Power receiver, vehicle, and wireless power transfer system

Abstract

A power-receiver control unit (230) supplies and stops supplying a power supply request signal, which indicates a power supply request to a power transmitting antenna (22), to a power-receiver communication antenna (170). A power-transmitter control unit (70) causes the power transmitting antenna to perform power supply to a power receiving antenna (102) when it determines that there is a power supply request based on the power supply request signal received by a power-transmitter communication antenna (40), and stop the power supply when it determines that there is no power supply request. The power-receiver control unit can communicate with a vehicle (11) equipped with a power receiver (100), and transmit a notification signal to the vehicle based on a fact that power supply is being performed despite no power supply being requested.

Description

POWER RECEIVER, VEHICLE, AND WIRELESS POWER TRANSFER SYSTEMCross Reference

[0001] This application is based on Japanese Patent Application No. 2024-208034 filed on November 29, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power receiver, a vehicle, and a wireless power transfer system.

[0003] For example, 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 power-transmitter communication antenna. The power receiver includes a power receiver coil and a power-receiver communication antenna. The power receiver coil is supplied with electric power wirelessly from the power transmitter coil. The power receiver supplies a power supply request signal, which indicates a power supply request to the power transmitter coil, to the power-receiver communication antenna. The power transmitter determines whether there is a power supply request based on an output signal of the power-transmitter communication antenna. When the power transmitter determines that there is the power supply request, the power transmitter energizes the power transmitter coil. On the other hand, when the power transmitter determines that there is no power supply request, the power transmitter stops energization of the power transmitter coil.

[0004] JP 2024-008088 A

[0005] However, for some reason, a communication range of the power supply request signal transmitted from the vehicle may be excessively expanded. In this case, even though no power supply request signal is transmitted to the power-receiver communication antenna, electric power may be supplied from the power transmitter coil (power transmitting antenna) to a power receiver coil (power receiving antenna) of another vehicle near the vehicle having the excessively expanded communication range.

[0006] It is preferable to take some kind of action in response to power supply being performed even though the power receiver has not requested power supply. In addition, the power receiver has not requested power supply, not only when a power supply request signal is not supplied to the power-receiver communication antenna, but also when a stop request signal indicating a request to stop power supply to the power transmitter coil is supplied to the power-receiver communication antenna.

[0007] It is a main object of the present disclosure is to facilitate necessary measures to be taken when power is supplied despite a power receiver requesting no power supply.

[0008] According to a first aspect of the present disclosure, a power receiver is applied to a wireless power transfer system. The system includes a power transmitter and the power receiver. The power transmitter includes a power transmitting antenna, at least one power-transmitter communication antenna, and a power-transmitter control unit. The power receiver includes a power receiving antenna configured to wirelessly receive power from the power transmitting antenna, at least one power-receiver communication antenna configured to perform wireless communication with the power-transmitter communication antenna, and a power-receiver control unit. The power-receiver control unit is configured to supply and stop supplying a power supply request signal, which indicates a power supply request to the power transmitting antenna, to the power-receiver communication antenna. The power-transmitter control unit is configured to cause the power transmitting antenna to perform power supply to the power receiving antenna when the power-transmitter control unit determines that there is the power supply request based on the power supply request signal received by the power-transmitter communication antenna. The power-transmitter control unit is configured to cause the power transmitting antenna to stop the power supply when the power-transmitter control unit determines that there is no power supply request. The power-receiver control unit is configured to communicate with a vehicle equipped with the power receiver, and transmit a notification signal to the vehicle based on a fact that the power supply is being performed despite no power supply being requested.

[0009] According to the above configuration, the power receiving antenna wirelessly receives power supply from the power transmitting antenna. The at least one power-receiver communication antenna performs wireless communication with the power-transmitter communication antenna.

[0010] Herein, the power-receiver control unit supplies and stops supplying the power supply request signal to the power-receiver communication antenna. The power-transmitter control unit causes the power transmitting antenna to perform power supply to the power receiving antenna when the power-transmitter control unit determines that there is the power supply request based on the power supply request signal received by the power-transmitter communication antenna, and causes the power transmitting antenna to stop the power supply when the power-transmitter control unit determines that there is no power supply request. Therefore, the power-receiver control unit is capable of switching between supplying power from the power transmitting antenna to the power receiving antenna and stopping the power supply, by supplying and stopping supplying the power supply request signal.

[0011] However, even though the power-receiver control unit does not supply the power supply request signal, for example, power may be supplied from the power transmitting antenna to the power receiving antenna.

[0012] In consideration of this point, the power-receiver control unit can communicate with the vehicle equipped with the power receiver, and transmit a notification signal to the vehicle based on a fact that the power supply is being performed despite no power supply being requested. Therefore, the vehicle that receives the notification signal can recognize that unrequested power supply is occurring, making it easier to take necessary measures such as displaying a notification of the abnormality occurrence in the vehicle.

[0013] According to an aspect of the present disclosure, a wireless power transfer system includes a power transmitter and a power receiver. The power transmitter includes a power transmitting antenna, at least one power-transmitter communication antenna, and a power-transmitter control unit. The power receiver includes a power receiving antenna configured to wirelessly receive power from the power transmitting antenna, at least one power-receiver communication antenna configured to perform wireless communication with the power-transmitter communication antenna, and a power-receiver control unit. The power-receiver control unit is configured to supply and stop supplying a power supply request signal, which indicates a power supply request to the power transmitting antenna, to the power-receiver communication antenna. The power-transmitter control unit is configured to cause the power transmitting antenna to perform power supply to the power receiving antenna when the power-transmitter control unit determines that there is the power supply request based on the power supply request signal received by the power-transmitter communication antenna, and cause the power transmitting antenna to stop the power supply when the power-transmitter control unit determines that there is no power supply request. The power-receiver control unit is configured to communicate with a vehicle equipped with the power receiver, and transmit a notification signal to the vehicle based on a fact that the power supply is being performed despite no power supply being requested.

