Non-contact charging system

Abstract

To provide a non-contact charging system capable of executing charging even when a position determination of a power transmission coil and a power reception coil is not finished at the time of READY-OFF of a vehicle.SOLUTION: A non-contact charging system receiving power transmitted from a power transmission coil of a power transmission unit of a power supply facility provided outside a vehicle by a power reception coil of a power reception unit provided in the vehicle in a non-contact manner, and charging a power storage device mounted on the vehicle, comprises a control device performing a control of executing charging when a position determination as to whether or not a relative position of the power transmission coil and the power reception coil is at a position where charging can be performed is not finished at the time of READY-OFF of the vehicle, and when the relative position is determined to be a position where charging can be performed as the position determination that the vehicle is stopped after a predetermined time has elapsed from the READY-OFF.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a wireless charging system. [Background technology]

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

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-121177 Summary of the Invention [Problem to be solved by the invention]

[0004] In the contactless charging device disclosed in Patent Document 1, there is a risk that charging will not be performed unless a position determination is completed to determine whether the relative position between the power supply coil and the power receiving coil is in a position where charging is possible when the vehicle is in READ-OFF mode.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a contactless charging system that can perform charging even when the position determination of the transmitting coil and the receiving coil has not been completed when the vehicle is in READY-OFF state. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the contactless charging system of the present invention is a contactless charging system that charges a storage device mounted on the vehicle by contactlessly receiving power transmitted from a power transmission coil of a power transmission unit of a power supply equipment provided outside the vehicle using a power receiving coil of a power receiving unit provided on the vehicle, and is characterized in that when the vehicle is READY-OFF, if a position determination has not been completed as to whether the relative position of the power transmission coil and the power receiving coil is in a position where charging is possible, the system has a control device that controls charging to be performed if the vehicle is stopped after a predetermined time has elapsed from READY-OFF and the position determination determines that the relative position is in a position where charging is possible.

[0007] As a result, in the contactless charging device according to the present invention, charging can be performed even when the positions of the power transmitting coil and the power receiving coil have not been determined when the vehicle is in the READY-OFF state.

[0008] In addition, in the above, after the READY-OFF, the control device may activate a position detection function to detect whether the relative position of the transmitting coil and the receiving coil is in a position where charging is possible, and if 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 may determine that the position is OK and perform charging.

[0009] As a result, even if the location detection function is activated after READY-OFF, the control device can determine that the location is OK and perform charging if the location information is below a predetermined threshold value when the two conditions of the vehicle being stopped and the location information being valid are met.

[0010] In the above configuration, the position information may be a positional deviation amount between a center position of the power receiving coil and a center position of the power transmitting coil.

[0011] This allows the control device to determine the position as OK when the amount of positional deviation is equal to or less than the threshold value at which charging is possible.

[0012] In the above, the control device may be provided in the vehicle.

[0013] This allows the control of charging to be performed by a control device provided in the vehicle. [Effects of the Invention]

[0014] The wireless charging system according to the present invention has the advantage that charging can be performed even when the positions of the power transmitting coil and the power receiving coil have not been determined when the vehicle is in the READY-OFF state. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram schematically showing a contactless charging system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing a parking space in which a contactless charging system according to an embodiment is installed. [Figure 3] FIG. 3 is a block diagram showing a schematic configuration of a contactless charging system according to an embodiment. [Figure 4] FIG. 4 is a timing chart showing an example of contactless charging control in the contactless charging system according to the embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of contactless charging control in the contactless charging system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the contactless charging system according to the present invention will be described, but the present invention is not limited to the embodiment.

[0017] Fig. 1 is a diagram schematically showing a contactless charging system 1 according to an embodiment. Fig. 2 is a diagram showing a parking space 4 in which the contactless charging system 1 according to an embodiment is installed. Fig. 3 is a block diagram showing a schematic configuration of the contactless charging system 1 according to an embodiment.

[0018] A contactless charging system 1 according to the embodiment includes a vehicle 2 and a power supply facility 3 provided outside the vehicle.

