. Thus, for the identified direction, the wireless power transmitter apparatus 100 can deliver z dBm of RF power using beam pattern P1. The wireless power transmitter apparatus 100 can then switch to CW operation for wireless power delivery using the identified direction and beam pattern P1.
In one embodiment, if the target wireless power receiver apparatus 200 is beyond a predetermined range, or too far away, from the wireless power transmitter apparatus 100, a narrower beam-width Pk to produce a higher gk may be used in order to find a direction to deliver the required amount of power.
Referring to
If one were to use the beam pattern P3 in each of the sixteen quadrants represented in
In one embodiment, after a response to signal f1 using beam pattern P1 is received, the wireless power transmitter apparatus 100 is configured to switch to signal f2 with the same beam pattern P1. The wireless power transmitter apparatus 100 is configured to scan the direction(s) from which it had a response to the signal f1, using signal f2 and beam pattern P1.
In a situation where the wireless power receiver 200 is far away, or beyond a pre-determined range, there will be no fBS to the query signal f2 while using beam pattern P1. In this case, the wireless power transmitter apparatus 100 will switch to beam pattern P2, which has a narrower beam width than beam pattern P1, Thus, beam pattern P2 will provide a higher gain and can deliver additional RF power.
Referring to
After a response to the query signal f2 is detected, the wireless power transmitter apparatus 100 is configured to switch to the query power signal f3 still using the beam pattern P2. The wireless power transmitter apparatus 100 is configured to scan the sub-directions 806 from which, in this example, it had a response to the signal f2, now using signal f3 and beam pattern P2.
If a response is received from the target wireless power receiver apparatus 200 to the query signal f3 and beam pattern P2 this indicates that the wireless power receiver apparatus 200 is located at or within a range that the beam pattern P2 can deliver z dBm of RF power to the target wireless power receiver apparatus 200.
However, if there is no response to the signal f3 from the target wireless power receiver 200, the wireless power transmitter apparatus 100 is configured to switch to beam pattern P3, which, in this example, is narrower than beam pattern P2. The narrower beam pattern P3 is configured to provide additional gain.
In the example of
When an fBS is received that is modulated by f3, this indicates that the identified direction will enable the wireless power receiver apparatus 200 to collect the required RF power for its proper operation. Once this direction is determined, the wireless power transmitter apparatus 100 can switch to CW operation for full charging mode (100% duty-cycle) and switch S3 of
At the start at 902 of the process, the initial values for n of the query modulation signal portion fn of the fQPS and k for the beam pattern Pk are set at 904. In this example, the initial values are n=1 and k=1. The fQPS includes or is associated with a wireless power transfer signal or carrier fWPT, the modulation component or low frequency oscillator signal fn and a beam pattern Pk. In one embodiment, the fWPT is mixed with fn.
In one embodiment, the query modulation signal f1 for the fQPS and the beam width φ1 of the beam pattern P1 can be obtained from the look-up table in the memory 110 of
In the first instance, the beam pattern P1 has the widest beam width of all of the beam patterns Pk and a corresponding gain gk. The query modulation signal f1 will generally be associated with a minimum amount of RF power that is received to have a first answer (backscatter signal fBS) from the wireless power receiver apparatus 200. Concurrently with the transmission of the fQPS, an fBC is also transmitted or being transmitted.
In one embodiment, the fQPS with f1 and P1 is transmitted at 906. Generally, the fQPS is transmitted in all Dm, or Dm,k. In one embodiment, one fQPS is transmitted in one direction at a time.
It is determined or detected at 908 if an fBS is received. The fBS generally comprises the fBC modulated by the fn.
If it is determined that the fBS has been received, the Dm of the fQPS associated with the received fBS is determined at 910. In one embodiment, Dm of the fQPS is known and stored in the memory 108 of
It is determined at 912 if a power delivery requirement of the wireless power receiver is met. If the wireless power receiver is receiving the required amount of power to operate, the wireless power transmitter apparatus can switch at 914 to the CW mode for wireless power delivery.
If it is determined at 912 that the power delivery requirement is not met, it is determined at 916 whether n is equal to N, where N is the last available fn. When n does not equal N, the value of n is increased at 916 to n+1. The fQPS with fn, where n=n+1, is transmitted at 906. Thus, in the example where n=1, the next fn is f2. In one embodiment, the RF power associated with query modulation signal f2 is higher than the RF power associated with query modulation signal f1. The beam pattern P1 in this example does not change.
