Wireless power transfer system, program, control method for wireless power transfer system, power transmitter and inspection vehicle

Abstract

The wireless power transfer system includes a power transmitter (20), a power receiver (100), and an inspection vehicle (400). The power transmitter includes a power-transmitter communication coil (40) and a power-transmitter control unit (70) that controls energization of a power transmitter coil (22) based on a power supply request signal received by the power-transmitter communication coil. The inspection vehicle includes a test communication coil (411) for wireless communication with the power-transmitter communication coil, and a transmission circuit (412) for supplying a diagnostic power supply request signal to the test communication coil. The power-transmitter control unit acquires the diagnostic power supply request signal received by the power-transmitter communication coil, and diagnoses a communication function of the power transmitter based on the acquired power supply request signal.

Description

WIRELESS POWER TRANSFER SYSTEM, PROGRAM, CONTROL METHOD FOR WIRELESS POWER TRANSFER SYSTEM, POWER TRANSMITTER AND INSPECTION VEHICLECross Reference

[0001] This application is based on Japanese Patent Application No. 2024-208016 filed on November 29, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a wireless power transfer system, a program, a control method for a wireless power transfer system, a power transmitter, and an inspection vehicle.

[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 power supply request signal 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] JP 2024-008088 A

[0006] If an abnormality occurs in the communication function of the power transmitter, the power supply request signal may not be properly received from the communication coil of the power receiver. For this reason, a technique that can grasp the state of the communication function of the power transmitter is desired.

[0007] It is a main object of the present disclosure is to provide a wireless power transfer system, a program, a control method for a wireless power transfer system, a power transmitter, and an inspection vehicle that are capable of grasping a state of a communication function of a power transmitter.

[0008] According to an aspect of the present disclosure, a wireless power transfer system includes a power transmitter and a power receiver. The power transmitter has a power transmitting antenna. The power receiver has a power receiving antenna and mounted on a vehicle. The power transmitting antenna is configured to wirelessly supply electric power to the power receiving antenna. The power receiver includes a power-receiver communication antenna, and a power-receiver control unit configured to control energization of the power-receiver communication antenna for supply of a power supply request signal to the power-receiver communication antenna to be transmitted to the power transmitting antenna. The power transmitter includes a power-transmitter communication antenna and a power-transmitter control unit. The power-transmitter communication antenna is configured to perform wireless communication with the power-receiver communication antenna. The power-transmitter control unit is configured to control energization of the power transmitting antenna based on the power supply request signal received by the power-transmitter communication antenna. The wireless power transfer system includes an inspection vehicle and a diagnostic unit. The inspection vehicle includes a test communication antenna and a signal supply unit. The test communication antenna is configured to perform wireless communication with the power-transmitter communication antenna. The signal supply unit is configured to supply a diagnostic power supply request signal to the test communication antenna. The diagnostic unit is configured to acquire the diagnostic power supply request signal received by the power-transmitter communication antenna, and diagnose a communication function of the power transmitter based on the acquired diagnostic power supply request signal.

[0009] According to the present disclosure, the state of the power transmitter can be grasped by using the test communication antenna and the diagnostic unit provided on the inspection vehicle.

[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 schematic diagram illustrating an inspection vehicle.FIG. 7 is a diagram illustrating each component of the inspection vehicle.FIG. 8 is a flowchart illustrating a procedure a diagnostic process for a communication function.FIG. 9 is a flowchart illustrating a procedure of a diagnostic process for a communication function, according to a second embodiment.FIG. 10 is a flowchart illustrating a procedure of a diagnostic process for a communication function, according to a third embodiment.FIG. 11 is a planar view of communication coils provided in an inspection vehicle and a general vehicle according to another embodiment.

[0011] First Embodiment A first embodiment of a wireless power transfer system of the present disclosure will be described below with reference to the drawings.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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).

[0023] 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.

[0024] 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.

[0025] 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. 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] When the power-receiver coil unit 101 of the vehicle 11 approaches the power-transmitter coil unit 21 on the ground side, the magnetic field generated by the power-receiver communication coil 170 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. 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.

[0040] 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).

[0041] 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, on condition that 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 at the first specified frequency 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.

[0042] The signal transmitter 240 and its peripheral configuration will be described with reference to FIG. 4.

[0043] 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.

[0044] 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.

