JP2018522513A - Wireless battery charging system that maintains the desired voltage-current phase relationship by varying the frequency of the magnetic field - Google Patents

Abstract

The charging system (12) is configured to wirelessly charge an energy storage device (14), such as a battery (14). The charging system (12) includes an off-vehicle transducer (18) that is in electrical communication with an alternating current power source (48) and is electromagnetically coupled to an on-vehicle transducer (20) connected to an energy storage device (14). . The controller (53) adjusts the variable frequency oscillator (71) in the power transmitter (16), thereby changing the frequency of the supplied power. The charging system (12) communicates with the controller (53) and the off-vehicle transducer (18) and is configured to determine the phase difference between the AC voltage and the AC current supplied by the power source (48). (72) is further provided. The controller (53) is configured to adjust the variable frequency oscillator (71) based on the phase difference so that the frequency of the supplied power maintains the phase difference within a desired range.
[Selection] Figure 2

Description

  [0001] This application claims the benefit of priority under Section 8 of the US Patent Application No. 14 / 708,526 filed May 11, 2015, the entire disclosure of which is hereby incorporated by reference. Are hereby incorporated herein by reference.

  [0002] The present invention relates to a charging system used to wirelessly charge a vehicle battery, and more particularly configured to vary a magnetic field frequency to maintain a desired voltage-current phase relationship. The present invention relates to a wireless battery charging system.

  [0003] Wireless charging systems are well known that include an out-of-vehicle transducer and an in-vehicle transducer that are magnetically coupled and transmit electrical energy wirelessly across physical distances. Due to various loads, component tolerances, and temperatures, the resonant frequency for optimal magnetic coupling between the off-vehicle transducer and the on-vehicle transducer can vary. In order to maintain the highest level of efficiency, there is a need for a way to operate the charging system to maintain optimal magnetic coupling of the system. In addition, the interoperability of wireless charging systems with in-vehicle transducers with different resonant frequencies built by different vendors does not require that each vendor's in-vehicle transducer be used only with that vendor's wireless charging system. Need to be dealt with.

  [0004] According to one embodiment of the present invention, a charging system is provided. The charging system is configured to charge the energy storage device wirelessly. The charging system functions to regulate the variable frequency oscillator and a power transmitter including a variable frequency oscillator configured to supply power having alternating current, alternating voltage and frequency, and the power supplied thereby A power configured to be electromagnetically coupled to a frequency varying controller and an in-vehicle transducer in electrical communication with the energy storage device, thereby causing the in-vehicle transducer to capture power to charge the energy storage device An out-of-vehicle transducer in electrical communication with the transmitter and a phase detection circuit configured to communicate with the controller and the out-of-vehicle transducer and to determine a phase difference between the alternating voltage and the alternating current. The controller is configured to adjust the variable frequency oscillator based on the phase difference such that the frequency of the supplied power maintains the phase difference within a desired range.

[0005] The controller may be configured to adjust the variable frequency oscillator such that the frequency of the supplied power sweeps within a frequency range of 10 kilohertz (kHz) to 450 kHz.
[0006] The charging system may further comprise a wireless transmitter in electrical communication with the controller. In this case, the in-vehicle transducer is in electrical communication with a power detection circuit configured to determine the value of the captured power. The power detection circuit is in electrical communication with a wireless receiver configured to wirelessly transmit the captured power value to the controller via a wireless transmitter, and the controller is configured to transmit the captured power value. The power efficiency is determined by comparing the value with the value of the supplied power. The controller is configured to adjust the variable frequency oscillator based on the power efficiency such that the frequency of the supplied power maximizes the power efficiency.

  [0007] The in-vehicle transducer and the energy storage device may be located inside the vehicle. The off-vehicle transducer and power transmitter may be located outside the vehicle. Alternatively, the off-vehicle transducer and power transmitter can be located inside the vehicle.

