Power transmission control device and power transmission control method

Abstract

To achieve efficient power transmission from a power transmission coil provided on a road to a power reception coil provided in a vehicle.SOLUTION: A power transmission control device includes: a power transmission unit 63 that transmits electric power from a power transmission coil 45 provided on a road to a power reception coil 52 provided in a vehicle when the vehicle 3 travels on the road; a position deviation estimation unit 64 for calculating an estimation value of a position deviation amount between the power transmission coil and the power reception coil based on data indicating a relative position relation between the power transmission coil and the power reception coil; and a vehicle speed acquisition unit 65 for acquiring speed of the vehicle. The power transmission unit starts power transmission from the power transmission coil to the power reception coil when the estimation value becomes equal to or less than a threshold, and sets the threshold to be smaller when speed of the vehicle is low than when the speed of the vehicle is high.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a power transmission control device and a power transmission control method.

Background Art

[0002] Conventionally, a technique for non-contact power transmission between a power supply device provided on a road and a vehicle using a transmission method such as magnetic resonance has been known (for example, Patent Document 1). By using such a technique, non-contact power supply to the vehicle can be performed while the vehicle is running.

[0003] Patent Document 1 describes that when the power transmission efficiency from the power supply device to the vehicle becomes less than a reference value due to the influence of foreign objects or the like, the power supply from this power supply device to other vehicles is stopped.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, if a misalignment occurs between the power transmission coil provided on the road and the power reception coil provided on the vehicle regardless of the influence of foreign objects or the like, the power transmission efficiency from the power transmission coil to the power reception coil decreases. For this reason, when the vehicle passes over the power transmission coil, the power transmission efficiency from the power transmission coil to the power reception coil changes according to the relative positional relationship between the power transmission coil and the power reception coil. In the power transmission method described in Patent Document 1, this phenomenon is not considered at all, and there is room for improvement in the method for realizing efficient power transmission from the power transmission coil to the power reception coil.

[0006] Therefore, in view of the above problems, an object of the present invention is to achieve efficient power transmission from a power transmission coil provided on a road to a power reception coil provided on a vehicle.

Means for Solving the Problems

[0007] The gist of the present disclosure is as follows.

[0008] (1) A power transmission control device including: a power transmission unit that transmits power from a power transmission coil provided on the road to a power reception coil provided on the vehicle when the vehicle is traveling on the road; a positional deviation estimation unit that calculates an estimated value of the amount of positional deviation between the power transmission coil and the power reception coil based on data indicating a relative positional relationship between the power transmission coil and the power reception coil; and a vehicle speed acquisition unit that acquires the speed of the vehicle, wherein the power transmission unit starts power transmission from the power transmission coil to the power reception coil when the estimated value becomes equal to or less than a threshold value, and reduces the threshold value when the speed of the vehicle is low as compared with when the speed of the vehicle is high.

[0009] (2) The power transmission control device according to (1) above, wherein the power transmission unit transmits power from the power transmission coil to the power reception coil when the estimated value is equal to or less than the threshold value.

[0010] (3) The power transmission control device according to (1) or (2) above, wherein the data is acquired in the vehicle.

[0011] (4) The power transmission control device according to (1) or (2) above, wherein the data is an input current of an inverter that supplies alternating current power to the power transmission coil.

[0012] (5) A power transmission control method executed by a computer for controlling power transmission from a power transmission coil provided on a road to a power reception coil provided on a vehicle, the method comprising: calculating an estimated value of a misalignment amount between the power transmission coil and the power reception coil based on data indicating a relative positional relationship between the power transmission coil and the power reception coil; starting power transmission from the power transmission coil to the power reception coil when the estimated value becomes equal to or less than a threshold value; acquiring the speed of the vehicle; and reducing the threshold value when the speed of the vehicle is low compared to when the speed of the vehicle is high.

Effect of the Invention

[0013] According to the present invention, efficient power transmission from a power transmission coil provided on a road to a power reception coil provided on a vehicle can be realized.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Best Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are given to similar components.

[0016] <First Embodiment> Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 8.

[0017] First, a configuration for non-contact power supply to a vehicle using a power supply device will be described. FIG. 1 is a diagram schematically showing the configuration of a non-contact power supply system 1. The non-contact power supply system 1 includes a power supply device 2 and a vehicle 3, and performs non-contact power supply between the power supply device 2 and the vehicle 3. In particular, in the present embodiment, the non-contact power supply system 1 performs non-contact power supply from the power supply device 2 to the vehicle 3 by magnetic field resonance coupling (magnetic field resonance) when the vehicle 3 is running. That is, the non-contact power supply system 1 transmits power from the power supply device 2 to the vehicle 3 using a magnetic field as a medium. Note that non-contact power supply is also referred to as non-contact power transmission, wireless power transmission, or wireless power supply.

[0018] The power supply device 2 is configured to perform non-contact power supply to the vehicle 3. Specifically, as shown in FIG. 1, the power supply device 2 includes a power transmission device 4 and a power source 21. In the present embodiment, the power supply device 2 is provided on a road on which the vehicle 3 travels and is embedded, for example, underground (below the road surface). Note that at least a part of the power supply device 2 (for example, the power source 21) may be disposed above the road surface.

[0019] The power source 21 is a power source of the power transmission device 4 and supplies power to the power transmission device 4. The power source 21 is, for example, a commercial AC power source that supplies single-phase AC power. Note that the power source 21 may be an AC power source that supplies three-phase AC power or the like.

