Non-contact charging system

Abstract

The invention provides a non-contact charging system which can perform charging even when the position determination of a power transmission coil and a power reception coil is not finished when a vehicle is not ready. This non-contact charging system charges a power storage device mounted in a vehicle by contactlessly receiving power transmitted from a power transmission coil provided in a power transmission unit of a power supply facility provided outside the vehicle by means of a power receiving coil provided in a power receiving unit provided in the vehicle, the non-contact charging system is provided with a control device which, when the vehicle is not ready and the position determination of whether the relative position between the power transmission coil and the power reception coil is a position at which charging can be performed is not finished, controls the power transmission coil to transmit power to the power reception coil. When the vehicle stops after a predetermined time has elapsed since the vehicle is not ready and the relative position is determined as a position determination that the relative position is a position where charging can be performed, control is performed to execute charging.

Description

Technical Field

[0001] The present invention relates to a contactless charging system. Background Art

[0002] Patent Document 1 discloses a contactless charging device that detects the relative position between a power supply coil on the ground and a power receiving coil on the vehicle after charging starts, and reduces the power supplied from the power supply coil as the distance increases.

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 2017-121177

[0004] Problems to be solved by the invention

[0005] In the non-contact charging device disclosed in Patent Document 1, if the position determination of whether the relative position between the power transmitting coil and the power receiving coil is at a chargeable position is not completed before the vehicle is not ready, charging may not be performed. Summary of the Invention

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a non-contact charging system capable of performing charging even when the position determination of the power transmission coil and the power reception coil is not completed when the vehicle is not ready (READY-OFF).

[0007] Technical solutions to problems

[0008] In order to solve the above-mentioned problems and achieve the purpose, the non-contact charging system involved in the present invention receives electric power in a non-contact manner by a power receiving coil provided in a power receiving unit provided in the vehicle, thereby charging a power storage device mounted on the vehicle, the electric power being transmitted from a power transmitting coil provided in a power transmitting unit of a power supply device provided outside the vehicle. The non-contact charging system is characterized in that the non-contact charging system includes a control device that, when the vehicle is not ready and a position determination as to whether the relative position between the power transmitting coil and the power receiving coil is a position where charging is possible has not yet been completed, controls the execution of charging when the vehicle stops after a predetermined time has passed since the vehicle was not ready and the position determination determines that the relative position is a position where charging is possible.

[0009] Thus, in the non-contact charging device according to the present invention, charging can be performed even when the vehicle is not ready and the position determination of the power transmitting coil and the power receiving coil is not completed.

[0010] In addition, in the above, it may be that the control device activates a position detection function after the not-ready state, and when the position information detected by the position detection function is in a valid state, the vehicle is stopped, and the position information is below a predetermined threshold value, the position judgment is set to qualified (OK) and charging is performed, and the position detection function is used to detect whether the relative position between the power transmitting coil and the power receiving coil is a position where charging is possible.

[0011] Thus, even if the position detection function is activated after not being ready, if the two conditions of the vehicle being stopped and the position information being valid are met, the control device can determine that the position determination is qualified and perform charging if the position information is below a preset threshold.

[0012] In the above, the position information may be an amount of positional deviation between a center position of the power receiving coil and a center position of the power transmitting coil.

[0013] Thus, the control device can determine that the position determination is acceptable when the position deviation amount is equal to or smaller than the chargeable threshold.

[0014] Furthermore, in the above, the vehicle may include the control device.

[0015] This allows the control of charging to be performed by the control device included in the vehicle.

[0016] Effects of the Invention

[0017] The non-contact charging system according to the present invention has the effect of enabling charging even when the vehicle is not ready and the position determination of the power transmitting coil and the power receiving coil is not completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a diagram schematically showing a non-contact charging system according to an embodiment. Figure 2 It is a diagram showing a parking space where the contactless charging system according to the embodiment is installed. Figure 3 This is a block diagram showing a schematic configuration of a non-contact charging system according to an embodiment. Figure 4 This is a timing chart showing an example of non-contact charging control in the non-contact charging system according to the embodiment. Figure 5 This is a flowchart showing an example of non-contact charging control in the non-contact charging system according to the embodiment.