  [0008] According to another embodiment of the present invention, a charging system is provided. The charging system is configured to charge the energy storage device wirelessly. The charging system functions to regulate the variable frequency oscillator and a power transmitter including a variable frequency oscillator configured to supply power having alternating current, alternating voltage and frequency, and the power supplied thereby A power configured to be electromagnetically coupled to a frequency varying controller and an in-vehicle transducer in electrical communication with the energy storage device, thereby causing the in-vehicle transducer to capture power to charge the energy storage device An out-of-vehicle transducer in electrical communication with the transmitter and a wireless transmitter in electrical communication with the controller. The onboard transducer is in electrical communication with a power detection circuit configured to determine the value of the captured power. The power detection circuit is in electrical communication with a wireless receiver configured to wirelessly transmit the captured power value to the controller via the wireless transmitter. The controller is configured to determine power efficiency by comparing the captured power value with the supplied power value. The controller is configured to adjust the variable frequency oscillator based on the power efficiency such that the frequency of the supplied power maximizes the power efficiency.

  [0009] The subject matter discussed in the background portion should not be considered as prior art merely as a result of that reference in the background portion. Similarly, problems referred to in the background portion or associated with the subject matter of the background portion should not be considered as previously recognized in the prior art. The subject matter of the background part only represents a different approach, and can themselves be an invention.

  [0010] The present invention will be further described with reference to the accompanying drawings.

[0011] FIG. 1 is a pictorial side view of a charging system including a variable frequency oscillator (VFO) circuit according to the present invention. [0012] FIG. 2 is a schematic diagram of the charging system shown in FIG. 1 positioned intermediate the battery and the on-vehicle transducer. [0013] FIG. 2 is a schematic diagram of the VFO circuit shown in FIG. [0014] FIG. 4 is a diagram illustrating the relationship between the voltage and current angular phase differences monitored by the VFO circuit shown in FIG. [0015] FIG. 5 is a schematic diagram of a VFO circuit of a charging system according to an alternative embodiment of the present invention.

  [0016] The resonant frequency of a wireless charging system may vary due to load variations, electrical component performance variations due to tolerance stackup, temperature variations, component placement and orientation variations. Resonant frequency mismatch can also occur when an out-of-vehicle transducer is frequency tuned for a particular vehicle-mounted transducer and then used with a different vehicle-mounted transducer that is not tuned to the same frequency or frequency range. This type of variation can undesirably reduce the power transfer efficiency of the wireless charging system. It has been found that power transfer efficiency can be effectively managed and controlled by adjusting the output frequency of the off-vehicle transducer with respect to the aforementioned variations.

  [0017] The output frequency of the power transmitter that supplies power to the off-vehicle transducer is determined by a variable frequency oscillator (VFO) circuit disposed within the power transmitter. Advantageously, the VFO circuit in the charging system adjusts the frequency of the magnetic energy generated by the off-vehicle transducer to more closely match the resonant frequency of the on-vehicle transducer. Advantageously, the VFO circuit allows for out-of-vehicle and in-vehicle transducer resonance frequencies to handle manufacturing tolerances, environmental conditions, and misalignment between the in-vehicle and in-vehicle transducers (misalignment, in other words, misalignment). Allows to be adjusted to. The VFO circuit also accommodates the difference in resonant frequency between an out-of-vehicle transducer and an in-vehicle transducer that is built with different manufacturing to different specifications.

  [0018] A non-limiting example of a wireless charging system 12 that implements features of the present invention is shown in FIGS. The wireless charging system 12 presented herein is configured to charge a battery 14 disposed in a vehicle 40. The vehicle 40 may be a hybrid vehicle or a hybrid electric vehicle, and the battery 14 may be configured to drive a propulsion system (not shown) of this vehicle. The wireless charging system 12 includes an AC power transmitter 16, an out-of-vehicle transducer 18, and an in-vehicle transducer 20. The power transmitter 16 further includes a variable frequency oscillator (VFO) circuit 24. The power transmitter 16 is disposed outside the vehicle 40. The off-vehicle transducer 18 is in electrical communication with the VFO circuit 24. The out-of-vehicle transducer 18 is preferably configured to be secured to the ground 22 such as a garage floor or parking lot surface. The on-vehicle transducer 20 is attached to the vehicle 40. The in-vehicle transducer 20 may be disposed on the chassis 26 of the vehicle 40.

