Non-contact power supply system, position estimation method, mobile object, and power supply device

Abstract

The present invention relates to a contactless power supply system, a position estimation method, a mobile body and a power supply device. The present invention provides a contactless power supply system, which includes: a transmission side resonance circuit, which is configured to transmit power; a receiving side resonance circuit, which is configured to receive power from the transmission side resonance circuit; an AC magnetic field generating circuit, which is configured to generate an AC magnetic field for detecting the relative position relationship between the transmission side resonance circuit and the receiving side resonance circuit; and a magnetic field detector, which is configured to detect the AC magnetic field. The contactless power supply system performs contactless power transmission by magnetic field resonance coupling between a ground side device and a mobile body. The frequency of the position detection AC magnetic field is different from the resonance frequency of each of the transmission side resonance circuit and the receiving side resonance circuit.

Description

Technical Field

[0001] The present invention relates to a contactless power supply system, a position estimation method, a mobile object and a power supply device. Background Art

[0002] Hitherto, there has been known a technology for non-contact transmission of electric power between a ground-side device set on the ground and a moving body such as a vehicle using a transmission method such as magnetic field coupling (electromagnetic induction), electric field coupling, magnetic field resonance coupling (magnetic field resonance), or electric field resonance coupling (electric field resonance). In particular, in non-contact power transmission using magnetic field resonance coupling of a transmission-side resonance circuit and a reception-side resonance circuit having the same resonance frequency, even if the moving body and the ground-side device are far from each other, large electric power can be transmitted via an AC magnetic field generated in the transmission-side resonance circuit.

[0003] However, the continuous generation of an AC magnetic field for power transmission between the ground-side device and the moving body results in a waste of power. There is also a concern about the influence of the AC magnetic field on electronic equipment, etc. Therefore, it is desirable to generate an AC magnetic field for power transmission at an appropriate timing when the moving body passes over the ground-side device.

[0004] In this regard, Japanese Unexamined Patent Application Publication No. 2018-157686 (JP 2018-157686A) describes that when a power supply request is wirelessly transmitted from a vehicle, a power supply device embedded in a road non-contactly transmits power to the vehicle when the vehicle passes over the road. Summary of the invention

[0005] However, in the case of detecting the approach of a vehicle to a ground-side device by wireless communication, there is a possibility that an AC magnetic field cannot be generated at an appropriate timing due to obstacles to wireless communication, etc. When a moving body such as a vehicle passes over the ground-side device, when the transmission-side resonant circuit and the reception-side resonant circuit are not aligned, the efficiency of power transmission decreases.

[0006] The present invention provides a contactless power supply system, a position estimation method, a mobile body and a power supply device, wherein during contactless power transmission by magnetic field resonance coupling between the mobile body and the ground side device, the relative position relationship between the transmission side resonant circuit and the reception side resonant circuit is accurately detected.

[0007] A first aspect of the present invention relates to a contactless power supply system, which is configured to perform contactless power transmission by magnetic field resonance coupling between a ground-side device and a mobile body. The contactless power supply system includes a transmission-side resonant circuit, a receiving-side resonant circuit, an AC magnetic field generating circuit, and a magnetic field detector. The transmission-side resonant circuit is configured to transmit power. The receiving-side resonant circuit is configured to receive power from the transmission-side resonant circuit. The AC magnetic field generating circuit is configured to generate an AC magnetic field for detecting the relative positional relationship between the transmission-side resonant circuit and the receiving-side resonant circuit. The magnetic field detector is configured to detect the AC magnetic field. The frequency of the AC magnetic field is different from the resonant frequency of each of the transmission-side resonant circuit and the receiving-side resonant circuit.

[0008] In the contactless power supply system of the first aspect, the frequency of the AC magnetic field may be lower than the resonance frequency.

[0009] The contactless power supply system of the first aspect may further include a filter circuit configured to filter the output of the magnetic field detector. The filter circuit may be configured to pass a signal having a frequency of the AC magnetic field and attenuate a signal having a resonant frequency.

[0010] In the contactless power supply system of the first aspect, the transmission side resonance circuit and the magnetic field detector may be provided in one of the moving body and the ground side device. The reception side resonance circuit and the AC magnetic field generating circuit may be provided in the other of the moving body and the ground side device.

[0011] In the non-contact power supply system of the above configuration, the transmission side resonance circuit and the magnetic field detector may be provided in the ground side device. The reception side resonance circuit and the AC magnetic field generating circuit may be provided in the moving body.

[0012] In the non-contact power supply system of the above configuration, the transmission side resonance circuit and the magnetic field detector may be provided in the moving body. The reception side resonance circuit and the AC magnetic field generating circuit may be provided in the ground side device.

[0013] In the contactless power supply system of the first aspect, a plurality of magnetic field detectors may be provided along a direction perpendicular to a traveling direction of the moving body.

[0014] The contactless power supply system having the above configuration may further include a position estimator and a power supply controller, the position estimator being configured to estimate the relative position relationship between the transmission side resonance circuit and the reception side resonance circuit based on the output of the magnetic field detector, and the power supply controller being configured to control the contactless power transmission based on the relative position relationship estimated by the position estimator. The power supply controller may be configured to prohibit power transmission from the transmission side resonance circuit to the reception side resonance circuit when the transmission side resonance circuit and the reception side resonance circuit are not aligned in a direction perpendicular to the traveling direction of the moving body.

[0015] The contactless power supply system having the above configuration may further include a position estimator and a power supply controller, the position estimator being configured to estimate the relative position relationship between the transmission side resonant circuit and the reception side resonant circuit based on the output of the magnetic field detector, and the power supply controller being configured to control the contactless power transmission based on the relative position relationship estimated by the position estimator. A plurality of transmission side resonant circuits may be arranged in a direction perpendicular to the traveling direction of the moving body, and the power supply controller may be configured to switch the transmission side resonant circuit that transmits power to the reception side resonant circuit based on the relative position relationship in the direction perpendicular to the traveling direction of the moving body.

[0016] In the contactless power supply system of the first aspect, the AC magnetic field may include identification information of the moving object.

[0017] A second aspect of the present invention relates to a position estimation method applied to a contactless power supply system, which is configured to perform contactless power transmission by magnetic field resonance coupling between a ground-side device and a mobile body. The contactless power supply system includes an AC magnetic field generating circuit, a magnetic field detector, a transmission-side resonant circuit, and a receiving-side resonant circuit. The position estimation method includes (i) generating an AC magnetic field by the AC magnetic field generating circuit, (ii) detecting the AC magnetic field by the magnetic field detector, and (iii) estimating the relative position relationship between the transmission-side resonant circuit that transmits power and the receiving-side resonant circuit that receives power from the transmission-side resonant circuit based on the output of the magnetic field detector. The frequency of the AC magnetic field is different from the resonant frequency of each of the transmission-side resonant circuit and the receiving-side resonant circuit.

[0018] A third aspect of the present invention relates to a mobile body configured to transmit power contactlessly from a ground-side device. The mobile body includes a receiving-side resonant circuit and an AC magnetic field generating circuit. The receiving-side resonant circuit is configured to receive power transmitted from a transmission-side resonant circuit provided in the ground-side device. The AC magnetic field generating circuit is configured to generate an AC magnetic field for detecting a relative positional relationship between the transmission-side resonant circuit and the receiving-side resonant circuit. The frequency of the AC magnetic field is different from the resonant frequency of each of the transmission-side resonant circuit and the receiving-side resonant circuit.

[0019] A fourth aspect of the present invention relates to a power supply device configured to perform contactless power supply to a mobile body. The power supply device includes a transmission side resonant circuit, a magnetic field detector, and a control device. The transmission side resonant circuit is configured to transmit power to a receiving side resonant circuit of the mobile body. The magnetic field detector is configured to detect the magnetic field around the power supply device. The control device is configured to extract an AC magnetic field with a specific frequency from the output of the magnetic field detector, and detect the relative position relationship between the transmission side resonant circuit and the receiving side resonant circuit based on the AC magnetic field with the specific frequency. The specific frequency is different from the resonant frequency of each of the transmission side resonant circuit and the receiving side resonant circuit.

