Wireless power transmission system

Abstract

To provide a wireless power transmission system that can align the positions of a power transmitting side and a power receiving side with high precision.SOLUTION: A wireless power transmission system according to the present disclosure includes: a supply device installed on a side of a road and transmitting electric power; and a vehicle equipped with a power receiving device and traveling on the road. In the wireless power transmission system, the power receiving device receives power from the supply device and wirelessly transmits the power to the vehicle. The supply device includes a primary coil that generates a magnetic field for transmitting power to the vehicle, and a first communication device that performs short-range wireless communication with the vehicle. The vehicle includes a secondary coil that receives power transmitted contactlessly from the primary coil, and a second communication device that performs short-range wireless communication with the supply device. In the first and second communication devices, one communication device has a single communication unit, and the other communication device has a plurality of communication units.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a wireless power transmission system. [Background technology]

[0002] Patent Document 1 discloses a technology for pairing a power transmission device and a power receiving device in a contactless power supply system that enables information transmission between the power transmission device and the power receiving device via wireless communication. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2013-240132 [Overview of the project] [Problems that the invention aims to solve]

[0004] By the way, in the case of in-vehicle power supply, where power is transmitted while a vehicle is in motion, it is important to align the positions of the power transmission and reception sides in order to charge efficiently. In particular, uninterrupted communication is required in narrow-range wireless communication.

[0005] This disclosure has been made in view of the above, and aims to provide a wireless power transmission system that can perform high-precision alignment between the power transmitting side and the power receiving side. [Means for solving the problem]

[0006] The wireless power transmission system according to this disclosure comprises a power supply device installed on the roadside for transmitting power, and a vehicle equipped with a power receiving device that travels on the road, wherein the power receiving device receives power from the power supply device and transmits power wirelessly to the vehicle, the power supply device having a primary coil for generating a magnetic field for transmitting power to the vehicle, and a first communication device for performing narrow-range wireless communication with the vehicle, the vehicle having a secondary coil for receiving power transmitted non-contactually from the primary coil, and a second communication device for performing narrow-range wireless communication with the power supply device, wherein in the first and second communication devices, one communication device has a single communication unit, and the other communication device has a plurality of communication units. [Effects of the Invention]

[0007] According to this disclosure, the positioning of the transmitting side and the receiving side in a wireless power transmission system can be performed with high precision. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing a wireless power transmission system in an embodiment. [Figure 2] Figure 2 shows the overall configuration of the wireless power transmission system. [Figure 3] Figure 3 is a schematic diagram illustrating wide-area wireless communication in a wireless power transmission system. [Figure 4] Figure 4 is a block diagram illustrating the functional configuration of the power transmission ECU. [Figure 5] Figure 5 is a block diagram illustrating the functional configuration of the vehicle's ECU. [Figure 6] Figure 6 is a diagram illustrating the power transmission process. [Figure 7] Figure 7 is a sequence diagram showing the case where communication is performed between a vehicle and a supply device using wide-area wireless communication. [Figure 8] Figure 8 is a sequence diagram showing the operation after the power supply from the power supply device to the vehicle during driving has ended. [Figure 9] FIG. 9 is a diagram for explaining the arrangement of the second communication device and the fourth device. [Figure 10] FIG. 10 is a diagram for explaining the arrangement of the second communication device and the fourth device in a modified example. Mode for Carrying Out the Invention

[0009] Hereinafter, the wireless power transmission system in an embodiment of the present invention will be specifically described. Note that the present invention is not limited to the embodiments described below.

[0010] FIG. 1 is a schematic diagram showing a wireless power transmission system in an embodiment. The wireless power transmission system 1 includes a supply facility 2 and a vehicle 3. The supply facility 2 is a facility that supplies power to the vehicle 3 traveling on the road in a non-contact manner. The vehicle 3 is an electric vehicle that can be charged with power supplied from an external power source, and is, for example, a battery electric vehicle (BEV) or a plug-in hybrid vehicle (PHEV).

[0011] This wireless power transmission system 1 performs wireless power transmission from the supply facility 2 to the vehicle 3 by magnetic field resonance coupling (magnetic field resonance). The wireless power transmission system 1 transmits power to the vehicle 3 traveling on the road 4 from the supply facility 2 in a non-contact manner. That is, the wireless power transmission system 1 transmits power by the magnetic field resonance method, and realizes power supply during travel to the vehicle 3 using magnetic field resonance coupling (magnetic field resonance). The wireless power transmission system 1 can be expressed as a dynamic wireless power transmission (D-WPT) system or a magnetic field dynamic wireless power transmission (MF-D-WPT) system.

[0012] The power supply device 2 includes a power supply unit 5 and an AC power source 6 that supplies power to the power supply unit 5. The power supply unit 5 transmits the power supplied from the AC power source 6 to the vehicle 3 in a non-contact manner. The AC power source 6 is, for example, a commercial power source. This power supply unit 5 includes a power transmission device 10 having a primary coil 11.

[0013] The power supply unit 5 includes a segment 7 including the primary coil 11 and a management device 8 that manages the segment 7. The segment 7 is embedded in the lane of the road 4. The management device 8 is installed beside the road 4. The segment 7 is electrically connected to the management device 8. The management device 8 is electrically connected to the AC power source 6 and supplies the power of the AC power source 6 to the segment 7. The segment 7 is electrically connected to the AC power source 6 via the management device 8. A plurality of such segments 7 can be arranged along the lane of the road 4. For example, as shown in FIG. 1, the power supply unit 5 includes three segments 7 arranged side by side along the lane in the road 4 and one management device 8 to which the three segments 7 are connected. The segment 7 has a function of transmitting power in a non-contact manner from the power supply unit 5 to the vehicle 3. The management device 8 has a function of controlling the wireless power transmission in the segment 7.

[0014] The vehicle 3 includes a power receiving device 20 having a secondary coil 21. The power receiving device 20 is provided at the bottom of the vehicle body of the vehicle 3. When the vehicle 3 travels on the road 4 where the primary coil 11 is installed, the primary coil 11 on the ground side and the secondary coil 21 on the vehicle side face each other in the vertical direction. The wireless power transmission system 1 transmits power in a non-contact manner from the primary coil 11 of the power transmission device 10 to the secondary coil 21 of the power receiving device 20 while the vehicle 3 is traveling on the road 4.

[0015] In this description, "traveling" means a state in which the vehicle 3 is located on the road 4 for traveling. The state of traveling includes a state in which the vehicle 3 temporarily stops on the road 4. For example, a state in which the vehicle 3 stops on the road 4 due to waiting for a signal is also included in traveling. On the other hand, even when the vehicle 3 is located on the road 4, for example, when the vehicle 3 is parked, it is not included in traveling.

[0016] Furthermore, in this explanation, a lane in which the primary coil 11 (segment 7) is embedded may be referred to as a D-WPT lane, and a section of road 4 where wireless power transmission by the supply device 5 is possible may be referred to as a D-WPT charging site. In both D-WPT lanes and D-WPT charging sites, multiple primary coils 11 (multiple segments 7) are installed in a line in the direction of travel of the vehicle 3 over a predetermined section of road 4.

[0017] Figure 2 shows the overall configuration of the wireless power transmission system. In supply equipment 2, the supply device 5 and the AC power supply 6 are electrically connected. In supply device 5, the segment 7 and the management device 8 are electrically connected.

[0018] The supply device 5 includes a configuration provided in the management device 8 and a configuration provided in the segment 7. The supply device 5 comprises a power transmission device 10, a power transmission ECU (Electronic Control Unit) 110, a first communication device 120, a second communication device 130, and a foreign object detection device 140.

[0019] The power transmission device 10 includes an electrical circuit connected to the AC power source 6. The power transmission device 10 comprises a PFC (Power Factor Collection) circuit 210, an inverter (INV) 220, a filter circuit 230, and a power transmission side resonant circuit 240.