  [0019] The off-vehicle transducer 18 is a source coil that generates a magnetic field that wirelessly transmits magnetic energy 44 to the in-vehicle transducer 20 when excited by electrical energy having alternating voltage and alternating current supplied by the power transmitter 16. (Not shown). When charging the battery 14, the in-vehicle transducer 20 is spaced from the out-of-vehicle transducer 18 and thus distances the out-of-vehicle transducer 18 from the in-vehicle transducer 20. The alternating magnetic field generated by the off-vehicle transducer 18 induces an alternating current having an alternating voltage in a capture coil (not shown). This captured electrical energy is used to charge the battery 14 of the vehicle 40.

  [0020] The efficiency of energy transfer of energy between the off-vehicle transducer 18 and the in-vehicle transducer 20 is the integrity of these transducers 18, 20 that allows energy to be transmitted wirelessly between them. Position). Such consistency of the transducers 18, 20 can be achieved when at least a portion of the in-vehicle transducer 20 overlies the off-vehicle transducer 18. Referring to FIG. 2, at least a part of the in-vehicle transducer 20 overlaps the outside-vehicle transducer 18. Alternatively, the in-vehicle transducer 20 may not overlap the out-of-vehicle transducer 18, but is still in close proximity to the in-vehicle transducer 20, resulting in wireless energy transfer.

  [0021] The power transmitter 16 is in electrical communication with the power supply 48. This power supply 48 can supply a voltage of 120 VAC or 240 VAC generally associated with the utility mains. The voltage of the power supply 48 may typically have an alternating frequency of 60 hertz (Hz) or 50 Hz, depending on the utility standard for the particular geographic location. Alternatively, the power supply 48 may have an operating voltage different from 120 VAC or 240 VAC, or an operating frequency different from 50 Hz or 60 Hz.

  [0022] The wireless charging system 12 is disposed within the vehicle 40 and is a controller / converter that provides current useful for charging the battery 14 in cooperation with the power transmitter 16, the off-vehicle transducer 18, and the on-vehicle transducer 20. A device 53 is further included. The converter portion of the controller / converter 53 comprises electrical components that form a rectifier circuit (not shown). This rectifier circuit is in electrical communication with the in-vehicle transducer 20 and converts the HV HF AC signal output by the in-vehicle transducer 20 into a more effective HV DC signal by charging the battery 14. The HV HF AC signal used in this specification is generated by the VFO circuit 24 and is input to the external transducer 18 by magnetic coupling between the external transducer 18 and the in-vehicle transducer 20, and is output from the in-vehicle transducer 20. Voltage, high frequency alternating current (AC) electrical signal. In the illustrated example, the voltage of the HV HF AC signal is greater than 120 VAC, and the frequency of the HV HF AC signal is greater than 60 hertz (Hz). The frequency may be in the range of 10 kHz to 450 kHz. For example, this range is the frequency typically used for tightly coupled resonators, generally in the range of 10 to 70 kHz, and the frequency typically used for loosely coupled resonators, generally in the range of 50 to 450 kHz. Can be covered. Further, the HV DC signal used in this specification is a high voltage, direct current (DC) electric signal, and the voltage and current do not change with time.

  [0023] The controller portion of the controller / converter 53 includes a central processing unit (not shown), which may be a microprocessor, application specific integrated circuit (ASIC), or discrete logic and timing. It may be constructed from a circuit (not shown). Software instructions for programming the controller portion may be stored in a non-volatile (NV) storage device (not shown). This NV storage device may be contained within a microprocessor or ASIC, or may be a separate device. Non-limiting examples of the types of NV memory that can be used include electrically erasable programmable read only memory (EEPROM), masked read only memory (ROM), and flash memory. The controller portion also provides a wired transceiver (such as a controller area network (CAN) transceiver) to allow the controller portion to establish electrical communication with other devices in the vehicle 40. (Not shown).