[0020] According to the contactless power supply system, position estimation method, mobile body and power supply equipment of the present invention, during the contactless power transmission of magnetic field resonance coupling between the mobile body and the ground side equipment, the relative position relationship between the transmission side resonant circuit and the receiving side resonant circuit can be accurately detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like symbols represent like elements, and in which:

[0022] Figure 1 is a diagram schematically showing a configuration of a contactless power supply system according to a first embodiment of the present invention;

[0023] Figure 2 is a schematic configuration diagram of a controller of a ground-side device as an example of the power supply device according to the first embodiment of the present invention;

[0024] Figure 3 is a schematic configuration diagram of an electronic control unit (ECU) of a vehicle that performs contactless power transmission by magnetic field resonance coupling (magnetic field resonance) with a ground-side device;

[0025] Figure 4 is a functional block diagram of a processor of a controller;

[0026] Figure 5 is a flowchart showing a control routine of a power supply process according to a first embodiment of the present invention;

[0027] Figure 6 is a diagram schematically showing a partial configuration of a contactless power supply system according to a second embodiment of the present invention;

[0028] Figure 7 is a diagram showing an arrangement example of a magnetic field detector according to a third embodiment of the present invention;

[0029] Figure 8 is a flowchart showing a control routine of a power supply process according to a third embodiment of the present invention;

[0030] Fig. 9 is a diagram showing an arrangement example of a magnetic field detector and a transmission-side resonance circuit according to a fourth embodiment of the present invention;

[0031] Fig.10 is a flowchart showing a control routine of a power supply process according to a fourth embodiment of the present invention;

[0032] Fig.11 is a diagram schematically showing a configuration of a contactless power supply system according to a fifth embodiment of the present invention;

[0033] Fig.12 is a functional block diagram of a processor of an ECU constituting a contactless power supply system according to a fifth embodiment; and

[0034] Fig.13 : is a flowchart showing a control routine of a power supply process according to a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0035] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, the same constituent elements are denoted by the same reference numerals.

[0036] The following will refer to Figures 1 to 5 A first embodiment of the present invention is described.

[0037] Figure 1 : is a diagram schematically showing the configuration of a contactless power supply system 1 according to a first embodiment of the present invention. The contactless power supply system 1 performs contactless power transmission by magnetic field resonance coupling (magnetic field resonance) between a ground-side device 2 and a vehicle 3. In particular, in the present embodiment, when the vehicle 3 is traveling, the contactless power supply system 1 performs contactless power transmission between the ground-side device 2 and the vehicle 3. The ground-side device 2 is an example of a power supply device, and the vehicle 3 is an example of a moving body. Contactless power transmission is also referred to as "contactless power supply", "wireless power transmission" or "wireless power supply".

[0038] The contactless power supply system 1 includes a power transmission device 4 configured to transmit power contactlessly, and a power receiving device 5 configured to receive power contactlessly from the power transmission device 4. In the present embodiment, the power transmission device 4 is mounted on the ground-side device 2, and the power receiving device 5 is mounted on the vehicle 3. That is, the ground-side device 2 performs contactless power supply to the vehicle 3, and the contactless power supply system 1 transmits power from the ground-side device 2 to the vehicle 3 contactlessly.

[0039] like Figure 1 As shown, in addition to the power transmission device 4, the ground-side device 2 also includes a power supply 21 and a controller 22. The ground-side device 2 is set on the road where the vehicle 3 passes, for example, embedded in the ground (under the road surface). At least a part of the ground-side device 2 (for example, the power supply 21 and the controller 22) can be arranged above the road surface.

[0040] The power source 21 is a power source of the power transmission device 4, and supplies power to the power transmission device 4. Examples of the power source 21 include a commercial AC power source that supplies single-phase AC power. The power source 21 may be, for example, an AC power source that supplies three-phase AC power.

[0041] The power transmission device 4 includes a transmission side rectifier circuit 41, an inverter 42, and a transmission side resonance circuit 43. In the power transmission device 4, appropriate AC power (high frequency power) is supplied to the transmission side resonance circuit 43 via the transmission side rectifier circuit 41 and the inverter 42.

[0042] The transmission side rectifier circuit 41 is electrically connected to the power source 21 and the inverter 42. The transmission side rectifier circuit 41 rectifies the AC power supplied from the power source 21 to convert the AC power into DC power and supplies the DC power to the inverter 42. Examples of the transmission side rectifier circuit 41 include an AC-DC converter.

[0043] The inverter 42 is electrically connected to the transmission side rectifier circuit 41 and the transmission side resonant circuit 43. The inverter 42 converts the direct current supplied from the transmission side rectifier circuit 41 into alternating current (high frequency power) having a frequency higher than that of the alternating current of the power source 21, and supplies the high frequency power to the transmission side resonant circuit 43.

[0044] The transmission side resonance circuit 43 includes a resonator including a coil 44 and a capacitor 45. Various parameters of the coil 44 and the capacitor 45 (the outer diameter and inner diameter of the coil 44, the number of turns of the coil 44, the capacitance of the capacitor 45, etc.) are determined so that the resonance frequency of the transmission side resonance circuit 43 reaches a predetermined setting value. The predetermined setting value is, for example, 10 kHz to 100 GHz, preferably 85 kHz, which is a frequency band for contactless power transmission defined by the SAE TIR J2954 standard.

[0045] The transmission side resonant circuit 43 is arranged at the center of the lane through which the vehicle 3 passes, so as to position the center of the coil 44 at the center of the lane. When the high frequency power supplied from the inverter 42 is applied to the transmission side resonant circuit 43, the transmission side resonant circuit 43 generates an AC magnetic field for transmitting power. The power supply 21 may be a DC power supply such as a fuel cell or a solar cell. In this case, the transmission side rectifier circuit 41 may be omitted.

[0046] The controller 22 is, for example, a general-purpose computer, and performs various types of control on the ground-side device 2. For example, the controller 22 is electrically connected to the inverter 42 of the power transmission device 4, and controls the inverter 42 to control power transmission of the power transmission device 4.

[0047] Figure 2 2 is a schematic configuration diagram of the controller 22. The controller 22 includes a memory 23 and a processor 24. The memory 23 and the processor 24 are connected to each other via a signal line. The controller 22 may also include, for example, a communication interface that enables communication between the ground-side device 2 and the outside of the ground-side device 2. The controller 22 is an example of a control device of the ground-side device 2.

[0048] The memory 23 includes, for example, a volatile semiconductor memory (e.g., a random access memory (RAM)) and a nonvolatile semiconductor memory (e.g., a read-only memory (ROM)). The memory 23 stores, for example, a program to be executed by the processor 24 and various types of data to be used when the processor 24 performs various processes.

[0049] The processor 24 includes one or more central processing units (CPUs) and their peripheral circuits, and performs various processes. The processor 24 may also include an arithmetic circuit such as a logic operation unit or a numerical operation unit.

[0050] like Figure 1 As shown, in addition to the power receiving device 5, the vehicle 3 includes a motor 31, a battery 32, a power control unit (PCU) 33, and an electronic control unit (ECU) 34. In the present embodiment, the vehicle 3 is a battery electric vehicle (BEV) not equipped with an internal combustion engine, and the motor 31 outputs driving power.

[0051] The motor 31 is, for example, an AC synchronous motor, and functions as a motor and a generator. When the motor 31 functions as a motor, the motor 31 is driven by using the power stored in the battery 32 as a power source. The output of the motor 31 is transmitted to the wheels 90 through the speed reducer and the axle. When the vehicle 3 decelerates, the motor 31 is driven by the rotation of the wheels 90, and the motor 31 functions as a generator to generate regenerative power.

[0052] The battery 32 is a rechargeable secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The battery 32 stores the power required for the vehicle 3 to travel (for example, the driving power of the motor 31). When the regenerative power generated by the motor 31 is supplied to the battery 32, the battery 32 is charged, and the charging rate (state of charge (SOC)) of the battery 32 is restored. In addition to the ground-side device 2, the battery 32 can be charged by an external power source via a charging port provided in the vehicle 3.