[0020] The power transmission device 4 is configured to generate an alternating magnetic field for transmitting power to the vehicle 3. In the present embodiment, the power transmission device 4 includes a power transmission side rectifier circuit 41, an inverter 42, a filter circuit 43, and a power transmission side resonance circuit 44. In the power transmission device 4, appropriate alternating current power (high-frequency power) is supplied to the power transmission side resonance circuit 44 via the power transmission side rectifier circuit 41 and the inverter 42.

[0021] The power transmission side rectifier circuit 41 is electrically connected to the power supply 21 and the inverter 42. The power transmission side rectifier circuit 41 rectifies the alternating current power supplied from the power supply 21 into direct current power and supplies the direct current power to the inverter 42. The power transmission side rectifier circuit 41 is, for example, an AC / DC converter.

[0022] The inverter 42 is electrically connected to the power transmission side rectifier circuit 41 and the filter circuit 43, and the filter circuit 43 is electrically connected to the inverter 42 and the power transmission side resonance circuit 44. The inverter 42 converts the direct current power supplied from the power transmission side rectifier circuit 41 into alternating current power (high-frequency power) having a frequency higher than that of the alternating current power of the power supply 21, and supplies the high-frequency power to the power transmission side resonance circuit 44 via the filter circuit 43. The filter circuit 43 suppresses the harmonic noise generated from the inverter 42.

[0023] The power transmission side resonance circuit 44 has a resonator composed of a power transmission coil 45 and a power transmission side capacitor 46. Various parameters of the power transmission coil 45 and the power transmission side capacitor 46 (such as the outer diameter and inner diameter of the power transmission coil 45, the number of turns of the power transmission coil 45, the capacitance of the power transmission side capacitor 46, etc.) are determined so that the resonance frequency of the power transmission side resonance circuit 44 becomes a predetermined set value. The predetermined set value is, for example, 10 kHz to 100 GHz, and preferably 85 kHz defined by the SAE TIR J2954 standard as the frequency band for non-contact power supply of the vehicle.

[0024] The power transmission side resonance circuit 44 is arranged directly below the road surface so that the distance from the road surface becomes small. Further, in the present embodiment, the power transmission side resonance circuit 44 is arranged on the road on which the vehicle 3 travels so that the center of the power transmission coil 45 is located at the center of the lane. When the high-frequency power supplied from the inverter 42 is applied to the power transmission side resonance circuit 44, an alternating current flows through the power transmission coil 45 of the power transmission side resonance circuit 44. As a result, the power transmission coil 45 generates an alternating magnetic field for transmitting power to the vehicle 3. In the power transmission device 4, the power source 21 may be a DC power source such as a fuel cell or a solar cell, and in this case, the power transmission side rectifier circuit 41 may be omitted.

[0025] FIG. 2 is a diagram schematically showing a part of the configuration of the power feeding device 2. As shown in FIG. 2, the power feeding device 2 further includes a controller 6 and a communication device 22.

[0026] The controller 6 is, for example, a general-purpose computer and performs various controls of the power feeding device 2. That is, the controller 6 functions as a control device of the power feeding device 2. As shown in FIG. 2, the controller 6 includes a memory 61 and a processor 62. The memory 61 and the processor 62 are connected to each other via a signal line. Note that the controller 6 may further include a communication interface or the like for connecting the controller 6 to a communication network such as the Internet.

[0027] The memory 61 has, for example, a volatile semiconductor memory (for example, RAM) and a non-volatile semiconductor memory (for example, ROM). The memory 61 stores a computer program executed in the processor 62, various data used when various processes are executed by the processor 62, and the like.

[0028] The processor 62 has one or more CPUs (Central Processing Unit) and its peripheral circuits, and executes various processes. Note that the processor 62 may further have an arithmetic circuit such as a logical arithmetic unit or a numerical arithmetic unit.

[0029] As shown in FIG. 2, the inverter 42 of the power transmission device 4 is electrically connected to the controller 6. The controller 6 controls the inverter 42 to control the power supply to the power transmission coil 45.

[0030] The communication device 22 is a device that enables communication between the power supply device 2 and the outside of the power supply device 2. For example, the communication device 22 is configured as a short-range wireless communication module that performs short-range wireless communication (for example, a DSRC (Dedicated Short Range Communication) antenna, a Bluetooth (registered trademark) module, etc.). The communication device 22 is electrically connected to the controller 6, and the controller 6 communicates with the vehicle 3 using the communication device 22.

[0031] On the other hand, the vehicle 3 is configured to be powered by the power supply device 2 when passing over the power transmission coil 45 provided on the road. Specifically, as shown in FIG. 1, the vehicle 3 includes a power receiving device 5, a motor 31, a battery 32, and a power control unit (PCU) 33. In this embodiment, the vehicle 3 is a battery electric vehicle (BEV) without an internal combustion engine, and the motor 31 outputs driving power for traveling.

[0032] The motor 31 is an electric motor (for example, an AC synchronous motor), and is driven using the electric power stored in the battery 32 as a power source. The output of the motor 31 is transmitted to the wheels 90 via a speed reducer and an axle. Note that the motor 31 may be a motor generator that functions as an electric motor and a generator. In this case, when the vehicle 3 decelerates, the motor 31 is driven by the rotation of the wheels 90, and the motor 31 generates regenerative power using the deceleration energy of the vehicle 3.

[0033] The battery 32 is a rechargeable secondary battery and is composed of, for example, a lithium-ion battery, a nickel-metal hydride battery, etc. The battery 32 stores electric power and supplies electric power to the electronic devices (such as the motor 31) of the vehicle 3. When electric power is supplied to the battery 32 from an external power source via a charging port provided in the vehicle 3, the battery 32 is charged and the state of charge (SOC) of the battery 32 is restored.