  [0024] As shown in FIG. 2, the charging system 12 includes a transmitter (not shown) located in the controller / converter 53 and a receiver (not shown) located in the power transmitter 16. These establish a wireless link 65 from the controller / converter 53 to the power transmitter 16. These transmitters and receivers may be configured as transceivers for establishing a return radio link 66 from the power transmitter 16 to the controller / converter 53.

  [0025] The controller portion measures voltage, current and power. The controller portion of the controller / converter 53 transmits the measured voltage, current and power data to the power transmitter 16 via the wireless link 65 so that the power transmitter 16 further includes the off-vehicle transducer 18. The amount of power supplied to the battery can be adjusted to ensure optimal charging system power efficiency. The optimal charging system power efficiency is preferably greater than 85%. Similarly, the power transmitter 16 can wirelessly transmit the supplied power data to the controller portion of the controller / converter 53 via the return wireless link 66. The controller / configuration described above in conjunction with other configurations herein is further described in US 2013/0015812 entitled “Charging System with Energy Coupling Device for Wireless Energy Transmission”. Which is incorporated herein by reference in its entirety.

  [0026] Referring now to FIG. 3, a block diagram of the VFO circuit 24 is shown. The VFO circuit 24 includes a voltage controlled oscillator (VCO) 71, an amplifier 70, a voltage monitoring circuit 73, a current monitoring circuit 74, and a phase detection circuit 72. VCO 71 is in electrical communication with the input of amplifier 70. A feedback loop is provided between the outside-vehicle transducer 18 and the VCO 71. The feedback loop includes a voltage monitoring circuit 73 and a current monitoring circuit 74 that are in electrical communication with the phase detection circuit 72. The voltage monitoring circuit 73 measures the voltage input to the external transducer 18 and the current monitoring circuit 74 measures the flow of current input to the external transducer 18. The phase detection circuit 72 is configured to measure the voltage and current phase difference at the input to the off-vehicle transducer 18. Phase detection circuit 72 is electrically coupled to VCO 71 that controls the frequency of the current supplied to output 67a.

  [0027] The phase detection circuit 72 is configured to determine whether the voltage and current are within a predetermined phase difference range. If the phase difference is not within the desired range, the voltage output of the phase detection circuit 72 will fluctuate, thereby increasing or decreasing the frequency of the VOC 71 and thus the VFO circuit 24 until the phase difference is within the desired range. . The output voltage and current are continuously monitored during the operation of the charging system 12, and the frequency is adjusted as necessary based on the phase difference. The power transmitter 16 then adjusts the frequency of power supplied to the off-vehicle transducer 18 to ensure that charging system power efficiency is maintained at a desired level. In one embodiment, the preferred charging system power efficiency is at least 85%. The operating frequency range of the VFO circuit 24 is preferably about 15 kHz to 200 kHz.

  [0028] Referring now to FIG. 4, a graph 69 illustrates the AC current flow measurement 77 and the AC voltage measurement 78 as a function of time at the outputs 67a, 67b of the VFO circuit 24 of the power transmitter 16. An example is shown. The AC current flow measurement 77 and the AC voltage measurement 78 are sinusoidal and they are out of phase by the amount represented by the angular phase difference, ie the phase difference Φ indicated by reference numeral 79 in the figure. To ensure optimal charging system power efficiency performance of the charging system 12, the energy between the off-board transducer 18 and the on-vehicle transducer 20 that is magnetically coupled with resonance, ie, sparsely (in other words, spaced apart). For transmission, the phase difference is preferably in the range of about 10 degrees to about 15 degrees, and for inductive or tightly coupled energy transfer, the phase difference is about 0 degrees to 2 degrees. The phase difference takes into account the effects of partial tolerance, temperature, and the consistency between the in-vehicle transducer 18 and the in-vehicle transducer 20.