[0045] The signal receiver 80 and its peripheral configuration will be described with reference to FIG. 5.

[0046] The signal receiver 80 includes a power-transmitter amplifier 81, a detection circuit 82 and a determination circuit 83. The power-transmitter amplifier 81 amplifies the high-frequency signal (high frequency current or voltage signal) output from the power-transmitter communication coil 40 and supplies the amplified signal to the detection circuit 82. The high-frequency signal output from the power-transmitter communication coil 40 contains a frequency component that fluctuates at the second specified frequency.

[0047] The detection circuit 82 detects the high-frequency signal input from the power-transmitter amplifier 81, and calculates an intensity Intd which is an amplitude or effective value of the input high-frequency signal. The calculated intensity Intd is input to the determination circuit 83.

[0048] The determination circuit 83 determines whether there is a power supply request to the power transmitter coil 22 based on the input intensity Intd. Specifically, when determining that the intensity Intd exceeds a determination threshold Ijde, the determination circuit 83 determines that there is a power supply request. On the other hand, when determining that the intensity Intd is lower than the determination threshold Ijde, the determination circuit 83 determines that there is no power supply request. The determination result information of the determination circuit 83 is input to the power-transmitter controller 71. In this embodiment, the determination circuit 83 corresponds to a "determination unit."

[0049] When the power-transmitter controller 71 determines that there is no power supply request based on the input determination result information, the power-transmitter controller 71 stops the switching control of the PFC circuit 61 and the inverter 60. As a result, no current is applied to the power transmitter coil 22.

[0050] On the other hand, when determining that there is a power supply request based on the determination result information, the power-transmitter controller 71 applies a high frequency voltage to the power transmitter coil 22 by performing switching control of the PFC circuit 61 and the inverter 60. 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. In addition, when the power-transmitter controller 71 determines that there is a power supply request, it 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. In this embodiment, the power-transmitter controller 71 corresponds to a "power supply control unit."

[0051] An abnormality may occur in a communication function of the power transmitter 20. If an abnormality occurs, the power supply request signal may not be properly received from the power-receiver communication coil 170 of the power receiver 100. Therefore, the wireless power transfer system 10 has a configuration for diagnosing the communication function of the power transmitter 20.

[0052] As shown in FIGS. 6 and 7, the wireless power transfer system 10 includes an inspection vehicle 400. The inspection vehicle 400 is a vehicle different from the general vehicle 11 and is operated by, for example, a management company of the wireless power transfer system 10. The inspection vehicle 400 is equipped with a test communication coil 411 (corresponding to a "test communication antenna"), a transmission circuit 412 and an inspection controller 413. The inspection controller 413 is an ECU that executes various controls of the inspection vehicle 400, and includes a processor, a storage unit, and a communication bus that connects the processor and storage unit, similarly to the power-transmitter controller 71 and power-receiver controller 231.

[0053] The test communication coil 411 is a coil for performing narrow area wireless communication with the power-transmitter communication coil 40. The transmission circuit 412 is a circuit that supplies a diagnostic power supply request signal to the test communication coil 411, and corresponds to a "signal supply unit".

[0054] The test communication coil 411 is provided at the bottom of the body of the inspection vehicle 400. The test communication coil 411 has an annular shape in a planar view seen from above the inspection vehicle 400, similar to the power-receiver communication coil 170. The test communication coil 411 is connected to the transmission circuit 412.

[0055] The inspection controller 413 instructs the transmission circuit 412 to supply a diagnostic power supply request signal to the test communication coil 411. Accordingly, the test transmission circuit 412 generates the diagnostic power supply request signal that fluctuates at the second specified frequency and supplies the signal to the test communication coil 411.

[0056] For example, when a diagnostic power supply request signal is input to the test communication coil 411 while the inspection vehicle 400 is travelling, a high-frequency current that fluctuates at the second specified frequency flows through the test communication coil 411. This causes a magnetic field to be generated in the test communication coil 411. When the generated magnetic field links with the power-transmitter communication coil 40, a high frequency current flows through the power-transmitter communication coil 40, similar to the case where a magnetic field from the power-receiver communication coil 170 links with the power-transmitter communication coil 40. This high-frequency current is input to the power-transmitter amplifier 81.