[0034] The PCU 33 is electrically connected to the battery 32 and the motor 31. The PCU 33 has 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 boost converter boosts the voltage of the battery 32 as necessary when the power stored in the battery 32 is supplied to the motor 31. The DC / DC converter steps down the voltage of the battery 32 when the power stored in the battery 32 is supplied to electronic devices such as headlights.

[0035] The power receiving device 5 is configured to receive power via the AC magnetic field emitted from the power transmitting device 4. In this embodiment, the power receiving device 5 includes a power receiving side resonance circuit 51, a power receiving side rectifying 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.

[0036] The power receiving side resonance circuit 51 is disposed at the bottom of the vehicle 3 so as to be closer to the road surface. Also, in this embodiment, the power receiving side resonance circuit 51 is disposed at the center of the vehicle 3 in the vehicle width direction and is disposed between the front wheels 90 and the rear wheels 90 in the longitudinal direction of the vehicle 3.

[0037] The power receiving side resonance circuit 51 has the same configuration as the power transmitting side resonance circuit 44, and has a resonator composed of a power receiving coil 52 and a power receiving side capacitor 53. Various parameters of the power receiving coil 52 and the power receiving side capacitor 53 (the outer diameter and inner diameter of the power receiving coil 52, the number of turns of the power receiving coil 52, the capacitance of the power receiving side capacitor 53, etc.) are determined such that the resonance frequency of the power receiving side resonance circuit 51 matches the resonance frequency of the power transmitting side resonance circuit 44. Note that if the deviation amount between the resonance frequency of the power receiving side resonance circuit 51 and the resonance frequency of the power transmitting side resonance circuit 44 is small, for example, if the resonance frequency of the power receiving side resonance circuit 51 is within the range of ±20% of the resonance frequency of the power transmitting side resonance circuit 44, the resonance frequency of the power receiving side resonance circuit 51 does not necessarily have to match the resonance frequency of the power transmitting side resonance circuit 44.

[0038] As shown in FIG. 1, when the power receiving coil 52 of the power receiving side resonance circuit 51 faces the power transmitting coil 45 of the power transmitting side resonance circuit 44, when an alternating magnetic field is generated in the power transmitting side resonance circuit 44, the vibration of the alternating magnetic field is transmitted to the power receiving side resonance circuit 51 that resonates at the same resonance frequency as the power transmitting side resonance circuit 44. As a result, an induced current flows through the power receiving coil 52 of the power receiving side resonance circuit 51 due to electromagnetic induction, and power is generated by the induced current. That is, the power receiving coil 52 receives power from the power transmitting coil 45 provided on the road.

[0039] The power receiving side rectifying circuit 54 is electrically connected to the power receiving side resonance circuit 51 and the charging circuit 55. The power receiving side rectifying circuit 54 rectifies the alternating current power supplied from the power receiving side resonance circuit 51 and converts it into direct current power, and supplies the direct current power to the charging circuit 55. The power receiving side rectifying circuit 54 is, for example, an AC / DC converter.

[0040] The charging circuit 55 is electrically connected to the power receiving side rectifying circuit 54 and the battery 32. The charging circuit 55 converts the direct current power supplied from the power receiving side rectifying circuit 54 to the voltage level of the battery 32 and supplies it to the battery 32. When the power transmitted from the power transmitting device 4 is supplied to the battery 32 by the power receiving device 5, the battery 32 is charged and the SOC of the battery 32 is restored. The charging circuit 55 is, for example, a DC / DC converter.

[0041] Figure 3 is a diagram schematically showing a part of the configuration of vehicle 3. As shown in Figure 3, vehicle 3 further includes an electronic control unit (ECU: Electronic Control Unit) 7, a GNSS (Global Navigation Satellite System) receiver 34, a map database 35, a vehicle speed sensor 36, a magnetic sensor 37, and a communication device 38.

[0042] ECU 7 is configured as a computer and performs various controls of vehicle 3. That is, ECU 7 functions as a control device of vehicle 3. As shown in Figure 3, ECU 7 has a communication interface 71, a memory 72, and a processor 73. The communication interface 71, the memory 72, and the processor 73 are connected to each other via signal lines.

[0043] The communication interface 71 has an interface circuit for connecting ECU 7 to an in-vehicle network conforming to a standard such as CAN (Controller Area Network).

[0044] The memory 72 has, for example, a volatile semiconductor memory (e.g., RAM) and a non-volatile semiconductor memory (e.g., ROM). The memory 72 stores programs executed in the processor 73, various data used when various processes are executed by the processor 73, and the like.

[0045] The processor 73 has one or more CPUs (Central Processing Unit) and its peripheral circuits, and executes various processes. Note that the processor 73 may further have an arithmetic circuit such as a logical arithmetic unit or a numerical arithmetic unit.

[0046] As shown in FIG. 3, the charging circuit 55 and the PCU 33 are electrically connected to the ECU 7. The ECU 7 controls the charging of the battery 32 with the power transmitted from the power transmission device 4 to the power reception device 5 via the charging circuit 55. Further, the ECU 7 controls the power transfer between the battery 32 and the electronic device (for example, the motor 31) via the PCU 33. Note that the ECU 7 may supply the power transmitted from the power transmission device 4 to the power reception device 5 to an electrical load (for example, the motor 31) instead of the battery 32.