[0014] According to the above configuration, in the wireless power transfer system, the same advantageous effects as those of the first aspect can be obtained.

[0015] 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 a diagram illustrating the wireless power transfer system and a vehicle.FIG. 3 is a diagram illustrating a power transmitter and a power receiver.FIG. 4 is a diagram illustrating a power-receiver control unit and its peripheral configuration.FIG. 5 is a flowchart illustrating a transmission process for a power supply request signal, executed by the power receiver.FIG. 6 is a diagram illustrating a state in which erroneous power supply occurs due to a vehicle with an expanded communication range.FIG. 7 is a flowchart of a transmission process for a stop request signal and an abnormality determination process, executed by the power receiver.FIG. 8 is a diagram illustrating an example of instructing a driver to deviate from a power supply lane.FIG. 9 is a flowchart of an energization control process for a power transmitter coil, executed by the power transmitter.FIG. 10 is a flowchart of a transmission process for a stop request signal and an abnormality determination process, executed by a power receiver, according to a second embodiment.FIG. 11 is a diagram illustrating a modified example of a power transmitter and a modified example of a power receiver.FIG. 12 is a diagram illustrating a modified example of a power transmitter and a power receiver.FIG. 13 is a diagram illustrating a modified example of a power transmitter and a power receiver.FIG. 14 is a diagram illustrating an arrangement of a power-transmitter communication coil.

[0016] 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.

[0017] First Embodiment A first embodiment of a wireless power transfer system of the present disclosure will be described below with reference to the drawings.

[0018] 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 (including parked). 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.

[0019] 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 (also indicated as "GA") is installed (for example, buried) in the road RS, a parking lot, and the like. The power-transmitter power supply unit 51 (also indicated as "MU") 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. 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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. 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.

[0024] 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. 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.

[0025] 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.

[0026] 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.

[0027] 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).

[0028] 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.

[0029] 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.

[0030] 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. 3, 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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 transmitter coil 22 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.

[0038] 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.

[0039] The power receiver 100 includes a voltage sensor 330, a current sensor 340, and an intensity sensor 350 (corresponding to an "intensity detection unit"). The voltage sensor 330 detects voltages of various in-vehicle devices of the vehicle 11 (specifically, components of the power receiver 100), for example, a voltage of the smoothing capacitor 210. The current sensor 340 detects currents flowing in various in-vehicle devices of the vehicle 11 (specifically, the components of the power receiver 100), for example, currents flowing in the power receiver coil 102 and the rectifier circuit 200. The intensity sensor 350 detects an intensity of signal transmitted from another vehicle present around the vehicle 11 via narrow area wireless communication. The intensity sensor 350 can be a variety of sensors, such as, for example, a magnetoresistive sensor or a Hall effect sensor. The detected values of the sensors 330, 340, 350 are input to the power-receiver controller 231.

[0040] 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). The power-receiver control unit 230 includes a signal transmitter 240 (also indicated as "TX").

[0041] The power-transmitter coil unit 21, which constitutes the power transmitter 20, includes a power-transmitter communication coil 40 (corresponding to a power-transmitter communication antenna). The power-transmitter control unit 70 includes a signal receiver 80 (also indicated as "RX"). 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 about 3 meters). Narrow area wireless communication is a communication with a shorter communication distance than wide area wireless communication.

[0042] 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.

[0043] 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 is a signal requesting the power transmitter coil 22 near the vehicle 11 to transmit power to the power receiver coil 102. For example, when the state of charge (SOC) of the high-voltage storage battery 300 is 70% or less, the power-receiver controller 231 controls the signal transmitter 240 to supply the power supply request signal to the power-receiver communication coil 170. The fact that the power-receiver controller 231 (power-receiver control unit 230) does not supply a power supply request signal to the power-receiver communication coil 170 corresponds to the power-receiver controller 231 not requesting power supply.

[0044] The power-receiver control unit 230 controls the signal transmitter 240 to supply a vehicle-side signal including, in one frame, the power supply request signal and a traveling speed signal (corresponding to a traveling state signal) indicating a traveling speed Vsp (corresponding to a traveling state) of the vehicle 11 to the power-receiver communication coil 170. 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. The power-receiver control unit 230 is capable of communicating with, for example, a vehicle ECU that controls the vehicle 11, and acquires the ID information and the traveling speed Vsp of the vehicle 11 from the vehicle ECU. The communication between the power-receiver control unit 230 and the vehicle ECU may be wired communication or wireless communication. That is, the power-receiver control unit 230 is capable of communicating with the vehicle 11.

[0045] 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. 3. 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.

[0046] 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).

[0047] 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 performing switching control of the inverter 60 and the PFC circuit 61. This results in a wireless power transmission from the power transmitter coil 22 to the power receiver coil 102. 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.

[0048] The signal transmitter 240 and its peripheral configuration will be described with reference to FIG. 4.

[0049] 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 vehicle-side signal, which is a high-frequency signal including a power supply request signal and a traveling speed signal, based on a command from the power-receiver controller 231. The frequency of the vehicle-side 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.

[0050] The power-receiver controller 231 instructs the generating circuit 241 to generate a vehicle-side 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.

[0051] FIG. 5 shows a flowchart of a transmission process of the power supply request signal executed by the power receiver 100.

[0052] In step S10, the power-receiver controller 231 determines whether there is a power supply request. When determining that there is the power supply request, the process proceeds to step S11 in which the power-receiver controller 231 instructs the generating circuit 241 to generate a vehicle-side signal including a power supply request signal. As a result, the vehicle-side signal from the generating circuit 241 is input to the power-receiver amplifier 242. The power-receiver amplifier 242 amplifies the input vehicle-side signal and supplies the amplified signal to the power-receiver communication coil 170.