[0053] The PCU 33 is electrically connected to the battery 32 and the motor 31. The PCU 33 includes an inverter, a boost converter, and a DC-DC converter. The inverter converts the DC power supplied from the battery 32 into AC power, and supplies the AC power to the motor 31. The inverter converts the AC power (regenerative power) generated by the motor 31 into DC power, and supplies the DC power to the battery 32. When the power stored in the battery 32 is supplied to the motor 31, the boost converter increases the voltage of the battery 32 as needed. When the power stored in the battery 32 is supplied to electronic devices such as headlights, the DC-DC converter reduces the voltage of the battery 32.

[0054] The power receiving device 5 includes a reception-side resonance circuit 51, a reception-side rectifier circuit 54, and a charging circuit 55. The power receiving device 5 receives power from the power transmitting device 4, and supplies the received power to the battery 32.

[0055] The receiving side resonant circuit 51 is arranged at the bottom of the vehicle 3 to reduce the distance from the road surface. In this embodiment, the receiving side resonant circuit 51 is arranged at the center of the vehicle 3 in the vehicle width direction and between the front wheel 90 and the rear wheel 90 in the front-rear direction of the vehicle 3.

[0056] The receiving-side resonant circuit 51 has the same configuration as the transmitting-side resonant circuit 43, and includes a resonator including a coil 52 and a capacitor 53. Various parameters of the coil 52 and the capacitor 53 (the outer diameter and inner diameter of the coil 52, the number of turns of the coil 52, the capacitance of the capacitor 53, etc.) are determined so that the resonant frequency of the receiving-side resonant circuit 51 coincides with the resonant frequency of the transmitting-side resonant circuit 43. When the amount of deviation between the resonant frequency of the receiving-side resonant circuit 51 and the resonant frequency of the transmitting-side resonant circuit 43 is small, for example, when the resonant frequency of the receiving-side resonant circuit 51 is within a range of ±20% of the resonant frequency of the transmitting-side resonant circuit 43, the resonant frequency of the receiving-side resonant circuit 51 does not need to coincide with the resonant frequency of the transmitting-side resonant circuit 43.

[0057] like Figure 1 As shown, when an AC magnetic field is generated in the transmission-side resonance circuit 43 while the reception-side resonance circuit 51 faces the transmission-side resonance circuit 43, the oscillation of the AC magnetic field is transmitted to the reception-side resonance circuit 51 which resonates at the same resonance frequency as the transmission-side resonance circuit 43. As a result, an induced current flows in the reception-side resonance circuit 51 by electromagnetic induction, and power is generated in the reception-side resonance circuit 51 by the induced current. That is, the transmission-side resonance circuit 43 transmits power to the reception-side resonance circuit 51, and the reception-side resonance circuit 51 receives power from the transmission-side resonance circuit 43.

[0058] The reception-side rectifier circuit 54 is electrically connected to the reception-side resonance circuit 51 and the charging circuit 55. The reception-side rectifier circuit 54 rectifies the AC power supplied from the reception-side resonance circuit 51 to convert the AC power into DC power, and supplies the DC power to the charging circuit 55. Examples of the reception-side rectifier circuit 54 include an AC-DC converter.

[0059] The charging circuit 55 is electrically connected to the receiving-side rectifier circuit 54 and the battery 32. The charging circuit 55 converts the DC power supplied from the receiving-side rectifier circuit 54 into a DC power at the voltage level of the battery 32, and supplies the DC power to the battery 32. When the power receiving device 5 supplies the power transmitted from the power transmitting device 4 to the battery 32, the battery 32 is charged, and the SOC of the battery 32 is restored. Examples of the charging circuit 55 include a DC-DC converter.

[0060] The ECU 34 performs various types of control on the vehicle 3. For example, the ECU 34 is electrically connected to the charging circuit 55 of the power receiving device 5, and controls the charging circuit 55 to control charging of the battery 32 with the power transmitted from the power transmitting device 4. The ECU 34 is electrically connected to the PCU 33, and controls the PCU 33 to control power transfer between the battery 32 and the motor 31.

[0061] Figure 3 34 is a schematic configuration diagram of the ECU 34. The ECU 34 includes a communication interface 35, a memory 36, and a processor 37. The communication interface 35, the memory 36, and the processor 37 are connected to each other via a signal line.

[0062] The communication interface 35 includes an interface circuit for connecting the ECU 34 to an in-vehicle network conforming to a standard such as a controller area network (CAN).

[0063] The memory 36 includes, for example, a volatile semiconductor memory (eg, RAM) and a nonvolatile semiconductor memory (eg, ROM). The memory 36 stores, for example, a program to be executed by the processor 37 and various types of data to be used when the processor 37 performs various processes.

[0064] The processor 37 includes one or more central processing units (CPUs) and their peripheral circuits, and performs various processes. The processor 37 may also include an arithmetic circuit such as a logic operation unit or a numerical operation unit.

[0065] like Figure 3 As shown, the vehicle 3 also includes a global navigation satellite system (GNSS) receiver 38, a map database 39, and a communication device 40. The GNSS receiver 38, the map database 39, and the communication device 40 are electrically connected to the ECU 34.

[0066] The GNSS receiver 38 detects the current position of the vehicle 3 (e.g., the latitude and longitude of the vehicle 3) based on positioning information obtained from a plurality of (e.g., three or more) positioning satellites. Specifically, the GNSS receiver 38 captures the positioning satellites and receives radio waves transmitted from the positioning satellites. Then, the GNSS receiver 38 calculates the distance to each positioning satellite based on the difference between the transmission time and the reception time of the radio waves, and detects the current position of the vehicle 3 based on the distance to the positioning satellites and the positions (orbital information) of the positioning satellites. The output of the GNSS receiver 38, that is, the current position of the vehicle 3 detected by the GNSS receiver 38, is transmitted to the ECU 34.

[0067] The Global Navigation Satellite System (GNSS) is a generic name for satellite positioning systems, such as the Global Positioning System (GPS) of the United States, the Global Navigation Satellite System (GLONASS) of Russia, the Galileo system of Europe, the Quasi-Zenith Satellite System (QZSS) of Japan, the BeiDou system of China, and the Indian Regional Navigation Satellite System (IRNSS) of India. Therefore, the GNSS receiver 38 includes a GPS receiver.

[0068] The map database 39 stores map information. The map information includes, for example, location information of the installation area of ​​the ground-side device 2. The ECU 34 acquires the map information from the map database 39. The map database 39 may be provided outside the vehicle 3 (for example, in a server), and the ECU 34 may acquire the map information from outside the vehicle 3.

[0069] The communication device 40 is a device (eg, a road-to-vehicle communication device or a data communication module (DCM)) capable of communicating between the vehicle 3 and the outside of the vehicle 3 . The ECU 34 communicates with the outside of the vehicle 3 via the communication device 40 .

[0070] As described above, the contactless power supply system 1 transmits power from the ground-side device 2 to the vehicle 3 via the AC magnetic field generated in the transmission-side resonant circuit 43 of the power transmission device 4. However, continuous generation of the AC magnetic field for power transmission between the ground-side device 2 and the vehicle 3 results in waste of power. There is also concern about the influence of the AC magnetic field on electronic devices and the like.

[0071] Therefore, when the vehicle 3 passes over the ground-side device 2, it is expected that an AC magnetic field for power transmission is generated at an appropriate timing. However, in the case where the vehicle 3 is detected to be close to the ground-side device 2 by wireless communication, there is a possibility that the AC magnetic field cannot be generated at an appropriate timing due to obstacles to wireless communication such as obstacles. When the transmission-side resonant circuit 43 and the reception-side resonant circuit 51 are not aligned when the vehicle 3 passes over the ground-side device 2, the power transmission efficiency decreases.