  [0029] Therefore, the design of the charging system 12 including the VFO circuit 24 is such that the voltage and current waveforms ensure that the charging system power efficiency supplied to the battery 14 is at an optimal level. Decide if it is in. The phase difference is analyzed by the charging system 12, more specifically the controller of the VFO circuit 24, so that the optimum level of charging system power efficiency is maintained. After analyzing the voltage and current waveform input to the off-vehicle transducer 18, the controller outputs a voltage that functions to adjust the frequency of the VOC 71, and thus the output signal of the power transmitter 16 to the off-vehicle transducer 18. Maintains the desired charging system power efficiency. This further means that the phase difference between the voltage and current is about 15 degrees when the out-of-vehicle transducer 18 and the in-vehicle transducer 20 are loosely coupled, and zero when the out-of-vehicle transducer 18 and the in-vehicle transducer 20 are tightly coupled. Ensure that it is maintained at (0) degrees. Therefore, the charging system 12 uses the angular phase difference value to determine whether the transducers 18, 20 are loosely coupled or tightly coupled.

  [0030] The charging system 12 further uses the voltage and current data from the controller / converter 53 via the wireless link 65 to convert the power input to the off-vehicle transducer 18 to the power output by the in-vehicle transducer 20. Can be compared. The frequency of the VFO circuit 24 can be further adjusted to maximize system power efficiency in addition to or instead of adjusting the frequency to maintain the desired phase angle difference.

  [0031] As described earlier in this specification, the value of the angular phase difference is associated with a wireless transmission mechanism (ie, whether it is tightly coupled or loosely coupled) and corresponds to a predetermined frequency range. Note that it is predetermined to be in the range of. The charging system 12 sweeps the output frequency of the VFO circuit 24 over a wide range of frequencies, for example from about 15 kHz to 200 kHz, and then measures system power efficiency and phase difference as the output frequency is swept over that range, It may be configured to determine whether the transducers 18, 20 are tightly coupled or loosely coupled. Based on system efficiency and phase difference measurements, the charging system 12 can determine whether the transducers 18, 20 are tightly coupled or loosely coupled, and can set the operating frequency range and desired phase difference range accordingly. You can do it.

  [0032] Referring now to FIG. 5, an alternative VFO circuit 225 is shown. Elements similar to those shown in the VFO circuit 24 shown in FIG. 3 have reference numerals that differ by 200. Similar to the VFO circuit 24 described above, the VCO circuit 225 uses a voltage controlled oscillator (VCO) 271, an amplifier 270, a voltage monitoring circuit 273, a current monitoring circuit 274, and a phase detection circuit 272. Phase detection circuit 272 includes flip-flop circuit 287 and controller 288. The flip-flop circuit 287 provides the count number to the controller 288, which allows the controller 288 to determine the voltage supplied to the output 299 and control the frequency of the VCO 271. Resistors 281-284, 289 allow the electrical signal to be biased at an appropriate voltage level. Current monitoring circuit 274 is electrically connected to a sense coil 285 that provides a measurement of the current from the output of amplifier 270. VCO 271 is in electrical communication with the input of amplifier 270. The voltage signal is carried on signal paths 292, 293 and is received by voltage monitoring circuit 273. The current signal is carried on signal paths 290 and 291 and is received by the current monitoring circuit 274. The flip-flop circuit 287 receives the output 296 from the voltage monitoring circuit 273 and the output 297 from the current monitoring circuit 274. The output 298 of the flip-flop circuit 287 is received by the controller 288. VCO 271 receives output 299 from controller 288. For example, if a zero electrical pulse is output from the flip-flop to the controller 288, adjustment of the frequency of the VCO 271 is not necessary. If the number of pulses at the output of the flip-flop is greater than zero pulses due to feedback of the voltage monitoring circuit 273 and current monitoring circuit 274, a voltage adjustment to the VFO can occur in relation to the amount of feedback signal received.

  [0033] Alternatively, the phase detection circuit 72 of the VFO circuit 24 may comprise an embedded controller. Such a circuit implementation can, for example, omit other electrical blocks / electrical components within the VFO circuit 24, simplify circuit design and allow lower costs. Referring again to FIG. 3, the embedded functionality is enabled by using the embedded controller so that the voltage monitoring circuit 73, current monitoring circuit 74, phase detection circuit 72 and VCO 71 are not necessarily required. Similarly, referring again to FIG. 5, when an embedded controller is used, the voltage monitoring circuit 273, current monitoring circuit 274, flip-flop circuit 287, controller 288 and VCO 271 are not necessarily required.