[0020] The PFC circuit 210 improves the power factor of the AC power input from the AC power supply 6, converts that AC power into DC power, and outputs it to the inverter 220. This PFC circuit 210 includes an AC / DC converter. The PFC circuit 210 is electrically connected to the AC power supply 6.

[0021] The inverter 220 converts the DC power input from the PFC circuit 210 into AC power. Each switching element of the inverter 220 is composed of IGBTs (Insulated Gate Bipolar Transistors) or MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors), and performs switching operations according to the control signal from the power transmission ECU 110. For example, the driving frequency of the inverter 220 is 85 kHz. The inverter 220 outputs the converted AC power to the filter circuit 230.

[0022] The filter circuit 230 removes noise contained in the AC current input from the inverter 220 and supplies the noise-free AC power to the transmission-side resonant circuit 240. The filter circuit 230 is an LC filter combining a coil and a capacitor. For example, the filter circuit 230 is composed of a T-type filter in which two coils and one capacitor are arranged in a T-shape. The PFC circuit 210, the inverter 220, and the filter circuit 230 constitute the power conversion section 12 of the power transmission device 10.

[0023] The transmitting-side resonant circuit 240 is a power transmission unit that transmits AC power supplied from the filter circuit 230 to the power receiving device 20 in a contactless manner. When AC power is supplied from the filter circuit 230 to the transmitting-side resonant circuit 240, current flows through the primary coil 11, generating a magnetic field for power transmission.

[0024] The power transmission side resonant circuit 240 comprises a primary coil 11 and a resonant capacitor. The primary coil 11 is a power transmission coil. This resonant capacitor is connected in series with one end of the primary coil 11 and adjusts the resonant frequency of the power transmission side resonant circuit. This resonant frequency is 10kHz to 100GHz, preferably 85kHz. For example, the power transmission device 10 is configured such that the resonant frequency of the power transmission side resonant circuit 240 matches the drive frequency of the inverter 220. The power transmission side resonant circuit 240 constitutes the primary device 13 of the power transmission device 10.

[0025] The power transmission device 10 comprises a power conversion unit 12 and a primary device 13. The power conversion unit 12 includes a PFC circuit 210, an inverter 220, and a filter circuit 230. The primary device 13 includes a power transmission side resonant circuit 240. The power transmission device 10 has a configuration in which the power conversion unit 12 is provided on the control device 8 and the primary device 13 is provided on segment 7.

[0026] In the power supply device 5, the power conversion unit 12 of the power transmission device 10, the power transmission ECU 110, and the first communication device 120 are provided in the management device 8, while the primary device 13 of the power transmission device 10, the second communication device 130, and the foreign object detection device 140 are provided in segment 7.

[0027] The power transmission ECU 110 is an electronic control unit that controls the power supply device 5. The power transmission ECU 110 includes a processor and memory. The processor consists of a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), etc. The memory is the main memory and consists of RAM (Random Access Memory), ROM (Read Only Memory), etc. The power transmission ECU 110 loads a program stored in the storage unit into the working area of ​​the memory (main memory) and executes it, and by controlling each component through the execution of the program, it realizes a function that matches a predetermined purpose. The storage unit consists of recording media such as EPROM (Erasable Programmable ROM), hard disk drive (HDD), and removable media. Examples of removable media include USB (Universal Serial Bus) memory, CD (Compact Disc), DVD (Digital Versatile Disc), and BD (Blu-ray® Disc). The memory unit can store the operating system (OS), various programs, various tables, various databases, etc. Signals from various sensors are input to the power transmission ECU 110. Signals from the foreign object detection device 140 are also input to the power transmission ECU 110. The power transmission ECU 110 then performs various controls based on the signals input from the various sensors.

[0028] For example, the power transmission ECU 110 performs power control to adjust the power for transmission. In power control, the power transmission ECU 110 controls the power transmission device 10. The power transmission ECU 110 outputs a control signal to the power conversion unit 12 in order to control the power supplied from the power conversion unit 12 to the primary device 13. The power transmission ECU 110 adjusts the power for transmission by controlling the switching elements included in the PFC circuit 210, and also adjusts the power for transmission by controlling the switching elements included in the inverter 220.

[0029] Furthermore, the power transmission ECU 110 performs communication control to control communication with the vehicle 3. In communication control, the power transmission ECU 110 controls the first communication device 120 and the second communication device 130.

[0030] The first communication device 120 is a ground-side communication device that performs wide-area wireless communication. The first communication device 120 performs wireless communication with vehicles 3 traveling on road 4, before they approach the WPT lane. The state before approaching the WPT lane means that the vehicle 3 is in a position where it cannot perform narrow-area wireless communication with the supply device 5.

[0031] Wide-area wireless communication is a type of communication with a communication range of 10 meters to 10 kilometers. Wide-area wireless communication has a longer communication range compared to narrow-area wireless communication. Various wireless communication methods with long communication ranges can be used for wide-area wireless communication. For example, communication compliant with communication standards such as 4G, LTE, 5G, and WiMAX, which have been established by 3GPP (registered trademark) and IEEE, is used for wide-area wireless communication. In the wireless power transmission system 1, vehicle information linked to vehicle identification information (vehicle ID) is transmitted from vehicle 3 to supply device 5 using wide-area wireless communication.

[0032] The second communication device 130 is a ground-side communication device that performs narrow-range wireless communication. The second communication device 130 performs wireless communication with vehicles 3 traveling on the road 4 that are approaching or entering the WPT lane. Approaching the WPT lane means that the vehicle 3 is in a position where it can perform narrow-range wireless communication with the supply device 5.

[0033] Short-range wireless communication is a type of communication with a communication range of less than 10 meters. Compared to wide-range wireless communication, short-range wireless communication has a shorter communication range. Various short-range wireless communication technologies can be used for short-range wireless communication. For example, communication conforming to any communication standard established by IEEE, ISO, IEC, etc., can be used for short-range wireless communication. Examples include Wi-Fi (registered trademark), Bluetooth (registered trademark), and ZigBee (registered trademark). Alternatively, technologies such as RFID (Radio Frequency Identification) and DSRC (Dedicated Short Range Communication) may be used for short-range wireless communication. In the wireless power transmission system 1, vehicle identification information and the like are transmitted from the vehicle 3 to the supply device 5 using short-range wireless communication.

[0034] The foreign object detection device 140 detects metallic foreign objects, living organisms, etc., that are located above the primary coil 11. The foreign object detection device 140 is composed of, for example, a sensor coil and an imaging device installed on the ground. The foreign object detection device 140 is intended to perform foreign object detection (FOD) and living object protection (LOP) functions in the wireless power transmission system 1.

[0035] In the power supply device 5, the power transmission device 10 is divided into segments 7 and a management device 8, and the three segments 7 are connected to one management device 8. The power transmission device 10 is configured so that one inverter supplies power to three power transmission side resonant circuits 240. In the power supply device 5, signals from each segment 7 are input to the management device 8. Signals from the second communication device 130 and foreign object detection device 140 located in the first segment are input to the power transmission ECU 110. Similarly, signals from the second communication device 130 and foreign object detection device 140 located in the second segment are input to the power transmission ECU 110. Signals from the second communication device 130 and foreign object detection device 140 located in the third segment are input to the power transmission ECU 110. The power transmission ECU 110 can determine the status of each segment 7 based on the signals input from each segment 7.

[0036] Vehicle 3 includes a power receiving device 20, a charging relay 310, a battery 320, a vehicle ECU 330, a third communication device 340, a fourth communication device 350, and a GPS (Global Positioning System) receiver 360.

[0037] The power receiving device 20 supplies power received from the power transmitting device 10 to the battery 320. The power receiving device 20 is electrically connected to the battery 320 via a charging relay 310. The power receiving device 20 includes a power receiving side resonant circuit 410, a filter circuit 420, and a rectifier circuit 430.