[0053] On the other hand, when determining in step S10 that there is no power supply request, the process proceeds to step S12, in which the power-receiver controller 231 instructs the generating circuit 241 to stop generating the vehicle-side signal. This causes the generating circuit 241 to stop outputting the vehicle-side signal. As a result, the supply of the vehicle-side signal to the power-receiver communication coil 170 is stopped.

[0054] Returning to FIG. 3, the signal receiver 80 amplifies the high-frequency signal (high-frequency current or 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.

[0055] Based on the high-frequency signal input from a power-transmitter amplifier, the signal receiver 80 calculates an intensity Intd which is an amplitude or effective value of the input high-frequency signal. The signal receiver 80 determines whether there is a power supply request to the power transmitter coil 22 based on the calculated intensity Intd. Specifically, when determining that the intensity Intd exceeds a determination threshold Ijde, the signal receiver 80 determines that there is the power supply request. On the other hand, when determining that the intensity Intd is lower than the determination threshold Ijde, the signal receiver 80 determines that there is no power supply request. The determination result information of the signal receiver 80 is input to the power-transmitter controller 71.

[0056] 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, the switches of the PFC circuit 61 and the inverter 60 are kept off, and the power transmitter coil 22 is not energized.

[0057] 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.

[0058] Herein, in some cases, the intensity of the power supply request signal supplied to the power-receiver communication coil 170 of the vehicle may become excessively large, and a communication range of the power supply request signal transmitted from the vehicle may be excessively expanded. In FIG. 6, the reference numeral 500 indicates a vehicle with an excessively expanded communication range. In case where the bottom of the vehicle 500 is at a high position, and the power-receiver coil unit 101 is at a high position, the communication range of the power supply request signal transmitted from the vehicle 500 may be excessively expanded.

[0059] In another vehicle 11 present near the vehicle 500 with the excessively expanded communication range, the power-transmitter communication coil 40 present nearby may receive the power supply request signal, even though the power supply request signal is not supplied to the power-receiver communication coil 170. As a result, the nearby power transmitter coil 22 is energized, and power is transmitted from the power transmitter coil 22 to the power receiver coil 102 of the vehicle 11, even though there is no power supply request from the vehicle 11. In other words, the fact that power is being transmitted to the power receiver coil 102 of the vehicle 11 (power supply is being performed) even though the vehicle 11 is not requesting power supply is due to a power supply request signal transmitted from the vehicle 500, which is different from the vehicle 11.

[0060] In addition to the case where the vehicle 500 with the expanded communication range and the other vehicle 11 are stopped, this issue may occur in a case where the vehicle 500 with the expanded communication range and the other vehicle 11 are traveling, and the relative speed between the vehicle 500 with the extended communication range and the other vehicle 11 is close to zero. Further, even if an abnormality occurs in a function that stops the power supply request signal (also if an abnormality occurs where the power supply request signal continues to be transmitted) in the power receiver 100, power may be transmitted from the power transmitter coil 22 to the power receiver coil 102 of the vehicle 11 even though the vehicle 11 is not requesting power supply.

[0061] In order to address such issues, the power-receiver control unit 230 supplies a stop request signal STOPCOMM to the power-receiver communication coil 170, when determining that a stop request condition (corresponding to a predetermined stop condition) for requesting the power transmitter coil 22 to stop power supply has been satisfied. The power-transmitter control unit 70 stops energization of the power transmitter coil 22, when determining that the stop request signal has been input based on the output signal of the power-transmitter communication coil 40. The fact that the power-receiver control unit 230 supplies a stop request signal to the power-receiver communication coil 170 corresponds to the power-receiver control unit 230 not requesting power supply.

[0062] FIG. 7 is a flowchart of a transmission process for the stop request signal executed by the power-receiver control unit 230.

[0063] In step S20, the power-receiver controller 231 determines whether the stop request condition is satisfied. The stop request condition is, for example, a condition for detecting the presence of the vehicle 500 with an excessively expanded communication range around the vehicle 11. The stop request condition is, for example, any one of the following conditions (A1) to (A4).

[0064] A condition (A1) is a condition that the power-receiver controller 231 determines that the vehicle 11 has switched from a state where there is a power supply request to a state where there is no power supply request. That is, in the process of FIG. 5, the condition (A1) is satisfied when a state where the determination in step S10 is affirmative is switched to a state where the determination is negative. According to the condition (A1), when there is no power supply request from the vehicle 11, energization of the power transmitter coil 22 present near the vehicle 11 is stopped.

[0065] A condition (A2) is a condition that there is no power supply request from the vehicle 11 and a current is flowing through the power receiver coil 102. The state in which a current flows through the power receiver coil 102 even though there is no power supply request from the vehicle 11 is a state where there is a high possibility that the vehicle 500, with the excessively expanded communication range for the power supply request signal, is present nearby. The stop request condition (A2) allows for an accurate determination of such a state. It may be determined whether a current flows through the power receiver coil 102 based on, for example, a current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or a voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0066] A condition (A3) is a condition that an intensity ILoud detected by the intensity sensor 350 exceeds an intensity threshold ILth. A state in which the intensity ILoud detected by the intensity sensor 350 becomes excessively large and exceeds the intensity threshold ILth is a state in which there is a high possibility that the vehicle 500 with the excessively expanded communication range for the power supply request signal is present nearby. The stop request condition (A3) allows for an accurate determination of such a state. The intensity threshold ILth is, for example, a value larger than the determination threshold Ijde.

[0067] A condition (A4) is a condition that the intensity ILoud detected by the intensity sensor 350 exceeds the intensity threshold ILth and there is no power supply request in the vehicle 11. The stop request condition (A4) allows more accurate determination that the vehicle 500 with the excessively expanded communication range is highly likely to be present near the vehicle 11.

[0068] When determining in step S20 that the stop request condition is satisfied, the process proceeds to step S21 in which the power-receiver controller 231 instructs the generating circuit 241 to generate the stop request signal, which is a high-frequency signal. As a result, the stop request signal generated by the generating circuit 241 is input to the power-receiver amplifier 242. The stop request signal amplified by the power-receiver amplifier 242 is supplied to the power-receiver communication coil 170. This causes the power-receiver communication coil 170 to transmit the stop request signal.