[0019] Label Description 1. Contactless charging system 2 vehicles 3 Power supply equipment 4 parking spaces 20 Power receiving unit 21 batteries 22 Charging control unit 23 CAN communication line 31 Power supply unit 32 Power transmission unit 33 Power cables 201 Receiving Coil 202 Power receiving side communication unit 203 Power receiving side control unit 204 Power receiving side power detection unit 321 Power Transmission Coil 322 Power transmission side communication unit 323 Power transmission side control unit 324 Power transmission side power detection unit DETAILED DESCRIPTION

[0020] Hereinafter, an embodiment of the non-contact charging system according to the present invention will be described. However, the present invention is not limited to this embodiment.

[0021] Figure 1 It is a diagram schematically showing a non-contact charging system 1 according to the embodiment. Figure 2 1 is a diagram showing a parking space 4 in which the contactless charging system 1 according to the embodiment is installed. Figure 3 It is a block diagram showing a schematic configuration of a non-contact charging system 1 according to the embodiment.

[0022] A non-contact charging system 1 according to the embodiment includes a vehicle 2 and a power supply device 3 provided outside the vehicle.

[0023] A contactless charging system 1 according to the embodiment includes a power transmission unit 32 of a power supply facility 3 installed on the ground, and a power receiving unit 20 installed in a vehicle 2. When vehicle 2 is parked in a parking space 4 where power transmission unit 32 is installed, contactless charging system 1 charges battery 21, a power storage device used to drive vehicle 2, with power transmitted contactlessly from power transmission unit 32 to power receiving unit 20. Vehicle 2 is an electric vehicle equipped with a motor for driving, and includes power receiving unit 20, battery 21, and a charging control unit 22. Vehicle 2 is an electric vehicle capable of external charging using contactless power supply.

[0024] Power supply equipment 3 includes a power supply device 31, a power transmission unit 32, and a power cable 33. Power supply device 31 and power transmission unit 32 are connected by power cable 33. Power supply device 31 outputs commercial AC power, for example, supplied from a system power supply, to power transmission unit 32 via power cable 33. Power transmission unit 32 is installed in parking space 4 on the ground.

[0025] The power transmission unit 32 includes a power transmission coil 321, a power transmission-side communication unit 322, a power transmission-side control unit 323, and a power transmission-side power detection unit 324. The power transmission coil 321 is a coil installed on the ground for contactless power transmission. The power transmission coil 321 transmits power to the power receiving coil 201 mounted on the vehicle 2 in a contactless manner. Power is supplied to the power transmission coil 321 from a power supply device 31 connected to the power grid via a power cable 33 or the like.

[0026] The power-transmitting-side communication unit 322 is a wireless device used for data communication with the power receiving unit 20. The power-transmitting-side communication unit 322 wirelessly communicates with the power receiving-side communication unit 202 mounted on the vehicle 2. The power-transmitting-side communication unit 322 and the power receiving-side communication unit 202 exchange information via wireless communication, thereby enabling data communication between the ground-side power transmission unit 32 and the vehicle-side power receiving unit 20.

[0027] The power transmission-side control unit 323 controls contactless power transmission from the ground-side power transmission coil 321 to the power receiving coil 201 on the vehicle 2. The power transmission-side control unit 323 controls the start and end of contactless charging based on a command signal from the power receiving unit 20. This command signal is received by the power transmission-side communication unit 322. The power transmission-side control unit 323 controls the power transmission coil 321 based on the command signal received by the power transmission-side communication unit 322.

[0028] The power transmitting side power detection unit 324 detects the power transmitted in a contactless manner by the power transmitting coil 321. The power transmitting side power detection unit 324 detects the power transmitted during the charging period (transmitted power), which is the period from the start to the end of contactless charging.

[0029] In the non-contact charging system 1 according to the embodiment, it is possible to detect the longitudinal and lateral positional offsets between the center positions of the power receiving unit 20 (receiving coil 201) on the vehicle 2 side and the center positions of the power transmitting unit 32 (transmitting coil 321) on the ground side. For example, the charging control unit 22 of the vehicle 2 detects the longitudinal positional offset between the center position of the power receiving unit 20 (receiving coil 201) on the vehicle 2 side and the center position of the power transmitting unit 32 (transmitting coil 321) on the ground side as the longitudinal positional offset. The charging control unit 22 obtains the longitudinal positional offset (relative distance) and the lateral positional offset (relative distance) between the power transmitting unit 32 (transmitting coil 321) and the power receiving unit 20 (receiving coil 201). This positional offset (relative distance) information is positional information indicating the relative positional relationship between the center positions of the power receiving unit 20 (receiving coil 201) and the center positions of the power transmitting unit 32 (transmitting coil 321).