[0038] The receiving-side resonant circuit 410 is a power receiving unit that receives power transmitted non-contactually from the power transmitting device 10. The receiving-side resonant circuit 410 is composed of a secondary coil 21 and a resonant capacitor. The secondary coil 21 is a power receiving coil that receives power transmitted non-contactually from the primary coil 11. This resonant capacitor is connected in series with one end of the secondary coil 21 and adjusts the resonant frequency of the receiving-side resonant circuit. The resonant frequency of the receiving-side resonant circuit 410 is set to match the resonant frequency of the power transmitting-side resonant circuit 240.

[0039] The resonant frequency of the receiving-side resonant circuit 410 is the same as that of the transmitting-side resonant circuit 240. Therefore, when the receiving-side resonant circuit 410 is facing the transmitting-side resonant circuit 240 and a magnetic field is generated by the transmitting-side resonant circuit 240, the vibration of the magnetic field is transmitted to the receiving-side resonant circuit 410. The primary coil 11 and the secondary coil 21 enter a resonant state. When an induced current flows through the secondary coil 21 due to electromagnetic induction, an induced electromotive force is generated in the receiving-side resonant circuit 410. In this way, the receiving-side resonant circuit 410 receives power transmitted non-contactually from the transmitting-side resonant circuit 240. The receiving-side resonant circuit 410 then supplies the power received from the transmitting-side resonant circuit 240 to the filter circuit 420. The receiving-side resonant circuit 410 constitutes the secondary device 22 of the power receiving device 20.

[0040] The filter circuit 420 removes noise contained in the AC current input from the receiving-side resonant circuit 410 and outputs the noise-free AC power to the rectifier circuit 430. The filter circuit 420 is an LC filter that combines a coil and a capacitor. For example, the filter circuit 420 is composed of a T-type filter in which two coils and one capacitor are arranged in a T-shape.

[0041] The rectifier circuit 430 converts the AC power input from the filter circuit 420 into DC power and outputs it to the battery 320. The rectifier circuit 430 is composed of a full-bridge circuit in which four diodes are connected in a full-bridge configuration as rectifier elements. A switching element is connected in parallel to each diode in the rectifier circuit 430. Each switching element in the rectifier circuit 430 is composed of an IGBT and performs switching operation in accordance with a control signal from the vehicle ECU 330. The rectifier circuit 430 supplies the converted DC power to the battery 320. The filter circuit 420 and the rectifier circuit 430 constitute the power conversion unit 23 of the power receiving device 20.

[0042] The power receiving device 20 comprises a secondary device 22 and a power conversion unit 23. The secondary device 22 includes a power receiving side resonant circuit 410. The power conversion unit 23 includes a filter circuit 420 and a rectifier circuit 430.

[0043] The charging relay 310 is located between the rectifier circuit 430 and the battery 320. The charging relay 310's open / closed state is controlled by the vehicle ECU 330. When the battery 320 is being charged by the power transmission device 10, the charging relay 310 is controlled to a closed state. When the charging relay 310 is closed, the rectifier circuit 430 and the battery 320 are connected in a way that allows current to flow. When the charging relay 310 is open, the connection between the rectifier circuit 430 and the battery 320 is cut off, preventing current flow. For example, if the charging relay 310 is open, the vehicle 3 does not request power supply.

[0044] The battery 320 is a rechargeable DC power source, composed of, for example, a lithium-ion battery or a nickel-metal hydride battery. The battery 320 stores the power supplied from the power transmission device 10 to the power receiving device 20. The battery 320 can also supply power to the vehicle's motor. The battery 320 is electrically connected to the motor via a PCU (Power Control Unit). The PCU is a power conversion device that converts the DC power from the battery 320 into AC power and supplies it to the motor. Each switching element of the PCU is composed of IGBTs and performs switching operations in accordance with control signals from the vehicle's ECU 330 and other devices.

[0045] The vehicle ECU 330 is an electronic control unit that controls vehicle 3. The vehicle ECU 330 has the same hardware configuration as the power transmission ECU 110. Signals from various sensors mounted on vehicle 3 are input to the vehicle ECU 330. Positioning signals received by the GPS receiver 360 are also input to the vehicle ECU 330. The vehicle ECU 330 can obtain the current location information of vehicle 3 from the GPS receiver 360. The vehicle ECU 330 then performs various controls based on the signals input from the various sensors.

[0046] For example, the vehicle ECU 330 performs contactless charging control, transmitting power from the primary coil 11 to the secondary coil 21 without contact, and storing the power received by the secondary coil 21 in the battery 320. In contactless charging control, the vehicle ECU 330 controls the rectifier circuit 430, the charging relay 310, the third communication device 340, and the fourth communication device 350. Contactless charging control includes power control, which controls the power for charging, and communication control, which controls communication with the supply device 5. In power control, the vehicle ECU 330 controls the switching elements included in the rectifier circuit 430 to adjust the power (charging power) supplied from the power receiving device 20 to the battery 320. In communication control, the vehicle ECU 330 controls the third communication device 340 and the fourth communication device 350.

[0047] The third communication device 340 is a vehicle-side communication device that performs wide-area wireless communication. The third communication device 340 performs wireless communication with the first communication device 120 of the supply device 5 when the vehicle 3, which is traveling on the road 4, is approaching the WPT lane. Wide-area wireless communication is two-way wireless communication. Communication between the first communication device 120 and the third communication device 340 is performed using high-speed wireless communication.

[0048] The fourth communication device 350 is a vehicle-side communication device that performs narrow-range wireless communication. The fourth communication device 350 performs wireless communication with the second communication device 130 of the supply device 5 when the vehicle 3 is approaching or entering the WPT lane. Narrow-range wireless communication is unidirectional wireless signaling. Unidirectional wireless signaling is P2PS (Point to Point signaling). P2PS is used to notify the supply device 5 of vehicle identification information from the vehicle 3 during the activities of pairing, alignment check, magnetic coupling check, and termination of power transmission. P2PS can also be used as a means of lateral alignment check (Alignment check). Lateral direction refers to the width direction of the lane, which is the width direction of the vehicle 3.

[0049] The GPS receiver 360 detects the current position of vehicle 3 based on positioning information obtained from multiple positioning satellites. The current position information of vehicle 3 detected by the GPS receiver 360 is transmitted to the vehicle ECU 330.

[0050] Furthermore, the power supply device 5 may include the filter circuit 230 in the management device 8 instead of segment 7. That is, the filter circuit 230 may be installed beside the road 4. In this case, the power conversion unit 12 includes the PFC circuit 210, the inverter 220, and the filter circuit 230, and the primary device 13 includes the power transmission side resonant circuit 240.

[0051] Furthermore, the filter circuit 230 may be provided for each primary coil 11, or it may be provided collectively for multiple primary coils 11.

[0052] Furthermore, the filter circuit 230 is not limited to a T-type filter; for example, it may be a bandpass filter in which a coil and a capacitor are connected in series. The same applies to the filter circuit 420 of vehicle 3.

[0053] Furthermore, in the power transmission device 10, when the inverter 220 connects to multiple primary coils 11, a changeover switch for switching which primary coil 11 to be energized may be provided in each primary device 13. This changeover switch may be provided in the management device 8 beside the road 4, or it may be provided near the primary coils 11.

[0054] Furthermore, the transmitting-side resonant circuit 240 is not limited to a configuration in which the primary coil 11 and the resonant capacitor are connected in series. The primary coil 11 and the resonant capacitor may be connected in parallel, or a combination of parallel and series. In short, the transmitting-side resonant circuit 240 only needs to be configured such that its resonant frequency matches the drive frequency of the inverter 220, and the connection relationships of its components are not particularly limited. The same applies to the receiving-side resonant circuit 410 of the vehicle 3.

[0055] Furthermore, the drive frequency of inverter 220 is not limited to 85kHz, but may be a frequency around 85kHz. In short, the drive frequency of inverter 220 may be a predetermined frequency band that includes 85kHz.

[0056] Furthermore, the power transmission device 10 may be configured in which multiple inverters 220 are connected to the output power line (DC power line) of the PFC circuit 210.