[0019] 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. The contactless charging system 1 is a system that charges a battery 21, which is a power storage device for driving the vehicle 2, with power transmitted contactlessly from the power transmission unit 32 to the power receiving unit 20 when the vehicle 2 is parked in a parking space 4 in which the power transmission unit 32 is installed. The vehicle 2 is an electric vehicle equipped with a traction motor, and includes the power receiving unit 20, the battery 21, and a charging control unit 22. The vehicle 2 is an electric vehicle that can be externally charged by contactless power supply.

[0020] The power supply facility 3 includes a power supply device 31, a power transmission unit 32, and a power cable 33. The power supply device 31 and the power transmission unit 32 are connected by the power cable 33. The power supply device 31 outputs commercial AC power supplied from a power grid, for example, to the power transmission unit 32 via the power cable 33. The power transmission unit 32 is provided in a parking space 4 on the ground.

[0021] 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 for contactless power transmission provided on the ground. The power transmission coil 321 transmits power contactlessly to the power receiving coil 201 mounted on the vehicle 2. 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.

[0022] The power transmitting-side communication unit 322 is a radio device for performing data communication with the power receiving unit 20. The power transmitting-side communication unit 322 performs wireless communication 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 transmit and receive information via wireless communication, thereby performing data communication between the power transmitting unit 32 on the ground side and the power receiving unit 20 on the vehicle 2 side.

[0023] The power transmitting-side control unit 323 controls contactless power transmission from the power transmitting coil 321 on the ground to the power receiving coil 201 on the vehicle 2. The power transmitting-side control unit 323 controls the start and end of contactless charging in response to a command signal from the power receiving unit 20. This command signal is received by the power transmitting-side communication unit 322. The power transmitting-side control unit 323 controls the power transmitting coil 321 based on the command signal received by the power transmitting-side communication unit 322.

[0024] The power transmission side power detection unit 324 detects the power transmitted contactlessly by the power transmission coil 321. The power transmission side power detection unit 324 detects the power transmitted during the period from the start to the end of contactless charging, that is, the power transmitted during charging (transmitted power).

[0025] The wireless charging system 1 according to this embodiment can detect a longitudinal positional deviation and a lateral positional deviation between the center position of the power receiving unit 20 (power receiving coil 201) on the vehicle 2 and the center position of the power transmitting unit 32 (power transmitting coil 321) on the ground. For example, the charging control unit 22 of the vehicle 2 detects a longitudinal positional deviation of the center position of the power receiving unit 20 (power receiving coil 201) on the vehicle 2 from the center position of the power transmitting unit 32 (power transmitting coil 321) on the ground as the longitudinal positional deviation. The charging control unit 22 acquires the longitudinal positional deviation (relative distance) and the lateral positional deviation (relative distance) between the power transmitting unit 32 (power transmitting coil 321) and the power receiving unit 20 (power receiving coil 201). This positional deviation (relative distance) information is positional information that indicates the relative positional relationship between the center position of the power receiving unit 20 (power receiving coil 201) and the center position of the power transmitting unit 32 (power transmitting coil 321).

[0026] Note that, as a position detection method, for example, a method of calculation using an imaging device such as a radar rangefinder or a camera is available. For example, a method of photographing a plurality of LEDs attached to the power receiving unit 20 on the vehicle 2 side with a camera attached to the power transmitting unit 32 on the ground and calculating the distance between the center position of the power transmitting unit 32 and the center position of the power receiving unit 20 is available. As a position detection method, for example, a method of photographing a plurality of LEDs attached to the power transmitting unit 32 on the ground side with a camera attached to the power receiving unit 20 on the vehicle 2 side and calculating the distance between the center position of the power transmitting unit 32 and the center position of the power receiving unit 20 is available. As a position detection method, a specified weak power that does not affect the human body is transmitted from the power transmitting coil 321 of the power transmitting unit 32 on the ground side to the power receiving coil 201 of the power receiving unit 20 on the vehicle 2 side, and the distance is calculated from the correspondence relationship between the value of the power received by the power receiving coil 201 and the preset positional deviation amount (relative distance) between the center position of the power transmitting coil 321 and the center position of the power receiving coil 201.