If it is determined at 916 that n=N, in one embodiment, this generally indicates that wireless power receiver apparatus 200 is receiving the required amount of power. In one embodiment, the power delivery requirement and fn=fN have the same meaning. The wireless power transmitter 100 can switch at 914 to CW mode of operation.
If it is determined at 908 that the fBS is not received, in one embodiment, it is determined at 920 if n=1 and k=1. If yes, the fQPS continues to be transmitted at 906 with query modulation signal f1 and beam pattern P1. Since the wireless power receiver apparatus 200 is in an energy depleted state, it cannot initiate a wireless power charge request. Thus, in this example, the wireless power transmitter apparatus 100 is configured to continue the querying process at 906 until a wireless power receiver apparatus 200 in need of charge comes into range of the wireless power transmitter apparatus 100.
If it is determined at 920 that one or more of n is not equal to 1, or k is not equal to 1, it is determined at 922 whether the beam pattern Pk=PK, where K is the narrowest beam width of the beam patterns available. If k-K, meaning that the fQPS has been transmitted with the narrowest available beam pattern PK, the target wireless power receiver apparatus is determined at 924 to be out of range of the wireless power transmitter apparatus. In one embodiment, when it is determined at 924 that the target wireless power receiver apparatus 200 is out of range, the wireless power transmitter apparatus can resume or start at 902 the process 900. In this manner, the wireless power transmitter apparatus 100 is configured to continue the process 900 until a wireless power receiver apparatus 200 in a depleted energy state comes into range of the wireless power transmitter apparatus 100.
In one embodiment, during CW operation at 914, from time to time, the wireless power receiver 200 shall send an “alive” signal to the wireless power transmitter apparatus 100. If the “alive” signal is not received by the wireless power transmitter apparatus 100 within a predefined time window, this generally indicates that the wireless power receiver apparatus 200 is no longer in range or that it moved to a new position and it no longer can collect enough RF power to operate.
If so, a reset is triggered and a new detection/scanning is performed, such as that described above with respect to
The aspects of the disclosed embodiments enable the wireless power transmitter apparatus 100 to select a specific target wireless power receiver apparatus 100. For that, the wireless power transmitter apparatus 100 may use additional query power signals fQPSn and fQPSn+1 which are pulsed at specific frequencies fn that match the desired wireless power receiver apparatus 200.
For example, a first wireless power receiver apparatus, such as a humidity sensor, may use query modulation signals f1, f2 and f3, and a second wireless power receiver apparatus, such as a temperature sensor, may use query modulation signals f4, f5 and f6 and so on. By transmitting an fQPS with specific fn, the wireless power transmitter apparatus 100 is able to target the desired wireless power receiver apparatus 200.
The aspects of the disclosed embodiments enable a rapid identification of an energy depleted wireless power receiver apparatus that cannot otherwise initiate signaling to request wireless power. The receiver can re-use the power query signals to provide the answer to the transmitter with zero latency. As soon as the remote apparatus receives a certain amount of energy, which is much lower than the energy used to keep it fully functional, it will instantaneously inform the transmitting system about its presence and if it is collecting at least a certain amount of RF power. There is no processing associated with the feedback mechanism.
The transmitter may also iteratively adjust the beam pattern based on the received feedback until it delivers the required amount of power to the remote power receiver. The aspects of the disclosed embodiments enable a fast selection of the best beam pattern and beam direction to transmit wireless energy towards a specific power receiver without trying every possible beam direction.
Thus, while there have been shown, described and pointed out, fundamental novel features as applied to the exemplary embodiments thereof, it will be understood that various omissions, substitutions and changes in the form and details of apparatus and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the present disclosure. Further, it is expressly intended that all combinations of those elements, which perform substantially the same function in substantially the same way to achieve the same results, are within the scope of the disclosure. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the disclosure may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
This is a continuation of International Patent Application No. PCT/EP2021/083218 filed on Nov. 26, 2021, the disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | PCT/EP2021/083218 | Nov 2021 | WO |
Child | 18673718 | US |