[0057] Furthermore, the foreign object detection device 140 may be provided not only on the ground side but also on the vehicle 3 side. For example, if the foreign object detection device on the vehicle 3 side detects a foreign object or living organism above the primary coil 11, the vehicle 3 can be configured to stop the power supply request until it has passed the primary coil 11.

[0058] Furthermore, in the wireless power transmission system 1, the information transmitted from the vehicle 3 to the power supply device 5 using narrow-range wireless communication includes, in addition to vehicle identification information, a power supply request and a power supply request value. The power supply request is information indicating a request for power transmission from the primary coil 11. The power supply request value is the requested amount of power to be transmitted from the power supply device 5 to the vehicle 3. The vehicle ECU 330 can calculate the power supply request value based on the State of Charge (SOC) of the battery 320.

[0059] Furthermore, the wireless power transmission system 1 is not limited to supplying power from the ground to the vehicle 3, but can also realize a method of supplying power from the vehicle 3 to the ground. In this case, the rectifier circuit 430 can be replaced with an inverter to realize rectification during power supply and power reception.

[0060] Figure 3 is a schematic diagram illustrating wide-area wireless communication in a wireless power transmission system.

[0061] In the wireless power transmission system 1, the vehicle 3 can communicate with the server 30, and the power supply device 5 can also communicate with the server 30. The server 30 is connected to a network 40 and can communicate with multiple vehicles 3 and multiple power supply devices 5 via the network 40. The network 40 consists of public communication networks such as the Internet, such as a WAN (Wide Area Network), and mobile phone communication networks.

[0062] Vehicle 3 connects to the network 40 via wide-area wireless communication using the third communication device 340. Vehicle 3 transmits information to the server 30 and receives information from the server 30.

[0063] The supply device 5 connects to the network 40 via wide-area wireless communication using the first communication device 120. The supply device 5 transmits information to the server 30 and receives information from the server 30.

[0064] Figure 4 is a block diagram showing the functional configuration of the power transmission ECU. The power transmission ECU 110 comprises a first communication control unit 510, a second communication control unit 520, and a power transmission control unit 530.

[0065] The first communication control unit 510 performs first communication control to control the first communication device 120. The first communication control controls wide-area wireless communication on the supply device 5 side and controls communication of the supply device 5 using the first communication device 120. In other words, the first communication control controls communication of the management device 8 of the supply device 5. The first communication control controls communication between the supply device 5 and the network 40, and also controls communication between the supply device 5 and the server 30 via the network 40. The first communication control unit 510 is a SECC (Supply Equipment Communication Controller).

[0066] The second communication control unit 520 performs second communication control to control the second communication device 130. The second communication control controls the narrow-range wireless communication on the supply device 5 side, and controls the communication of the supply device 5 using the second communication device 130. In other words, the second communication control controls the communication of segment 7 of the supply device 5. The second communication control controls the communication between the supply device 5 and the vehicle 3 as communication that does not go through the network 40. The second communication control unit 520 is a PDCC (Primary Device Communication Controller).

[0067] The power transmission control unit 530 performs power transmission control to control the power transmission device 10. Power transmission control controls the power for transmission and controls the power conversion unit 12 of the power transmission device 10. The power transmission control unit 530 performs power control to control the PFC circuit 210 and the inverter 220.

[0068] Figure 5 is a block diagram showing the functional configuration of the vehicle ECU. The vehicle ECU 330 comprises a third communication control unit 610, a fourth communication control unit 620, and a charging control unit 630.

[0069] The third communication control unit 610 performs third communication control to control the third communication device 340. The third communication control controls wide-area wireless communication on the vehicle 3 side and controls communication of the vehicle 3 using the third communication device 340. The third communication control controls communication between the vehicle 3 and the network 40, as well as communication between the vehicle 3 and the server 30 via the network 40. The third communication control unit 610 is an EVCC (EV Communication Controller).

[0070] The fourth communication control unit 620 performs fourth communication control to control the fourth communication device 350. The fourth communication control controls the narrow-range wireless communication on the vehicle 3 side and controls the communication of the vehicle 3 using the fourth communication device 350. The fourth communication control controls the communication between the vehicle 3 and the supply device 5 as communication that does not go through the network 40. The fourth communication control unit 620 is an SDCC (Secondary Device Communication Controller).

[0071] The charging control unit 630 performs charging control to control the power receiving device 20 and the charging relay 310. The charging control includes power control to control the power received by the power receiving device 20 and relay control to control the connection state between the secondary device 22 and the battery 320. The charging control unit 630 also performs power control to control the rectifier circuit 430. The charging control unit 630 also performs relay control to switch the open / closed state of the charging relay 310.

[0072] In the wireless power transmission system 1 configured in this way, wireless power transmission from the supply device 5 to the vehicle 3 occurs when wireless communication is established between the vehicle 3 and the supply device 5. Once pairing has been established between the vehicle 3 and the supply device 5 via wireless communication, power is transmitted non-contactually from the primary coil 11 on the ground to the secondary coil 21 on the vehicle. The vehicle 3 then performs charging control, supplying the power received by the secondary coil 21 to the battery 320.

[0073] Next, with reference to Figure 6, the power transmission process (D-WPT process) will be described. The power transmission process is structured as a chain of multiple activities and is a process derived from states and corresponding transitions.

[0074] Figure 6 is a diagram illustrating the power transmission process. Figure 6 shows the basic activities that illustrate the power transmission process. The thick arrows in Figure 6 represent transition lines. The state of wireless power transmission system 1 in the power transmission process is represented by the activities that constitute the power transmission process.

[0075] The activities constituting the power transmission process include the power transmission service session (D-WPT service session A70), which is the activity at the power transmission stage, the activities before power transmission, and the activities after power transmission. Furthermore, the activities can be described separately depending on whether or not there is communication between the power supply device 5 and the vehicle 3. The activities can be divided into those representing the state of the power supply device 5 only without communication, those representing the state of the vehicle 3 only without communication, and those representing the state of both the power supply device 5 and the vehicle 3 with communication.

[0076] As shown in Figure 6, the activities include Master power On (A10), Preparation (A20), Waiting for D-WPT service request (A30), Master power On (A40), Preparation (A50), Communication setup and Request D-WPT service (A60), D-WPT service session (A70), and Terminate D-WPT service session (A80).

[0077] Preparation A20 is the ready state of the power supply device 5. In Preparation A20, the power supply device 5 starts the circuit and performs safety checks without communication with the vehicle 3. The power supply device 5 transitions to the Preparation A20 state when the master power supply is turned ON A10. If the power supply device 5 starts the circuit and confirms safety in Preparation A20, the state transitions to Waiting for D-WPT service request A30 from the vehicle 3. On the other hand, if there is a problem with the power supply device 5, the power supply device 5 notifies the vehicle 3 via wide-area wireless communication that the wireless power transmission system 1 is unavailable (unavailability notification). The first communication device 120 transmits the unavailability notification to the vehicle 3.

[0078] Preparation A50 is the ready state of vehicle 3. In Preparation A50, vehicle 3 starts the circuit and performs safety checks without communication with the supply device 5. When the master power is turned ON A40, vehicle 3 transitions to the Preparation A50 state. If vehicle 3 starts the circuit and confirms safety in Preparation A50, the state transitions to Communication setup and Request D-WPT service A60. On the other hand, if there is a problem with vehicle 3, vehicle 3 will not start wide-area wireless communication and will not perform the subsequent sequences in the D-WPT process.

[0079] The communication setup and D-WPT service request A60 is initiated by the vehicle ECU 330. In the communication setup and D-WPT service request A60, the vehicle ECU 330 initiates wide-area wireless communication. First, when vehicle 3 transitions from preparation A50 to communication setup and D-WPT service request A60, the third communication device 340 transmits a D-WPT service request signal. The third communication device 340 communicates wirelessly with the first communication device 120 corresponding to the D-WPT lane that vehicle 3 is planning to enter or has entered. The first communication device 120 to communicate with is selected based on the relative positional relationship between the current position of vehicle 3 and the position of the D-WPT lane. On the supply device 5 side, when the first communication device 120 receives the D-WPT service request signal while in the waiting state A30 from vehicle 3, the state transitions to communication setup and D-WPT service request A60. Various information between wide-area wireless communication and P2PS communication is linked using vehicle identification information. Figure 7 shows the processing sequence for this communication setup and the D-WPT service request A60.