[0047] The GNSS receiver 34 detects the current position of the vehicle 3 (for example, the latitude and longitude of the vehicle 3) based on the positioning information obtained from a plurality (for example, three or more) of positioning satellites. Specifically, the GNSS receiver 34 captures a plurality of positioning satellites and receives the radio waves transmitted from the positioning satellites. Then, the GNSS receiver 34 calculates the distance to the positioning satellite based on the difference between the transmission time and the reception time of the radio wave, and detects the current position of the vehicle 3 based on the distance to the positioning satellite and the position (orbit information) of the positioning satellite. A specific example of the GNSS receiver 34 is a GPS receiver. The GNSS receiver 34 is electrically connected to the ECU 7, and the output of the GNSS receiver 34, that is, the current position of the vehicle 3 detected by the GNSS receiver 34 is transmitted to the ECU 7.

[0048] The map database 35 stores map information. The map information includes the position information of the power supply area where the power transmission coil 45 of the power supply device 2 is installed. The map database 35 is electrically connected to the ECU 7, and the ECU 7 acquires the map information from the map database 35. Note that the map database may be provided outside the vehicle 3 (for example, a server, etc.), and the ECU 7 may acquire the map information from outside the vehicle 3.

[0049] The vehicle speed sensor 36 detects the speed of the vehicle 3. The vehicle speed sensor 36 detects the speed of the vehicle 3 by detecting, for example, the rotation speed of the wheels. The vehicle speed sensor 36 is electrically connected to the ECU 7, and the output of the vehicle speed sensor 36, that is, the speed of the vehicle 3 detected by the vehicle speed sensor 36 is transmitted to the ECU 7.

[0050] The magnetic sensor 37 detects the magnetic field intensity around the vehicle 3. The magnetic sensor 37 is, for example, a magneto-impedance (MI) sensor, a Hall sensor, a magneto resistive (MR) sensor, or the like. The magnetic sensor 37 is disposed, for example, at the bottom of the vehicle 3. The magnetic sensor 37 is electrically connected to the ECU 7, and the output of the magnetic sensor 37, that is, the magnetic field intensity detected by the magnetic sensor 37, is transmitted to the ECU 7.

[0051] The communication device 38 is a device that enables communication between the vehicle 3 and the outside of the vehicle 3. For example, the communication device 38 is configured as a short-range wireless communication module that performs short-range wireless communication (for example, a dedicated short range communication (DSRC) in-vehicle unit, a Bluetooth (registered trademark) module, an RFID reader, etc.). The communication device 38 is electrically connected to the ECU 7, and the ECU 7 communicates with the power supply device 2 (specifically, the controller 6) using the communication device 38.

[0052] FIG. 4 is a diagram showing an example of a power supply area where the power transmission coil 45 of the power supply device 2 is installed. In the example of FIG. 4, three power transmission coils 45 are arranged at intervals along the traveling direction of the vehicle 3 on the same lane of the road. The range on the lane where the power transmission coil 45 is installed corresponds to the power supply area. Note that the number of power transmission coils 45 installed in one power supply area may be another number (for example, one).

[0053] When power is supplied to the vehicle 3 in the power supply area, the ECU 7 of the vehicle 3 transmits a power supply request signal for requesting power supply to the vehicle 3 to the power supply device 2 using the communication device 38 when the vehicle 3 approaches the power supply area. When the controller 6 of the power supply device 2 receives the power supply request signal from the vehicle 3, the controller 6 generates an alternating magnetic field for power transmission by the power transmission device 4. That is, when the controller 6 receives the power supply request signal from the vehicle 3, the controller 6 performs non-contact power supply from the power supply device 2 to the vehicle 3. As a result, when the vehicle 3 is traveling on the road, the state of charge (SOC) of the battery 32 of the vehicle 3 can be recovered by non-contact power supply from the power supply device 2 to the vehicle 3.

[0054] However, when there is a misalignment between the power transmission coil 45 of the power supply device 2 and the power reception coil 52 of the vehicle 3, the power transmission efficiency from the power transmission coil 45 to the power reception coil 52 decreases. Therefore, when the vehicle 3 passes over the power transmission coil 45 in the power supply area, the power transmission efficiency from the power transmission coil 45 to the power reception coil 52 changes according to the relative positional relationship between the power transmission coil 45 and the power reception coil 52.

[0055] In order to minimize the waste of power in non-contact power supply, it is desirable to perform power transmission from the power transmission coil 45 to the power reception coil 52 only when the power transmission efficiency is high. On the other hand, when the vehicle 3 is running at high speed, the power consumption in the vehicle 3 increases, and the power demand in the vehicle 3 tends to increase. However, when the vehicle 3 passes through the power supply area at high speed, since the time during which the power reception coil 52 overlaps the power transmission coil 45 in the traveling direction of the vehicle 3 is short, it is difficult to ensure the required power supply amount with power transmission only when the power transmission efficiency is high.

[0056] Therefore, in the present embodiment, the power transmission timing from the power transmission coil 45 of the power supply device 2 to the power reception coil 52 of the vehicle 3 when the vehicle 3 passes through the power supply area is changed according to the speed of the vehicle 3 by the power transmission control device provided in the power supply device 2. In the present embodiment, the controller 6 of the power supply device 2 functions as the power transmission control device.

[0057] FIG. 5 is a functional block diagram of the processor 62 of the controller 6. In the present embodiment, the processor 62 includes a power transmission unit 63, a misalignment estimation unit 64, and a vehicle speed acquisition unit 65. The power transmission unit 63, the misalignment estimation unit 64, and the vehicle speed acquisition unit 65 are functional modules realized by the processor 62 of the controller 6 executing a computer program stored in the memory 61 of the controller 6. Note that the power transmission unit 63, the misalignment estimation unit 64, and the vehicle speed acquisition unit 65 may be realized by dedicated arithmetic circuits provided in the processor 62.