[0030] Another method for detecting the position includes, for example, a method that uses an imaging device such as a radar rangefinder or a camera for calculation. For example, a method uses a camera on the ground-mounted power transmission unit 32 to capture images of multiple LEDs on the power receiving unit 20 mounted on the vehicle 2, and calculates the distance between the center position of the power transmission unit 32 and the center position of the power receiving unit 20. Another method for detecting the position includes, for example, a method that uses a camera on the power receiving unit 20 mounted on the vehicle 2 to capture images of multiple LEDs on the ground-mounted power transmission unit 32, and calculates the distance between the center position of the power transmission unit 32 and the center position of the power receiving unit 20. Another method for detecting the position includes transmitting a predetermined weak power that does not affect the human body from the power transmission coil 321 of the ground-mounted power transmission unit 32 to the power receiving coil 201 of the power receiving unit 20 on the vehicle 2. The position is then calculated based on the correspondence between the power value received by the power receiving coil 201 and a predetermined positional offset (relative distance) between the center positions of the power transmission coil 321 and the center positions of the power receiving coil 201.

[0031] The power receiving unit 20 is a contactless charging onboard unit equipped with a power receiving coil 201 for receiving power. The power receiving unit 20 is installed in the lower portion of the vehicle 2. The power receiving unit 20 includes the power receiving coil 201, a power receiving communication unit 202, a power receiving control unit 203, and a power receiving power detection unit 204.

[0032] The power receiving coil 201 is a coil mounted on the vehicle 2 for contactless power reception and is located on the lower portion of the vehicle 2. The power receiving coil 201 receives power transmitted contactlessly from the power transmitting coil 321. In the vehicle 2, the power received by the power receiving coil 201 is supplied to the battery 21, thereby charging the battery 21.

[0033] The power receiving-side communication unit 202 is a wireless device for performing data communication with the power transmitting unit 32. The power receiving-side communication unit 202 performs wireless communication with the power transmitting-side communication unit 322 provided in the power transmitting unit 32.

[0034] The power receiving control unit 203 controls the power receiving coil 201 on the vehicle 2 side, which receives power transmitted non-contactably from the power transmitting coil 321 on the ground. The power receiving control unit 203 controls the start and end of non-contact charging. The power receiving control unit 203 controls communication, sending command signals for controlling the start and end of non-contact charging from the power receiving communication unit 202 to the power transmitting communication unit 322, and also controls the power receiving coil 201.

[0035] In contactless charging system 1 , a control unit including power transmission-side control unit 323 and power reception-side control unit 203 is configured to control power transmission between ground-side power transmission unit 32 and vehicle-side power reception unit 20 .

[0036] The receiving-side power detection unit 204 detects the power received in a contactless manner by the receiving coil 201. The receiving-side power detection unit 204 detects the power received during the charging period (received power) from the start to the end of contactless charging.

[0037] The battery 21 supplies electric power to the electric motor for traveling mounted on the vehicle 2. The battery 21 is formed of a secondary battery capable of storing electric power to be supplied to the electric motor for traveling.

[0038] The charging control unit 22 performs charging control to charge the battery 21 with the power received by the power receiving coil 201. The charging control unit 22 also functions as a control device for determining the start and end of contactless charging.

[0039] The charging control unit 22 also calculates the transmission efficiency during contactless charging. The charging control unit 22 includes a transmission efficiency calculation unit that calculates the transmission efficiency. The transmission efficiency is the ratio of the power received by the receiving coil 201 to the power transmitted by the transmitting coil 321. Both power levels are actual values ​​measured during contactless charging. The transmitted power is the actual value detected by the transmitting-side power detection unit 324 during charging. The received power is the actual value detected by the receiving-side power detection unit 204 during charging.

[0040] The information on the transmitted power detected by the transmitting-side power detection unit 324 is input from the transmitting-side power detection unit 324 to the transmitting-side control unit 323 and is transmitted from the transmitting-side communication unit 322 to the receiving-side communication unit 202 on the vehicle 2 side. The receiving-side communication unit 202 receives the signal from the transmitting-side communication unit 322, allowing the charging control unit 22 to obtain the information on the transmitted power.

[0041] The received power information detected by the receiving-side power detection unit 204 is input from the receiving-side power detection unit 204 to the receiving-side control unit 203 and then transmitted from the receiving-side control unit 203 to the charging control unit 22. The receiving-side control unit 203 and the charging control unit 22 are communicatively connected via the CAN communication line 23. The receiving-side control unit 203 transmits the transmitted power information received by the receiving-side communication unit 202 to the charging control unit 22. The charging control unit 22 receives the signal from the receiving-side control unit 203 to obtain the received power information and the transmitted power information.