  [0034] Turning now to FIG. 2, an extended charging system 12a is shown that further includes an integrated charger 60 and a changeover switch 57. The integrated charger 60 and the changeover switch 57 are disposed in the vehicle 40 and cooperate with the power transmitter 16, the external transducer 18, and the in-vehicle transducer 20 to supply current and charge the battery 14. The controller / converter 53, the integrated charger 60, and the changeover switch 57 include electrical components that form the electrical signal shaping device 45.

  [0035] The secondary charging system 62 (ie, the pre-charging system) is also in electrical communication with an integrated charger 60 located within the vehicle 40, and access to the wireless charging system 12 is not available. The battery 14 can be charged by supplying current. Advantageously, the secondary charging system 62 provides an alternative mode of charging the battery 14 for improved convenience.

  [0036] The changeover switch 57 is operatively controlled by the controller portion of the controller / converter 53 via the signal line 55 to switch between the secondary charging system 62 and the wireless charging system 12. The output 52 carries an electrical signal generated by the onboard transducer 20, which is received by the converter portion of the controller / converter 53. Output 56 carries an electrical signal from the converter portion of controller / converter 53, which is received by changeover switch 57. Output 58 carries an electrical signal from changeover switch 57 to battery 14. A communication data bus 54, such as a controller area network (CAN) bus, communicates with the controller portion of the controller / converter 53 to receive / transmit vehicle data information to / from the extended charging system 12a or the charging system. Data is received / transmitted to other electrical devices located in the vehicle 40.

  [0037] The wheels 51a, 51b, 51c, 51d of the vehicle 40 are used to support the consistency between the in-vehicle transducer 20 and the out-of-vehicle transducer 18. Consistency means 99, such as wheel stops 63, can further assist in this consistency between the in-vehicle transducer 18 and the in-vehicle transducer 20. The alignment device 64 can also assist in positioning the vehicle 40 so that the out-of-vehicle transducer 18 and the in-vehicle transducer 20 are properly aligned. Consistency between the out-of-vehicle transducer 18 and the in-vehicle transducer 20 is required to maximize energy transfer from the out-of-vehicle transducer 18 to the in-vehicle transducer 20. As shown in FIG. 2, the consistency between the in-vehicle transducer 18 and the in-vehicle transducer 20 is best seen when at least a portion of the in-vehicle transducer 20 overlies the out-of-vehicle transducer 18, as best shown in FIG. Can occur. Alternatively, the consistency between the out-of-vehicle transducer 18 and the in-vehicle transducer 20 is such that the out-of-vehicle transducer 18 and the in-vehicle transducer 20 are spaced sufficiently apart, but the energy of the battery 14 of the vehicle 40 is charged. This can occur when wireless transmissions can occur between them.

  [0038] The secondary charging system 62 generates an output 61 that carries the electrical signal received by the integrated charger 60, which generates an output 59 that carries the electrical signal received by the changeover switch 57. To do.

  [0039] Thus, a robust charging system 12 is presented that adjusts the operating frequency of the charging system 12 to optimize charging system power efficiency. In addition, the charging system 12 may be configured to wirelessly transmit magnetic energy beyond the distance between the in-vehicle transducer 18 and the in-vehicle transducer 20 that are tightly or loosely coupled. The VFO circuit 24 is used to effectively manage the frequency of the electrical signal so that the phase difference between the voltage and current supplied to the off-vehicle transducer 18 is maintained to optimize charging system power efficiency.

  [0040] Charging systems are typically composed of electrical components such as resistors, capacitors, repeaters, etc. that are commercially available in the electrotechnical field. The VCO 71 can be purchased as a commonly available component at the frequency of interest. The phase detection circuit 272 can be easily configured using the flip-flop circuit 287 and the controller 288.

  [0041] The charging system 12 can further determine the system power efficiency between the off-vehicle transducer 18 and the in-vehicle transducer 20, and further adjust the operating frequency to optimize the charging system power efficiency.