[0069] Regardless of the result of the determination of the presence or absence of the power supply request in the process of FIG. 5, when determining that the stop request condition is satisfied, the power-receiver controller 231 instructs the generating circuit 241 to stop generating the power supply request signal. That is, when it is determined that there is a power supply stop request based on the stop request signal received by the power-transmitter communication coil 40, the stop of the power supply is prioritized even if it has been previously determined that there is a power supply request.

[0070] The stop request signal is a signal different from the power supply request signal.

[0071] For example, the stop request signal is a signal having a greater intensity than the power supply request signal. A large intensity means that the amplitude or effective value of the signal is large. In this case, the frequency of the stop request signal may be, for example, the same as the frequency of the power supply request signal.

[0072] For example, the stop request signal is a signal having a different bit length from the power supply request signal. In this case, the frequency of the stop request signal may be, for example, the same as the frequency of the power supply request signal.

[0073] For example, the stop request signal is a signal having a different frequency from the power supply request signal.

[0074] Such stop request signal allows the power-transmitter control unit 70 to appropriately distinguish between the power supply request signal and the stop request signal.

[0075] When the stop request signal is a signal having a different bit length from the power supply request signal, the stop request signal may be a signal having a shorter bit length than the power supply request signal. Therefore, an energization stop request to the power transmitter coil 22 can be notified to the power-transmitter control unit 70 as early as possible.

[0076] When determining in step S20 that the stop request condition is not satisfied, the process proceeds to step S22 where the power-receiver controller 231 instructs the generating circuit 241 to stop generating the stop request signal, and the process proceeds to step S20. As a result, the generating circuit 241 does not output the stop request signal.

[0077] After completion of step S21, the process proceeds to step S23 in which the power-receiver controller 231 determines whether power supply from the power transmitter coil 22 to the power receiver coil 102 is being performed. Specifically, the power-receiver controller 231 determines whether a period during which a current has continuously flowed through the power receiver coil 102 has exceeded a continuity threshold since the supply of the stop request signal was started in the process of step S21. That is, it is determined whether the period during which the power receiver coil 102 has continuously received power since the stop request signal was supplied to the power-receiver communication coil 170 has exceeded the continuity threshold. The continuity threshold is set to an appropriate value in advance, based on an expected manner of power supply to the power receiver coil 102, for example. It may be determined whether a current flows through the power receiver coil 102 based on, for example, a current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or a voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0078] When it is determined in step S23 that power supply from the power transmitter coil 22 to the power receiver coil 102 is being performed, the process proceeds to step S24, and it is determined that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal (malfunctioning). Specifically, it is determined that the function of the power-receiver communication coil 170 to transmit the stop request signal or the function of the power-transmitter communication coil 40 to receive the stop request signal is abnormal (malfunctioning).

[0079] Next, the process proceeds to step S25, where the power-receiver controller 231 transmits a notification signal to the vehicle ECU. The notification signal includes a signal instructing a driver of the vehicle 11 to move the vehicle 11 away from the place where power supply is performed. The place where power supply is performed includes a lane or location within a parking lot, a taxi pool, a bus stop, a charging station, and the like, where power is supplied to the vehicle 11 that is moving, stopped, or parked. The place where power supply is performed further includes a lane in the road RS where multiple power transmitter coils 22 are embedded to supply power to the traveling vehicle 11.

[0080] FIG. 8 shows an example of a case where the driver is instructed to deviate from a driving lane DL1 (corresponding to power supply lane) in which multiple power transmitter coils 22 are embedded on a one-way or two-lane road RS. Specifically, the vehicle ECU that has received the notification signal causes an instrument panel of the vehicle 11 to display, for example, a message instructing the driver to deviate from the driving lane DL1. This prompts the driver to drive the vehicle 11 so as to move from the driving lane DL1 to a driving lane DL2. Then, the series of processing described above is terminated (END).

[0081] On the other hand, when it is determined in step S23 that power supply from the power transmitter coil 22 to the power receiver coil 102 is not being performed, in step S26, the power-receiver controller 231 determines whether an end condition for terminating the transmission of the stop request signal is satisfied.

[0082] For example, when the stop request condition is the condition (A1), the end condition may be a condition that a state where there is no power supply request is switched to a state where there is the power supply request. That is, in the process of FIG. 5, the end condition is satisfied when the state where the determination is negative in step S10 is switched to a state where the determination is affirmative.

[0083] For example, when the stop request condition is the condition (A2), the end condition may be a condition that a current no longer flows through the power receiver coil 102. It may be determined whether a current flows through the power receiver coil 102 based on, for example, a current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or a voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0084] For example, when the stop request condition is the condition (A3) or (A4), the end condition may be a condition that the intensity ILoud detected by the intensity sensor 350 is lower than the intensity threshold ILth. Accordingly, supply of the stop request signal can be stopped when the narrow area wireless communication of the vehicle 500 with the excessively expanded communication range no longer reaches the vehicle 11.

[0085] When it is determined in step S26 that the end condition is satisfied, the process proceeds to step S27 where the power-receiver controller 231 instructs the generating circuit 241 to stop generating the stop request signal. Then, the series of processing described above is terminated (END). When determination in step S26 is affirmative in a state where there is the power supply request in the process shown in the flowchart of FIG. 5, the power-receiver controller 231 instructs the generating circuit 241 to start generating the power supply request signal.

[0086] On the other hand, when it is determined in step S26 that the end condition is not satisfied, the power-receiver controller 231 executes the process of step S23 again.

[0087] FIG. 9 is a flowchart of an energization control process for the power transmitter coil 22, executed by the power-transmitter control unit 70.

