Power transmitter for dynamic inductive charging for electric vehicle

Abstract

A power-transmitter control unit (70) includes determination circuits (83A, 83B) which receive an output signal from a power-transmitter communication coil (40) and determine whether there is a power supply request based on the output signal, and a power-transmitter controller (71) which controls energization of a power transmitter coil based on determination results in order to wirelessly supply power to a power receiver coil of a vehicle. The power-transmitter controller energizes the power transmitter coil on condition that the determination results indicating that there is a power supply request are input from the determination circuits.

Description

POWER TRANSMITTER FOR DYNAMIC INDUCTIVE CHARGING FOR ELECTRIC VEHICLECross Reference

[0001] This application is based on Japanese Patent Application No. 2024-208013 filed on November 29, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power transmitter.

[0003] Patent Literature 1 discloses a system for executing wireless power transfer from a ground-based power transmitter to a power receiver installed in an electric vehicle. The power transmitter includes a power transmitter coil and a controller that energizes the power transmitter coil. The power receiver includes a power receiver coil that is supplied with power wirelessly from the power transmitter coil.

[0004] The power transmitter and the power receiver include communication coils for narrow area wireless communication. The power receiver supplies a signal, which indicates a power supply request to the power transmitter coil, to the communication coil of the power receiver. The power transmitter determines whether there is a power supply request based on an output signal from the communication coil of the power transmitter. When the power transmitter determines that there is a power supply request, the power transmitter energizes the power transmitter coil.

[0005] JP2024-008088A

[0006] An abnormality may occur in the signal indicating the result of the determination whether there is a power supply request. In this case, the power transmitter coil may be energized even when there is no power supply request. Such a problem may also occur when the power transmitter is a vehicle-side device and the power receiver is a ground-side device.

[0007] It is a main object of the present disclosure to provide a power transmitter capable of reducing an occurrence of a situation in which a power transmitting antenna is energized even when there is no power supply request.

[0008] According to an aspect of the present disclosure, a power transmitter is applied to a wireless power transfer system. The system includes a ground-side device and a vehicle-side device. One of the ground-side device and the vehicle-side device is the power transmitter having a power transmitting antenna. The other of the ground-side device and the vehicle-side device is a power receiver having a power receiving antenna. The power receiver is configured to transmit a power supply request signal for a power supply request to the power transmitter. The power transmitter is configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal. The power transmitter includes a power-transmitter communication antenna and a power-transmitter control unit. The power-transmitter communication antenna is configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna of the power receiver. The power-transmitter control unit includes a determination unit and a power-transmitter controller. The determination unit is configured to determine whether there is the power supply request based on an output signal of the power-transmitter communication antenna. The power-transmitter controller is configured to control energization of the power transmitting antenna to perform wireless power transfer to the power receiving antenna based on a determination result of the determination unit. The determination unit of the power-transmitter control unit is one of determination units. The power-transmitter control unit is configured to receive a determination result of each of the determination units by the power-transmitter controller. The power-transmitter controller is configured to energize the power transmitting antenna on condition that the determination result indicating that there is a power supply request is input from each of the determination units.

[0009] As a result, the power transmitting antenna is not energized, even if an abnormality occurs where one of the determination results of the determination units indicates that there is a power supply request when there is no power supply request. This can prevent an occurrence of a situation in which the power transmitting antenna is energized even though there is no power supply request. As a result, for example, unnecessary power consumption can be reduced.

[0010] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.FIG. 1 is an overall configuration diagram of a wireless power transfer system according to a first embodiment.FIG. 2 is an overall configuration diagram of the wireless power transfer system.FIG. 3 is a diagram illustrating a power transmitter and a power receiver.FIG. 4 is a diagram showing a power-receiver control unit and its peripheral configuration.FIG. 5 is a diagram showing the power-transmitter control unit and its peripheral configuration.FIG. 6 is a flowchart illustrating a procedure of an energization control process for a power transmitter coil.FIG. 7 is a flowchart illustrating a procedure of an energization control process for a power transmitter coil, according to a modification of the first embodiment.FIG. 8 is a diagram illustrating a power-transmitter control unit and its peripheral configuration, according to a second embodiment.FIG. 9 is a diagram illustrating an arrangement of the power transmitter coil and a power-transmitter communication coil.FIG. 10 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil according to a third embodiment.FIG. 11 is a diagram illustrating an arrangement of the power transmitter coil and the power-transmitter communication coil.FIG. 12 is a diagram illustrating a power-transmitter control unit and its peripheral configuration, according to a fourth embodiment.FIG. 13 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil.FIG. 14 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil according to a fifth embodiment.FIG. 15 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil according to a sixth embodiment.FIG. 16 is a diagram illustrating an arrangement of the power transmitter coil and the power-transmitter communication coil.FIG. 17 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil according to a modification of the sixth embodiment.FIG. 18 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil according to a modification of the sixth embodiment.FIG. 19 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil according to a seventh embodiment.FIG. 20 is a diagram illustrating an arrangement of a power transmitter coil and a power-transmitter communication coil according to a modification of the seventh embodiment.FIG. 21 is a diagram illustrating a power-transmitter control unit and its peripheral configuration, according to an eighth embodiment.FIG. 22 is a flowchart illustrating a procedure a diagnostic process for a communication function.

[0011] Multiple embodiments will be described with reference to the drawings. In the embodiments, parts that functionally and / or structurally correspond to or are associated with each other may be assigned the same reference numeral, or reference numerals different in digit in the hundreds or higher place. The corresponding and / or associated parts may refer to the explanation in the other embodiments.

[0012] First EmbodimentA first embodiment of a wireless power transfer system of the present disclosure will be described below with reference to the drawings.

[0013] First, an overall configuration of the wireless power transfer system will be described. As shown in FIGS. 1, 2, and 3, the wireless power transfer system 10 includes a power transmitter 20 and a power receiver 100. The power receiver 100 is mounted on a vehicle 11 as a moving object that travels on a road RS, and is a vehicle-side device. The vehicle 11 is, for example, an electric automobile or a hybrid vehicle. The power is supplied from the power transmitter 20 to the power receiver 100 while the vehicle 11 is travelling or stopped. The wireless power transfer system 10 executes wireless power transfer from the power transmitter 20 to the power receiver 100 through magnetic field resonance coupling (magnetic field resonance). The wireless power transfer system 10 is also referred to as a dynamic wireless power transfer (D-WPT) system.

[0014] The power transmitter 20 is a ground-side device and has a power-transmitter coil unit 21 and a power-transmitter power supply unit 51 that supplies power to the power-transmitter coil unit 21. The power transmitter 20 is, for example, a stationary device. The power-transmitter coil unit 21 is installed (for example, buried) in the road RS, a parking lot, or the like. The power-transmitter power supply unit 51 is installed, for example, on the side of the road RS. The power-transmitter coil unit 21 is connected to the power-transmitter power supply unit 51. The power-transmitter power supply unit 51 is connected to an AC power source 15 and supplies AC (alternating-current) power from the AC power source 15 to the power-transmitter coil unit 21. The AC power source 15 is, for example, a commercial power source. Multiple power-transmitter coil units 21 are arranged along the lanes of the road RS. FIG. 2 shows an example of four power-transmitter coil units 21 aligned along the road RS and connected to one power-transmitter power supply unit 51. In other words, one power-transmitter power supply unit 51 is provided for each of the four power-transmitter coil units 21.