[0058] When the vehicle 3 is traveling on the road, the power transmission unit 63 transmits power from the power transmission coil 45 provided on the road to the power reception coil 52 provided on the vehicle 3. The power transmission unit 63 controls the power transmission from the power transmission coil 45 to the power reception coil 52 via the inverter 42.

[0059] Based on the data indicating the relative positional relationship between the power transmission coil 45 and the power reception coil 52, the position deviation estimation unit 64 calculates an estimated value of the amount of position deviation between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3. Note that the amount of position deviation between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3 is defined as the distance between the center of the power transmission coil 45 and the center of the power reception coil 52 in the traveling direction of the vehicle 3, and becomes zero when the center of the power reception coil 52 coincides with the center of the power transmission coil 45 in the traveling direction of the vehicle 3.

[0060] In the present embodiment, data indicating the relative positional relationship between the power transmission coil 45 and the power reception coil 52 is acquired in the vehicle 3. As a result, it is not necessary to separately provide an expensive configuration for acquiring such data for each of the numerous power transmission coils 45 provided on the road, and an increase in the installation cost of the power supply device 2 can be suppressed.

[0061] For example, the data indicating the relative positional relationship between the power transmission coil 45 and the power reception coil 52 is magnetic data acquired in the vehicle 3. In this case, a magnetic field generator (for example, a magnetic marker) that generates a magnetic field is provided on the road, and the magnetic sensor 37 of the vehicle 3 detects the intensity of the magnetic field emitted from the magnetic field generator.

[0062] For example, as shown in FIG. 4, the same number of magnetic markers 47 as the power transmission coil 45 are provided on the road, and the magnetic markers 47 are arranged in front of the power transmission coil 45 in the traveling direction of the vehicle 3. When the vehicle 3 travels in the power supply area, the magnetic sensor 37 of the vehicle 3 detects the intensity of the magnetic field emitted from the magnetic marker 47, and the output of the magnetic sensor 37 is transmitted from the vehicle 3 to the power supply device 2 by wireless communication. The position deviation estimation unit 64 calculates an estimated value of the amount of position deviation between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3 based on the output of the magnetic sensor 37 transmitted from the vehicle 3. Note that the configuration of the magnetic marker 47 shown in FIG. 4 is an example, and the position and number of the magnetic markers 47 are not limited to those shown in FIG. 4. Further, the magnetic marker 47 may have an RFID tag or the like that transmits position information (for example, a position ID) of the magnetic marker 47.

[0063] The vehicle speed acquisition unit 65 acquires the speed of the vehicle 3. In the present embodiment, the vehicle speed sensor 36 of the vehicle 3 detects the speed of the vehicle 3, and the output of the vehicle speed sensor 36 is transmitted from the vehicle 3 to the power supply device 2 by wireless communication. That is, the vehicle speed acquisition unit 65 acquires the output of the vehicle speed sensor 36 as the speed of the vehicle 3.

[0064] When the estimated value of the amount of position deviation estimated by the position deviation estimation unit 64 is equal to or less than the threshold value, the power transmission unit 63 transmits power from the power transmission coil 45 to the power reception coil 52. When the speed of the vehicle 3 is low, the threshold value is made smaller than when the speed of the vehicle 3 is high. By this, power can be transmitted from the power transmission coil 45 to the power reception coil 52 at an appropriate timing according to the speed of the vehicle 3.

[0065] Hereinafter, with reference to FIG. 6, the above-described power transmission control will be specifically described. FIG. 6 is a time chart showing the power transmission control from the power transmission coil 45 to the power reception coil 52 when the vehicle 3 passes through the power supply area. The time chart shows the amount of position deviation between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3 and the presence or absence (ON / OFF) of power transmission from the power transmission coil 45 to the power reception coil 52.

[0066] FIG. 6(a) shows the power transmission control when the speed of the vehicle 3 is low, and the threshold value for switching the presence or absence of power transmission is set to THa. At time t0, the vehicle 3 is located in front of the power supply area provided with the three power transmission coils 45. After time t0, as the vehicle 3 approaches the first power transmission coil 45, the amount of misalignment gradually decreases. As a result, at time ta, the amount of misalignment reaches the threshold value THa, and power transmission from the first power transmission coil 45 to the power reception coil 52 is started.

[0067] After time ta, when the center of the power reception coil 52 coincides with the center of the first power transmission coil 45 in the traveling direction of the vehicle 3, the amount of misalignment becomes zero. Thereafter, as the vehicle 3 moves away from the first power transmission coil 45, the amount of misalignment gradually increases. As a result, at time tb, the amount of misalignment becomes larger than the threshold value THa, and power transmission from the first power transmission coil 45 to the power reception coil 52 is stopped.

[0068] After time tb, when the vehicle 3 reaches the intermediate position between the first power transmission coil 45 and the second power transmission coil 45, the amount of misalignment becomes maximum. Thereafter, as the vehicle 3 approaches the second power transmission coil 45, the amount of misalignment gradually decreases. As a result, at time tc, the amount of misalignment reaches the threshold value THa, and power transmission from the second power transmission coil 45 to the power reception coil 52 is started.

[0069] After time tc, when the center of the power reception coil 52 coincides with the center of the second power transmission coil 45 in the traveling direction of the vehicle 3, the amount of misalignment becomes zero. Thereafter, as the vehicle 3 moves away from the second power transmission coil 45, the amount of misalignment gradually increases. As a result, at time td, the amount of misalignment becomes larger than the threshold value THa, and power transmission from the second power transmission coil 45 to the power reception coil 52 is stopped.