[0027] The power receiving unit 20 is a contactless charging in-vehicle unit equipped with a power receiving coil 201 for receiving power. The power receiving unit 20 is provided at the bottom of the vehicle 2. The power receiving unit 20 is equipped with the power receiving coil 201, a power receiving side communication unit 202, a power receiving side control unit 203, a power receiving side power detection unit 204, and the like.

[0028] The power receiving coil 201 is a coil for contactless power reception mounted on the vehicle 2, and is provided at the bottom 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.

[0029] The power receiving side communication unit 202 is a radio device for performing data communication with the power transmitting unit 32. The power receiving side communication unit 202 performs wireless communication with a power transmitting side communication unit 322 provided in the power transmitting unit 32.

[0030] The power receiving-side control unit 203 executes control to receive power transmitted contactlessly from the power transmitting coil 321 on the ground at the power receiving coil 201 on the vehicle 2 side. The power receiving-side control unit 203 controls the start and end of contactless charging. The power receiving-side control unit 203 executes communication control to cause the power receiving-side communication unit 202 to transmit a command signal for controlling the start and end of contactless charging to the power transmitting-side communication unit 322, and also controls the power receiving coil 201.

[0031] In the contactless charging system 1, a control unit including a power transmitting side control unit 323 and a power receiving side control unit 203 is configured to control power transmission between a power transmitting unit 32 on the ground side and a power receiving unit 20 on the vehicle 2 side.

[0032] The power receiving side power detection unit 204 detects the power received contactlessly by the power receiving coil 201. The power receiving side power detection unit 204 detects the power received during the period from the start to the end of contactless charging, that is, during charging (received power).

[0033] The battery 21 supplies power to a traction motor mounted on the vehicle 2. The battery 21 is configured by a secondary battery that can store power to be supplied to the traction motor.

[0034] The charging control unit 22 executes 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.

[0035] Furthermore, the charging control unit 22 calculates the transmission efficiency during contactless charging. The charging control unit 22 is configured to include a transmission efficiency calculation unit that calculates the transmission efficiency. The transmission efficiency is the ratio of the received power of the receiving coil 201 to the transmitted power of the transmitting coil 321. Both powers are actually measured during contactless charging. The transmitted power is an actual measurement value detected by the transmitting-side power detection unit 324 during charging. The received power is an actual measurement value detected by the receiving-side power detection unit 204 during charging.

[0036] Information about the transmitted power detected by the power transmitting-side power detection unit 324 is input from the power transmitting-side power detection unit 324 to the power transmitting-side control unit 323, and is then transmitted from the power transmitting-side communication unit 322 to the power receiving-side communication unit 202 on the vehicle 2 side. When the power receiving-side communication unit 202 receives the signal from the power transmitting-side communication unit 322, the charging control unit 22 can obtain the information about the transmitted power.

[0037] Information on the received power detected by the power receiving-side power detection unit 204 is input from the power receiving-side power detection unit 204 to the power receiving-side control unit 203, and is transmitted from the power receiving-side control unit 203 to the charging control unit 22. The power receiving-side control unit 203 and the charging control unit 22 are communicatively connected via a CAN communication line 23. The power receiving-side control unit 203 transmits the information on the transmitted power received by the power receiving-side communication unit 202 to the charging control unit 22. The charging control unit 22 receives signals from the power receiving-side control unit 203 to obtain information on the received power and information on the transmitted power.

[0038] Then, the charging control unit 22 stores the transmission efficiency calculated by the transmission efficiency calculation unit in a transmission efficiency database. At that time, the charging control unit 22 stores the transmission efficiency calculated during charging and the positional deviation amount detected during charging as a set in the transmission efficiency database. The transmission efficiency database is a storage unit that stores actually measured power transmission efficiency (=transmission efficiency). Since the transmission efficiency depends on the state of charge (SOC) of the battery 21, when storing information on the transmission efficiency in the transmission efficiency database, a database is created for each SOC.