[0015] The configuration is not limited to one power-transmitter power supply unit 51 for each of the multiple power-transmitter coil units 21, but one power-transmitter power supply unit 51 may be provided for each power-transmitter coil unit 21.

[0016] The power-transmitter power supply unit 51 includes a PFC (Power Factor Correction) circuit 61, an inverter 60, and a filter circuit 52. The PFC circuit 61 includes an AC / DC converter and is connected to the AC power source 15. The PFC circuit 61 includes switching elements (e.g., IGBTs or MOSFETs) that are switched and controlled to convert the input AC power to DC (direct current) power and improve a power factor of the AC power input from the AC power source 15. IGBT is an abbreviation of Insulated Gate Bipolar Transistor. MOSFET is an abbreviation of Metal-Oxide-Semiconductor Field-Effect Transistor.

[0017] The inverter 60 is connected to the PFC circuit 61. The inverter 60 includes switching elements (e.g., IGBTs or MOSFETs) that are switched and controlled to convert the DC power input from the PFC circuit 61 to AC power.

[0018] The filter circuit 52 removes noise contained in the AC current input from the inverter 60 and supplies the AC current from which noise has been removed to the power-transmitter coil unit 21. The filter circuit 52 is, for example, an LC filter that includes a coil and a capacitor. Circuits having various configurations can be used as the filter circuit 52, and, for example, a T-type filter circuit is used as the filter circuit 52.

[0019] The power-transmitter coil unit 21 includes a power transmitter coil 22 (corresponding to "power transmitting antenna"), a power-transmitter resonant circuit 30, and a power-transmitter communication coil 40 (corresponding to "power-transmitter communication antenna"). The power-transmitter resonant circuit 30 supplies the AC power supplied by the filter circuit 52 to the power transmitter coil 22. The power-transmitter resonant circuit 30 can employ various well-known resonant circuits such as a circuit including a resonant capacitor.

[0020] The power receiver 100 includes a power-receiver coil unit 101 and a power-receiver power supply unit 181. The power-receiver coil unit 101 includes a power receiver coil 102 (corresponding to a "power receiving antenna"). The power-receiver coil unit 101 is located at the bottom of the vehicle body of the vehicle 11. The power-receiver coil unit 101 is located at the bottom of the vehicle body to face the ground surface. When the vehicle 11 travels on the road RS where the power transmitter coil 22 is buried, the power transmitter coil 22 on the ground side and the power receiver coil 102 of the vehicle 11 face each other in the vertical direction.

[0021] The power receiver 100 includes a power-receiver resonant circuit 140. The power receiver coil 102 is connected to the power-receiver resonant circuit 140. The power receiver coil 102 is supplied with power from the power transmitter coil 22. The power receiver coil 102 supplies the received power to the power-receiver resonant circuit 140. The power-receiver resonant circuit 140 can employ various well-known resonant circuits such as a circuit including a resonant capacitor.

[0022] The power receiver 100 includes a filter circuit 182, a rectifier circuit 200 that functions as a DC-AC conversion circuit, and a smoothing capacitor 210. The filter circuit 182 removes noise contained in the AC current input from the power-receiver resonant circuit 140 and supplies the AC current from which noise has been removed to the rectifier circuit 200. The filter circuit 182 of the present embodiment is, for example, an LC filter that includes reactor and a capacitor.

[0023] The rectifier circuit 200 converts the input AC current into a DC current and outputs the DC current. The rectifier circuit 200 is, for example, a full-bridge circuit including semiconductor switching elements, or a diode rectifier circuit. A first end of the smoothing capacitor 210 is connected to a high potential side output terminal of the rectifier circuit 200. A second end of the smoothing capacitor 210 is connected to a low potential side output terminal of the rectifier circuit 200. The rectifier circuit 200 is also referred to as an ERB (Electronic Rectification Box).

[0024] The vehicle 11 includes a high potential main switch 301H, a low potential main switch 301L, and a high-voltage storage battery 300 as a power storage unit. The high potential main switch 301H and the low potential main switch 301L are, for example, relays (specifically, mechanical relays). The high potential side output terminal of the rectifier circuit 200 is connected to a positive terminal of the high-voltage storage battery 300 via the high potential main switch 301H. The low potential side output terminal of the rectifier circuit 200 is connected to a negative terminal of the high-voltage storage battery 300 via the low potential main switch 301L. The high-voltage storage battery 300 is a secondary battery that can be charged and discharged and has a rated voltage of several hundred volts, for example. The high-voltage storage battery 300 is, for example, a lithium-ion storage battery or a nickel-metal hydride storage battery.

[0025] The vehicle 11 includes a travelling inverter 310 and a rotary electric machine 320. The travelling inverter 310 is a 3-phase inverter and is connected to the high-voltage storage battery 300 via the high potential main switch 301H and the low potential main switch 301L. The armature windings of the rotary electric machine 320 are connected to the upper and lower arm switches that constitute the travelling inverter 310. By switching control of the upper and lower arm switches of the travelling inverter 310 while the high potential main switch 301H and the low potential main switch 301L are turned on, the travelling inverter 310 converts the DC power supplied from the high-voltage storage battery 300 into AC power and supplies it to the armature winding. This causes the rotor of the rotary electric machine 320 to rotate, and the rotational power of the rotor rotates drive wheels of the vehicle 11. As a result, the vehicle 11 travels.

[0026] As shown in FIG. 3, the power-transmitter power supply unit 51, which constitutes the power transmitter 20, includes a power-transmitter control unit 70. As shown in FIG. 5, the power-transmitter control unit 70 includes a power-transmitter controller 71. The power-transmitter controller 71 is an electronic control unit (ECU) that executes various controls of the power transmitters 20 and includes a processor as hardware, a storage unit, and a communication bus connecting the processor and storage unit.

[0027] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the power-transmitter controller 71. The memory, for example, provides the processor with a work area for temporary use when the processor performs processing. The memory includes, for example, RAM and ROM. The storage is a storage device that stores various programs and data to be read and executed by the processor and is a non-transitory tangible storage medium. The storage includes, for example, HDD or flash memory. The storage contains program information and other information for the processes described below.

[0028] The power-receiver power supply unit 181, which constitutes the power receiver 100, includes a power-receiver controller 231. The power-receiver controller 231 is an ECU that executes various controls of the power receiver 100, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and storage unit.

[0029] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the power-receiver controller 231. The memory, for example, provides the processor with a work area for temporary use when the processor performs processing. The memory includes, for example, RAM and ROM. The storage is a storage device that stores various programs and data to be read and executed by the processor and is a non-transitory tangible storage medium. The storage includes, for example, HDD or flash memory. The storage contains program information and other information for the processes described below.

[0030] For example, the program information stored on the non-transitory tangible storage medium is installed in the storage units of the power-receiver controller 231 and power-transmitter controller 71. The storage medium is, for example, a USB memory, CD-ROM or DVD. In addition, the program information transmitted over a communication network, such as OTA (Over The Air), for example, is installed in the storage unit.

[0031] The power-transmitter controller 71 executes a switching control of the PFC circuit 61 and a switching control of the inverter 60. Through the switching control of the inverter 60, a high-frequency AC voltage is applied to the power transmitter coil 22. This causes a high-frequency current to flow in the power transmitter coils 22 and a magnetic field for power transmission is generated in the power transmitter coils 22.