[0088] In step S30, the power-transmitter controller 71 acquires determination result of whether there is the power supply request from the signal receiver 80. The power-transmitter controller 71 determines whether there is the power supply request based on the determination result.

[0089] In step S30, when the power-transmitter controller 71 determines that there is the power supply request, the process proceeds to step S31. In step S31, the power-transmitter controller 71 acquires from the signal receiver 80 the determination result of whether the stop request signal has been received. The signal receiver 80 determines whether the stop request signal has been received based on the high-frequency signal input from a power-transmitter amplifier.

[0090] When determining in step S31 that the stop request signal has not been received, the process proceeds to step S32 where the power-transmitter controller 71 sets a flag F to 0. In the following step S33, the power-transmitter controller 71 performs the switching control of the inverter 60 and the PFC circuit 61 to energize the power transmitter coil 22.

[0091] On the other hand, when determining in step S31 that the stop request signal has been received, the process proceeds to step S34 where the power-transmitter controller 71 sets the flag F to 1. In the following step S35, 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. The power-transmitter controller 71 executes the process of step S35 also when determination in step S30 is negative.

[0092] When the stop request signal is a signal having a different frequency from the power supply request signal, a carrier frequency and a modulation frequency for generating the stop request signal may be different from each other. In digital communication using a subcarrier, for example, in a case where the modulation frequency is normally set to 3.3 kHz, the power-transmitter control unit 70 may determine that the stop request signal has been received, when a modulation frequency of 1 kHz has been received by the power-transmitter control unit 70.

[0093] In step S36, the power-transmitter controller 71 determines whether the flag F is 1. When determining that the flag F is 0 (that is, the flag F is not 1), the power-transmitter controller 71 determines that the stop request signal has not been received, and the process proceeds to step S30.

[0094] On the other hand, when determining that the flag F is 1, the power-transmitter controller 71 determines that the stop request signal has been received, and the process proceeds to step S37. In step S37, the power-transmitter controller 71 determines whether a release condition for releasing energization stop of the power transmitter coil 22 is satisfied. The release condition is, for example, the following condition (B1) or (B2).

[0095] A condition (B1) is a condition in which it is determined that a power supply stop request has not been received, and the intensity Intd of the power supply request signal is lower than a detection threshold Ith. The detection threshold Ith is a value for determining whether the vehicle 500 with the excessively expanded communication range is present near the vehicle 11, and is, for example, a value higher than the determination threshold Ijde.

[0096] A condition (B2) is a condition that a predetermined period has elapsed since it was determined that a power supply stop request has not been received. The predetermined period is, for example, a period on the order of several seconds to several minutes. For example, the condition (B2) is used when the vehicle 11 is stopped.

[0097] When the power-transmitter controller 71 determines in step S37 that the release condition is not satisfied, the process proceeds to step S30. On the other hand, when the power-transmitter controller 71 determines that the release condition is satisfied, the process proceeds to step S38, and the power-transmitter controller 71 releases energization stop of the power transmitter coil 22. As a result, when determining that there is the power supply request, the power-transmitter controller 71 performs the switching control of the inverter 60 and the PFC circuit 61 to energize the power transmitter coil 22. Then, the series of processing described above is terminated (END).

[0098] A program for causing the wireless power transfer system 10 to execute the processes shown in the flowcharts of FIGS. 7 and 9 corresponds to a wireless power transfer program. A method for causing the wireless power transfer system 10 to execute the processes shown in the flowcharts of FIGS. 7 and 9 corresponds to a control method for the wireless power transfer system.

[0099] The present embodiment described above has the following advantages.

[0100] The power-receiver control unit 230 supplies and stops supplying the power supply request signal COMM to the power-receiver communication coil 170. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is a power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Therefore, the power-receiver control unit 230 is capable of switching between supplying power from the power transmitter coil 22 to the power receiver coil 102 and stopping the power supply, by supplying and stopping supplying the power supply request signal.

[0101] The power-receiver control unit 230 supplies the stop request signal STOPCOMM, which indicates a power supply stop request to the power transmitter coil 22 to stop power supply, to the power-receiver communication coil 170, when the stop request condition to request stop of power supply to the power transmitter coil 22 is satisfied. When the power-transmitter control unit 70 determines that there is a power supply stop request based on the stop request signal received by the power-transmitter communication coil 40, the power-transmitter control unit 70 prioritizes stopping the power supply even if it has previously determined that there is a power supply request. Therefore, the power-receiver control unit 230 can stop the power supply if power is transmitted from the power transmitter coil 22 to the power receiver coil 102 despite no power supply being requested.

[0102] The power-receiver control unit 230 determines that there is abnormality in the function of the power-receiver communication coil 170 to transmit the stop request signal or in the function of the power-transmitter communication coil 40 to receive the stop request signal, based on the fact that power supply being performed despite the stop request signal being supplied to the power-receiver communication coil 170. Therefore, it is possible to determine that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal.

[0103] The power-receiver control unit 230 determines that there is an abnormality in a function of the power-receiver communication coil 170 to transmit the stop request signal or in a function of the power-transmitter communication coil 40 to receive the stop request signal, when a period, during which the power receiver coil 102 has continuously received power since the stop request signal was supplied to the power-receiver communication coil 170, exceeds a continuity threshold. This configuration allows for easy determination of an abnormality when the power receiver coil 102 continues to receive power even after the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170.

[0104] The power-receiver control unit 230 is capable of communicating with the vehicle ECU of the vehicle 11 having the power receiver 100. The power-receiver control unit 230 transmits a notification signal to the vehicle ECU, when determining that there is an abnormality in the function of the power-receiver communication coil 170 to transmit the stop request signal or in the function of the power-transmitter communication coil 40 to receive the stop request signal. This configuration allows the notification of an abnormality to the vehicle ECU via the notification signal, thereby facilitating the display of an indication of the abnormality in the vehicle 11, for example. That is, the vehicle 11 that receives the notification signal can recognize that unrequested power supply is occurring, making it easier to take necessary measures.