[0039] In the wireless charging system 1 configured as described above, the target parking position is set to a position (maximum transmission efficiency position) where the transmission efficiency is maximized, estimated based on previously measured power transmission efficiencies in the vehicle's longitudinal and lateral directions. The charging control unit 22 sets the maximum transmission efficiency position to the position with the highest transmission efficiency in the transmission efficiency database 50, or the position with the highest transmission efficiency determined by interpolation. The charging control unit 22 sets the set maximum transmission efficiency position as the target parking position. In other words, when the vehicle 2 parks in the parking space 4 where the power supply equipment 3 is installed, the parking position where the transmission efficiency is maximized is calculated from previously measured power transmission efficiency data, and the calculated position is set to the target parking position. This makes it possible to maximize charging efficiency.

[0040] In the wireless charging system 1 according to the embodiment, the charging control unit 22 of the vehicle 2 determines whether the relative positions of the power transmitting coil 321 on the ground side and the power receiving coil 201 on the vehicle 2 are suitable for charging, and then performs (starts) charging. For example, the charging control unit 22 of the vehicle 2 determines the position as OK when, as the position information, the positional deviation (relative distance) between the center position of the power receiving unit 20 (power receiving coil 201) on the vehicle 2 and the center position of the power transmitting unit 32 (power transmitting coil 321) on the ground side is equal to or less than a preset threshold. Furthermore, the position determination requires two conditions to be met: "the vehicle 2 is stopped" and "the position information can be monitored (the position information is valid)." However, there may be cases where the determination cannot be made due to a fast parking operation or a delay in activating the position detection function. In such cases, charging may not start even though the user parked the vehicle in an area suitable for charging.

[0041] For example, as shown in Fig. 2, when parking vehicle 2 by forward parking, that is, by driving forward into parking space 4, the parking operation can generally be faster than when parking vehicle 2 by backward parking, that is, by driving backward into parking space 4. Also, when a driver with high driving skills parks vehicle 2 in parking space 4, the parking operation can be faster than when a driver with low driving skills parks vehicle 2 in parking space 4.

[0042] Therefore, in the contactless charging system 1 according to the embodiment, if the determination of the relative position of the vehicle 2 parked in the parking space 4 in which the power transmission unit 32 is installed has not been completed at the time of READY-OFF, the charging control unit 22 of the vehicle 2 determines again whether to execute (start) charging after a predetermined time has elapsed since READY-OFF. As a result, in the contactless charging system 1 according to the embodiment, it becomes possible to execute (start) charging even if the parking operation is too fast to make a determination or the activation of the position detection function is too late to make a determination.

[0043] FIG. 4 is a timing chart showing an example of contactless charging control in the contactless charging system 1 according to the embodiment.