[0072] In the present embodiment, the contactless power supply system 1 includes an AC magnetic field generating circuit 6 and a magnetic field detector 7, and detects the relative positional relationship between the transmission side resonance circuit 43 of the power transmission device 4 and the reception side resonance circuit 51 of the power reception device 5 by using the AC magnetic field generating circuit 6 and the magnetic field detector 7. In the present embodiment, as Figure 1 As shown, the AC magnetic field generating circuit 6 is provided in the vehicle 3 , and the magnetic field detector 7 is provided in the ground-side device 2 .

[0073] The AC magnetic field generating circuit 6 generates an AC magnetic field (hereinafter referred to as "position detection AC magnetic field") for detecting the relative positional relationship between the transmission side resonance circuit 43 and the reception side resonance circuit 51. The AC magnetic field generating circuit 6 is arranged at the bottom of the vehicle 3 to reduce the distance from the road surface. In the present embodiment, the AC magnetic field generating circuit 6 is arranged at the center of the vehicle 3 in the vehicle width direction, and is arranged behind the reception side resonance circuit 51 in the front-rear direction of the vehicle 3. The AC magnetic field generating circuit 6 may be arranged at the same position as the reception side resonance circuit 51, or may be arranged in front of the reception side resonance circuit 51 in the front-rear direction of the vehicle 3.

[0074] The AC magnetic field generating circuit 6 has the same configuration as that of the transmission side resonance circuit 43 and the reception side resonance circuit 51, and includes a resonator including a coil 61 and a capacitor 62. Various parameters of the coil 61 and the capacitor 62 (the outer diameter and inner diameter of the coil 61, the number of turns of the coil 61, the capacitance of the capacitor 62, etc.) are determined so that the resonance frequency of the AC magnetic field generating circuit 6 reaches a predetermined setting value. The predetermined setting value is set to a value different from the resonance frequency of the transmission side resonance circuit 43 and the reception side resonance circuit 51, that is, the resonance frequency of the magnetic field resonance coupling.

[0075] like Figure 1 As shown, the AC magnetic field generating circuit 6 is electrically connected to the PCU 33, and the ECU 34 controls the AC magnetic field generating circuit 6 via the PCU 33. The inverter of the PCU 33 converts the DC power supplied from the battery 32 into AC power based on a command from the ECU 34, and supplies the AC power to the AC magnetic field generating circuit 6. When the AC power supplied from the PCU 33 is applied to the AC magnetic field generating circuit 6, the AC magnetic field generating circuit 6 generates a position detection AC magnetic field. That is, the AC magnetic field generating circuit 6 generates an AC magnetic field as a position signal of the vehicle 3.

[0076] For example, when the distance between the installation area of ​​the ground-side device 2 and the vehicle 3 is equal to or less than a predetermined value, the ECU 34 controls the PCU 33 to generate a position detection AC magnetic field through the AC magnetic field generating circuit 6. The distance between the installation area of ​​the ground-side device 2 and the vehicle 3 is calculated by, for example, comparing the current position of the vehicle 3 detected by the GNSS receiver 38 and the position of the installation area of ​​the ground-side device 2 stored in the map database 39. When a predetermined signal is received from a road-side unit provided in front of the ground-side device 2 via the communication device 40, the ECU 34 may control the PCU 33 to generate a position detection AC magnetic field through the AC magnetic field generating circuit 6. When the vehicle 3 is traveling, the ECU 34 may constantly generate a weak AC magnetic field through the AC magnetic field generating circuit 6. The ECU 34 may control the AC magnetic field generating circuit 6 via an inverter provided separately from the PCU 33.

[0077] The AC magnetic field generated by the AC magnetic field generating circuit 6 as the position signal of the vehicle 3 may include identification information (e.g., a vehicle identifier (ID)) of the vehicle 3. That is, in addition to the position signal of the vehicle 3, the vehicle 3 may also transmit the identification information of the vehicle 3 to the ground-side device 2 via the AC magnetic field. In this case, when the AC magnetic field generating circuit 6 generates the AC magnetic field, the ECU 34 of the vehicle 3 transmits the position signal and identification information of the vehicle 3 to the ground-side device 2, for example, by modulating the AC magnetic field based on the identification information of the vehicle 3.

[0078] The magnetic field detector 7 detects the magnetic field around the ground-side device 2. Examples of the magnetic field detector 7 include a magneto-impedance (MI) sensor. The driving power of the magnetic field detector 7 is supplied to the magnetic field detector 7 from, for example, a power supply 21 via a driving circuit. The magnetic field detector 7 may be a Hall sensor, a magnetoresistive (MR) sensor, or the like.

[0079] The magnetic field detector 7 is arranged in front of the transmission-side resonant circuit 43 of the power transmission device 4 in the traveling direction of the vehicle 3 on the road where the power transmission device 4 is provided, and is arranged at the center of the lane where the vehicle 3 passes. The magnetic field detector 7 is arranged in the ground (under the road surface) or above the road surface. When the vehicle 3 around the magnetic field detector 7 generates a position detection AC magnetic field, the magnetic field detector 7 detects the position detection AC magnetic field.

[0080] The magnetic field detector 7 is electrically connected to the controller 22, and the output of the magnetic field detector 7 is transmitted to the controller 22. In the present embodiment, the contactless power supply system 1 includes the controller 22, and the controller 22 controls the contactless power supply between the ground-side device 2 and the vehicle 3.

[0081] Figure 42 is a functional block diagram of the processor 24 of the controller 22. In the present embodiment, the processor 24 includes a position estimator 25 and a power supply controller 26. The position estimator 25 and the power supply controller 26 are functional modules implemented by the processor 24 of the controller 22 executing a computer program stored in the memory 23 of the controller 22. The position estimator 25 and the power supply controller 26 can be implemented by a dedicated arithmetic circuit provided in the processor 24.

[0082] The position estimator 25 estimates the relative position relationship between the transmission side resonant circuit 43 and the reception side resonant circuit 51 based on the output of the magnetic field detector 7. Specifically, the position estimator 25 extracts the AC magnetic field of a specific frequency from the output of the magnetic field detector 7, and estimates the relative position relationship between the transmission side resonant circuit 43 and the reception side resonant circuit 51 based on the extracted AC magnetic field of the specific frequency. The specific frequency is the frequency of the AC magnetic field generated from the vehicle 3 as a position signal, and corresponds to the frequency of the AC magnetic field to be detected. That is, the position estimator 25 estimates the relative position relationship between the transmission side resonant circuit 43 and the reception side resonant circuit 51 by detecting the position detection AC magnetic field generated from the AC magnetic field generating circuit 6.

[0083] In this embodiment, by using an AC magnetic field as a position detection signal, the influence of obstacles in signal transmission and reception can be reduced. Even when metal or the like existing around the ground-side device 2 generates a stable magnetic field (DC magnetic field), it is easy to distinguish between the stable magnetic field and the position detection signal (AC magnetic field).

[0084] In the present embodiment, the frequency of the position detection AC magnetic field is different from the resonance frequency of the transmission side resonance circuit 43 and the reception side resonance circuit 51. Therefore, it is easy to distinguish the AC magnetic field generated in the transmission side resonance circuit 43 for power transmission and the AC magnetic field generated in the AC magnetic field generating circuit 6 for position detection. By using the AC magnetic field having a frequency different from the frequency of the AC magnetic field for power transmission as the position detection signal, the relative positional relationship between the transmission side resonance circuit 43 and the reception side resonance circuit 51 can be accurately detected.

[0085] The frequency of the position detection AC magnetic field is preferably set to a value lower than the resonant frequency of the transmission side resonant circuit 43 and the reception side resonant circuit 51. Therefore, the position detection AC magnetic field can be generated more easily. For example, when the resonant frequency of the transmission side resonant circuit 43 and the reception side resonant circuit 51 is 85kHz, the frequency of the position detection AC magnetic field is set to 50Hz to 50kHz, for example, 1kHz.