[0105] The notification signal includes a signal that instructs the driver of the vehicle 11 to deviate from the driving lane DL1 in which power supply is performed. This configuration enables the vehicle 11 that receives the notification signal to easily display a message or the like to the driver, instructing the driver to deviate from the driving lane DL1, thereby encouraging the driver to move outside the driving lane DL1.

[0106] 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, as shown in FIG. 10, the transmission process of the stop request signal is modified.

[0107] In step S20, when determining that the stop request condition is satisfied, the process proceeds to step S20A where the power-receiver controller 231 determines whether there is the power supply request from the vehicle 11. When the power-receiver controller 231 determines that there is no power supply request, the process proceeds to step S22.

[0108] On the other hand, when determining that there is the power supply request, the process proceeds to step S20B where the power-receiver controller 231 determines whether a received power Wr of the power receiver coil exceeds the requested power Weq. The received power Wr of the power receiver coil 102 may be calculated, for example, based on the current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or the voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0109] When determining that the received power Wr is lower than (does not exceed) the requested power Weq, the process proceeds to step S22 where the power-receiver controller 231 instructs the generating circuit 241 to stop generating the stop request signal. As a result, power is transmitted from the power transmitter coil 22 to the power receiver coil 102 of the vehicle 11 in response to the power supply request signal transmitted from the vehicle 11.

[0110] On the other hand, when determining that the received power Wr exceeds the requested power Weq, the process proceeds to step S21 where the power-receiver controller 231 instructs the generating circuit 241 to stop generating the power supply request signal and to start generating the stop request signal.

[0111] According to the present embodiment described above, when the vehicle 11 can accept the received power, wireless power transfer to the vehicle 11 can be continued, even when it is determined that the stop request condition is satisfied.

[0112] Other Embodiments The above embodiments may be changed and carried out as follows. The same parts as those in each embodiment are assigned the same reference numerals, and their descriptions thereof are incorporated herein.

[0113] Even when the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170 and power supply is temporarily stopped, power supply may still be performed intermittently. In view of this, the process of step S23 in the flowchart of FIG. 7 may be executed in the following manner. That is, the power-receiver controller 231 determines whether a cumulative value of power supplied to the power receiver coil 102, since starting supply of the stop request signal in the process of step S21, has exceeded an integrated threshold. The integrated threshold is set to an appropriate value in advance, based on an expected manner of power supply to the power receiver coil 102, for example. According to this configuration, even if power supply is performed intermittently, an occurrence of an abnormality can be determined when the cumulative value of the power supplied to the power receiver coil 102 exceeds the integrated threshold.

[0114] The power-receiver control unit 230 may determine that there is an abnormality in the function of the power-receiver communication coil 170 to transmit the stop request signal or in the function of the power-transmitter communication coil 40 to receive the stop request signal, when: 1) the period during which the power receiver coil 102 continuously receives power after initiation of supply of the stop request signal exceeds the continuity threshold, and 2) the cumulative value of the power supplied to the power receiver coil 102 after the initiation of supply of the stop request signal exceeds the integrated threshold. This configuration allows for a more accurate determination of whether power is being supplied to the power receiver coil 102.

[0115] The process of step S25 in the flowcharts of FIGS. 7 and 10 may be modified as follows. The power-receiver controller 231 may cause the instrument panel of the vehicle 11 to display a message, instructing the driver to move out of the driving lane DL1 (corresponding to the location where power supply is performed), without using the vehicle ECU.

[0116] The notification signal may include a signal that instructs a display to indicate that the function of the power-receiver communication coil 170 to transmit the stop request signal is abnormal. The vehicle ECU that receives the notification signal displays, for example, a message on the instrument panel of the vehicle 11 to inform the driver that the power-receiver communication coil 170 is abnormal.

[0117] The notification signal may include a signal that instructs the vehicle 11 to perform automated driving to move out of the driving lane DL1 (corresponding to the location where power supply is performed). Then, the vehicle 11 may have a function to perform the automated driving to move out of the location where power supply is performed when receiving the notification signal. For example, the vehicle 11 may include, based on control of the vehicle ECU, a function to control the rotary electric machine 320 via the travelling inverter 310, a function to control steering wheels via a steering device, and a function to control a brake via a brake device. This configuration enables the vehicle 11 that receives the notification signal to perform the automated driving to move out of the driving lane DL1. Therefore, it is possible to more reliably eliminate the state in which, even though the power-receiver control unit 230 is not supplying the power supply request signal, power is supplied from the power transmitter coil 22 to the power receiver coil 102.

[0118] As shown in FIG. 11, the power receiver 100 may include, in addition to the power-receiver communication coil 170 (corresponding to first power-receiver communication antenna) and the signal transmitter 240, a power-receiver communication coil 170A (corresponding to second power-receiver communication antenna) and a signal transmitter 240A. Furthermore, the power transmitter 20 may include, in addition to the power-transmitter communication coil 40 (corresponding to first power-transmitter communication antenna) and the signal receiver 80, a power-transmitter communication coil 40A (corresponding to second power-transmitter communication antenna) and a signal receiver 80A.

[0119] The power-receiver control unit 230 supplies and stops supplying the power supply request signal to the power-receiver communication coil 170, based on the process of the flowchart in FIG. 5. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is a power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Furthermore, when determining in the process of step S20 of the flowcharts in FIGS. 7 and 10 that the stop request condition is satisfied, the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170A. In accordance with the process of the flowchart in FIG. 9, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication coil 40A, the power-transmitter control unit 70 prioritizes stopping the power supply even if it has previously determined that there is a power supply request.

[0120] According to the above configuration, the function of transmitting and stopping the power supply request signal and the function of transmitting and stopping the stop request signal can be allocated to the power-receiver communication coil 170 and the power-receiver communication coil 170A, respectively. Therefore, even when an abnormality occurs in the function of the power-receiver communication coil 170 to stop the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the power-receiver communication coil 170A to transmit the stop request signal.