[0032] In this embodiment, the power-transmitter controller 71 switches and controls the inverter 60 so that the frequency of the high-frequency voltage applied to the power transmitter coil 22 is becomes a first specified frequency between 10 kHz and 100 GHz, specifically, 85 kHz. The resonant frequencies of the power-transmitter resonant circuit 30 and the power-receiver resonant circuit 140 are set at the same frequency or close to the first specified frequency.

[0033] When the magnetic field generated in the power transmitter coil 22 links with the power receiver coil 102 of the vehicle 11, a high-frequency current flows in the power receiver coil 102, varying with the frequency of the high-frequency current flowing in the power transmitter coil 22. The high-frequency current flowing in the power receiver coil 102 is supplied to the rectifier circuit 200 through the power-receiver resonant circuit 140 and the filter circuit 182. The rectifier circuit 200 converts the supplied AC current into a DC current and outputs the DC current. While the high potential main switch 301H and the low potential main switch 301L are turned on, the output current of the rectifier circuit 200 is supplied to the high-voltage storage battery 300 and the travelling inverter 310.

[0034] The vehicle 11 includes a low-voltage storage battery 302. The rated voltage of the low-voltage storage battery 302 is lower than the rated voltage of the high-voltage storage battery 300. The low-voltage storage battery 302 is, for example, a lead-acid battery. The power supplied from the low-voltage storage battery 302 to the power-receiver controller 231 enables the power-receiver controller 231 to operate.

[0035] The power receiver 100 and the power transmitter 20 each have a configuration for communication between the power receiver 100 and the power transmitter 20. In detail, the power-receiver coil unit 101, which constitutes the power receiver 100, includes a power-receiver communication coil 170 (corresponding to a power-receiver communication antenna). A power-receiver control unit 230 includes a signal transmitter 240.

[0036] The power-transmitter coil unit 21, which constitutes the power transmitter 20, includes the power-transmitter communication coil 40. The power-transmitter control unit 70 includes a signal receiver 80. The power-receiver communication coil 170 and the power-transmitter communication coil 40 are communication coils for narrow area wireless communication. Narrow area wireless communications are those with a communication distance of less than 10 meters (e.g., a maximum of 3 meters). Narrow area wireless communication is a communication with a shorter communication distance than wide area wireless communication.

[0037] Various short-range wireless communications can be used as the narrow area wireless communication. For example, communications compliant with any communication standards established by IEEE, ISO, and IEC can be used. Specifically, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), RFID (Radio Frequency Identification), or DSRC (Dedicated Short Range Communication) can used as the narrow area wireless communication.

[0038] The signal transmitter 240 is connected to the power-receiver controller 231. The signal transmitter 240 is connected to the power-receiver communication coil 170. The power-receiver controller 231 controls the signal transmitter 240 to supply a power supply request signal COMM to the power-receiver communication coil 170. The power supply request signal COMM is a signal requesting the power transmitter coil 22 near the vehicle 11 to transmit power to the power receiver coil 102.

[0039] The power-receiver control unit 230 controls the signal transmitter 240 to supply information including a power supply request signal COMM in one frame to the power-receiver communication coil 170. In this embodiment, the power supply request signal includes ID information of the vehicle 11 and a requested power Weq that is a requested value of power to be supplied to the vehicle 11. This control causes a high-frequency voltage to be applied from the signal transmitter 240 to the power-receiver communication coil 170. Consequently, a high-frequency current flows in the power-receiver communication coil 170, and a magnetic field for information communication is generated in the power-receiver communication coil 170.

[0040] When the power-receiver coil unit 101 of the vehicle 11 approaches the power-transmitter coil unit 21 on the ground side, the generated magnetic field links to the power-transmitter communication coil 40, and a high-frequency current flows through the power-transmitter communication coil 40. This high frequency current is input to the signal receiver 80 shown in FIG. 5. The signal receiver 80 recognizes the presence or absence of a power supply request and ID information based on the input signal from the power-transmitter communication coil 40. The signal receiver 80 also acquires the requested power Weq for the vehicle 11 with the recognized ID information, based on the signal from the power-transmitter communication coil 40. The information recognized by the signal receiver 80 and the requested power Weq are input to the power-transmitter controller 71.

[0041] In this embodiment, the power-receiver controller 231 controls the signal transmitter 240 so that the frequency of the high-frequency voltage applied to the power-receiver communication coil 170 becomes a second specified frequency between 10 kHz and 100 GHz. In this embodiment, the second specified frequency is a frequency that deviates from the first specified frequency above, specifically a frequency higher than the first specified frequency (e.g., 13.56 MHz).

[0042] The power-transmitter controller 71 determines whether to energize the power transmitter coil 22 based on the input signal from the signal receiver 80. In detail, when the power-transmitter controller 71 determines that there is a power supply request based on the input signal from the signal receiver 80, the power-transmitter controller 71 applies high-frequency voltage to the power transmitter coil 22 by controlling the inverter 60 and the PFC circuit 61. This results in a wireless power transfer from the power transmitter coil 22 to the power receiver coil 102.

[0043] The signal transmitter 240 and its peripheral configuration will be described with reference to FIG. 4.

[0044] The signal transmitter 240 includes a generating circuit 241, and a power-receiver amplifier 242. The generating circuit 241 is connected to the power-receiver controller 231 and the power-receiver amplifier 242. The generating circuit 241 generates a high-frequency signal as a power supply request signal based on a command from the power-receiver controller 231. The frequency of this high-frequency signal is the second specified frequency. The power-receiver amplifier 242 amplifies the high-frequency signal generated by the generating circuit 241 and supplies the amplified signal to the power-receiver communication coil 170.

[0045] The power-receiver controller 231 instructs the generating circuit 241 to generate a high-frequency signal as the power supply request signal. The high-frequency signal output from the generating circuit 241 is amplified by the power-receiver amplifier 242. The amplified signal is supplied to the power-receiver communication coil 170 as the power supply request signal.

[0046] The signal receiver 80 and its peripheral configuration will be described with reference to FIG. 5.

[0047] The signal receiver 80 includes a power-transmitter amplifier 81. The power-transmitter amplifier 81 amplifies a high-frequency signal (high-frequency current signal or high-frequency voltage signal) output from the power-transmitter communication coil 40. The high-frequency signal output from the power-transmitter communication coil 40 contains a frequency component that fluctuates at the second specified frequency.

[0048] The signal receiver 80 includes multiple pairs of detection circuits and determination circuits. In the present embodiment, the signal receiver 80 includes two pairs. In detail, the signal receiver 80 includes a first detection circuit 82A, a first determination circuit 83A, a second detection circuit 82B, and a second determination circuit 83B. In this embodiment, the first determination circuit 83A and the second determination circuit 83B correspond to a "determination unit."

[0049] The output signal of the power-transmitter amplifier 81 is input to the first detection circuit 82A. The first detection circuit 82A detects the high-frequency signal input from the power-transmitter amplifier 81, and calculates a first intensity Intd1 which is an amplitude or effective value of the input high-frequency signal. The calculated first intensity Intd1 is input to the first determination circuit 83A.

[0050] The first determination circuit 83A determines whether there is a power supply request to the power transmitter coil 22 based on the input first intensity Intd1. Specifically, when determining that the first intensity Intd1 exceeds a determination threshold Ijde, the first determination circuit 83A determines that there is a power supply request. On the other hand, when determining that the first intensity Intd1 is lower than the determination threshold Ijde, the first determination circuit 83A determines that there is no power supply request. The determination result information of the first determination circuit 83A is input to the power-transmitter controller 71.

