Patent Application
20140152094
The invention generally relates to capacitive powering systems for wireless power transfers, and more particularly to structures for allowing efficient power transfers in a tube-shaped structure.
A wireless power transfer refers to the supply of electrical power without any wires or contacts, thus the powering of electronic devices is performed through a wireless medium. One popular application for contactless powering is for the charging of portable electronic devices, e.g., mobiles phones, laptop computers, and the like.
One implementation for wireless power transfers is by an inductive powering system. In such a system, the electromagnetic inductance between a power source (transmitter) and the device (receiver) allows for contactless power transfers. Both the transmitter and receiver are fitted with electrical coils, and when brought into physical proximity, an electrical signal flows from the transmitter to the receiver.
In inductive powering systems, the generated magnetic field is concentrated within the coils. As a result, the power transfer to the receiver pick-up field is very concentrated in space. This phenomenon creates hot-spots in the system which limits the efficiency of the system. To improve the efficiency of the power transfer, a high quality factor for each coil is needed. To this end, the coil should be characterized with an optimal ratio of an inductance to resistance, be composed of materials with low resistance, and fabricated using a Litze-wire process to reduce skin-effect. Moreover, the coils should be designed to meet complicated geometries to avoid Eddy-currents. Therefore, expensive coils are required for efficient inductive powering systems. A design for a contactless power transfer system for large areas would necessitate many expensive coils, thus for such applications an inductive powering system may not be feasible.
Capacitive coupling is another technique for transferring power wirelessly. This technique is predominantly utilized in data transfer and sensing applications. A car-radio antenna glued on the window with a pick-up element inside the car is an example of a capacitive coupling. The capacitive coupling technique is also utilized for contactless charging of electronic devices. For such applications, the charging unit (implementing the capacitive coupling) operates at frequencies outside the inherent resonance frequency of the device.
A capacitive power transfer system can also be utilized to transfer power over large areas, e.g., windows, walls, having a flat structure and so on. An example for such a captive power transfer system 100 is depicted in
The transmitter electrodes 141, 142 are coupled to one side of the insulating layer 160 and the receiver electrodes 111, 112 are coupled from the other side of the insulating layer 160. This arrangement forms capacitive impedance between the pair of transmitter electrodes 141, 142 and the receiver electrodes 111, 112. Therefore, a power signal generated by the power driver can be wirelessly transferred from the transmitter electrodes 141, 142 to the receiver electrodes 111, 112 to power the load 120, when a frequency of the power signal matches a series-resonance frequency of the system. The load may be, for example, a LED, a LED string, a lamp, and the like.
As an example, the system 100 can be utilized to power lighting fixtures installed on a wall.
Capacitive power transfer may be designed to transfer power over a large area; such a system was primarily designed to support flat surfaces and structures, e.g., walls, windows, etc. Thus, the system 100 is limited in the applications that it can support. For example, the system 100 cannot optimally allow wireless power transfer along pipes which may be very long (e.g., hundreds of kilometers) or a garden hose. That is, the capacitive power system 100 is not optimally designed to allow wireless power transfer over tube-shaped structures.
In the related art, the power distribution across a tube is typically achieved using conductive wires that are integrated inside the tube-shaped structure (e.g., a pipe). A conductive connection is made with the conductive wires to enable a power transfer from a power source to a load. However, cracks in the tube may cause the wires to break or change the conductive capacity, thus they cannot conduct power. In addition, for applications that require power transmission along a long pipe the solution is costly as the wires may run across the entire length of the tube.
Therefore, it would be advantageous to provide a solution for efficient wireless power transfers in a large area in a tube-shaped structure.
Certain embodiments disclosed herein include a capacitive powering system constructed to enable wireless power transfers inside a tube-shaped structure. The system includes a capacitive tube including a pair of receiver electrodes connected to a load through a first inductor, wherein the first inductor is coupled to the load to resonate the system; a transmitter device clipped onto the capacitive tube, the transmitter device includes a pair of transmitter electrodes connected to a power driver; and an insulating layer for electrically insulating the capacitive tube from the transmitter device to form a capacitive impedance between the pair of transmitter electrodes and the pair of receiver electrodes, wherein a power signal generated by the power driver is wirelessly transferred from the pair of transmitter electrodes to the pair of receiver electrodes to power the load when a frequency of the power signal substantially matches a series-resonance frequency of the first inductor and the capacitive impedance.