[0057] The high-frequency signal input to the power-transmitter amplifier 81 is amplified and input to the detection circuit 82. The detection circuit 82 detects the high-frequency signal input from the power-transmitter amplifier 81, thereby calculating an intensity Intd. The calculated intensity Intd 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 input intensity Intd.

[0058] FIG. 8 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 20 and the inspection vehicle 400 in cooperation with each other, for example, in a predetermined control cycle. The diagnostic process is executed, for example, when the inspection vehicle 400 is traveling on the road RS on which the power-transmitter coil units 21 are arranged.

[0059] In step S10, the inspection controller 413 controls the transmission circuit 412 to supply a signal including the ID information of the inspection vehicle 400 to the test communication coil 411 together with a diagnostic power supply request signal.

[0060] In step S20, the power-transmitter controller 71 functioning as a diagnostic unit determines whether the ID information of the inspection vehicle 400 has been received based on the output signal of the power-transmitter amplifier 81. When it is determined that the ID information has been received, the power-transmitter controller 71 proceeds to step S21 and transitions to a diagnosis mode in which the communication function of the power transmitter 20 is diagnosed.

[0061] The use of the ID information of the inspection vehicle 400 makes it easier for the power transmitter 20 to determine whether it is in the diagnosis mode. When the power-transmitter controller 71 determines that it is in the diagnosis mode, the power-transmitter controller 71 prevents energization of the power transmitter coil 22 by, for example, preventing the switching control of the inverter 60 and the PFC circuit 61. Accordingly, unnecessary power consumption can be reduced.

[0062] In this embodiment, the intensity of the diagnostic power supply request signal supplied from the transmission circuit 412 to the test communication coil 411 is greater than an intensity of a power supply request signal supplied to the power-receiver communication coil 170 in the power receiver 100 of a general vehicle 11 that is not the inspection vehicle 400. This makes it possible to grasp a state that cannot be properly diagnosed by a power supply request signal from the general vehicle 11. Therefore, an accuracy of diagnosing the communication function of the power transmitter 20 can be improved.

[0063] In step S22, when the diagnostic power supply request signal is being supplied to the test communication coil 411, the detection circuit 82 of the power transmitter 20 detects a high-frequency signal input from the power-transmitter amplifier 81, thereby calculating the intensity Intd. The calculated intensity Intd is input to the power-transmitter controller 71.

[0064] In step S23, the power-transmitter controller 71 determines whether the acquired intensity Intd is below a lower limit threshold ILlimit indicating an abnormality in the communication function of the power transmitter 20.

[0065] When a negative determination is made in step S23, the power-transmitter controller 71 determines in step S26 whether the acquired intensity Intd 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.

[0066] 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 power-transmitter communication coil 40, the power-transmitter amplifier 81, or the detection circuit 82.

[0067] 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.

[0068] When a negative determination is made in step S26, the power-transmitter controller 71 proceeds to step S27. In step S27, the power-transmitter controller 71 determines whether the acquired intensity Intd 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).

[0069] When the power-transmitter controller 71 determines in step S27 that the intensity Intd 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 power-transmitter amplifier 81.

[0070] 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 intensity Intd 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).

[0071] When the power-transmitter controller 71 determines in step S29 that the intensity Intd 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 power-transmitter amplifier 81.

[0072] 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 power-transmitter amplifier 81 so that the intensity of the power supply request signal falls within the expected intensity range.

[0073] The determination threshold Ijde used by the determination circuit 83 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.

[0074] 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.

[0075] Second Embodiment A second embodiment will be described below with reference to the drawings mainly in terms of differences from the first embodiment. In this embodiment, the power-transmitter controller 71 determines whether an abnormality has occurred in the signal-receiving function of the power transmitter 20, based on the gain of the power-transmitter amplifier 81 adjusted in step S18 or S20.

[0076] FIG. 9 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 20 and the inspection vehicle 400 in cooperation with each other, for example, in a predetermined control cycle.

[0077] After step S28 or S30, in step S31, the power-transmitter controller 71 determines whether either a first condition that the gain exceeds an upper limit gain GHth or a second condition that the gain is below a lower limit gain GLth is satisfied. The lower limit gain GLth is smaller than the upper limit gain GHth.

[0078] When determining that neither the first condition nor the second condition is satisfied, the power-transmitter controller 71 determines that no abnormality has occurred in the communication function of the power transmitter 20. On the other hand, when the power-transmitter controller 71 determines that either the first condition or the second condition is satisfied, the process proceeds to step S24, where the power-transmitter controller 71 determines that an abnormality has occurred in the communication function of the power transmitter 20.