[0051] The output signal of the power-transmitter amplifier 81 is input to the second detection circuit 82B, similarly to the first detection circuit 82A. The second detection circuit 82B detects the high-frequency signal input from the power-transmitter amplifier 81, and calculates a second intensity Intd2 which is an amplitude or effective value of the input high-frequency signal. The calculated second intensity Intd2 is input to the second determination circuit 83B.

[0052] The second determination circuit 83B determines whether there is a power supply request to the power transmitter coil 22 based on the input second intensity Intd2. Specifically, when determining that the second intensity Intd2 exceeds a determination threshold Ijde, the second determination circuit 83B determines that there is a power supply request. On the other hand, when determining that the second intensity Intd2 is lower than the determination threshold Ijde, the second determination circuit 83B determines that there is no power supply request. The determination result information of the second determination circuit 83B is input to the power-transmitter controller 71.

[0053] The power-transmitter controller 71 switches between executing and stopping the switching control of the PFC circuit 61 and the inverter 60 based on the two pieces of input determination result information. When the switching control of the PFC circuit 61 and the inverter 60 is executed, a high-frequency voltage is applied to the power transmitter coil 22. This causes a high-frequency current to flow through the power transmitter coil 22. In this case, wireless power transfer from the power transmitter coil 22 to the power receiver coil 102 that faces the power transmitter coil 22 in the vertical direction is performed.

[0054] An abnormality may occur in the signal indicating the result of the determination whether there is a power supply request. In this case, the power transmitter coil 22 may be energized even when there is no power supply request. As a result, there unnecessary power consumption may occur and leakage magnetic fields may increase. In order to deal with such a problem, two pieces of determination result information are input to the power-transmitter controller 71.

[0055] FIG. 6 is a flowchart illustrating a procedure of an energization control process for the power transmitter coil 22 executed by the power-transmitter controller 71.

[0056] In step S10, information on the determination results of both the first determination circuit 83A and the second determination circuit 83B is acquired.

[0057] In step S11, it is determined whether the determination results of both the first determination circuit 83A and the second determination circuit 83B indicate presence of a power supply request, based on the information acquired in step S10.

[0058] When it is determined that both determination results indicate that there is a power supply request, the process proceeds to step S12, where the switching control of the inverter 60 and the PFC circuit 61 is executed to energize the power transmitter coil 22. In addition, when it is determined that both determination results indicate that there is a power supply request, the power-transmitter controller 71 actually performs a coupling determination process prior to executing the switching control of the inverter 60 and the PFC circuit 61 to determine whether the degree of magnetic coupling between the power receiver coil 102 and the power transmitter coil 22 is appropriate for power transmission. The power-transmitter controller 71 executes the switching control of the inverter 60 and the PFC circuit 61 on condition that the power-transmitter controller 71 has determined that the degree of magnetic coupling between the power receiver coil 102 and the power transmitter coil 22 is appropriate. As a result, the power transmitter coil 22 is energized while the power receiver coil 102 and the power transmitter coil 22 are in close proximity to each other.

[0059] On the other hand, when the result of the determination by either one of the first determination circuit 83A and the second determination circuit 83B is that there is no power supply request, or when the result of the determination by both of the first determination circuit 83A and the second determination circuit 83B is that there is no power supply request, the process proceeds to step S13. In step S13, the switching control of the inverter 60 and the PFC circuit 61 is stopped to stop energization of the power transmitter coil 22.

[0060] As described above, in this embodiment, two determination results are used to determine whether to energize the power transmitter coil 22. As a result, the power transmitter coil 22 is not energized, even if an abnormality occurs where one of the determination results of the determination circuits 83A, 83B indicates that there is a power supply request when there is no power supply request. This can prevent an occurrence of a situation in which the power transmitter coil 22 is energized even though there is no power supply request.

[0061] Modification of First EmbodimentEach of the determination circuits 83A, 83B may determine that there is a power supply request based on determination that the requested power Weq or ID information has been input, instead of the intensity of the high-frequency signal. Each of the detection circuits 82A, 82B extracts the requested power Weq and the ID information based on the high-frequency signal input from the power-transmitter amplifier 81.

[0062] The power-transmitter controller 71 may acquire information on the requested power Weq input via each determination circuit 83A, 83B. When the power-transmitter controller 71 determines that the two acquired requested powers Weq are different, the power-transmitter controller 71 may perform a process to stop energization of the power transmitter coil 22. FIG. 7 is a flowchart showing this process.

[0063] In step S20, the two requested powers Weq are acquired. In step S21, it is determined whether the two acquired requested powers Weq are different. When it is determined that the two requested powers Weq are the same, the process proceeds to step S22, where the switching control of the inverter 60 and the PFC circuit 61 is performed to energize the power transmitter coil 22. On the other hand, when it is determined that the two requested powers Weq are different (for example, one is 10 kW and the other is 3 kW), the process proceeds to step S23, and the switching control of the inverter 60 and the PFC circuit 61 is stopped to stop energization of the power transmitter coil 22. Accordingly, erroneous detection of the requested power Weq of the vehicle 11 can be prevented.

[0064] In steps S20 and S21, vehicle ID information may be used instead of the requested power Weq.

[0065] Second EmbodimentA second embodiment will be described below with reference to the drawings mainly in terms of differences from the first embodiment. In this embodiment, as shown in FIG. 8, a power-transmitter communication coil is provided individually corresponding to each determination circuit.

[0066] The power transmitter 20 includes a first communication coil 40A and a second communication coil 40B as power-transmitter communication coils. The first communication coil 40A and the second communication coil 40B are provided in a common power-transmitter coil unit 21.

[0067] The signal receiver 80 includes a first power-transmitter amplifier 81A and a second power-transmitter amplifier 81B. The first power-transmitter amplifier 81A and the first communication coil 40A correspond to the first determination circuit 83A, and the second power-transmitter amplifier 81B and the second communication coil 40B correspond to the second determination circuit 83B.

[0068] The first power-transmitter amplifier 81A amplifies a high-frequency signal (high-frequency current signal or high-frequency voltage signal) output from the first communication coil 40A. The high-frequency signal output from the first communication coil 40A contains a frequency component that fluctuates at the second specified frequency. The output signal of a first power-transmitter amplifier 81A is input to the first detection circuit 82A.

[0069] The second power-transmitter amplifier 81B amplifies a high-frequency signal (high-frequency current signal or high-frequency voltage signal) output from the second communication coil 40B. The high-frequency signal output from the second communication coil 40B contains a frequency component that fluctuates at the second specified frequency. The output signal of the second power-transmitter amplifier 81B is input to the second detection circuit 82B.

[0070] Even when there is no power supply request from the vehicle 11, noise may be superimposed on either the first communication coil 40A or the second communication coil 40B. Furthermore, noise may be superimposed on the output signal of either the first power-transmitter amplifier 81A or the second power-transmitter amplifier 81B. In these cases, the result of the determination by either the first determination circuit 83A or the second determination circuit 83B may indicate that there is a power supply request. Even in this case, the occurrence of a situation, in which the power transmitter coil 22 is energized, can be reduced by the process shown in FIG. 6.