Certain embodiments disclosed herein also include a capacitive powering system constructed to enable wireless power transfers inside a tube-shaped structure. The system includes a receiver device including a pair of receiver electrodes connected to a load through an inductor, wherein the first inductor is coupled to the load to resonate the system; a capacitive tube including a pair of transmitter electrodes connected to a power driver, wherein the receiver device is clipped onto the capacitive tube; and an insulating layer to electrically insulate the capacitive tube from the receiver device for forming a capacitive impedance between the pair of transmitter electrodes and the pair of receiver electrodes, wherein a power signal generated by the power driver is wirelessly transferred from the pair of transmitter electrodes to the pair of receiver electrodes to power the load when a frequency of the power signal substantially matches a series-resonance frequency of the inductor and the capacitive impedance.
Certain embodiments disclosed herein also include a coupling tube for wireless coupling electric energy from a first section of a capacitive tube to a second section of the capacitive tube. The coupling tube a pair of conductive electrodes placed inside the coupling tube and covered by an insulating material, the coupling tube has a tube-shaped structure with an opening wider than a diameter of the capacitive tube, when the pair of conductive electrodes are placed in proximity over electrodes of the capacitive tube, capacitive impedance is created that at a series-resonance frequency allows wireless electric energy coupling between the first section and the second section of the capacitive tube, wherein the first section and the second section are detached sections of the capacitive tube.
The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.
It is important to note that the embodiments disclosed are only examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others. In general, unless otherwise indicated, singular elements may be in plural and vice versa with no loss of generality. In the drawings, like numerals refer to like parts through several views.
According to one embodiment, the capacitive tube 220 includes a load 221, which may be clipped into the capacitive tube 220 from the outside, while the device 210 is connected to a power driver 211. An arrangement of such a transmitter device 210 is shown in
In the embodiment illustrated in
The transmitter electrodes 213, 214 are attached on an insulating layer 230. The insulating layer 230 is a thin layer substrate material that can be of any insulating material, including for example, air, paper, wood, textile, glass, DI-water, and so on. In an embodiment, a material with dielectric permittivity is selected. The thickness of the insulating layer 230 is typically between 10 microns (e.g., a paint layer) and a few millimeters (e.g., a glass layer).
The capacitive tube 220, acting as a receiver, in the embodiment illustrated in the
The receiver electrodes (RX1, RX2) 223, 224 are placed inside the capacitive tube 220 and are covered with an insulating material. This structure is further illustrated in
The conductive material of each of the receiver electrodes 223, 224 may be, for example, carbon, aluminum, indium tin oxide (ITO), organic material, such as PEDOT, copper, silver, conducting paint, or any conductive material. Each of pair of transmitter electrodes 213, 214 can be of the same conductive material as the receiver electrodes, or made of different conductive material. In one embodiment, each of the receiver and transmitter electrodes is formed as a thin sheet of aluminum glue to the inside wall of the tube.
Referring back to
The driver 211 generates an AC signal of which amplitude, frequency, and waveform can be controlled. To allow the system to properly operate, the driver 211 outputs an AC power signal having a frequency as the series-resonance frequency of a circuit consisting of a series of capacitors (equivalent to the capacitive impedance) and the inductor 222. The impedances of such capacitors and the inductor cancel each other out at the resonance frequency, resulting in a low-ohmic circuit.
The amplitude of the AC power signal is the amplitude required to power the load 211. The power level of an AC power signal transferred to the load 211 can be changed by controlling the frequency, phase, or duty cycle of the signal output by the driver 211, thereby causing the signal to be different from the series-resonance frequency of the system. The maximum power transmission in the capacitive powering system 200 is achieved when the frequency of the AC signal is close to the series-resonance derived from the impedance values of the inductor 222 and capacitive impedance formed between the electrodes.
In one embodiment, the tube 220 may include multiple loads each being connected to a different pair of receiver electrodes and resonating at the same or a different series-resonance frequency. In this configuration, each load of the multiple of loads is powered by a power signal generated by the driver 211 and wirelessly transferred through the pair of transmitter electrodes in the device 210. According to an embodiment, the device 210 can control the functionally of the load 221. To this end, the driver 211 generates a control signal that is modulated on the AC power signal or detunes the frequency of the AC power signal from the series-resonance frequency of the system. For example, if the load 221 is a LED, then a control signal output by the driver 211 may be utilized for dimming or color setting of the LED. As another example, if the load 221 is a water valve, the control to the valve can be modulated on the AC power signal to control the opening of the valve. The control signal may be generated by a controller, a microprocessor, or any electronic circuit that can be configured to control or program the various functions of the load 221.