  [0042] While this invention has been described in terms of its preferred embodiments, it is not intended to be so limited, but rather is intended to be limited only to the scope described in the following claims. Also, the use of terms such as first, second, etc. does not imply any order of importance; rather, terms such as first, second, etc. are used to distinguish one element from another. Used for. Furthermore, the use of the terms a, an, etc. does not imply quantitative limitations, but rather means that there is at least one of those mentioned.

Claims (11)

A charging system (12) configured to wirelessly charge an energy storage device (14), the charging system (12) comprising:
A power transmitter (16) including a variable frequency oscillator (71) configured to supply power having alternating current, alternating voltage and frequency;
A controller (53) that functions to adjust the variable frequency oscillator (71), thereby changing the frequency of the supplied power;
An on-vehicle transducer (18) in electrical communication with the power transmitter (16), wherein the on-vehicle transducer (18) is in electrical communication with the energy storage device (14); Is configured to be electromagnetically coupled to the vehicle-mounted transducer (20) so that it can capture power for charging the energy storage device (14);
The charging system (12) also includes
A phase detection circuit (72) configured to communicate with the controller (53) and the off-vehicle transducer (18) and configured to determine a phase difference between the alternating voltage and the alternating current;
The controller (53) is configured to adjust the variable frequency oscillator (71) based on the phase difference so that the frequency of the supplied power maintains the phase difference within a desired range. Charging system (12). The charging system (12) according to claim 1, wherein
A charging system configured to adjust the variable frequency oscillator (71) so that the controller (53) sweeps the frequency of the supplied power within a frequency range of 10 kilohertz (kHz) to 450 kHz. . The charging system (12) according to claim 1, wherein
A wireless transmitter (65) in electrical communication with the controller (53);
The onboard transducer (20) is in electrical communication with a power detection circuit (24) configured to determine the value of the captured power;
The power detection circuit (24) is configured to wirelessly send the value of the captured power to the controller (53) via the wireless transmitter (65); Communicate electrically,
The charging system, wherein the controller (53) is configured to determine power efficiency by comparing the value of the captured power with the value of the supplied power. The charging system (12) according to claim 3,
A charging system wherein the controller (53) is configured to adjust the variable frequency oscillator (71) based on the power efficiency such that the frequency of the supplied power maximizes the power efficiency . In system charging (12) according to claim 1,
A charging system wherein the desired range of the phase difference is between 10 degrees and 21 degrees. The charging system (12) according to claim 5,
A charging system wherein the desired range of the phase difference is between 10 degrees and 15 degrees. The charging system (12) according to claim 6,
A charging system wherein the desired range of the phase difference is between 0 degrees and 10 degrees. Charging system (12) according to claim 7,
A charging system in which the phase difference is about 0 degrees. The charging system (12) according to claim 1, wherein
A charging system in which the in-vehicle transducer (20) and the energy storage device (14) are arranged inside a vehicle (40). Charging system (12) according to claim 9,
A charging system in which the vehicle exterior transducer (18) and the power transmitter (16) are arranged outside the vehicle (40). A charging system (12) configured to wirelessly charge an energy storage device (14), comprising:
A power transmitter (16) including a variable frequency oscillator (71) configured to supply power having alternating current, alternating voltage and frequency;
A controller (53) that functions to adjust the variable frequency oscillator (71), thereby changing the frequency of the supplied power;
An on-vehicle transducer (18) in electrical communication with the power transmitter (16), wherein the on-vehicle transducer (18) is in electrical communication with the energy storage device (14); Is configured to be electromagnetically coupled to the vehicle-mounted transducer (20) so that it can capture power for charging the energy storage device (14);
The charging system (12) also includes
A wireless transmitter (65) in electrical communication with the controller (53);
The onboard transducer (20) is in electrical communication with a power detection circuit (24) configured to determine the value of the captured power;
The power detection circuit (24) is configured to wirelessly send the value of the captured power to the controller (53) via the wireless transmitter (65); Communicate electrically,
The controller (53) is configured to determine power efficiency by comparing the value of the captured power with the value of the supplied power;
The controller (53) is configured to adjust the variable frequency oscillator (71) based on the power efficiency such that the frequency of the supplied power maximizes the power efficiency (12).

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