[0070] After time td, when the vehicle 3 reaches the intermediate position between the second power transmission coil 45 and the third power transmission coil 45, the amount of positional deviation becomes maximum. Thereafter, as the vehicle 3 approaches the third power transmission coil 45, the amount of positional deviation gradually decreases. As a result, at time te, the amount of positional deviation reaches the threshold value THa, and power transmission from the third power transmission coil 45 to the power reception coil 52 is started.

[0071] After time te, when the center of the power reception coil 52 coincides with the center of the third power transmission coil 45 in the traveling direction of the vehicle 3, the amount of positional deviation becomes zero. Thereafter, as the vehicle 3 moves away from the third power transmission coil 45, the amount of positional deviation gradually increases. As a result, at time tf, the amount of positional deviation becomes larger than the threshold value THa, and power transmission from the third power transmission coil 45 to the power reception coil 52 is stopped.

[0072] FIG. 6(b) shows power transmission control when the speed of the vehicle 3 is high, and the threshold value for switching the presence or absence of power transmission is set to THb. The threshold value THb is larger than the threshold value THa in FIG. 6(a). Therefore, when the speed of the vehicle 3 is high, the amount of positional deviation between the power transmission coil 45 and the power reception coil 52 when starting or stopping power transmission from the power transmission coil 45 to the power reception coil 52 becomes larger than when the speed of the vehicle 3 is low.

[0073] Similar to FIG. 6(a), at time t0, the vehicle 3 is located in front of the power supply area provided with the three power transmission coils 45. After time t0, when the vehicle 3 passes through the power supply area as in FIG. 6(a), the amount of positional deviation between the power transmission coil 45 and the power reception coil 52 increases and decreases. At this time, in FIG. 6(b), since the speed of the vehicle 3 is higher than that in FIG. 6(a), the speed at which the amount of positional deviation increases and decreases becomes faster.

[0074] In Fig. 6(b), after time t0, from time tg to time th, the amount of displacement between the first power transmission coil 45 and the power reception coil 52 becomes equal to or less than the threshold value THb, and power is transmitted from the first power transmission coil 45 to the power reception coil 52. After time th, from time ti to time tj, the amount of displacement between the second power transmission coil 45 and the power reception coil 52 becomes equal to or less than the threshold value THb, and power is transmitted from the second power transmission coil 45 to the power reception coil 52. After time tj, from time tk to time tl, the amount of displacement between the third power transmission coil 45 and the power reception coil 52 becomes equal to or less than the threshold value THb, and power is transmitted from the third power transmission coil 45 to the power reception coil 52.

[0075] As can be seen from Fig. 6(b), when the speed of the vehicle 3 is high, that is, when the power demand is high and the time for the vehicle 3 to pass through the power transmission coil 45 is short, power is transmitted from the power transmission coil 45 to the power reception coil 52 even when the amount of displacement is large, and the power supply amount to the vehicle 3 can be ensured. On the other hand, as can be seen from Fig. 6(a), when the speed of the vehicle 3 is low, that is, when the power demand is low and the time for the vehicle 3 to pass through the power transmission coil 45 is long, power is transmitted from the power transmission coil 45 to the power reception coil 52 only when the amount of displacement is small, and it is possible to reduce the waste of power when the power transmission efficiency decreases while ensuring the power supply amount to the vehicle 3. Therefore, by controlling the power transmission from the power transmission coil 45 to the power reception coil 52 as described above, efficient power transmission from the power transmission coil 45 to the power reception coil 52 can be realized.

[0076] Hereinafter, with reference to the flowchart of Fig. 7, the control flow described above will be explained. Fig. 7 is a flowchart showing a control routine for power transmission processing. This control routine is repeatedly executed by the ECU 7 at a predetermined execution interval.

[0077] First, in step S101, the power transmission unit 63 determines whether power supply to the vehicle 3 in the power supply area is requested. For example, when a power supply request signal is transmitted from the vehicle 3 to the power supply device 2, the power transmission unit 63 determines that power supply to the vehicle 3 in the power supply area is requested. If it is determined in step S101 that power supply to the vehicle 3 is not requested, this control routine ends. On the other hand, if it is determined in step S101 that power supply to the vehicle 3 is requested, this control routine proceeds to step S102.

[0078] In step S102, the vehicle speed acquisition unit 65 acquires the speed of the vehicle 3 from the vehicle 3.

[0079] Next, in step S103, the power transmission unit 63 sets a threshold value based on the speed of the vehicle 3 using a map or a calculation formula. At this time, when the speed of the vehicle 3 is low, the power transmission unit 63 sets the threshold value to be smaller than when the speed of the vehicle 3 is high. For example, as shown by the solid line in FIG. 8, the power transmission unit 63 gradually (stepwise) reduces the threshold value as the speed of the vehicle 3 decreases. Note that, as shown by the dashed line in FIG. 8, the power transmission unit 63 may linearly reduce the threshold value as the speed of the vehicle 3 decreases.

[0080] Next, in step S104, the position deviation estimation unit 64 acquires the output of the magnetic sensor 37 from the vehicle 3 as data indicating the relative positional relationship between the power transmission coil 45 and the power reception coil 52 (hereinafter referred to as "relative position data"). Next, in step S105, the position deviation estimation unit 64 calculates an estimated value of the amount of position deviation between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3 based on the relative position data.