[0086] In the present embodiment, the transmission side resonant circuit 43 and the magnetic field detector 7 are provided in the ground side device 2, and the receiving side resonant circuit 51 and the AC magnetic field generating circuit 6 are provided in the vehicle 3. That is, the transmission side resonant circuit 43 and the magnetic field detector 7 are provided in one of the vehicle 3 and the ground side device 2, and the receiving side resonant circuit 51 and the AC magnetic field generating circuit 6 are provided in the other of the vehicle 3 and the ground side device 2. In this case, the source of the power transmission AC magnetic field and the source of the position detection AC magnetic field are different. Therefore, the time variation of the signal intensity detected by the magnetic field detector 7 is different between the position detection AC magnetic field and the power transmission AC magnetic field. As a result, the position detection AC magnetic field and the power transmission AC magnetic field can be distinguished more easily, and further, the relative positional relationship between the transmission side resonant circuit 43 and the receiving side resonant circuit 51 can be detected more accurately.

[0087] When the AC magnetic field generated by the AC magnetic field generating circuit 6 includes the identification information of the vehicle 3, the position estimator 25 acquires the identification information of the vehicle 3 from the output of the magnetic field detector 7. Therefore, the vehicle 3 to be supplied with power can be identified. As a result, the vehicle 3 can be easily charged for power supply, for example.

[0088] The power supply controller 26 controls the contactless power transmission between the ground-side device 2 and the vehicle 3 based on the relative positional relationship between the transmission-side resonance circuit 43 and the reception-side resonance circuit 51 estimated by the position estimator 25. That is, the power supply controller 26 controls the power transmission from the transmission-side resonance circuit 43 of the power transmission device 4 to the reception-side resonance circuit 51 of the power reception device 5 based on the estimation result from the position estimator 25. For example, when the position estimator 25 detects that the vehicle 3 including the reception-side resonance circuit 51 is approaching the ground-side device 2, the power supply controller 26 starts the power transmission from the transmission-side resonance circuit 43 to the reception-side resonance circuit 51.

[0089] The following will refer to Figure 5 The flowchart describes the above control flow. Figure 5 1 is a flowchart showing a control routine of the power supply process according to the first embodiment of the present invention. The control routine is repeatedly executed by the processor 24 of the controller 22.

[0090] In step S101 , the position estimator 25 first acquires the output of the magnetic field detector 7 .

[0091] In step S102, the position estimator 25 determines whether the vehicle 3 is approaching the ground-side device 2, that is, whether the receiving-side resonant circuit 51 is approaching the transmitting-side resonant circuit 43, based on the output of the magnetic field detector 7. For example, the position estimator 25 performs frequency analysis on the output of the magnetic field detector 7 to extract the frequency component of the position detection AC magnetic field, and when the value (peak value) of the extracted frequency component is equal to or greater than a predetermined value, it is determined that the vehicle 3 is approaching the ground-side device 2. Examples of methods for frequency analysis include Fourier transform.

[0092] When it is determined in step S102 that the vehicle 3 is not approaching the ground-side device 2, the control routine is terminated. When it is determined in step S102 that the vehicle 3 is approaching the ground-side device 2, the control routine proceeds to step S103.

[0093] In step S103, the power supply controller 26 transmits power from the ground side device 2 to the vehicle 3. Specifically, the power supply controller 26 controls the inverter 42 of the power transmission device 4 to supply high frequency power to the transmission side resonance circuit 43, thereby transmitting power from the transmission side resonance circuit 43 to the reception side resonance circuit 51.

[0094] For example, the power supply controller 26 transmits power from the transmission side resonance circuit 43 to the receiving side resonance circuit 51 within a predetermined period. The predetermined period is predetermined in consideration of the period during which the vehicle 3 passes over the ground side device 2. When it is detected that the vehicle 3 passes over the ground side device 2, the power supply controller 26 may stop the power transmission from the transmission side resonance circuit 43 to the receiving side resonance circuit 51. In this case, for example, the magnetic field detector 7 is arranged in front and rear of the transmission side resonance circuit 43 in the driving direction of the vehicle 3, and the passage of the vehicle 3 over the ground side device 2 is detected based on the output of the magnetic field detector 7 in front of the transmission side resonance circuit 43. The passage of the vehicle 3 can be detected by, for example, road-to-vehicle communication between the vehicle 3 and the road side unit. After step S103, the control routine is terminated.

[0095] Next, a second embodiment of the present invention will be described. Except for the following points, the configuration and control of the contactless power supply system according to the second embodiment are substantially the same as those of the contactless power supply system according to the first embodiment. Therefore, the second embodiment of the present invention will be described below focusing on the differences from the first embodiment.

[0096] Figure 6 2 is a diagram schematically showing a partial configuration of a contactless power supply system 1 ′ according to a second embodiment of the present invention. In the second embodiment, the contactless power supply system 1 ′ further includes a filter circuit 8 that filters the output of the magnetic field detector 7 .

[0097] The filter circuit 8 is provided between the magnetic field detector 7 and the controller 22 in the ground side device 2, and is electrically connected to the magnetic field detector 7 and the controller 22. The filter circuit 8 passes a signal having a frequency of the position detection AC magnetic field, and attenuates a signal having a resonance frequency of each of the transmission side resonance circuit 43 and the reception side resonance circuit 51.

[0098] The position estimator 25 of the controller 22 acquires the output of the magnetic field detector 7 filtered by the filter circuit 8, that is, the output of the magnetic field detector 7 corresponding to the frequency component of the position detection AC magnetic field. Then, the position estimator 25 estimates the relative position relationship between the transmission side resonance circuit 43 and the reception side resonance circuit 51 based on the filtered output of the magnetic field detector 7. Therefore, in the second embodiment, the frequency analysis of the magnetic field detector 7 is omitted or simplified, thereby reducing the calculation load of the controller 22 for position detection.

[0099] When the frequency of the position detection AC magnetic field is higher than the resonant frequency of the transmission side resonant circuit 43 and the receiving side resonant circuit 51, for example, a high pass filter (HPF) is used as the filter circuit 8. When the frequency of the position detection AC magnetic field is lower than the resonant frequency of the transmission side resonant circuit 43 and the receiving side resonant circuit 51, for example, a low pass filter (LPF) is used as the filter circuit 8. The filter circuit 8 can be a band pass filter (BPF) that passes only signals in a specific frequency band that includes the frequency of the position detection AC magnetic field and does not include the frequency of the power transmission AC magnetic field. Therefore, the frequency component of the position detection AC magnetic field can be more accurately extracted from the output of the magnetic field detector 7.

[0100] Also in the second embodiment, executing Figure 5 In step S101, the position estimator 25 acquires the output of the magnetic field detector 7 filtered by the filter circuit 8. In step S102, the position estimator 25 determines whether the vehicle 3 is approaching the ground-side device 2 based on the filtered output of the magnetic field detector 7.

[0101] Next, a third embodiment of the present invention will be described. Except for the following points, the configuration and control of the contactless power supply system according to the third embodiment are substantially the same as those of the contactless power supply system according to the first embodiment. Therefore, the third embodiment of the present invention will be described below focusing on the differences from the first embodiment.

[0102] Figure 7is a diagram showing an example of arrangement of a magnetic field detector 7 according to a third embodiment of the present invention. In the third embodiment, a plurality of magnetic field detectors 7 are arranged along a direction perpendicular to the traveling direction of the vehicle 3. That is, the contactless power supply system 1 includes a plurality of magnetic field detectors 7, and the magnetic field detectors 7 are arranged in the ground-side device 2. The magnetic field detectors 7 are spaced apart from each other along a direction perpendicular to the traveling direction of the vehicle 3. For example, the magnetic field detectors 7 are arranged at equal intervals along a direction perpendicular to the traveling direction of the vehicle 3.