[0071] A specific example of the first communication coil 40A and the second communication coil 40B will be described with reference to FIG. 9. The power transmitter coil 22 is a DD coil including a first coil 23 and a second coil 24 that have annular shapes. The second coil 24 is disposed adjacent to the first coil 23 and has a winding direction opposite to that of the first coil 23. FIG. 9 is a planar view of each coil as viewed from above the vehicle 11. In FIG. 9, the power transmitter coil 22 is indicated by dot hatching.

[0072] The first communication coil 40A and the second communication coil 40B are annular. The first communication coil 40A and the second communication coil 40B extend in the arrangement direction of the first coil 23 and the second coil 24 in the planar view of each of the communication coils 40A, 40B and the power transmitter coil 22. Each of the communication coils 40A, 40B encloses the power transmitter coil 22 in the planar view.

[0073] Third EmbodimentHereinafter, a third embodiment will be described with reference to the drawings, focusing on differences from the second embodiment. In the present embodiment, as shown in FIG. 10, a first communication coil 40A and a second communication coil 40B extend in the arrangement direction of the first coil 23 and the second coil 24 in a planar view of each of the communication coils 40A, 40B and the power transmitter coil 22. In this embodiment, a direction perpendicular to the arrangement direction of the first coil 23 and the second coil 24 in the above-mentioned planar view is referred to as a width direction.

[0074] In the planar view of each of the communication coils 40A, 40B and the power transmitter coil 22, the first communication coil 40A and the second communication coil 40B are arranged so that a part of each of the first coil 23 and the second coil 24 is included in regions enclosed by the peripheral portions of the first communication coil 40A and the second communication coil 40B. Therefore, the power transmitter coil 22 and the communication coils 40A, 40B can be disposed close to each other.

[0075] Here, for example, when the power transmitter coil 22 and the communication coils 40A, 40B are arranged close to each other as shown in FIG. 9, communication interference may occur between the communication coils 40A, 40B. Therefore, in the planar view of each of the communication coils 40A, 40B and the power transmitter coil 22, the communication coils 40A, 40B are arranged spaced apart from each other in the width direction so that the regions enclosed by the peripheral portions of the communication coils 40A, 40B do not overlap. This can prevent communication interference from occurring between the communication coils 40A and 40B.

[0076] As shown in FIG. 11, in the planar view of each of the communication coils 40A, 40B and the power transmitter coil 22, an area S1 of a region enclosed by the peripheral portion of the first communication coil 40A (or the second communication coil 40B) and the peripheral portion of the first coil 23 are equivalent to an area S2 of a region enclosed by the peripheral portion of the first communication coil 40A (or the second communication coil 40B) and the peripheral portion of the second coil 24. Accordingly, when magnetic flux generated by energizing the first coil 23 links with the second coil 24, the influence of the magnetic flux on communication of the communication coils 40A, 40B can be reduced.

[0077] In addition, S1 and S2 being equivalent includes both the case where "S1=S2" and the case where "the difference between S1 and S2 is 10% or less, or 5% or less, of the larger of S1 and S2."

[0078] Fourth EmbodimentA fourth embodiment will be described below with reference to the drawings mainly in terms of differences from the second embodiment. In this embodiment, as shown in FIG. 12, three power-transmitter communication coils are provided.

[0079] The power transmitter 20 includes a third communication coil 40C as a power-transmitter communication coil in addition to the first communication coil 40A and the second communication coil 40B. The communication coils 40A, 40B, 40C are provided in a common power-transmitter coil unit 21.

[0080] The signal receiver 80 includes a third power-transmitter amplifier 81C. The third power-transmitter amplifier 81C amplifies a high-frequency signal (high-frequency current signal or high-frequency voltage signal) output from the third communication coil 40C. The high-frequency signal output from the third communication coil 40C contains a frequency component that fluctuates at the second specified frequency.

[0081] The signal receiver 80 includes a third detection circuit 82C and a third determination circuit 83C. The output signal of the third power-transmitter amplifier 81C is input to the third detection circuit 82C. The third detection circuit 82C detects the high-frequency signal input from the third power-transmitter amplifier 81C, and calculates a third intensity Intd3 which is an amplitude or effective value of the input high-frequency signal. The calculated third intensity Intd3 is input to the third determination circuit 83C.

[0082] The third determination circuit 83C determines whether there is a power supply request to the power transmitter coil 22 based on the input third intensity Intd3. Specifically, when determining that the third intensity Intd3 exceeds a determination threshold Ijde, the third determination circuit 83C determines that there is a power supply request. On the other hand, when determining that the third intensity Intd3 is lower than the determination threshold Ijde, the third determination circuit 83C determines that there is no power supply request. The determination result information of the third determination circuit 83C is input to the power-transmitter controller 71.

[0083] When it is determined that all the determination results of the determination circuits 83A, 83B, 83C indicate that there is a power supply request, the power-transmitter controller 71 executes the switching control of the inverter 60 and the PFC circuit 61 to energize the power transmitter coil 22.

[0084] When it is determined that at least one of the determination results of the determination circuits 83A, 83B, 83C indicates that there is no power supply request, the power-transmitter controller 71 stops the switching control of the inverter 60 and the PFC circuit 61 to stop energization of the power transmitter coil 22.

[0085] FIG. 13 is a planar view of each coil. The third communication coil 40C is disposed so as to span across the first communication coil 40A and the second communication coil 40B in the width direction. The third communication coil 40C is disposed in the middle of the first communication coil 40A and the second communication coil 40B in the direction in which the first coil 23 and the second coil 24 are arranged. The third communication coil 40C is disposed so as to intersect with a part of each of the first coil 23 and the second coil 24 in the planar view. This coil 40C may have the shape of one of the communication coils in FIG. 9.

[0086] This modification also provides the effects of the second embodiment.

[0087] For example, while the vehicle 11 is stopped, the power-transmitter controller 71 may calculate the amount of displacement of the vehicle 11 in the front-rear direction relative to the power transmitter coil 22 based on the first, second, and third intensities Intd1, Intd2, and Intd3. This calculation method is based on the fact that there is a correlation between the amount of displacement, the difference between the first and third intensities Intd1 and Intd3, and the difference between the second and third intensities Intd2 and Intd3.

[0088] Fifth EmbodimentA fifth embodiment will be described below with reference to the drawings mainly in terms of differences from the second embodiment. In this embodiment, as shown in FIG. 14, shapes of a first communication coil 340A and a second communication coil 340B are modified.

[0089] The first communication coil 340A extends in a direction in which the first coil 23 and the second coil 24 are arranged, and as indicated by the dashed dotted line, includes a first portion 341A and a second portion 342A. The first portion 341A has an annular shape and is provided on a first side with respect to the center of the first coil 23 in the width direction. The second portion 342A has an annular shape and is provided on a second side opposite to the first side with respect to the center of the second coil 24 in the width direction. The first portion 341A and the second portion 342A are disposed so as to intersect with a part of the first coil 23 in a planar view. For example, the first portion 341A and the second portion 342A are formed by winding one coil wire. The output signal of the first communication coil 340A is input to the first power-transmitter amplifier 81A.

[0090] The second communication coil 340B extends in the direction in which the first coil 23 and the second coil 24 are arranged, and as indicated by the solid line, includes a first portion 341B and a second portion 342B. The first portion 341B has an annular shape and is provided on the second side with respect to the center of the first coil 23 in the width direction. In other words, the first portion 341B of the second communication coil 340B is disposed adjacent to the first portion 341A of the first communication coil 340A in the width direction. For example, the first portion 341B and the second portion 342B are formed by winding one coil wire. The output signal of the second communication coil 340B is input to the second power-transmitter amplifier 81B.