[0081] Next, in step S106, the power transmission unit 63 determines whether the estimated value of the amount of position deviation calculated by the position deviation estimation unit 64 is equal to or less than the threshold value set in step S103. If it is determined that the estimated value of the amount of position deviation is equal to or less than the threshold value, this control routine proceeds to step S107.

[0082] In step S107, the power transmission unit 63 transmits power from the power transmission coil 45 to the power reception coil 52 of the vehicle 3. Specifically, the power transmission unit 63 supplies AC power from the inverter 42 to the power transmission coil 45, and the power transmission coil 45 generates an AC magnetic field with a predetermined resonance frequency.

[0083] After step S107, this control routine proceeds to step S108. On the other hand, if it is determined in step S106 that the estimated value of the misalignment amount is greater than the threshold value, this control routine skips step S107 and proceeds to step S108. That is, when the estimated value of the misalignment amount is greater than the threshold value, power is not transmitted from the power transmission coil 45 to the power reception coil 52.

[0084] In step S108, the power transmission unit 63 determines whether the vehicle 3 has passed through the power supply area. For example, when the power transmission from the power transmission coil 45 (the third power transmission coil 45 in the example of FIG. 4) arranged at the rearmost part of the power supply area to the power reception coil 52 is stopped according to the determination result of step S106, the power transmission unit 63 determines that the vehicle 3 has passed through the power supply area. Note that the power transmission unit 63 may determine whether the vehicle 3 has passed through the power supply area based on other criteria. For example, a vehicle detection device capable of detecting the vehicle 3, such as a metal detector, a photoelectric sensor, a camera, or a roadside unit, is provided at the end of the power supply area, and the power transmission unit 63 may determine whether the vehicle 3 has passed through the power supply area based on the output of the vehicle detection device. Further, the power transmission unit 63 may determine that the vehicle 3 has passed through the power supply area when a power supply end signal or the like is transmitted from the vehicle 3 to the power supply device 2.

[0085] If it is determined in step S108 that the vehicle 3 has not passed through the power supply area, this control routine returns to step S104, and the necessity of power transmission to the power reception coil 52 is determined again. On the other hand, if it is determined in step S108 that the vehicle 3 has passed through the power supply area, this control routine ends.

[0086] Note that the relative position data acquired by the vehicle 3 may be the position data of the vehicle 3. In this case, for example, the vehicle 3 is equipped with an RTK-GNSS (Real Time Kinematic-Global Navigation Satellite System) as the GNSS receiver 34 that can detect the position of the vehicle 3 with high precision, and the output of the RTK-GNSS is transmitted from the vehicle 3 to the power feeding device 2 by wireless communication. Further, the relative position data acquired by the vehicle 3 may be data around the vehicle 3 (for example, image data, point cloud data, etc.). In this case, the vehicle 3 is equipped with a peripheral information detection device, and the output of the peripheral information detection device is transmitted from the vehicle 3 to the power feeding device 2 by wireless communication. Examples of such a peripheral information detection device include a millimeter wave radar, a camera (for example, a stereo camera), a lidar (Laser Imaging Detection And Ranging), or an ultrasonic sensor (sonar).

[0087] Further, the processor 73 of the ECU 7 of the vehicle 3 may calculate an estimated value of the amount of misalignment between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3 based on the relative position data, and the estimated value of the amount of misalignment may be transmitted from the vehicle 3 to the power feeding device 2 instead of the relative position data. That is, the processor 73 of the ECU 7 may function as a misalignment estimation unit.

[0088] <Second Embodiment> The configuration and control of the power transmission control device according to the second embodiment are basically the same as those of the power transmission control device according to the first embodiment, except for the points described below. Therefore, hereinafter, the second embodiment of the present invention will be described centering on the parts different from the first embodiment.

[0089] When AC power is supplied from the inverter 42 to the power transmission coil 45, the input current of the inverter 42 changes according to the relative positional relationship between the power transmission coil 45 and the power reception coil 52 of the vehicle 3. In the second embodiment, paying attention to this phenomenon, the misalignment estimation unit 64 uses, as the relative position data, the EnterThe power current is acquired. As a result, since it is not necessary to separately provide the configurations for acquiring the relative position data in the vehicle 3 and on the road, power transmission control based on the positional deviation between the power transmission coil 45 and the power reception coil 52 can be realized with a simple configuration. Further, since the relative position data is acquired in the power supply device 2 instead of the vehicle 3, it is possible to suppress a delay in the calculation of the amount of positional deviation and a deviation in the power transmission timing.

[0090] FIG. 9 is a diagram showing an example of the configuration of a circuit for detecting the input current of the inverter 42. FIG. 9 shows the circuit of the power transmission device 4 including the inverter 42, the filter circuit 43, and the power transmission side resonance circuit 44. In the circuit shown in FIG. 9, an ammeter 48 for detecting the input current of the inverter 42 is provided on the input side of the inverter 42. The ammeter 48 is electrically connected to the controller 6, and the output of the ammeter 48 is transmitted to the controller 6.

[0091] Also in the second embodiment, similar to the first embodiment, the control routine of the power transmission process in FIG. 7 is executed. At this time, in step S104, the positional deviation estimation unit 64 acquires, as the relative position data, the output of the ammeter 48, that is, the input current of the inverter 42. Note that in the second embodiment, even when power is not transmitted from the power transmission coil 45 to the power reception coil 52, weak power for position detection is supplied from the inverter 42 to the power transmission coil 45.

[0092] <Other Embodiments> As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims. For example, the vehicle 3 may be a hybrid vehicle (HEV) or a plug-in hybrid vehicle (PHEV) equipped with an internal combustion engine and a motor as a power source for traveling.