[0103] As described above, the receiving side resonance circuit 51 and the AC magnetic field generating circuit 6 provided in the vehicle 3 are arranged at the center of the vehicle 3 in the vehicle width direction, and the transmitting side resonance circuit 43 is arranged at the center of the lane through which the vehicle 3 passes, so as to position the center of the coil 44 at the center of the lane. Therefore, one of the magnetic field detectors 7 is arranged at the center of the lane through which the vehicle 3 passes. Therefore, in the direction perpendicular to the traveling direction of the vehicle 3, one of the magnetic field detectors 7 is arranged at the same position as that of the transmission side resonance circuit 43. Figure 7 In the example of , the magnetic field detector 7 is arranged at the center of the lane, and the magnetic field detectors 7 are arranged on the right and left sides of the central magnetic field detector 7. Therefore, a total of three magnetic field detectors 7 are arranged at equal intervals.

[0104] When the receiving-side resonance circuit 51 and the transmission-side resonance circuit 43 are misaligned while the vehicle 3 is passing over the ground-side device 2, that is, when the vehicle 3 travels while deviating from the center of the lane, the efficiency of power transmission from the transmission-side resonance circuit 43 to the receiving-side resonance circuit 51 is reduced. In the third embodiment, when the receiving-side resonance circuit 51 and the transmission-side resonance circuit 43 are misaligned in the direction perpendicular to the traveling direction of the vehicle 3, the power supply controller 26 prohibits power transmission from the transmission-side resonance circuit 43 to the receiving-side resonance circuit 51. As a result, power transmission can be suppressed when the power transmission efficiency is reduced, and waste of power consumption in the power transmission device 4 is further reduced.

[0105] Figure 8 1 is a flowchart showing a control routine of the power supply process according to the third embodiment of the present invention. The control routine is repeatedly executed by the processor 24 of the controller 22.

[0106] In step S201 , the position estimator 25 first acquires the output of the magnetic field detector 7 .

[0107] In step S202, similar to Figure 5In step S102 in the embodiment, the position estimator 25 determines whether the vehicle 3 is approaching the ground-side device 2. For example, when the value (peak value) of the frequency component of the position detection AC magnetic field in the output of at least one of the magnetic field detectors 7 is equal to or greater than a predetermined value, the position estimator 25 determines that the vehicle 3 is approaching the ground-side device 2.

[0108] When it is determined in step S202 that the vehicle 3 is not approaching the ground-side device 2, the control routine is terminated. When it is determined in step S202 that the vehicle 3 is approaching the ground-side device 2, the control routine proceeds to step S203.

[0109] In step S203, the position estimator 25 determines whether the receiving-side resonant circuit 51 and the transmitting-side resonant circuit 43 are misaligned in the direction perpendicular to the traveling direction of the vehicle 3. For example, when the output of the magnetic field detector 7 arranged at the center of the lane is not the largest among the outputs of the magnetic field detector 7, that is, when the output of the magnetic field detector 7 arranged at a position other than the center of the lane is the largest, the position estimator 25 determines that the receiving-side resonant circuit 51 and the transmitting-side resonant circuit 43 are misaligned. When the output of the magnetic field detector 7 arranged at the outermost side in the lane width direction is the largest, the position estimator 25 can determine that the receiving-side resonant circuit 51 and the transmitting-side resonant circuit 43 are misaligned. The position estimator 25 can calculate the misalignment amount between the receiving-side resonant circuit 51 and the transmitting-side resonant circuit 43 based on the output of the magnetic field detector 7, and when the calculated misalignment amount is equal to or greater than a predetermined value, determine that the receiving-side resonant circuit 51 and the transmitting-side resonant circuit 43 are misaligned.

[0110] When it is determined in step S203 that the reception side resonance circuit 51 and the transmission side resonance circuit 43 are not aligned, the control routine is terminated. That is, when the vehicle 3 passes over the ground side device 2, power transmission from the transmission side resonance circuit 43 to the reception side resonance circuit 51 is prohibited.

[0111] When it is determined in step S203 that the reception side resonance circuit 51 and the transmission side resonance circuit 43 are not misaligned, the control routine proceeds to step S204. Figure 5 In step S103 in FIG. 1 , the power supply controller 26 transmits power from the ground-side device 2 to the vehicle 3. After step S204, this control routine is terminated.

[0112] Next, a fourth embodiment of the present invention will be described. Except for the following points, the configuration and control of the contactless power supply system according to the fourth embodiment are substantially the same as those of the contactless power supply system according to the first embodiment. Therefore, the fourth embodiment of the present invention will be described below focusing on the differences from the first embodiment.

[0113] Fig. 91 is a diagram showing an arrangement example of a magnetic field detector 7 and a transmission side resonance circuit 43 according to a fourth embodiment of the present invention. In the fourth embodiment, similarly to the third embodiment, the magnetic field detector 7 is arranged in a direction perpendicular to the traveling direction of the vehicle 3.

[0114] In the fourth embodiment, a plurality of transmission-side resonant circuits 43 of the power transmission device 4 and the magnetic field detector 7 are arranged along a direction perpendicular to the traveling direction of the vehicle 3. That is, the contactless power supply system 1 includes a plurality of transmission-side resonant circuits 43, and the transmission-side resonant circuits 43 are arranged in the ground-side device 2. The transmission-side resonant circuits 43 are spaced apart from each other along a direction perpendicular to the traveling direction of the vehicle 3. For example, the transmission-side resonant circuits 43 are arranged at equal intervals along a direction perpendicular to the traveling direction of the vehicle 3.

[0115] As described above, the reception-side resonance circuit 51 provided in the vehicle 3 is arranged at the center of the vehicle 3 in the vehicle width direction. Therefore, one of the transmission-side resonance circuits 43 is arranged at the center of the lane of the road on which the vehicle 3 passes. Fig. 9 In the example of , the transmission side resonant circuit 43 is arranged in the center of the lane, and the transmission side resonant circuit 43 is arranged on the right and left sides of the central transmission side resonant circuit 43. Therefore, a total of three transmission side resonant circuits 43 are arranged at equal intervals. That is, the number of transmission side resonant circuits 43 is equal to the number of magnetic field detectors 7.

[0116] When a plurality of transmission-side resonance circuits 43 are arranged in the vehicle width direction, the transmission-side resonance circuit 43 closest to the reception-side resonance circuit 51 provided in the vehicle 3 differs depending on the lateral position of the vehicle 3. For example, when the vehicle 3 is traveling with a shift to the right in the traveling direction, the right transmission-side resonance circuit 43 is closest to the reception-side resonance circuit 51. When the vehicle 3 is traveling with a shift to the left in the traveling direction, the left transmission-side resonance circuit 43 is closest to the reception-side resonance circuit 51.

[0117] In the fourth embodiment, the power supply controller 26 switches the transmission-side resonance circuit 43 that transmits power to the reception-side resonance circuit 51 based on the relative positional relationship between the transmission-side resonance circuit 43 and the reception-side resonance circuit 51 in the direction perpendicular to the traveling direction of the vehicle 3. As a result, it is possible to suppress a decrease in power transmission efficiency due to misalignment between the reception-side resonance circuit 51 and the transmission-side resonance circuit 43, and further reduce wasteful power consumption in the power transmission device 4.

[0118] Fig.10 4 is a flowchart showing a control routine of the power supply process according to the fourth embodiment of the present invention. The control routine is repeatedly executed by the processor 24 of the controller 22.

[0119] Similar to Figure 8In step S201 and S202, steps S301 and S302 are executed. When it is determined in step S302 that the vehicle 3 is approaching the ground-side device 2, the control routine proceeds to step S303.

[0120] In step S303, the position estimator 25 determines whether the output of the magnetic field detector 7 on the right side in the traveling direction of the vehicle 3 is greater than the output of the magnetic field detector 7 at the center of the lane in terms of the frequency component of the position detection AC magnetic field. When it is determined that the output of the right magnetic field detector 7 is equal to or less than the output of the center magnetic field detector 7, the control routine proceeds to step S304.

[0121] In step S304, the position estimator 25 determines whether the output of the magnetic field detector 7 on the left side in the traveling direction of the vehicle 3 is greater than the output of the magnetic field detector 7 at the center of the lane in terms of the frequency component of the position detection AC magnetic field. When it is determined that the output of the left magnetic field detector 7 is equal to or less than the output of the central magnetic field detector 7, that is, when the output of the central magnetic field detector 7 is maximum, the position estimator 25 determines that the vehicle 3 is not displaced, and the control routine proceeds to step S305.