[0121] However, when the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal, power may be supplied from the power transmitter coil 22 to the power receiver coil 102 even when no power supply request is made. In view of this, the power-receiver control unit 230 determines that there is an abnormality in the function of the power-receiver communication coil 170A to transmit the stop request signal or in the function of the power-transmitter communication coil 40A to receive the stop request signal, based on power supply that is performed even though the stop request signal is supplied to the power-receiver communication coil 170A. Therefore, it is possible to determine that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal.

[0122] In addition, the function to receive the power supply request signal and the function to receive the stop request signal can be allocated to the power-transmitter communication coil 40 and the power-transmitter communication coil 40A, respectively. Therefore, even when an abnormality occurs in the function of the power-transmitter communication coil 40 to recognize stop of the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the power-transmitter communication coil 40A to receive the stop request signal.

[0123] The wireless power transfer system 10 in FIG. 11 may be modified as shown in FIG. 12. That is, the power receiver 100 includes the power-receiver communication coil 170 and the signal transmitter 240, but does not include the power-receiver communication coil 170A and the signal transmitter 240A. In this case, the power-receiver control unit 230 supplies and stops supplying the power supply request signal to the power-receiver communication coil 170, based on the process of the flowchart in FIG. 5. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is a power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Furthermore, when determining in the process of step S20 of the flowcharts in FIGS. 7 and 10 that the stop request condition is satisfied, the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170. In accordance with the process of the flowchart in FIG. 9, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication coil 40A, the power-transmitter control unit 70 prioritizes stopping the power supply even if it has previously determined that there is a power supply request.

[0124] In the above configuration also, the function to receive the power supply request signal and the function to receive the stop request signal can be allocated to the power-transmitter communication coil 40 and the power-transmitter communication coil 40A, respectively. Therefore, even when an abnormality occurs in the function of the power-transmitter communication coil 40 to recognize stop of the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the power-transmitter communication coil 40A to receive the stop request signal.

[0125] The wireless power transfer system 10 in FIG. 11 may be modified as shown in FIG. 13. That is, the power transmitter 20 includes the power-transmitter communication coil 40 and the signal receiver 80, but does not include the power-transmitter communication coil 40A and the signal receiver 80A. In this case, the power-receiver control unit 230 supplies and stops supplying the power supply request signal to the power-receiver communication coil 170, based on the process of the flowchart in FIG. 5. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is a power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Furthermore, when determining in the process of step S20 of the flowcharts in FIGS. 7 and 10 that the stop request condition is satisfied, the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170A. In accordance with the process of the flowchart in FIG. 9, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication coil 40, the power-transmitter control unit 70 prioritizes stopping the power supply even if it has previously determined that there is a power supply request.

[0126] According to the above configuration, the function of transmitting and stopping the power supply request signal and the function of transmitting and stopping the stop request signal can be allocated to the power-receiver communication coil 170 and the power-receiver communication coil 170A, respectively. Therefore, even when an abnormality occurs in the function of the power-receiver communication coil 170 to stop the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the power-receiver communication coil 170A to transmit the stop request signal. The power-receiver control unit 230 determines that there is abnormality in the function of the power-receiver communication coil 170A to transmit the stop request signal or in the function of the power-transmitter communication coil 40 to receive the stop request signal, based on the fact that power supply being performed despite the stop request signal being supplied to the power-receiver communication coil 170A. Therefore, it is possible to determine that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal.

[0127] In the power receiver 100 in FIGS. 11 and 13, both the power-receiver communication coil 170 and the power-receiver communication coil 170A may transmit the stop request signal. In the power transmitter 20 in FIGS. 11 and 12, both the power-transmitter communication coil 40 and the power-transmitter communication coil 40A may receive the stop request signal.

[0128] As shown by the solid line in FIG. 14, the power-transmitter communication coil 40A (corresponding to second power-transmitter communication antenna) in FIGS. 11 and 12 may be, for example, buried (installed) in an edge part of the driving lane DL1 on the outer side of the road RS. In a case where the power-transmitter communication coil 40A is configured to receive the power supply request signal and the stop request signal, the power-transmitter communication coil 40A can be prevented from receiving the power supply request signal transmitted from a vehicle that travels in the driving lane DL2. As shown by the dashed line in FIG. 14, the power-transmitter communication coil 40A may be buried in an edge part of the driving lane DL1 on the center side of the road RS, or may be buried near the center of the driving lane DL1. In addition, the power-transmitter communication coil 40A may be of the same size as the power-transmitter communication coil 40 and installed one per power transmitter coil 22, or smaller than the power-transmitter communication coil 40 and installed in multiple units per power transmitter coil 22.

[0129] The power-transmitter communication coil 40A may be modified to include a passive element such as a coil, a capacitor, and an LED, without including a power source. The LED may be turned on by an induced electromotive force generated when the stop request signal is input to the coil, thereby notifying the driver that the power receiver 100 is transmitting the stop request signal.

[0130] The power-receiver communication antenna and the power-transmitter communication antenna are not limited to communication coils, and may employ various antennas.

[0131] 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.

[0132] In the wireless power transfer system 10, the power transmitter 20 may perform wide area wireless communication with the power receiver 100. Wide area wireless communication is a communication with a longer communication distance than the narrow area wireless communication. Examples of the wide area wireless communication include 3GPP (registered trademark), 4G, LTE, 5G, and WiMAX (registered trademark) developed by IEEE. The power-transmitter control unit 70 and the power-receiver control unit 230 may transmit and receive information (including the notification signal) using the wide area wireless communication. Furthermore, when the power-receiver control unit determines that there is an abnormality in the function of the power-receiver communication coil 170, 170A to transmit the stop request signal or in the function of the power-transmitter communication coil 40, 40A to receive the stop request signal, the power-receiver control unit 230 may transmit a power supply stop signal to the power transmitter 20 to stop power supply. In this case, power supply from the power transmitter coil 22 to the power receiver coil 102 is being performed (S23 in FIG. 7: YES) even though a stop request signal is being supplied (S21 in FIG. 7), which corresponds to a case in which the power-receiver control unit 230 has determined that power supply is being performed even though it has not requested power supply. When receiving the power supply stop signal from the power-transmitter communication coil 40, 40A, the power-transmitter control unit 70 may prioritize stopping the power supply even if it has determined that there is a power supply request. According to this configuration, power supply to the power transmitter 20 can be stopped by using wide area wireless communication even when the power transmitter 20 is away from the vehicle 11 while the vehicle 11 is traveling.