[0080] Figure 7 is a sequence diagram showing the case where communication is performed between a vehicle and a supply device using wide-area wireless communication. Vehicle 3 transmits vehicle information to server 30 (step S11). In step S11, the third communication device 340 of vehicle 3 transmits vehicle information to server 30. The vehicle information includes vehicle identification information, various parameters of the power receiving device 20, the current location information of vehicle 3, and the requested power. The vehicle ECU 330 calculates the requested power based on the SOC (State of Charge) of the battery 320. In step S11, the vehicle ECU 330 causes the third communication device 340 to transmit vehicle information at predetermined intervals. The predetermined interval is set according to the distance from the current location of vehicle 3 to the starting point of the WPT lane. The shorter the distance from vehicle 3 to the starting point of the WPT lane, the shorter the interval of the predetermined time.

[0081] When the server 30 receives vehicle information from vehicle 3, it identifies the vehicle identification information of vehicle 3 located within the vicinity area of ​​the supply device 5 based on the current location information of vehicle 3 included in the vehicle information (step S12). In step S12, the server 30 identifies vehicle 3 located within a predetermined vicinity area from the supply device 5 based on the current location information of vehicle 3 and the location information of the supply device 5. The vicinity area is set to, for example, an area within 500 meters.

[0082] When the server 30 identifies the vehicle identification information of vehicle 3, it transmits the vehicle information to the supply device 5 (step S13). In step S13, the transmitting device of the server 30 transmits the vehicle information to the supply device 5.

[0083] When the power supply device 5 receives vehicle information from the server 30, it registers and deletes vehicle identification information in the identification information list (step S14). In step S14, the power transmission ECU 110 registers and deletes vehicle identification information in the identification information list so that all vehicle identification information associated with the vehicle information is registered in the identification information list without any discrepancies.

[0084] When the supply device 5 registers or deletes vehicle identification information in the identification information list, it transmits the vehicle identification information registered in the identification information list to the server 30 (step S15). In step S15, the first communication device 120 of the supply device 5 transmits the vehicle identification information to the server 30.

[0085] Then, when the server 30 receives vehicle identification information from the supply device 5, it sends a list registration notification to the vehicle 3 corresponding to the vehicle identification information registered in the identification information list (step S16). In step S16, the communication device of the server 30 sends the list registration notification to the vehicle 3. The list registration notification is a notification indicating that the vehicle identification information has been registered in the identification information list, and includes the identification information of the supply device 5 and the location information of the supply device 5.

[0086] When vehicle 3 initiates wide-area wireless communication and both the supply device 5 and vehicle 3 reach the state of communication setup and D-WPT service request A60, the communication setup via wide-area wireless communication is considered successful. Upon successful communication setup, the state transitions to D-WPT service session A70.

[0087] Return to Figure 6. In D-WPT service session A70, power is transmitted non-contact from the power-transmitting resonant circuit 240 of the power supply device 5 to the power-receiving resonant circuit 410 of the vehicle 3, when a communication connection has been established between the power supply device 5 and the vehicle 3. D-WPT service session A70 begins with the success of the communication setup and ends with the completion of communication. In the state of D-WPT service session A70, when communication ends, the state transitions to Terminate D-WPT service session A80.

[0088] At the end of the D-WPT service session A80, vehicle 3 terminates wide-area wireless communication with supply device 5. Vehicle 3 and supply device 5 can receive the trigger for the end of the D-WPT service session A70. Then, vehicle ECU 330 prevents D-WPT from being started for secondary device 22 and vehicle 3 until the third communication device 340 receives the next notification (D-WPT service request signal).

[0089] Here, we will describe the detailed activities of D-WPT service session A70.

[0090] D-WPT service session A70 includes compatibility check and service authentication A110, fine positioning of the vehicle laterally A120, pairing and alignment check A130, magnetic coupling check A140, perform power transfer A150, stand-by A160, and power transfer terminated A170.

[0091] Compatibility checks and service certification A110 are described below. After successful communication setup, the vehicle ECU 330 and the power transmission ECU 110 verify that the primary device 13 and the secondary device 22 are compatible. The compatibility check is performed on the supply device 5 side based on information associated with the vehicle identification information obtained through communication. Check items include the minimum ground clearance of the secondary device 22, the shape type of the secondary device 22, the circuit topology of the secondary device 22, the self-resonant frequency of the secondary device 22, and the number of secondary coils 21.

[0092] In compatibility check and service certification A110, first, vehicle 3 transmits compatibility information for the power receiving device 20 from the third communication device 340 to the power supply device 5. The first communication device 120 of the power supply device 5 receives the compatibility information for the power receiving device 20 from vehicle 3. Then, the first communication device 120 of the power supply device 5 transmits compatibility information for the power transmitting device 10 to vehicle 3. The third communication device 340 of vehicle 3 receives the compatibility information for the power transmitting device 10 from the power supply device 5.

[0093] The elements of compatibility information transmitted by vehicle 3 to supply device 5 include vehicle identification information, WPT power classes, air gap class, WPT operating frequencies, WPT frequency adjustment, WPT type, WPT circuit topology, fine positioning method, pairing method, alignment method, and information on the presence or absence of power adjustment function.

[0094] The elements of compatibility information transmitted by the supply device 5 to the vehicle 3 include supply device identification information, WPT power class, gap class, WPT drive frequency, WPT frequency adjustment, WPT type, WPT circuit topology, detailed alignment method, pairing method, alignment method, and information on the presence or absence of power adjustment function.

[0095] Each element name will be explained in detail. Note that while each element of the compatibility information transmitted from vehicle 3 to supply device 5 will be explained, any compatibility information transmitted from supply device 5 to vehicle 3 that overlaps with the compatibility information transmitted from vehicle 3 to supply device 5 will be omitted from the explanation.

[0096] The gap class indicates the gap class to which the secondary device 22 can receive power. The WPT power class indicates the power class to which the secondary device 22 can receive power. The WPT drive frequency indicates the frequency of the power received by the secondary device 22. The WPT frequency adjustment indicates whether the drive frequency can be adjusted. The WPT type indicates the shape type of the secondary device 22 and shows the coil shape of the secondary coil 21. Examples of WPT types include circular and solenoid. The WPT circuit topology indicates the connection structure between the secondary coil 21 and the resonant capacitor. WPT circuit topologies include series and parallel. The detailed alignment method indicates how alignment is performed when alignment is performed. The pairing method is the method by which the vehicle 3 performs pairing to identify the supply device 5. The alignment method indicates the method of confirming the relative positions of the secondary device 22 and the primary device 13 before power transmission begins.

[0097] Next, the detailed lateral alignment A120 of the vehicle will be described. Vehicle 3 performs the detailed lateral alignment A120 prior to or in parallel with the pairing and alignment check A130. When the vehicle ECU 330 determines that vehicle 3 is approaching or entering the area where the supply device 5 is installed (WPT lane), it begins the detailed lateral alignment A120 of the vehicle.

[0098] The vehicle ECU 330 guides the vehicle 3 to align the primary device 13 and the secondary device 22 within a range that establishes sufficient magnetic coupling for wireless power transmission.

[0099] Detailed lateral vehicle alignment A120 is basically performed manually or automatically on vehicle 3. Detailed lateral vehicle alignment A120 can be linked with ADAS (Advanced Driver-Assistance Systems).

[0100] The detailed lateral alignment activity of the vehicle (A120) continues until the vehicle 3 leaves the D-WPT charging site or the status changes to communication termination, and can be performed based on alignment information transmitted from the supply unit 5 to the vehicle 3 via wide-area wireless communication. This communication termination is the termination of the D-WPT service session (A80).