[0042] The charging control unit 22 then stores the transmission efficiency calculated by the transmission efficiency calculation unit in a transmission efficiency database. In this case, the charging control unit 22 stores the transmission efficiency calculated during charging and the positional offset detected during charging as a set in the transmission efficiency database. The transmission efficiency database is a storage unit that stores the actually measured power transmission efficiency (=transmission efficiency). Because the transmission efficiency depends on the state of charge (SOC) of the battery 21, the transmission efficiency information is stored in the transmission efficiency database for each SOC.

[0043] In the thus configured non-contact charging system 1, the target parking position is determined based on previously measured power transmission efficiencies in the vehicle's longitudinal and lateral directions (maximum transmission efficiency position). The charging control unit 22 sets the maximum transmission efficiency position as the target parking position, using the position with the highest transmission efficiency found in the transmission efficiency database 50 or the position with the highest transmission efficiency determined through interpolation. The charging control unit 22 sets the maximum transmission efficiency position as the target parking position. Specifically, when the vehicle 2 is parked in the parking space 4 where the power supply equipment 3 is located, the parking position with the highest transmission efficiency is calculated based on previously measured power transmission efficiency data, and this calculated position is used as the target parking position. This maximizes charging efficiency.

[0044] In the contactless charging system 1 according to the embodiment, the charging control unit 22 of vehicle 2 determines whether the relative position between the ground-side power transmission coil 321 and the ground-side power reception coil 201 is in a chargeable position and then initiates (starts) charging. For example, if the position information indicates that the offset (relative distance) between the center of the power reception unit 20 (receiving coil 201) on vehicle 2 and the center of the ground-side power transmission unit 32 (transmitting coil 321) is below a predetermined threshold, the charging control unit 22 of vehicle 2 determines the position determination as satisfactory. Furthermore, position determination requires that both the vehicle 2 be stopped and the position information be monitorable (position information is valid). On the other hand, it is conceivable that the vehicle 2 cannot be determined due to a rapid parking action or the slow activation of the position detection function. In such cases, charging may not begin even though the user has parked the vehicle in a chargeable area.

[0045] For example, Figure 2 As shown, generally speaking, when the vehicle 2 is parked in a forward direction by moving forward into the parking space 4, the parking operation can be faster than when the vehicle 2 is parked in a rearward direction by moving backward into the parking space 4. Furthermore, when a driver with high driving skills parks the vehicle 2 in the parking space 4, the parking operation can be faster than when a driver with low driving skills parks the vehicle 2 in the parking space 4.

[0046] Therefore, in the non-contact charging system 1 according to the embodiment, if vehicle 2 parked in parking space 4 equipped with power transmission unit 32 is not ready, and position determination that the relative position is a chargeable position has not yet been completed, vehicle 2's charging control unit 22 re-determines whether charging should be executed (started) after a predetermined time has passed since the time vehicle 2 was not ready. This allows non-contact charging system 1 according to the embodiment to execute (start) charging even if a determination cannot be made due to a rapid parking motion or a slow activation of the position detection function.

[0047] Figure 4 1 is a timing chart showing an example of non-contact charging control in the non-contact charging system 1 according to the embodiment.

[0048] exist Figure 4In the example shown, vehicle 2 begins parking in parking space 4, where power transmission unit 32 is installed. At time T1, vehicle 2's shift position is changed to the P position, and vehicle 2 comes to a stop. In the contactless charging system 1 according to the embodiment, when vehicle 2's shift position is changed to the P position, vehicle 2 is detected to have stopped. Subsequently, at time T2, after a time has elapsed since time T1, vehicle 2 enters a non-ready state. Subsequently, at time T3, after vehicle 2 has become non-ready and after a time has elapsed since time T2, the position detection function of charging control unit 22 is activated to detect whether the relative position between power transmission unit 32 (power transmission coil 321) and power reception unit 20 (power reception coil 201) is in a charging-capable position. Furthermore, even after vehicle 2 becomes non-ready, charging control unit 22 continues to supply power from the auxiliary battery mounted on vehicle 2 for a certain period of time (e.g., 30 seconds), enabling various control operations by charging control unit 22. Next, at time T4, after a time delay from time T3, position detection becomes active, and position information is acquired. While the position detection function is active from time T3 to time T4, the position information remains inactive because it is an initial check and cannot yet be transmitted. When position detection is inactive, position information (X) assumes a predetermined constant value. When position detection becomes active, the distance corresponding to the position of vehicle 2's power receiving unit 20 relative to ground-based power transmitting unit 32 is acquired as position information. In position information (X), the closer vehicle 2's power receiving unit 20 is to ground-based power transmitting unit 32, the smaller the value on the vertical axis representing the relative distance (position offset) between power transmitting unit 32 and power receiving unit 20. If position information (X) is below the predetermined threshold, which is the relative distance (position offset) required for charging, the position determination is considered acceptable. Then, at time T5 after time T4, in other words, after a predetermined time (eg, 20 seconds) has passed since time T2 when the vehicle 2 is not ready, charging is executed (started) if the vehicle 2 stops and the position determination is acceptable.