[0091] The second portion 342B has an annular shape and is provided on the first side with respect to the center of the second coil 24 in the width direction. In other words, the second portion 342B of the second communication coil 340B is disposed adjacent to the second portion 342A of the first communication coil 340A in the width direction. The first portion 341B and the second portion 342B of the second communication coil 340B are disposed so as to intersect with a part of the second coil 24 in the planar view.

[0092] According to this embodiment, even when the vehicle 11 is shifted in the width direction relative to each communication coil 340A, 340B, a signal from the power-receiver communication coil 170 can be received by either the first or second portion 341A, 342A constituting the first communication coil 340A, and either the first or second portion 341B, 342B constituting the second communication coil 340B. Thus, the impact of a positional displacement of the vehicle 11 on reception of the power supply request signal can be reduced. Advantageously, this embodiment effectively implements receive diversity where multiple communication coils 340A and 340B are used to receive the same power request signal. The receive diversity leads to higher reliability of the determination circuits and also improves communication in misalignment.

[0093] Sixth EmbodimentA sixth embodiment will be described below with reference to the drawings mainly in terms of differences from the first embodiment. In the present embodiment, as shown in FIG. 15, the power transmitter coil 422 is a circular coil having an annular shape. Additionally, the shapes of first communication coil 440A and second communication coil 440B are modified. FIG. 15 is a planar view of each coil.

[0094] The first communication coil 440A has a first loop portion 441A and a second loop portion 442A, forming a figure-eight shape in a planar view. The second loop portion 442A is disposed adjacent to the first loop portion 441A, and has a winding direction opposite to that of the first loop portion 441A.

[0095] The second communication coil 440B has a first loop portion 441B and a second loop portion 442B, forming a figure-eight shape in a planar view. The second loop portion 442B is disposed adjacent to the first loop portion 441B, and has a winding direction opposite to that of the first loop portion 441B.

[0096] The first communication coil 440A and the second communication coil 440B are disposed within a region enclosed by the peripheral portion of the power transmitter coil 422. In other words, the first communication coil 440A and the second communication coil 440B are disposed in an inner region of the power transmitter coil 422. In this embodiment, a direction perpendicular to the assumed travel direction of the vehicle 11 in the planar view of each of the coils 422, 440A, 440B is referred to as the width direction.

[0097] The first communication coil 440A and the second communication coil 440B are arranged side by side in the width direction. The first loop portion 441A of the first communication coil 440A and the first loop portion 441B of the second communication coil 440B are arranged in the width direction. The second loop portion 442A of first communication coil 440A and the second loop portion 442B of the second communication coil 440B are arranged in the width direction.

[0098] Here, when the power transmitter coil 422 and the communication coils 440A, 440B are arranged close to each other, communication interference may occur between the communication coils 440A, 440B. Therefore, in the planar view of each of the communication coils 440A, 440B and the power transmitter coil 422, the communication coils 440A, 440B are arranged spaced apart from each other in the width direction so that the regions enclosed by the peripheral portions of the communication coils 440A, 440B do not overlap. This can prevent communication interference from occurring between the communication coils 440A and 440B.

[0099] As shown in FIG. 16, in a planar view of each of the communication coils 440A, 440B and the power transmitter coil 422, an area S1 of the first loop portions 441A, 441B and an area S2 of the second loop portions 442A, 442B are equivalent to each other. Accordingly, the effect of magnetic flux on communication between communication coils 440A, 440B can be reduced when magnetic flux is generated by energization of the power transmitter coil 422.

[0100] In addition, S1 and S2 being equivalent includes both the case where "S1=S2" and the case where "the difference between S1 and S2 is 10% or less, or 5% or less, of the larger of S1 and S2."

[0101] Modification of Sixth EmbodimentAs shown in FIGS. 17 and 18, the first communication coil 440A and the second communication coil 440B may be arranged side by side in the assumed travel direction of the vehicle 11.

[0102] Seventh EmbodimentA seventh embodiment will be described below with reference to the drawings mainly in terms of differences from the sixth embodiment. In this embodiment, as shown in FIG. 19, in a planar view of each of a first communication coil 540A, a second communication coil 540B, and a power transmitter coil 422, the first communication coil 540A and the second communication coil 540B extend beyond the region enclosed by the peripheral portion of the power transmitter coil 422.

[0103] The first communication coil 540A has a first loop portion 541A and a second loop portion 542A, forming a figure-eight shape in a planar view. The second communication coil 540B has a first loop portion 541B and a second loop portion 542B, forming a figure-eight shape in a planar view.

[0104] In the planar view, the area of the region enclosed by first loop portion 541A, 541B in the inner region of power transmitter coil 422 and the inner peripheral portion of power transmitter coil 422 is defined as S1. The area of the region surrounded by the second loop portion 542A, 542B in the inner region of the power transmitter coil 422 and the inner peripheral portion of the power transmitter coil 422 is defined as S2. In this embodiment, S1 and S2 are equivalent. Accordingly, the effect of magnetic flux on communication between communication coils 540A, 540B can be reduced when magnetic flux is generated by energization of the power transmitter coil 422.

[0105] In addition, S1 and S2 being equivalent includes both the case where "S1=S2" and the case where "the difference between S1 and S2 is 10% or less, or 5% or less, of the larger of S1 and S2."

[0106] Modification of Seventh EmbodimentInstead of the configuration of the seventh embodiment, as shown in FIG. 20, the first communication coil 540A and the second communication coil 540B may be arranged side by side in the assumed travel direction of the vehicle 11. In this case, the impact of displacement in the width direction of the vehicle 11 with respect to the communication coils 540A, 540B on reception of the power supply request signal can be reduced.

[0107] Eighth EmbodimentHereinafter, an eighth embodiment will be described with reference to the drawings, focusing on the differences from the above-described embodiments. In the present embodiment, the power transmitter 20 diagnoses whether there is an abnormality in its own communication function.

[0108] As shown in FIG. 21, the power-transmitter control unit 70 includes a test transmission circuit 600 connected to the second communication coil 40B. The test transmission circuit 600 receives a command from the power-transmitter controller 71 to supply the second communication coil 40B with a diagnostic power supply request signal. The test transmission circuit 600 generates the diagnostic power supply request signal that fluctuates at the second specified frequency and supplies the signal to the second communication coil 40B. The second communication coil 40B is used as a test communication coil (corresponding to a "test communication antenna") for performing wireless communication with the first communication coil 40A. As each of the communication coils 40A, 40B, various coils such as those shown in FIGS. 9 to 11, 13 to 20 may be used.

[0109] When a diagnostic power supply request signal is input to the second communication coil 40B, a high-frequency current that fluctuates at the second specified frequency flows through the second communication coil 40B. This causes a magnetic field to be generated in the second communication coil 40B. When the generated magnetic field links with the first communication coil 40A, a high frequency current flows through the first communication coil 40A, similar to the case where a magnetic field from the power-receiver communication coil 170 links with the first communication coil 40A. This high-frequency current is input to the first power-transmitter amplifier 81A.

[0110] The high-frequency signal input to the first power-transmitter amplifier 81A is amplified and input to the first detection circuit 82A. The first detection circuit 82A detects the high-frequency signal input from the first power-transmitter amplifier 81A, thereby calculating a first intensity Intd1. The calculated first intensity Intd1 is input to the power-transmitter controller 71. The power-transmitter controller 71 diagnoses the communication function of the power transmitter 20 based on the first input intensity Intd1.