[0101] This section explains the pairing and alignment check (A130). Here, pairing and alignment check are explained separately.

[0102] The pairing process is described below. The P2PS interface, which performs narrow-range wireless communication, ensures that the primary device 13 and the secondary device 22 are uniquely paired. The pairing process is as follows.

[0103] First, the vehicle ECU 330 recognizes that vehicle 3 is approaching or entering a D-WPT lane. For example, the vehicle ECU 330 has map information including D-WPT lanes and recognizes approach or entry by comparing it with the vehicle's position information obtained by the GPS receiver 360, based on the straight-line distance. Vehicle 3 transmits to the server 30 via wide-area wireless communication which D-WPT lane it is approaching. In short, the third communication device 340 notifies the cloud of a signal indicating that vehicle 3 is approaching one of the D-WPT lanes. Furthermore, once the vehicle ECU 330 recognizes that vehicle 3 is approaching or entering a D-WPT lane, the fourth communication device 350 starts transmitting modulated signals at regular intervals for pairing between the primary device 13 and the secondary device 22.

[0104] Furthermore, the supply device 5 may use information acquired from the server 30 via wide-area wireless communication to recognize when vehicle 3 approaches or enters a D-WPT lane. The server 30 assigns the vehicle identification information of the approaching vehicle 3 in each D-WPT lane to the supply device 5 corresponding to that lane. Since the supply device 5 only needs to refer to the vehicle identification information narrowed down by the server 30, the authentication process can be completed in a short time. When the supply device 5 recognizes that vehicle 3 is approaching a D-WPT lane, the second communication device 130 enters standby mode. In standby mode, it waits to receive a modulated signal from the fourth communication device 350 of vehicle 3. This modulated signal includes vehicle identification information.

[0105] When the second communication device 130 receives a modulated signal from vehicle 3, the supply device 5 compares the vehicle identification information received via narrow-range wireless communication with the vehicle identification information in the identification information list obtained from the results of wide-range wireless communication with multiple vehicles 3 approaching the D-WPT lane. Through this comparison, the supply device 5 identifies vehicle 3.

[0106] When the vehicle ECU 330 recognizes that vehicle 3 is outside the D-WPT lane, it stops transmitting the modulated signal from the fourth communication device 350. The vehicle ECU 330 can determine whether or not the vehicle has passed through the D-WPT lane based on map information and the vehicle's position information.

[0107] If the supply device 5 determines that vehicle 3 is not traveling in the D-WPT lane, or that vehicle 3 is not approaching the D-WPT lane, it stops waiting for the modulated signal from the fourth communication device 350.

[0108] Pairing is performed on the primary device 13 until vehicle 3 leaves the D-WPT charging site or the status changes to communication termination. Once pairing is complete, the status transitions to alignment check.

[0109] The alignment check is explained below. The purpose of the alignment check is to confirm that the lateral distance between the primary device 13 and the secondary device 22 is within the acceptable range. The alignment check is performed using narrow-range wireless communication (P2PS). The configuration for alignment will be described later.

[0110] The alignment check is performed continuously based on P2PS until vehicle 3 leaves the D-WPT charging site or the status changes to communication termination. The results of the alignment check can be transmitted from the first communication device 120 to the third communication device 340 via wide-area wireless communication.

[0111] The magnetic coupling check A140 is described below. In the magnetic coupling check A140, the supply device 5 checks the magnetic coupling state and confirms that the secondary device 22 is within the acceptable range. When the magnetic coupling check A140 is completed, the state transitions to power transmission execution A150.

[0112] The execution of power transmission A150 is described below. In this state, the power supply device 5 transmits power to the power receiving device 20. The power transmission device 10 and the power receiving device 20 need to have the ability to control the transmitted power (transmitted power and received power) for the usefulness of MF-D-WPT and the protection of the power receiving device 20 and the battery 320. Greater power transmission helps to increase the range of the power receiving device 20 without static wireless charging and conductive charging. However, the capacity of the battery 320 varies depending on the type of vehicle 3, and the power demand for driving can fluctuate rapidly. One example of such rapid fluctuation is sudden regenerative braking. When regenerative braking is performed while driving in the D-WPT lane, regenerative braking takes priority, so in addition to regenerative power, power received from the power receiving device 20 is supplied to the battery 320. In this case, adjustment of the transmitted power by the power receiving device 20 is necessary to protect the battery 320 from overcharging.

[0113] Despite the need for power control, no new communication is initiated between the power supply device 5 and the power receiving device 20 in this state. This is because communication, due to its instability and latency, could impair the response and accuracy of power control. Therefore, the power supply device 5 and the power receiving device 20 perform power transmission and control based on the known information up to this point.

[0114] The power supply device 5 increases the transmission power for magnetic coupling check in response to the power request transmitted from the third communication device 340 using wide-area wireless communication in advance. The power supply device 5 maintains current and voltage fluctuations within a certain range and attempts to maximize the power transmitted during the transition.

[0115] The power receiving device 20 accepts power transmitted from the power transmitting device 10 without any control. However, the power receiving device 20 initiates control when the transmitted power exceeds or is about to exceed a limit, such as the rated power of the battery 320 which fluctuates according to the charge state and the power demand of the vehicle 3. Furthermore, power control in the vehicle ECU 330 is required to handle malfunctions in wide-area wireless communication. These malfunctions can lead to a conflict between the power control target in the primary device 13 and the request from the third communication device 340, and to a sudden failure of the power receiving device 20 or battery 320 during power transmission. The power receiving device 20 controls the power transmitted under the power demand rate notified by the first communication device 120.

[0116] Power requirements are determined based on compatibility check information such as the WPT circuit topology, geometry, ground clearance, and EMC (electromagnetic compatibility) of the vehicle 3 and primary equipment 13. These specifications result in different magnetic fields, and power must be transmitted within the range that satisfies EMC requirements.

[0117] Power control in the power transmission ECU 110 and power receiving device 20 may interfere with each other. Interference is particularly likely when the supply device 5 attempts to achieve a power request larger than the latest power limit in the power receiving device 20 via wide-area wireless communication. An example of this is rapid regenerative control in the relatively small battery 320 of vehicle 3. If possible, it is desirable that the supply device 5 be able to detect the mismatch between the power control target and the limit and adjust the power transmission to resolve the mismatch.

[0118] For example, if a foreign object is detected on the primary device 13 by the foreign object detection device 140, or if the magnetic coupling becomes weak due to misalignment of the secondary device 22, and power transmission is interrupted for a short period while the secondary device 22 is still on the primary device 13, the state transitions to Standby A160. If the vehicle 3 is equipped with a foreign object detection device, the vehicle 3 may detect the foreign object.

[0119] When the secondary device 22 passes over the primary device 13, the state transitions to power transmission termination A170. In this case, the magnetic coupling between the two devices weakens, and therefore less power is transmitted. The power supply device 5 can detect that the magnetic coupling has weakened by monitoring the transmitted power, and thus the power supply device 5 essentially decides to transition to power transmission termination A170, and then begins to lower the voltage to stop power transmission.

[0120] The standby state A160 is described below. In this state, if power transmission is interrupted for any reason and D-WPT is ready in both vehicle 3 and supply unit 5, the state returns to power transmission execution A150. If there is a possibility of power transmission being interrupted, the state becomes standby A160.

[0121] Next, we will describe the termination of power transmission A170. In this state, the power supply device 5 reduces the transmitted power to zero and retains or uploads power transmission result data such as total transmitted power, power transmission efficiency, and fault history. Each data is tagged with vehicle identification information. Finally, the power supply device 5 deletes the vehicle identification information of vehicle 3 that has passed through the D-WPT lane. This allows the power supply device 5 to prepare for subsequent pairing and power transmission to other vehicles. The processing sequence for the termination of power transmission A170 is shown in Figure 8.