[0133] The power-transmitter control unit 70 and the power-receiver control unit 230 (wireless power transfer system 10), as well as the method thereof described in the present disclosure, may be implemented by a special purpose computer that includes a memory and a processor programmed to execute one or more specific functions embodied in computer programs stored in the memory. Alternatively, the power-transmitter control unit 70 and the power-receiver control unit 230, as well as the method thereof described in the present disclosure, may be implemented by a dedicated computer that includes a processor with one or more dedicated hardware logic circuits. Alternatively, the power-transmitter control unit 70 and the power-receiver control unit 230, as well as the method thereof described in the present disclosure, may be implemented by one or more dedicated computers that include a combination of the memory, the processor programmed to execute one or more functions, and the processor with one or more hardware logic circuits. The computer programs may be stored, as instructions to be executed by a computer, in a tangible non-transitory computer-readable medium.

[0134] The above-described embodiments and the modifications can be implemented in any combination within a possible range.

[0135] 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 receiver (100) applied to a wireless power transfer system (10), the system including a power transmitter (20) and the power receiver, the power transmitter including a power transmitting antenna (22), at least one power-transmitter communication antenna (40, 40A), and a power-transmitter control unit (70), the power receiver (100) comprising: a power receiving antenna (102) configured to wirelessly receive power from the power transmitting antenna; at least one power-receiver communication antenna (170, 170A) configured to perform wireless communication with the power-transmitter communication antenna; and a power-receiver control unit (230), wherein the power-receiver control unit is configured to supply and stop supplying a power supply request signal, which indicates a power supply request to the power transmitting antenna, to the power-receiver communication antenna, the power-transmitter control unit is configured to cause the power transmitting antenna to perform power supply to the power receiving antenna when the power-transmitter control unit determines that there is the power supply request based on the power supply request signal received by the power-transmitter communication antenna, and stop the power supply when the power-transmitter control unit determines that there is no power supply request, and the power-receiver control unit is configured to communicate with a vehicle (11) equipped with the power receiver, and transmit a notification signal to the vehicle based on a fact that the power supply is being performed despite no power supply being requested.

2. The power receiver according to claim 1, wherein the notification signal includes a signal instructing a driver of the vehicle to move out of a location where the power supply is performed.

3. The power receiver according to claim 1 or 2, wherein the power-receiver control unit is configured to communicate with power transmitter via wide area wireless communication, and transmit a power supply stop signal to the power transmitter to stop the power supply when the power-receiver control unit determines that the power supply is being performed despite no power supply being requested.

4. The power receiver according to any one of claims 1 to 3, wherein the power-receiver control unit is configured to determine that no power supply is requested when the power-receiver control unit does not supply the power supply request signal to the power-receiver communication antenna.

5. The power receiver according to any one of claims 1 to 3, wherein, in the wireless power transfer system, the power-receiver control unit is configured to supply a stop request signal, which indicates a power supply stop request to the power transmitting antenna, to the power-receiver communication antenna when a predetermined stop condition for requesting the power transmitting antenna to stop power supply is satisfied, the power-transmitter control unit is configured to stop the power supply when it determines that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna, giving priority to the stop request over the power supply request, and the power-receiver control unit is configured to determine that no power supply is requested when the power-receiver control unit supplies the stop request signal to the power-receiver communication antenna.

6. The power receiver according to any one of claims 1 to 5, wherein the fact that the power supply is being performed despite no power supply being requested is due to a power supply request signal transmitted from another vehicle which is different from the vehicle.

7. A vehicle equipped with the power receiver according to claim 1, wherein the notification signal includes a signal instructing the vehicle to perform automated driving to move out of a location where the power supply is performed, and the vehicle has a function to perform the automated driving to move out of the location where power supply is performed when receiving the notification signal.

8. A wireless power transfer system (10) comprising: a power transmitter (20) including a power transmitting antenna (22), at least one power-transmitter communication antenna (40, 40A), and a power-transmitter control unit (70); and a power receiver (100) including a power receiving antenna (102) configured to wirelessly receive power from the power transmitting antenna, at least one power-receiver communication antenna (170, 170A) configured to perform wireless communication with the power-transmitter communication antenna, and a power-receiver control unit (230), wherein the power-receiver control unit is configured to supply and stop supplying a power supply request signal, which indicates a power supply request to the power transmitting antenna, to the power-receiver communication antenna, the power-transmitter control unit is configured to cause the power transmitting antenna to perform power supply to the power receiving antenna when the power-transmitter control unit determines that there is the power supply request based on the power supply request signal received by the power-transmitter communication antenna, and stop the power supply when the power-transmitter control unit determines that there is no power supply request, and the power-receiver control unit is configured to communicate with a vehicle (11) equipped with the power receiver, and transmit a notification signal to the vehicle based on a fact that the power supply is being performed despite no power supply being requested.

9. The wireless power transfer system according to claim 8, wherein the power-receiver control unit is configured to communicate with power transmitter via wide area wireless communication, and transmit a power supply stop signal to the power transmitter to stop the power supply when the power-receiver control unit determines that no power supply is requested, and the power-transmitter control unit is configured to stop the power supply when the power-transmitter communication antenna receives the power supply stop signal, giving priority to the power supply stop signal over the power supply request.

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