[0079] Third Embodiment A third embodiment will be described below with reference to the drawings mainly in terms of differences from the first and second embodiments. In this embodiment, when the power-transmitter controller 71 determines that a diagnostic power supply request signal is not received by the power-transmitter communication coil 40 even in a diagnosis period in which the diagnostic power supply request signal is transmitted from the inspection vehicle 400, the power-transmitter controller 71 determines that an abnormality has occurred in the communication function of the power transmitter 20.

[0080] The process of this embodiment is executed by the power-transmitter controller 71 provided in each power-transmitter power supply unit 51. FIG. 10 is a flowchart illustrating a procedure of a diagnostic process for the communication function of the power transmitter 20. This process is repeatedly executed by the power-transmitter controller 71 of each power-transmitter power supply unit 51 at a predetermined control period, for example.

[0081] In step S40, the power-transmitter controller 71 determines whether it is in the diagnosis period. Two examples of this determination method will be described below.

[0082] The first example will be described. As shown in FIG. 2 above, power-transmitter coil units 21 are arranged at predetermined intervals in a vehicle travel direction of a vehicle 11. Among any two adjacent power-transmitter coil units 21, an upstream power-transmitter coil unit in the travel direction is defined as a previously-adjacent unit, and a downstream power-transmitter coil unit in the travel direction is defined as a subsequently-adjacent unit. The power-transmitter controller 71 may set the diagnosis period as a period from when it receives information from a power-transmitter controller that controls energization of the previously-adjacent unit indicating that a diagnostic power supply request signal has been received to when it receives information from a power-transmitter controller that controls energization of the subsequently-adjacent unit indicating that a diagnostic power supply request signal has been received. In addition, the power-transmitter controller 71 may acquire the information from the power-transmitter controllers that control energization of the previously-adjacent unit and the subsequently-adjacent unit, for example, using wide area wireless communication or a communication line connecting each power-transmitter controller 71.

[0083] The second example will be described. The power-transmitter controller 71 may acquire information about a planned time period during which the inspection vehicle 400 is scheduled to travel near the power-transmitter power supply unit 51 that is the target of energization control by the power-transmitter controller 71, for example, using wide area wireless communication. Then, the power-transmitter controller 71 may set the acquired time period as the diagnosis period.

[0084] When the power-transmitter controller 71 determines in step S40 that it is in the diagnosis period, the power-transmitter controller 71 proceeds to step S41 and determines whether a diagnostic power supply request signal has been received by the power-transmitter communication coil 40 that is the target of energization control by the power-transmitter controller 71. When the power-transmitter controller 71 that the signal has not been received, 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.

[0085] Other Embodiments The above embodiments may be changed and carried out as follows.

[0086] As shown in FIG. 11, the dimension Wa of the test communication coil 411 in the vehicle width direction may be larger than the dimension Wb of the power-receiver communication coil 170 provided in the general vehicle 11 in the vehicle width direction. In this case, the power-transmitter communication coil 40 can easily receive a diagnostic power supply request signal from the test communication coil 411 even if the central position in the vehicle width direction of the test communication coil 411 of the inspection vehicle 400 is shifted in the vehicle width direction relative to the central position of the power-transmitter communication coil 40 buried in the road RS.

[0087] The transmission circuit 412 of the inspection vehicle 400 may not transmit the ID information of the inspection vehicle 400. In this case, for example, information on the time period during which the inspection vehicle 400 travels for diagnosis may be input to the power-transmitter controller 71, for example, by wide area wireless communication. When the power-transmitter controller 71 receives a diagnostic power supply request signal during the above-mentioned time period, the power-transmitter controller 71 prevents energization of the power transmitter coil 22. The wide area wireless communication is a communication with a longer communication distance than the narrow area wireless communication.

[0088] The diagnostic unit is not limited to one being provided in the power-transmitter controller 71, and may be one provided in, for example, a server (for example, a cloud server) provided outside the power transmitter 20. In this case, the power-transmitter controller 71 may transmit, for example, information on the output signal of the power-transmitter amplifier 81 when a diagnostic power supply request signal is supplied to the test communication coil 411 to the server via wide area wireless communication. The server may then execute the above-mentioned diagnostic process based on the received information.