[0122] Figure 8 is a sequence diagram showing the operation after the power supply from the power supply device to the vehicle during driving has ended. When the power receiving device 20 of vehicle 3 ends receiving power from the power supply device 5 (step S21), vehicle 3 transmits power reception termination information to the server 30 (step S22). In step S22, power reception termination information is transmitted from the third communication device 340 of vehicle 3. The power reception termination information includes, for example, vehicle identification information of vehicle 3, power received from power supply device 5, power reception efficiency, and abnormality detection results, as information related to power reception from the power supply device 5.

[0123] When the process in step S21 is performed, the power supply device 5 terminates power supply to the vehicle 3 (step S23). The processes in step S21 and step S23 may be performed simultaneously or not. When the process in step S23 is performed, the power supply device 5 sends power supply termination information to the server 30 (step S24). In step S24, the power supply termination information is sent from the first communication device 120 of the power supply device 5.

[0124] When server 30 receives power reception termination information from vehicle 3 and power transmission termination information from power supply device 5, it performs a power supply termination process to terminate the power supply from power supply device 5 to vehicle 3 (step S25). In the power supply termination process, based on the power reception termination information and power transmission termination information, the amount of power supplied from power supply device 5 to vehicle 3 is calculated, and the user of vehicle 3 is charged based on the calculated amount of power supplied.

[0125] Furthermore, vehicle 3 transmits vehicle information to server 30 independently of the power supply termination process (step S26). In step S26, vehicle information is transmitted from the third communication device 340 of vehicle 3.

[0126] After the power supply termination process is completed, the server 30 receives vehicle information from the vehicle 3 and identifies the vehicle identification information of the vehicle 3 located within the vicinity area of ​​each power supply device 5 based on the vehicle information (step S27).

[0127] Then, if a power supply termination process has already been performed on a certain power supply device 5, the server 30 deletes the vehicle identification information of the vehicle 3 for which the power supply termination process has already been performed from the vehicle identification information of the vehicle 3 in the vicinity area of ​​the power supply device 5 identified in step S27 (step S28).

[0128] Subsequently, the server 30 transmits to each supply device 5 the vehicle information associated with the vehicle identification information of the vehicle 3 that has been identified as being located within the vicinity of each supply device 5, and which has not been deleted in the process of step S28 (step S29).

[0129] After the vehicle information is transmitted to each supply device 5 in step S29, when the supply device 5 receives the vehicle information from the server 30, the supply device 5 registers and deletes vehicle identification information in the identification information list (step S30). The process in step S30 is the same as the process in step S14 in Figure 7. Subsequently, the supply device 5 transmits the vehicle identification information registered in the identification information list to the server 30 (step S31). The process in step S51 is the same as the process in step S15 in Figure 7.

[0130] Then, when the server 30 receives vehicle identification information from the supply device 5, it sends a list registration notification to the vehicle 3 corresponding to the vehicle identification information registered in the identification information list (step S32). The process in step S32 is the same as the process in step S16 in Figure 7.

[0131] As a result, when the process shown in Figure 8 is performed, the identification information list will contain vehicle identification information for vehicles 3 that are located within the vicinity of each supply device 5, are not receiving power from that supply device 5, and have not received a request to erase their vehicle identification information. If vehicle 3's vehicle identification information is registered in the identification information list of any of the supply equipment 2, it will receive a list registration notification. Therefore, the vehicle ECU 330 can determine that its vehicle is registered in any of the supply equipment 5 by receiving the list registration notification. When vehicle 3 leaves the vicinity of the supply device 5, its vehicle identification information is erased from the identification information list of the supply device 5.

[0132] Return to Figure 6. Also, at the end of power transmission A170, the power receiving device 20 does not need to do anything to reduce the transmitted power to zero. The P2PS interface is kept active when the vehicle 3 is in the D-WPT lane, and the state of the power receiving device 20 automatically transitions to pairing for the next power transmission from the primary device 13. As shown in the transition line in Figure 6, the state transitions from the end of power transmission A170 to pairing and alignment check A130. As shown in Figure 6, it is possible to transition from magnetic coupling check A140 to pairing and alignment check A130, or from power transmission execution A150 to pairing and alignment check A130, depending on the predetermined transition conditions. Pairing may be performed individually for multiple primary coils 11, or it may be performed on multiple primary coils 11 bundled together at a representative point.

[0133] Then, if there is no D-WPT request from the vehicle ECU 330, or if the sequence of states from the communication setup and D-WPT service request A60 to the termination of power transmission A170 is prohibited, the D-WPT service session A70 transitions to termination of D-WPT service session A80, stopping wide-area radio communication between the first communication device 120 and the third communication device 340. For example, D-WPT is stopped when the charge state in the battery 320 is too high, or when the power receiving device 20 is too hot for continuous power transmission. Such unnecessary D-WPT can be disabled simply by deactivating the P2PS interface. However, by stopping wide-area radio communication, the power transmission ECU 110 can free up the memory occupied for the vehicle 3 without requiring D-WPT by terminating the established wide-area radio communication.

[0134] Furthermore, the D-WPT service session A70 is not limited to transitions like those shown in the transition lines in Figure 6. When the activities from pairing and alignment check A130 onward are completed in the D-WPT service session A70, if the conditions for the power transmission process to remain in the D-WPT service session A70 are met, the system does not transition to the termination of the D-WPT service session A80, but instead transitions to compatibility check and service authentication A110. For example, if predetermined transition conditions are met in the state of magnetic coupling check A140, the state can transition to compatibility check and service authentication A110.

[0135] Here, the arrangement of the second communication device 130 and the fourth communication device 350 will be explained with reference to Figure 9. Figure 9 is a diagram illustrating the arrangement of the second communication device and the fourth device. Note that arrow D in Figure 9 F This refers to the direction of travel of vehicle 3 (hereinafter, direction of travel D). F This indicates that (this can also be the case). This direction of travel D F This is the forward direction of vehicle 3. That is, in vehicle 3, the direction of travel D F The front side in the direction of travel D F Forward, direction of travel D FThe rear side is in the traveling direction D F is the rear. Also, in the vehicle 3, the traveling direction D F and the direction orthogonal to the vertical direction of the vehicle 3 (the direction orthogonal to the plane of FIG. 1) are defined as the lateral direction.

[0136] The fourth communication device 350 consists of one communication part located on the front side with respect to the secondary coil 21 in the traveling direction D F The fourth communication device 350 is provided at the central part of the secondary coil 21 in the lateral direction of the vehicle 3.

[0137] The second communication device 130 provided in the segment 7 has two communication parts (communication parts 130a, 130b) located on the rear side with respect to the primary coil 11 in the traveling direction D F Each communication part adopts the configuration related to the above-mentioned short-range wireless communication. Here, the primary coil 11 and the second communication device 130 may be integrally mounted on, for example, the substrate constituting the segment 7, or may be mounted on different substrates from each other. Also, the secondary coil 21 and the fourth communication device 350 may be integrally mounted on, for example, the substrate constituting the power receiving device 20, or may be mounted on different substrates from each other.

[0138] The communication parts 130a and 130b are provided side by side in the width direction of the road 4 (here, the direction corresponding to the lateral direction of the vehicle 3 traveling on the road 4), and are provided on opposite sides and at the same distance from the central part in the width direction of the primary coil 11. That is, when the power receiving device 20 passes over the segment 7, when the central part in the width direction of the primary coil 11 and the central part in the lateral direction of the secondary coil 21 are located on the same straight line extending in the traveling direction, the fourth communication device 350 will pass through the central part between the communication parts 130a and 130b.

[0139]

[0140] ​This allows the communication units 130a and 130b to adjust the position of the secondary coil 21 relative to the primary coil 11 when communicating with the fourth communication device 350 via narrow-range wireless communication. Specifically, for example, the signal strength is detected when the communication units 130a and 130b communicate with the fourth communication device 350, and the widthwise displacement of the secondary coil 21 relative to the primary coil 11 is detected based on the relative magnitudes of these signal strengths. When the communication units are arranged as described above, if the signal strengths of the communication units 130a and 130b are the same, no displacement occurs, and the greater the difference in these strengths, the greater the displacement can be determined. Furthermore, the direction of the displacement can be detected from the relative magnitudes of the strengths.