[0122] In step S305, the power supply controller 26 transmits power from the transmission side resonance circuit 43 at the center of the lane to the reception side resonance circuit 51. Specifically, the power supply controller 26 controls the inverter 42 of the power transmission device 4 to supply high-frequency power to the transmission side resonance circuit 43 at the center of the lane. After step S305, this control routine is terminated.

[0123] When it is determined in step S303 that the output of the right magnetic field detector 7 is greater than the output of the central magnetic field detector 7, the position estimator 25 determines that the vehicle 3 is shifted to the right in the traveling direction, and the control routine proceeds to step S306. In step S306, the power supply controller 26 transmits power from the transmission side resonance circuit 43 on the right side in the traveling direction of the vehicle 3 to the reception side resonance circuit 51. Specifically, the power supply controller 26 controls the inverter 42 of the power transmission device 4 to supply high-frequency power to the right transmission side resonance circuit 43. After step S306, the control routine is terminated.

[0124] When it is determined in step S304 that the output of the left magnetic field detector 7 is greater than the output of the central magnetic field detector 7, the position estimator 25 determines that the vehicle 3 is shifted to the left in the traveling direction, and the control routine proceeds to step S307. In step S307, the power supply controller 26 transmits power from the transmission side resonance circuit 43 on the left side in the traveling direction of the vehicle 3 to the reception side resonance circuit 51. Specifically, the power supply controller 26 controls the inverter 42 of the power transmission device 4 to supply high-frequency power to the left transmission side resonance circuit 43. After step S307, the control routine is terminated.

[0125] In step S305, the power supply controller 26 may transmit power from all transmission-side resonant circuits 43 to the reception-side resonant circuit 51. In step S306, the power supply controller 26 may transmit power from the transmission-side resonant circuit 43 on the right side in the driving direction of the vehicle 3 and the transmission-side resonant circuit 43 at the center of the lane to the reception-side resonant circuit 51. In step S307, the power supply controller 26 may transmit power from the transmission-side resonant circuit 43 on the left side in the driving direction of the vehicle 3 and the transmission-side resonant circuit 43 at the center of the lane to the reception-side resonant circuit 51.

[0126] Next, the fifth embodiment of the present invention will be described. Except for the following points, the configuration and control of the contactless power supply system according to the fifth embodiment are substantially the same as the configuration and control of the contactless power supply system according to the first embodiment. Therefore, the fifth embodiment of the present invention will be described below focusing on the differences from the first embodiment.

[0127] Fig.11 is a diagram schematically showing the configuration of a contactless power supply system 1" according to a fifth embodiment of the present invention. As described above, the battery 32 of the vehicle 3 can be charged with the regenerative power generated by the motor 31. However, when the SOC of the battery 32 is high, the regenerative power cannot be supplied to the battery 32. When the SOC of the battery 32 remains high, the degradation of the battery 32 is aggravated. Therefore, when the vehicle 3 is traveling, it is necessary to reduce the SOC of the battery 32.

[0128] In the fifth embodiment, unlike the first embodiment, the power transmission device 4 is installed on the vehicle 3, and the power receiving device 5 is installed on the ground-side device 2. That is, when the vehicle 3 is traveling, the non-contact power supply system 1" transmits power from the vehicle 3 to the ground-side device 2 in a non-contact manner.

[0129] In the fifth embodiment, the power transmission device 4 includes an inverter 42 and a transmission-side resonance circuit 43. The battery 32 is used as a power source of the power transmission device 4, and the power of the battery 32 is consumed by power transmission from the vehicle 3 to the ground-side device 2.

[0130] The inverter 42 is electrically connected to the battery 32 and the transmission-side resonant circuit 43. The inverter 42 converts the DC power supplied from the battery 32 into high-frequency power, and supplies the high-frequency power to the transmission-side resonant circuit 43. When the high-frequency power supplied from the inverter 42 is applied to the transmission-side resonant circuit 43, the transmission-side resonant circuit 43 generates an AC magnetic field for transmitting power. The ECU 34 is electrically connected to the inverter 42 of the power transmission device 4, and controls the inverter 42 to control the power transmission through the power transmission device 4. The inverter 42 may be omitted, and the PCU 33 may be electrically connected to the transmission-side resonant circuit 43 to serve as the inverter of the power transmission device 4.

[0131] Similar to the first embodiment, the power receiving device 5 includes a receiving side resonant circuit 51, a receiving side rectifier circuit 54, and a charging circuit 55. The ground side device 2 includes a storage battery 27, and the power transmitted from the power transmission device 4 to the power receiving device 5 is supplied to the storage battery 27. The storage battery 27 is a rechargeable secondary battery such as a lithium ion battery or a nickel metal hydride battery.

[0132] like Fig.11 As shown, when an AC magnetic field is generated in the transmission-side resonance circuit 43 while the reception-side resonance circuit 51 faces the transmission-side resonance circuit 43, the oscillation of the AC magnetic field is transmitted to the reception-side resonance circuit 51 which resonates at the same resonance frequency as the transmission-side resonance circuit 43. As a result, an induced current flows in the reception-side resonance circuit 51 by electromagnetic induction, and power is generated in the reception-side resonance circuit 51 by the induced current. That is, the transmission-side resonance circuit 43 transmits power to the reception-side resonance circuit 51, and the reception-side resonance circuit 51 receives power from the transmission-side resonance circuit 43.

[0133] The charging circuit 55 is electrically connected to the receiving-side rectifier circuit 54 and the battery 27. The charging circuit 55 converts the DC power supplied from the receiving-side rectifier circuit 54 into DC power of the voltage level of the battery 27, and supplies the DC power to the battery 27. When the power receiving device 5 supplies the power transmitted from the power transmitting device 4 to the battery 27, the battery 27 is charged.

[0134] In the fifth embodiment, the AC magnetic field generating circuit 6 is provided in the ground side device 2, and the magnetic field detector 7 is provided in the vehicle 3. The AC magnetic field generating circuit 6 is arranged at the center of the lane through which the vehicle 3 passes, and is arranged in front of the receiving side resonant circuit 51 in the traveling direction of the vehicle 3. The AC magnetic field generating circuit 6 may be arranged at the same position as the receiving side resonant circuit 51, or may be arranged in front of the receiving side resonant circuit 51 in the traveling direction of the vehicle 3.

[0135] The ground-side device 2 includes an inverter 28, and the AC magnetic field generating circuit 6 generates a position detection AC magnetic field by using power supplied from the inverter 28. The inverter 28 is electrically connected to the storage battery 27 and the AC magnetic field generating circuit 6. The controller 22 is electrically connected to the inverter 28, and controls the AC magnetic field generating circuit 6 via the inverter 28.

[0136] The inverter 28 converts the DC power supplied from the battery 27 into AC power based on a command from the controller 22, and supplies the AC power to the AC magnetic field generating circuit 6. When the AC power supplied from the inverter 28 is applied to the AC magnetic field generating circuit 6, the AC magnetic field generating circuit 6 generates a position detection AC magnetic field.

[0137] For example, when the road side unit provided in front of the ground side device 2 detects the vehicle 3 and the controller 22 receives a signal from the road side unit, the controller 22 controls the inverter 28 to generate a position detection AC magnetic field through the AC magnetic field generating circuit 6. The controller 22 may constantly generate a weak AC magnetic field through the AC magnetic field generating circuit 6 within a predetermined time range (e.g., a time range other than nighttime) or throughout the day.

[0138] like Fig.11 As shown, the magnetic field detector 7 is arranged in front of the transmission side resonance circuit 43 in the vehicle 3. The magnetic field detector 7 is electrically connected to the ECU 34, and the output of the magnetic field detector 7 is transmitted to the ECU 34. In the fifth embodiment, the contactless power supply system 1" includes the ECU 34, and the ECU 34 controls the contactless power supply between the ground side device 2 and the vehicle 3.