[0089] The inspection vehicle is not limited to a vehicle operated by the management company, and may be, for example, a general vehicle equipped with a power receiver that has been calibrated in accordance with a specified standard.

[0090] The test communication coil can also be used as a normal communication coil.

[0091] 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.

[0092] The power-receiver communication antenna, the power-transmitter communication antenna and the test 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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 wireless power transfer system (10) comprising: a power transmitter (20) having a power transmitting antenna (22); and a power receiver (100) having a power receiving antenna (102) and mounted on a vehicle (11), wherein the power transmitting antenna is configured to wirelessly supply electric power to the power receiving antenna, the power receiver includes a power-receiver communication antenna (170), and a power-receiver control unit (230) configured to control energization of the power-receiver communication antenna for supply of a power supply request signal to the power-receiver communication antenna to be transmitted to the power transmitting antenna, and the power transmitter includes a power-transmitter communication antenna (40) configured to perform wireless communication with the power-receiver communication antenna, and a power-transmitter control unit (70) configured to control energization of the power transmitting antenna based on the power supply request signal received by the power-transmitter communication antenna, the wireless power transfer system comprising: an inspection vehicle (400); and a diagnostic unit (71), wherein the inspection vehicle includes a test communication antenna (411) configured to perform wireless communication with the power-transmitter communication antenna, and a signal supply unit (412) configured to supply a diagnostic power supply request signal to the test communication antenna, the diagnostic unit is configured to acquire the diagnostic power supply request signal received by the power-transmitter communication antenna, and diagnose a communication function of the power transmitter based on the acquired diagnostic power supply request signal.

2. The wireless power transfer system according to claim 1, wherein the power-transmitter control unit includes a power-transmitter amplifier (81) configured to amplify a signal received by the power-transmitter communication antenna, a determination unit (83) configured to determine whether there is a power supply request to the power transmitting antenna based on an output signal of the power-transmitter amplifier, and a power supply control unit (71) configured to supply power to the power transmitting antenna when it is determined that there is a power supply request, and the diagnostic unit is configured to acquire an intensity of the power supply request signal received by the power-transmitter communication antenna based on the output signal of the power-transmitter amplifier, perform a process of increasing a gain of the power-transmitter amplifier when it is determined that the acquired intensity is lower than a lower limit value of an expected intensity range, and perform a process of decreasing the gain of the power-transmitter amplifier when it is determined that the acquired intensity is higher than an upper limit value of the expected intensity range.

3. The wireless power transfer system according to claim 2, wherein the diagnostic unit is configured to determine that an abnormality has occurred in the communication function of the power transmitter when the diagnostic unit determines that the gain of the power-transmitter amplifier is higher than an upper limit gain, or when the diagnostic unit determines that the gain is lower than a lower limit gain that is smaller than the upper limit gain, as a result of adjusting the gain based on the acquired intensity.

4. The wireless power transfer system according to claim 1, wherein the power-transmitter control unit is configured to acquire an intensity of the power supply request signal received by the power-transmitter communication antenna, and determine that an abnormality has occurred in the communication function of the power transmitter when it is determined that the acquired intensity is lower than a lower threshold indicating an abnormality in the communication function of the power transmitter, or when it is determined that the acquired intensity is higher than an upper threshold indicating an abnormality in the communication function of the power transmitter.

5. The wireless power transfer system according to any one of claims 1 to 4, wherein the signal supply unit is configured to supply a signal including ID information of the inspection vehicle together with the diagnostic power supply request signal to the test communication antenna, and the diagnostic unit is configured to determine whether it is in a diagnosis mode in which the communication function of the power transmitter is diagnosed, based on the ID information of the inspection vehicle.

6. The wireless power transfer system according to any one of claims 1 to 4, wherein an intensity of the diagnostic power supply request signal supplied from the signal supply unit to the test communication antenna is greater than an intensity of the power supply request signal supplied to the power-receiver communication antenna in the power receiver of the vehicle (11) that is a general vehicle different from the inspection vehicle.

7. The wireless power transfer system according to any one of claims 1 to 4, wherein a dimension of the test communication antenna in a vehicle width direction is larger than a dimension of the power-receiver communication antenna in the vehicle width direction provided on the vehicle (11) that is a general vehicle different from the inspection vehicle.