In an optional embodiment, the driver 211 is connected to an inductor 216 that can be utilized to adjust the series-resonance frequency the system 200. In this embodiment, the series-resonance frequency is determined by the inductors 216, 222 and the capacitive impedance. In another optional embodiment, the driver 210 may be connected to a controller 215 connected to the driver 211. The controller 215 may be utilized to generate a control signal for programming and controlling the functionality of the load 221 as discussed above.
Specifically, the capacitive tube 520 includes a power driver 521, which may be clipped onto the capacitive tube 520 from the outside. The capacitive tube 520 also includes a pair of transmitter (TX1, TX2) electrodes 523, 524. The connection between the transmitter electrodes 523, 524 and the driver 521 may be by means of a galvanic contact or a capacitive in-coupling. In one embodiment, the transmitter electrodes 523, 524 are formed inside of the tube as illustrated in
The receiver device 510 includes a load 511 and an inductor 512 connected to a pair of receiver electrodes (RX1, RX2) 513 and 514. The receiver electrodes 513, 514 are attached on an insulating layer 530. The insulating layer 530 is a thin layer of substrate material that can be of any insulating material that may be formed using any of the materials mentioned above. The load 511 may be a lighting element, a sensor, a controller, a water pump, a valve, and the like. The receiver electrodes 513 and 514 and transmitter electrodes 523, 524 may be formed using any of the conducting materials mentioned above. In one embodiment, each of the receiver and transmitter electrodes is formed as a thin sheet of aluminum.
In the arrangement illustrated in
The receivers and transmitter devices have been described above as each having a pair of electrodes. However, it should be noted that each of the receiver and transmitter devices can include any number of electrodes greater than 2.
In one embodiment, the coupling tube 700 is constructed to include a pair of conductive electrodes placed inside of the coupling tube and covered by an insulating material. For example, the conductive electrodes are formed as shown in
The coupling tube 700 also includes a pair of electrodes that when placed in proximity over the electrodes in the capacitive tube creates capacitive impedance that at the resonance frequency results in a low-ohmic circuit. Thus, electric energy can be wirelessly transferred from the electrodes of the capacitive tube at section 701 to the electrodes at section 702 through the electrodes of the coupling tube 700. The transmitter electrodes 510 and 520 may be formed using any of the conductive materials mentioned above. In an embodiment of the invention, the connection between the coupling tube 700 and sections 701 and 702 can be a galvanic contact.
The various embodiments described herein can be utilized in numerous partial applications. For example, a garden hose can be equipped with a clip-on light device that includes a LED. In this example, the garden hose is the capacitive tube having a power driver and the LED is the load clipped onto the hose. In another example, the clip-on device has a LED can be also placed on a vacuum cleaner hose that includes the power driver to light the vacuum cleaner foot.
Yet in another example, the capacitive power system discussed herein can be implemented in a greenhouse water pipe that includes several water valves. The power and control needed to operate the valves can be wirelessly provided to the valves using the capacitive tube. The driver (that may be connected to a controller) is connected in the driver in the water inlet and at the end of the pipe a clip-on device that controls the operation of the tube. As another example, a capacitive tube can be used that includes a central heating, ventilating and air conditioning (HVAC) sensor (i.e., a load) utilized in a HVAC system. For example, each room could be equipped with such a tube allowing the resident to control the temperature in the room based on the reading of the sensor.
Certain embodiments of the invention can be implemented as hardware, firmware, software or any combination thereof. Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage unit, a non-transitory computer readable medium, or a non-transitory machine-readable storage medium that can be in a form of a digital circuit, an analogy circuit, a magnetic medium, or combination thereof. The application program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (“CPUs”), a memory, and input/output interfaces. The computer platform may also include an operating system and microinstruction code. The various processes and functions described herein may be either part of the microinstruction code or part of the application program, or any combination thereof, which may be executed by a CPU, whether or not such computer or processor is explicitly shown. In addition, various other peripheral units may be connected to the computer platform such as an additional data storage unit and a printing unit.
While the present invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed with references to the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention. Furthermore, the foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalents thereto.
This application claims the benefit of U.S. provisional application No. 61/523,919 filed Aug. 16, 2011 and US provisional application No. 61/622,103 filed Apr. 10, 2012.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2012/054112 | 8/13/2012 | WO | 00 | 1/30/2014 |
| Number | Date | Country | |
|---|---|---|---|
| 61523919 | Aug 2011 | US | |
| 61622103 | Apr 2012 | US |