[0141] Also, vehicle 3 is in the direction of travel D F When the vehicle moves, before the secondary coil 21 passes over the primary coil 11, vehicle identification information, as well as power supply requests and power supply power request values, are transmitted from the vehicle 3 to the power supply device 5 via narrow-range wireless communication between the second communication device 130 and the fourth communication device 350.

[0142] Here, when the communication units 130a and 130b are constructed using coils, the winding configuration is such that, in terms of improving detection accuracy, the direction of travel D F It is preferable that they are symmetrical with respect to the axis extending in that direction.

[0143] In the embodiment described above, in the wireless power transmission system 1, two communication units (communication units 130a and 130b) are provided in segment 7 to the fourth communication device 350 installed on the vehicle 3, and the vehicle 3 travels in the direction D F As the secondary coil 21 moves and passes over the primary coil 11, narrow-range wireless communication is performed between the second communication device 130 and the fourth communication device 350. According to this embodiment, since the position of the communication device (fourth communication device 350) of the power receiving device 20 is detected by the two communication units, the positional relationship between the secondary coil 21 of the vehicle 3 and the primary coil 11 of segment 7 can be detected with high precision in the wireless power transmission system 1. As a result, the positional alignment between the power transmitting side and the power receiving side can be performed with high precision in the wireless power transmission system 1.

[0144] Furthermore, in this embodiment, when the power transmission ECU 110 performs alignment using the communication results between the second communication device 130 and the fourth communication device 350, position detection is possible without performing wide-area wireless communication, resulting in a faster position detection speed and enabling high-speed alignment.

[0145] (modified version) Next, a modified example of the embodiment will be described with reference to Figure 10. In the modified example, the arrangement of the second communication device and the fourth device differs from that of the embodiment. Figure 10 is a diagram illustrating the arrangement of the second communication device and the fourth device in the modified example. Note that arrow D in Figure 10 F This indicates the direction of travel of vehicle 3, similar to Figure 9.

[0146] In the modified example, the second communication device 130 is configured to move in the direction D relative to the primary coil 11. F It consists of a single communication unit located on the front side. The second communication device 130 is provided in the center of the primary coil 11 in the width direction of the road 4. Here, the width direction corresponds to the direction perpendicular to the extension direction of the road 4 and the direction of gravity, and will be described as being the same direction as the lateral direction of the vehicle 3.

[0147] The fourth communication device 350 controls the secondary coil 21 in the direction of travel D F It has two communication units (communication units 350a and 350b) located on the rear side. The communication units 350a and 350b are arranged side by side in the lateral direction of the vehicle 3, and are located on opposite sides of the lateral center of the secondary coil 21, and at the same distance from this center. That is, when the power receiving device 20 passes over the segment 7, if the widthwise center of the primary coil 11 and the lateral center of the secondary coil 21 are located on the same straight line extending in the direction of travel, the second communication device 130 will pass through the center between the communication units 350a and 350b.

[0148] In a modified configuration, the position of the secondary coil 21 relative to the primary coil 11 can be adjusted by having the communication units 350a and 350b each perform narrow-range wireless communication with the second communication device 130. Specifically, for example, the signal strength when the communication units 350a and 350b each communicate with the second communication device 130 is detected, and the widthwise displacement of the secondary coil 21 relative to the primary coil 11 is detected based on the relative magnitudes of these signal strengths. When the communication units are arranged as described above, if the signal strengths of the communication units 350a and 350b are the same, no displacement has occurred, and the greater the difference in these strengths, the greater the displacement can be determined. Furthermore, the direction of the displacement can be detected from the relative magnitudes of the strengths.

[0149] Here, when the communication units 350a and 350b are constructed using coils, the winding configuration is such that, in terms of improving detection accuracy, the direction of travel D F It is preferable that they are symmetrical with respect to the axis extending in that direction.

[0150] Also, similar to the embodiment, vehicle 3 is in the direction of travel D F When the vehicle moves, before the secondary coil 21 passes over the primary coil 11, vehicle identification information, as well as power supply requests and power supply power request values, are transmitted from the vehicle 3 to the power supply device 5 via narrow-range wireless communication between the second communication device 130 and the fourth communication device 350.

[0151] In the modified example described above, in the wireless power transmission system 1, two communication units (communication units 350a and 350b) are provided on the vehicle 3, and the vehicle 3 travels in the direction D FAs the secondary coil 21 moves and passes over the primary coil 11, narrow-range wireless communication is performed between the second communication device 130 and the fourth communication device 350. According to this modified example, since the position of the communication device (second communication device 130) of segment 7 is detected by the two communication units, the positional relationship between the secondary coil 21 of the vehicle 3 and the primary coil 11 of segment 7 can be detected with high precision in the wireless power transmission system 1. As a result, the positional alignment between the transmitting side and the receiving side can be performed with high precision in the wireless power transmission system 1.

[0152] Furthermore, according to the modified version, since the position detection is performed using the communication results of two communication units provided on the vehicle 3 side, even if there are disturbance factors such as puddles on the road, the influence of these disturbances can be suppressed and the position detection can be performed.

[0153] In the embodiments and modified examples, a configuration having one (single) communication unit on one side and two communication units on the other side was described as an example. However, the number of communication units in each communication device is not limited to this. For example, the other device may have three or more communication units, or each device may have two or more communication units. For example, in the case of having three communication units, communication units are provided in the center and at both ends in the width direction of the coil, and the positional relationship between the vehicle 3 (secondary coil 21) and the segment 7 (primary coil 11) is detected based on the signal strength of each communication unit.

[0154] Furthermore, in the embodiments and modified examples, the fourth communication device 350 may communicate only with the second communication device 130 corresponding to the first segment 7 of the supply device 5, and may not communicate with the other segments 7, or it may communicate with all segments 7 but with some exceptions. In addition, the number and arrangement of communication units in the second communication device 130 can be appropriately set depending on the type of road (e.g., straight or curved).

[0155] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of Symbols]

[0156] 1. Wireless Power Transmission System 2 Supply equipment 3 vehicles 4 road 5 Feeding device 6 AC power supply 10 Power transmission equipment 11 Primary coil 20 Power receiving equipment 21 Secondary coil 120 First communication device 130 Second communication device 130a, 130b, 350a, 350b Communication Department 340 Third communication device 350 Fourth Communication Device

Claims

1. A power supply device installed on the roadside, which transmits electricity, A vehicle equipped with a power receiving device and traveling on the aforementioned road, A wireless power transmission system comprising the power receiving device receiving power from the power supply device and wirelessly transmitting power to the vehicle, The supply device is A primary coil that generates a magnetic field for supplying power to the vehicle, A first communication device for performing narrow-range wireless communication with the aforementioned vehicle, It has, The aforementioned vehicle is A secondary coil that receives power transmitted non-contactually from the primary coil, The supply device and a second communication device for performing narrow-range wireless communication, It has, In the first and second communication devices, one communication device has a single communication unit, and the other communication device has multiple communication units. The plurality of communication units are arranged symmetrically with respect to the center in the width direction of either the road or the vehicle. The single communication unit is provided in the center of the other of the road and the vehicle in the width direction, Based on the difference in signal strength between the first and second communication devices via the narrow-range wireless communication, the position of the secondary coil relative to the primary coil is adjusted. Wireless power transmission system.

2. The first communication device has a single communication unit, The second communication device has multiple communication units, The wireless power transmission system according to claim 1.

3. The aforementioned multiple communication units are arranged side by side in the lateral direction of the vehicle, The single communication unit is positioned in the center of the primary coil in the width direction of the road. The wireless power transmission system according to claim 2.

4. The first communication device has a plurality of communication units, The second communication device has a single communication unit. The wireless power transmission system according to claim 1.

5. The single communication unit is positioned in the center of the primary coil in the lateral direction of the vehicle. The aforementioned plurality of communication units are arranged in a line in the width direction of the road. The wireless power transmission system according to claim 4.

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