[0111] FIG. 22 is a flowchart illustrating a procedure of a diagnostic process for the communication function of the power transmitter 20. This process is performed repeatedly by the power-transmitter control unit 70, for example, in a predetermined control cycle. In this embodiment, the power-transmitter controller 71 corresponds to a "diagnostic unit."

[0112] In step S20, the power-transmitter controller 71 determines whether an execution condition of the diagnostic process is satisfied. The execution condition is, for example, a condition that a specified period of time having passed since the last diagnosis, a condition that a predetermined diagnosis time having been reached, or a condition that an abnormality has been determined in another diagnostic process executed by the power-transmitter controller 71.

[0113] In step S21, the power-transmitter controller 71 instructs the test transmission circuit 600 to supply a diagnostic power supply request signal to the second communication coil 40B.

[0114] In step S22, when the diagnostic power supply request signal is being supplied to the second communication coil 40B, the first detection circuit 82A detects a high-frequency signal input from the first power-transmitter amplifier 81A, thereby calculating the first intensity Intd1. The calculated first intensity Intd1 is input to the power-transmitter controller 71.

[0115] In step S23, the power-transmitter controller 71 determines whether the acquired first intensity Intd1 is below a lower limit threshold ILlimit indicating an abnormality in the communication function of the power transmitter 20.

[0116] When a negative determination is made in step S23, the power-transmitter controller 71 determines in step S26 whether the acquired first intensity Intd1 exceeds an upper limit threshold IHlimit indicating an abnormality in the communication function of the power transmitter 20. The upper threshold IHlimit is a value greater than the lower threshold ILlimit. The upper threshold IHlimit and the lower threshold ILlimit are values that are determined in advance by, for example, experiment or calculation.

[0117] When the power-transmitter controller 71 makes a positive determination in step S23 or S26, the power-transmitter controller 71 proceeds to step S24 and determines that an abnormality has occurred in the communication function of the power transmitter 20. The abnormality in the communication function of the power transmitter 20 includes an abnormality in any one of the first communication coil 40A, the first power-transmitter amplifier 81A, or the first detection circuit 82A.

[0118] In step S25, the power-transmitter controller 71 prevents energization of the power transmitter coil 22. Specifically, the power-transmitter controller 71 prevents switching control of the inverter 60 and the PFC circuit 61 from being performed. As a result, the power transmitter coil 22 is not energized. Furthermore, the power-transmitter controller 71 transmits a notification that an abnormality has occurred to the outside. Accordingly, the power transmitter 20 can be prevented from being used continuously in an undesirable state. The power-transmitter controller 71 may store the result data of the abnormality diagnosis in a storage unit.

[0119] When the power-transmitter controller 71 makes a negative determination in step S26, the power-transmitter controller 71 determines that an abnormality has not occurred in the communication function of the power transmitter 20 and proceeds to step S27. In step S27, the power-transmitter controller 71 determines whether the acquired first intensity Intd1 is greater than an upper limit value IHth of an expected intensity range. The upper limit value IHth is lower than the upper limit threshold IHlimit and is greater than the lower limit threshold ILlimit (IHlimit > IHth > ILlimit).

[0120] When the power-transmitter controller 71 determines in step S27 that the first intensity Intd1 is greater than the upper limit value IHth, the power-transmitter controller 71 proceeds to step S28. In step S28, the power-transmitter controller 71 performs a process of decreasing the gain of the first power-transmitter amplifier 81A.

[0121] When a negative determination is made in step S27, the power-transmitter controller 71 proceeds to step S29. In step S29, the power-transmitter controller 71 determines whether the acquired first intensity Intd1 is lower than a lower limit value ILth of the expected intensity range. The lower limit value ILth is lower than the upper limit value IHth and is greater than the lower threshold ILlimit (IHlimit > IHth > ILth > ILlimit).

[0122] When the power-transmitter controller 71 determines in step S29 that the first intensity Intd1 is lower than the lower limit value ILth, the power-transmitter controller 71 proceeds to step S30. In step S30, the power-transmitter controller 71 performs a process of increasing the gain of the first power-transmitter amplifier 81A.

[0123] Due to deterioration of the power transmitter 20 over time, the intensity of the power supply request signal may deviate from the expected intensity range. Even in this case, the processing in steps S28 and S30 can adjust the gain of the first power-transmitter amplifier 81A so that the intensity of the power supply request signal falls within the expected intensity range.

[0124] The determination threshold Ijde used by the determination circuits 83A, 83B to determine the presence or absence of a power supply request may be a value that is smaller than the lower limit value ILth of the expected intensity range and larger than the lower limit threshold ILlimit, for example.

[0125] According to the present embodiment described above, it is possible to prevent the power transmitter 20 from being continuously used in a state in which an abnormality occurs in the communication function of the power transmitter 20.

[0126] Other EmbodimentsThe above embodiments may be changed and carried out as follows.

[0127] In the eighth embodiment, the power transmitter 20 may include a switching circuit that switches the communication coil connected to the test transmission circuit 600 between the first communication coil 40A and the second communication coil 40B. In this case, the first communication coil 40A is used as a test communication coil for performing wireless communication with the second communication coil 40B.

[0128] In the sixth and seventh embodiments, the number of communication coils is not limited to two, and three or more communication coils may be arranged.

[0129] The wireless power transfer system may have the first function of wirelessly supplying power from the vehicle-side device to the ground-side device, in addition to the second function of wirelessly supplying power from the ground-side device to the vehicle-side device. In this case, the in-vehicle power receiver 100 has a power transmitting function in addition to the power receiving function. Moreover, the power transmitter 20 on the ground side has a power receiving function in addition to the power transmitting function. The second function will be described below with reference to FIG. 3.

[0130] The power-receiver controller 231 applies a high frequency AC voltage to the power receiver coil 102 by controlling the switching of the rectifier circuit 200. This causes a high-frequency current to flow in the power receiver coil 102 and a magnetic field for power transmission is generated in the power receiver coil 102.

[0131] When the magnetic field generated in the power receiver coil 102 links with the power transmitter coil 22, a high-frequency current flows in the power transmitter coil 22, varying with the frequency of the high-frequency current flowing in the power receiver coil 102. The high-frequency current flowing through the power transmitter coil 22 is supplied to the AC power source 15 via the power-transmitter resonant circuit 30, the filter circuit 52, the inverter 60 and the PFC circuit 61. In this case, the power-transmitter controller 71 controls the switching of the inverter 60 and the PFC circuit 61.

[0132] In the wireless power transfer system having the second function, for example, the power transmitter 20 may include a signal transmitter that supplies a power supply request signal to the power-transmitter communication coil 40. Furthermore, the power receiver 100 may include a signal receiver that receives the power supply request signal received by the power-receiver communication coil 170 and inputs the information to the power-receiver controller 231.

[0133] The wireless power transfer system may have the function of wirelessly supplying power from the vehicle-side device to the ground-side device, instead of the function of wirelessly supplying power from the ground-side device to the vehicle-side device.

[0134] The vehicle identification information used in the processes of the above embodiments is not limited to vehicle ID information, and may be, for example, a token or credit card information of a vehicle user.

[0135] The power-receiver communication antenna and the power-transmitter communication antenna are not limited to communication coils, and may employ various antennas. For example, the communication antenna is a dipole antenna or a monopole antenna.