8. The wireless power transfer system according to any one of claims 1 to 4, wherein the diagnostic unit is configured to determine that an abnormality has occurred in the communication function of the power transmitter when determining that the diagnostic power supply request signal is not received by the power-transmitter communication antenna even in a diagnosis period in which the diagnostic power supply request signal is transmitted from the inspection vehicle.

9. A program for a wireless power transfer system (10), the system including a power transmitter (20) having a power transmitting antenna (22), and a power receiver (100) having a power receiving antenna (102) and mounted on a vehicle (11), the power transmitting antenna configured to wirelessly supply electric power to the power receiving antenna, the power receiver including a power-receiver communication antenna (170), and a power-receiver control unit (230) configured to control energization of the power-receiver communication antenna for supply of a power supply request signal to the power-receiver communication antenna to be transmitted to the power transmitting antenna, the power transmitter including a power-transmitter communication antenna (40) configured to perform wireless communication with the power-receiver communication antenna, and a power-transmitter control unit (70) configured to control energization of the power transmitting antenna based on the power supply request signal received by the power-transmitter communication antenna, the wireless power transfer system including an inspection vehicle (400), and a diagnostic unit (71), the inspection vehicle including a test communication antenna (411) configured to perform wireless communication with the power-transmitter communication antenna, and a signal supply unit (412) configured to supply a diagnostic power supply request signal to the test communication antenna, the program configured to cause the diagnostic unit to carry out: acquiring the diagnostic power supply request signal received by the power-transmitter communication antenna; and diagnosing a communication function of the power transmitter based on the acquired diagnostic power supply request signal.

10. A control method for a wireless power transfer system (10), the system including a power transmitter (20) having a power transmitting antenna (22), and a power receiver (100) having a power receiving antenna (102) and mounted on a vehicle (11), the power transmitting antenna configured to wirelessly supply electric power to the power receiving antenna, the power receiver including a power-receiver communication antenna (170), and a power-receiver control unit (230) configured to control energization of the power-receiver communication antenna for supply of a power supply request signal to the power-receiver communication antenna to be transmitted to the power transmitting antenna, the power transmitter including a power-transmitter communication antenna (40) configured to perform wireless communication with the power-receiver communication antenna, and a power-transmitter control unit (70) configured to control energization of the power transmitting antenna based on the power supply request signal received by the power-transmitter communication antenna, the wireless power transfer system including an inspection vehicle (400), and a diagnostic unit (71), the inspection vehicle including a test communication antenna (411) configured to perform wireless communication with the power-transmitter communication antenna, and a signal supply unit (412) configured to supply a diagnostic power supply request signal to the test communication antenna, the control method, executed by the diagnostic unit, comprising: acquiring the diagnostic power supply request signal received by the power-transmitter communication antenna; and diagnosing a communication function of the power transmitter based on the acquired diagnostic power supply request signal.

11. A power transmitter applied to a wireless power transfer system, the system including the power transmitter (20) provided as a ground-side device and having a power transmitting antenna (22), and a power receiver (100) provided on a vehicle (11) and 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) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) of the power receiver; and a power-transmitter control unit (70) configured to control energization of the power transmitting antenna, wherein the wireless power transfer system includes an inspection vehicle (400), the inspection vehicle includes a test communication antenna (411) configured to perform wireless communication with the power-transmitter communication antenna, and a signal supply unit (412) configured to supply a diagnostic power supply request signal to the test communication antenna, the power-transmitter control unit is configured to acquire the diagnostic power supply request signal received by the power-transmitter communication antenna, and diagnose a communication function of the power transmitter based on the acquired diagnostic power supply request signal.

12. An inspection vehicle for diagnosis of communication function of a power transmitter applied to a wireless power transfer system, the system including the power transmitter (20) provided as a ground-side device and having a power transmitting antenna (22), and a power receiver (100) provided on a vehicle (11) and 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 including a power-transmitter communication antenna (40) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) of the power receiver, the inspection vehicle comprising: a test communication antenna (411) configured to perform wireless communication with the power-transmitter communication antenna; and a signal supply unit (412) configured to supply a diagnostic power supply request signal to the test communication antenna, wherein the wireless power transfer system includes a diagnostic unit (71) configured to acquire the diagnostic power supply request signal received by the power-transmitter communication antenna, and diagnose a communication function of the power transmitter based on the acquired diagnostic power supply request signal.

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