[0139] Fig.12 34 is a functional block diagram of the processor 37 of the ECU 34. In the present embodiment, the processor 37 includes the position estimator 25 and the power supply controller 26. The position estimator 25 and the power supply controller 26 are functional modules implemented by the processor 37 of the ECU 34 executing a computer program stored in the memory 36 of the ECU 34. The position estimator 25 and the power supply controller 26 may be implemented by a dedicated arithmetic circuit provided in the processor 37.

[0140] Fig.13 1 is a flowchart showing a control routine of the power supply process according to the fifth embodiment of the present invention. The control routine is repeatedly executed by the processor 37 of the ECU 34.

[0141] Similar to Figure 5 Steps S401 and S402 are performed in the same manner as steps S101 and S102 in the control routine. When it is determined in step S402 that the vehicle 3 is approaching the ground-side device 2, the control routine proceeds to step S403.

[0142] In step S403, the power supply controller 26 determines whether the SOC of the battery 32 of the vehicle 3 is equal to or higher than a predetermined value. The predetermined value is set as, for example, an upper limit of a value at which the regenerative power can be collected.

[0143] The SOC of the battery 32 is calculated by a known method. For example, a battery sensor for detecting a state parameter of the battery 32 is provided in the battery 32, and the power supply controller 26 calculates the SOC of the battery 32 based on the voltage and temperature of the battery 32 detected by the battery sensor. The power supply controller 26 can calculate the SOC of the battery 32 by integrating the input and output currents of the battery 32 detected by the battery sensor. The power supply controller 26 can calculate the SOC of the battery 32 by using a state estimation method such as a Kalman filter.

[0144] When it is determined in step S403 that the SOC of the battery 32 is lower than the predetermined value, the control routine is terminated. When it is determined in step S403 that the SOC of the battery 32 is equal to or higher than the predetermined value, the control routine proceeds to step S404.

[0145] In step S404, the power supply controller 26 transmits power from the vehicle 3 to the ground-side device 2. Specifically, similar to Figure 5 In step S103 in FIG. 4 , the power supply controller 26 controls the inverter 42 of the power transmission device 4 to supply high-frequency power to the transmission-side resonance circuit 43, thereby transmitting power from the transmission-side resonance circuit 43 to the reception-side resonance circuit 51. After step S404, this control routine is terminated.

[0146] Next, other embodiments of the present invention will be described. Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and variations can be made within the scope of the claims. For example, the configuration of the resonators of the transmission side resonant circuit 43, the receiving side resonant circuit 51, and the AC magnetic field generating circuit 6 is only illustrative. For example, the number of capacitors 45, 53, and 62 can be one. Since the AC magnetic field generating circuit 6 that generates the position detection AC magnetic field does not need to use magnetic field resonance coupling, the capacitor 62 can be omitted.

[0147] The vehicle 3 may be a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV) including an internal combustion engine and an electric motor as a driving power source. The vehicle 3 may be an autonomous vehicle in which at least a part of the acceleration, steering, and deceleration (braking) of the vehicle 3 is automatically controlled. The mobile body that transmits power to the ground-side device 2 may be a commercial vehicle such as a bus or a truck, an automated guided vehicle (AGV), a drone, etc.

[0148] exist Figure 1 In the first embodiment shown, the AC magnetic field generating circuit 6 can be provided in the ground-side device 2, and the magnetic field detector 7 and the position estimator 25 can be provided in the vehicle 3. In this case, for example, the relative positional relationship between the transmission-side resonant circuit 43 and the reception-side resonant circuit 51 estimated by the position estimator 25 based on the output of the magnetic field detector 7 is presented to the driver via a display device (human-machine interface (HMI) etc.) of the vehicle 3. As a result, the driver can, for example, decelerate or turn the vehicle 3 as required to increase the amount of power transmission. Based on the estimation result from the position estimator 25, the vehicle 3 can be automatically controlled to increase the amount of power transmission.

[0149] The above-described embodiments may be implemented in any combination. For example, in the third to fifth embodiments, similarly to the second embodiment, the filter circuit 8 may be provided between the magnetic field detector 7 and the controller 22 or between the magnetic field detector 7 and the ECU 34 .

[0150] The fifth embodiment may be combined with the third embodiment, and the vehicle 3 may include a plurality of magnetic field detectors 7 spaced apart from each other in the vehicle width direction of the vehicle 3. Also in this case, the magnetic field detector 7 is arranged in a direction perpendicular to the traveling direction of the vehicle 3. The fifth embodiment may be combined with the fourth embodiment, and the vehicle 3 may include a plurality of magnetic field detectors 7 spaced apart from each other in the vehicle width direction of the vehicle 3 and a plurality of transmission-side resonant circuits 43. Also in this case, the magnetic field detector 7 and the transmission-side resonant circuit 43 are arranged in a direction perpendicular to the traveling direction of the vehicle 3.

Claims

1. A contactless power supply system configured to perform contactless power transmission by magnetic field resonance coupling between a ground-side device and a moving body, the contactless power supply system comprising: a transmission-side resonant circuit configured to transmit electric power; a receiving-side resonant circuit configured to receive power from the transmitting-side resonant circuit; an AC magnetic field generating circuit configured to generate an AC magnetic field for detecting a relative positional relationship between the transmission-side resonant circuit and the reception-side resonant circuit; and a magnetic field detector configured to detect the AC magnetic field, wherein a frequency of the AC magnetic field is different from a resonant frequency of each of the transmission-side resonant circuit and the reception-side resonant circuit, Wherein, a plurality of magnetic field detectors are arranged along a direction perpendicular to the traveling direction of the moving body, Wherein, the contactless power supply system further comprises: a position estimator configured to estimate a relative positional relationship between the transmission-side resonance circuit and the reception-side resonance circuit based on an output of the magnetic field detector; and a power supply controller configured to control the contactless power transmission based on the relative position relationship estimated by the position estimator, wherein: arranging a plurality of the transmission-side resonance circuits in a direction perpendicular to the traveling direction of the moving body; and The power supply controller is configured to switch the transmission-side resonance circuit that transmits power to the reception-side resonance circuit based on the relative positional relationship in a direction perpendicular to a traveling direction of the moving body.

2. The contactless power supply system according to claim 1, characterized in that: The frequency of the AC magnetic field is lower than the resonant frequency.

3. The contactless power supply system according to claim 1, characterized in that: Further included is a filter circuit configured to filter the output of the magnetic field detector, wherein the filter circuit is configured to pass a signal having a frequency of the alternating magnetic field and to attenuate a signal having the resonant frequency.

4. The contactless power supply system according to claim 1, characterized in that: The transmission-side resonance circuit and the magnetic field detector are provided in one of the moving object and the ground-side device; and The receiving-side resonance circuit and the AC magnetic field generating circuit are provided in the other of the moving object and the ground-side device.

5. The contactless power supply system according to claim 4, characterized in that: The transmission-side resonant circuit and the magnetic field detector are provided in the ground-side device; and The receiving-side resonance circuit and the AC magnetic field generating circuit are provided in the moving object.

6. The contactless power supply system according to claim 4, characterized in that: The transmission-side resonance circuit and the magnetic field detector are provided in the moving body; and The receiving-side resonant circuit and the AC magnetic field generating circuit are arranged in the ground-side device.

7. The contactless power supply system according to claim 1, characterized in that: Further including: a position estimator configured to estimate a relative position relationship between the transmission-side resonance circuit and the reception-side resonance circuit based on an output of the magnetic field detector; and A power supply controller, the power supply controller being configured to control the contactless power transmission based on the relative position relationship estimated by the position estimator, wherein the power supply controller is configured to prohibit power transmission from the transmission side resonance circuit to the reception side resonance circuit when the transmission side resonance circuit and the reception side resonance circuit are not aligned in a direction perpendicular to the travel direction of the moving body.

8. The contactless power supply system according to any one of claims 1 to 7, characterized in that: The AC magnetic field includes identification information of the moving object.

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