[0093] Further, the power transmission unit 63 may start power transmission from the power transmission coil 45 to the power reception coil 52 when the estimated value of the amount of misalignment calculated by the misalignment estimation unit 64 becomes equal to or less than the threshold value, and may stop power transmission from the power transmission coil 45 to the power reception coil 52 at a predetermined timing. In this case, for example, the predetermined timing is when a predetermined time has elapsed since the start of power transmission from the power transmission coil 45 to the power reception coil 52, and the predetermined time is shortened as the speed of the vehicle 3 is higher.

[0094] Further, a magnetic field generator (for example, a magnetic marker, an alternating magnetic field generator, etc.) that generates a magnetic field indicating the position of the vehicle 3 may be provided on the vehicle 3, and a magnetic sensor that detects the intensity of the magnetic field emitted from the magnetic field generator may be provided on the ground side (for example, a road). In this case, the misalignment estimation unit 64 calculates an estimated value of the amount of misalignment between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3 based on the output of the magnetic sensor provided on the ground side.

[0095] Further, a vehicle speed sensor (for example, a loop coil type or radar type vehicle speed sensor) that detects the speed of the vehicle 3 may be provided on the ground side, and the vehicle speed acquisition unit 65 may acquire the speed of the vehicle 3 based on the output of the vehicle speed sensor provided on the ground side.

[0096] Further, in the above-described embodiment, the power transmission timing from the power transmission coil 45 to the power reception coil 52 is determined based on the estimated value of the amount of misalignment between the power transmission coil 45 and the power reception coil 52 in the traveling direction of the vehicle 3. However, the power transmission timing may be determined based on the estimated value of the amount of misalignment including the lateral misalignment (misalignment in the vehicle width direction) between the power transmission coil 45 and the power reception coil 52. Further, in the above-described embodiment, since the threshold value of the amount of misalignment for determining the power transmission timing is changed according to the speed of the vehicle 3, depending on the setting of the threshold value, power may be supplied simultaneously from a plurality of power transmission coils 45 to the power reception coil 52 of one vehicle 3.

Explanation of Reference Numerals

[0097] 3 Vehicle 7 Electronic Control Unit (ECU) 73 Processor 45 Power transmission coil 52 Power reception coil 6 Controller 62 Processor 63 Power transmission unit 64 Displacement estimation unit 65 Vehicle speed acquisition unit

Claims

1. When a vehicle is traveling on a road, a power transmission unit that transmits power from a power transmission coil of a power supply device provided on the road to a power reception coil provided on the vehicle, a position deviation estimation unit that calculates an estimated value of the amount of position deviation between the power transmission coil and the power reception coil, a vehicle speed acquisition unit that acquires the speed of the vehicle and comprising, when the estimated value becomes equal to or less than a threshold value, the power transmission unit starts power transmission from the power transmission coil to the power reception coil, and when the speed of the vehicle is low, the threshold value is made smaller than when the speed of the vehicle is high, a magnetic field generator that generates a magnetic field is provided on the road, the vehicle includes a magnetic sensor that detects the intensity of the magnetic field emitted from the magnetic field generator, and the position deviation estimation unit calculates the estimated value based on the output of the magnetic sensor transmitted from the vehicle to the power supply device by wireless communication, a power transmission control device.

2. When a vehicle is traveling on a road, a power transmission unit that transmits power from a power transmission coil of a power supply device provided on the road to a power reception coil provided on the vehicle, a position deviation estimation unit that calculates an estimated value of the amount of position deviation between the power transmission coil and the power reception coil, a vehicle speed acquisition unit that acquires the speed of the vehicle and comprising, when the estimated value becomes equal to or less than a threshold value, the power transmission unit starts power transmission from the power transmission coil to the power reception coil, and when the speed of the vehicle is low, the threshold value is made smaller than when the speed of the vehicle is high, the power supply device includes an inverter that supplies AC power to the power transmission coil and an ammeter that detects the input current of the inverter, and the position deviation estimation unit calculates the estimated value based on the output of the ammeter, a power transmission control device.

3. The power transmission unit transmits power from the power transmission coil to the power reception coil when the estimated value is equal to or less than the threshold value, the power transmission control device according to claim 1 or 2.

4. A power transmission control method executed by a computer for controlling power transmission from a power transmission coil of a power supply device provided on a road to a power reception coil provided on a vehicle, a magnetic field generator that generates a magnetic field is provided on the road, the vehicle includes a magnetic sensor that detects the intensity of the magnetic field emitted from the magnetic field generator, the power transmission control method includes, calculating an estimated value of the amount of position deviation between the power transmission coil and the power reception coil based on the output of the magnetic sensor transmitted from the vehicle to the power supply device by wireless communication, starting power transmission from the power transmission coil to the power reception coil when the estimated value becomes equal to or less than a threshold value; acquiring the speed of the vehicle; when the speed of the vehicle is low, making the threshold value smaller than when the speed of the vehicle is high A power transmission control method comprising the above.

5. A power transmission control method executed by a computer for controlling power transmission from a power transmission coil of a power feeding device provided on a road to a power reception coil provided on a vehicle, wherein the power feeding device includes an inverter that supplies AC power to the power transmission coil and an ammeter that detects an input current of the inverter, and the power transmission control method includes calculating an estimated value of a misalignment amount between the power transmission coil and the power reception coil based on an output of the ammeter; starting power transmission from the power transmission coil to the power reception coil when the estimated value becomes equal to or less than a threshold value; acquiring the speed of the vehicle; when the speed of the vehicle is low, making the threshold value smaller than when the speed of the vehicle is high A power transmission control method comprising the above.

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