[0049] Figure 5 This is a flowchart showing an example of non-contact charging control in the non-contact charging system 1 according to the embodiment.

[0050] First, the charging control unit 22 of vehicle 2 detects that the gear position of vehicle 2 is in the P range and that vehicle 2 has stopped (step S1). Next, the charging control unit 22 detects that vehicle 2 is not ready (step S2). Next, the charging control unit 22 determines whether the position detection function is activated (step S3). If the position detection function is activated ("YES" in step S3), the charging control unit 22 determines whether the position determination result is acceptable (step S4). If the position determination result is acceptable ("YES" in step S4), the charging control unit 22 performs charging (step S5). The charging control unit 22 then terminates the series of control operations. On the other hand, if the position determination result is unacceptable ("NG" in step S4), the charging control unit 22 does not perform charging (step S6). The charging control unit 22 then terminates the series of control operations.

[0051] Furthermore, in step S3, if the position detection function is determined to be inactive ("No" in step S3), and a predetermined time has elapsed since the vehicle is not ready (step S7), the charging control unit 22 determines whether the position detection function is active (step S8). If the position detection function is determined to be inactive ("No" in step S8), the charging control unit 22 does not perform charging (step S12). The charging control unit 22 then terminates the series of controls. On the other hand, if the position detection function is determined to be active ("Yes" in step S8), the charging control unit 22 determines whether the vehicle 2 is stopped (step S9). If the vehicle 2 is not stopped ("No" in step S9), the charging control unit 22 does not perform charging (step S12). The charging control unit 22 then terminates the series of controls. On the other hand, if the vehicle 2 is determined to be stopped ("Yes" in step S9), the charging control unit 22 determines whether the position determination result is acceptable (step S10). If the position determination result is determined to be acceptable ("YES" in step S10), the charging control unit 22 performs charging (step S11). The charging control unit 22 then terminates the series of controls. On the other hand, if the position determination result is determined to be unacceptable ("Position determination result is unacceptable") ("NO" in step S10), the charging control unit 22 does not perform charging (step S12). The charging control unit 22 then terminates the series of controls.

[0052] Even when the non-contact charging system 1 according to the embodiment cannot perform position determination at the not-ready time point, it can still execute (start) charging when predetermined conditions are satisfied.

Claims

1. A contactless charging system for charging a power storage device mounted on a vehicle by contactlessly receiving electric power via a power receiving coil of a power receiving unit provided in a vehicle, wherein the electric power is transmitted from a power transmitting coil of a power transmitting unit provided in a power supply device external to the vehicle, characterized in that: The contactless charging system includes a control device that controls charging when the vehicle is not ready and a position determination of whether the relative position between the power transmitting coil and the power receiving coil is a position where charging is possible has not yet been completed. If the vehicle stops after a predetermined time has passed since the vehicle was not ready and the position determination determines that the relative position is a position where charging is possible, the control device performs charging control.

2. The contactless charging system according to claim 1, wherein: After the vehicle is not ready, the control device starts a position detection function. When the position information detected by the position detection function is valid, the vehicle is stopped, and the position information is below a predetermined threshold, the control device sets the position judgment to be qualified and performs charging. The position detection function is used to detect whether the relative position between the power transmitting coil and the power receiving coil is a position where charging is possible.

3. The contactless charging system according to claim 2, wherein: The position information is a positional offset between a center position of the power receiving coil and a center position of the power transmitting coil.

4. The contactless charging system according to any one of claims 1 to 3, characterized in that: The vehicle includes the control device.

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