[0136] The method of wireless power transmission by the power transmitting antenna and the power receiving antenna is not limited to the magnetic field resonance method, and may be an electric field coupling method. In this case, a power transmitting antenna and a power receiving antenna that are different in form from coils and use an electric field coupling method may be used.

[0137] The vehicle on which the power receiver 100 is mounted is not limited to a vehicle traveling on the road RS, but may be, for example, an AGV (Automated Guided Vehicle) or a traveling robot. In this case, the power-transmitter coil unit 21 is not buried in the road RS, but may be installed on a sidewalk adjacent to the road RS, in a parking lot, or in the path along which the AGV travels.

[0138] The control units and methods thereof described in the present disclosure may be implemented by a dedicated computer including a processor programmed to execute one or more functions embodied by a computer program and a memory. Alternatively, the control units and methods thereof described in the present disclosure may be implemented using a dedicated computer with a processor consisting of one or more dedicated hardware logic circuits. Alternatively, the controller and method described in the present disclosure may be implemented using one or more dedicated computers, which include a combination of a processor consisting of one or more hardware logic circuits, and a processor and memory programmed to perform one or more functions. The computer programs may be stored, as instructions to be executed by a computer, in a tangible non-transitory computer-readable medium.

[0139] While the present disclosure has been described with reference to various exemplary embodiments thereof, it is to be understood that the disclosure is not limited to the disclosed embodiments and constructions. To the contrary, the disclosure is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the disclosure are shown in various combinations and configurations, which are exemplary, other various combinations and configurations, including more, less or only a single element, are also within the spirit of the disclosure.

Claims

1.A power transmitter (20) applied to a wireless power transfer system including a ground-side device and a vehicle-side device, one of the ground-side device and the vehicle-side device being the power transmitter having a power transmitting antenna (22), the other of the ground-side device and the vehicle-side device being a power receiver (100) having a power receiving antenna (102), the power receiver being configured to transmit a power supply request signal for a power supply request to the power transmitter, the power transmitter being configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal, the power transmitter comprising:a power-transmitter communication antenna (40, 40A, 40B, 40C, 340A, 340B, 440A, 440B, 540A, 540B) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) of the power receiver; anda power-transmitter control unit (70), whereinthe power-transmitter control unit includesa determination unit (83A, 83B, 83C) configured to determine whether there is the power supply request based on an output signal of the power-transmitter communication antenna, anda power-transmitter controller (71) configured to control energization of the power transmitting antenna to perform wireless power transfer to the power receiving antenna based on a determination result of the determination unit,the determination unit of the power-transmitter control unit is one of determination units,the power-transmitter control unit is configured to receive a determination result of each of the determination units by the power-transmitter controller, andthe power-transmitter controller is configured to energize the power transmitting antenna on condition that the determination result indicating that there is a power supply request is input from each of the determination units.2.The power transmitter according to claim 1, whereina signal indicating the power supply request includes information on requested power that is requested by the power receiver, andthe power-transmitter control unit is configured toacquire information on requested powers input to the determination units based on the output signal of the power-transmitter communication antenna input to each of the determination units, andstop energization of the power transmitting antenna when it is determined that the requested powers are different from each other.3.The power transmitter according to claim 1, whereinthe power-transmitter communication antenna is one of power-transmitter communication antennas (40A, 40B, 40C, 340A, 340B, 440A, 440B, 540A, 540B) that are provided individually corresponding to the determination units.4.The power transmitter according to claim 3, whereinthe power transmitting antenna (22) is a DD coil including a first coil (23) and a second coil (24),the power-transmitter communication antennas are power-transmitter communication coils (40A, 40B, 40C),each of the power-transmitter communication coils extends in an arrangement direction of the first coil and the second coil, and has an annular shape in a planar view of each of the DD coil and the power-transmitter communication coils,each of the power-transmitter communication coils is disposed such that a part of each of the first coil and the second coil is included in a region enclosed by a peripheral portion of each of the power-transmitter communication coils in the planar view of each of the DD coil and the power-transmitter communication coils, andthe power-transmitter communication coils are spaced apart from each other so that regions enclosed by peripheral portions of the power-transmitter communication coils do not overlap in the planar view of each of the DD coil and the power-transmitter communication coils.5.The power transmitter according to claim 4, whereinan area of a region enclosed by the peripheral portion of each of the power-transmitter communication coils and a peripheral portion of the first coil is equivalent to an area of a region enclosed by the peripheral portion of each of the power-transmitter communication coils and a peripheral portion of the second coil, in the planar view of each of the DD coil and the power-transmitter communication coils.6.The power transmitter according to claim 3, whereinthe power transmitting antenna (22) is a DD coil including a first coil (23) and a second coil (24),the power-transmitter communication antennas include a first communication coil (340A) and a second communication coil (340B),a width direction is a direction perpendicular to an arrangement direction of the first coil and the second coil in a planar view of each of the first communication coil, the second communication coil, and the DD coil,the first communication coil includesa first portion (341A) provided on a first side with respect to a center of the first coil in the width direction, anda second portion (342A) provided on a second side opposite to the first side with respect to a center of the second coil in the width direction, andthe second communication coil includesa first portion (341B) provided on the second side with respect to the center of the first coil in the width direction, anda second portion (342B) provided on the first side with respect to the center of the second coil in the width direction.7.The power transmitter according to claim 3, whereinthe power transmitting antenna (422) is a power transmitter coil having an annular shape,the power-transmitter communication antennas are power-transmitter communication coils (440A, 440B, 540A, 540B),each of the power-transmitter communication coils has a figure-eight shape, and includes a first loop portion (441A, 441B, 541A, 541B) and a second loop portion (442A, 442B, 542A, 542B) in a planar view,each of the power-transmitter communication coils is arranged such that at least a part of regions enclosed by the first loop portion and the second loop portion is included in a region enclosed by a peripheral portion of the power transmitter coil in a planar view of each of the power transmitter coil and the power-transmitter communication coils,the power-transmitter communication coils are spaced apart from each other so that regions enclosed by peripheral portions of the power-transmitter communication coils do not overlap in the planar view of each of the power transmitter coil and the power-transmitter communication coils.8.The power transmitter according to claim 7, whereineach of the power-transmitter communication coils are included in the region enclosed by the peripheral portion of the power transmitter coil in the planar view of each of the power transmitter coil and the power-transmitter communication coils, andan area of the first loop portion is equivalent to an area of the second loop portion.9.The power transmitter according to claim 7, whereineach of the power-transmitter communication coils (540A, 540B) extends beyond the region enclosed by the peripheral portion of the power transmitter coil in the planar view of each of the power transmitter coil and the power-transmitter communication coils, andan area of a region enclosed by the first loop portion (541A, 541B) and the peripheral portion of the power transmitter coil is equivalent to an area of a region enclosed by the second loop portion (542A, 542B) and the peripheral portion of the power transmitter coil in the planar view of each of the power transmitter coil and the power-transmitter communication coils.10.The power transmitter according to any one of claims 3 to 9, whereinthe power-transmitter control unit is configured tosupply a diagnostic power supply request signal to a test communication antenna (40B) which is one of the power-transmitter communication antennas,acquire a power supply request signal received by a communication antenna (40A), which is one of the power-transmitter communication antennas other than the test communication antenna, when the diagnostic power supply request signal is supplied to the test communication antenna, anddiagnose a communication function of the power transmitter based on the acquired power supply request signal.

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