[0044] In the example shown in FIG. 4 , the vehicle 2 starts parking in the parking space 4 in which the power transmitting unit 32 is installed, and at time T1, the shift position of the vehicle 2 is set to the P position, causing the vehicle 2 to stop. In the contactless charging system 1 according to the embodiment, when the shift position of the vehicle 2 is set to the P position, it is detected that the vehicle 2 has stopped. Next, at time T2, after time has elapsed since time T1, the vehicle 2 enters a READY-OFF state. Next, at time T3, after the vehicle 2 has been set to READY-OFF and after time has elapsed since time T2, a position detection function of the charging control unit 22 is activated to detect whether the relative positions of the power transmitting unit 32 (power transmitting coil 321) and the power receiving unit 20 (power receiving coil 201) are such that charging is possible. Note that power continues to be supplied to the charging control unit 22 from the auxiliary battery mounted on the vehicle 2 for a certain period of time (e.g., 30 seconds) even after the vehicle 2 has been set to READY-OFF, allowing the charging control unit 22 to perform various control operations and other operations. Next, after time T3, at time T4, position detection is enabled and position information is acquired. Note that between time T3 and time T4, the position detection function is activated, but the position information remains disabled due to an initial check and because position information has not yet been released. A preset value is acquired as position information (X) when position detection is disabled, and when position detection is enabled, the distance corresponding to the position of the power receiving unit 20 of the vehicle 2 relative to the power transmitting unit 32 on the ground is acquired as position information. The closer the power receiving unit 20 of the vehicle 2 is to the power transmitting unit 32 on the ground, the smaller the value of the vertical axis of position information (X), which represents the relative distance (amount of positional deviation) between the power transmitting unit 32 and the power receiving unit 20. Then, when the position information (X) becomes equal to or less than a threshold value, which is a preset relative distance (amount of positional deviation) at which charging is possible, the position determination is deemed OK. Then, after time has passed from time T4, at time T5, in other words, at time T5 after a predetermined time has passed (for example, 20 seconds) from time T2 when READY-OFF occurs, if vehicle 2 is stopped and the position determination is OK, charging is performed (started).

[0045] FIG. 5 is a flowchart showing an example of contactless charging control in the contactless charging system 1 according to the embodiment.

[0046] First, the charging control unit 22 of the vehicle 2 detects that the shift position of the vehicle 2 is in the P position and that the vehicle 2 has stopped (step S1). Next, the charging control unit 22 detects that the vehicle 2 is in READY-OFF state (step S2). Next, the charging control unit 22 determines whether the position detection function is activated (step S3). If it is determined that the position detection function is activated (Yes in step S3), the charging control unit 22 determines whether the position determination result is OK (step S4). If it is determined that the position determination result is OK (Yes in step S4), the charging control unit 22 executes charging (step S5). Thereafter, the charging control unit 22 ends the series of controls. On the other hand, if it is determined that the position determination result is not OK (the position determination result is NG) (No in step S4), the charging control unit 22 does not execute charging (step S6). Thereafter, the charging control unit 22 ends the series of controls.

[0047] Furthermore, if it is determined in the processing of step S3 that the location detection function is not activated (No in step S3), the charging control unit 22 determines whether or not the location detection function is activated after a predetermined time has elapsed since READY-OFF (step S7) (step S8). If it is determined that the location detection function is not activated (No in step S8), the charging control unit 22 does not execute charging (step S12). Thereafter, the charging control unit 22 ends the series of controls. On the other hand, if it is determined that the location detection function is activated (Yes in step S8), the charging control unit 22 determines whether or not the vehicle 2 is stopped (step S9). If it is determined that the vehicle 2 is not stopped (No in step S9), the charging control unit 22 does not execute charging (step S12). Thereafter, the charging control unit 22 ends the series of controls. On the other hand, if it is determined that the vehicle 2 is stopped (Yes in step S9), the charging control unit 22 determines whether or not the position determination result is OK (step S10). If it is determined that the position determination result is OK (Yes in step S10), the charging control unit 22 executes charging (step S11). Then, the charging control unit 22 ends the series of controls. On the other hand, if it is determined that the position determination result is not OK (the position determination result is NG) (No in step S10), the charging control unit 22 does not execute charging (step S12). Then, the charging control unit 22 ends the series of controls.

[0048] The contactless charging system 1 according to the embodiment can execute (start) charging if a predetermined condition is met, even if the position cannot be determined at the time of READY-OFF. [Explanation of symbols]

[0049] 1. Wireless charging system 2 vehicles 3 Power supply equipment 4 Parking spaces 20 Power receiving unit 21 Battery 22 Charging control unit 23 CAN communication lines 31 Power supply 32 Power Transmission Unit 33 Power Cable 201 receiving coil 202 Power receiving communication unit 203 Power receiving side control unit 204 Receiving side power detection unit 321 Transmission Coil 322 Transmission side communication unit 323 Transmission side control unit 324 Power detection unit on the transmitting side

Claims

1. A wireless charging system in which power transmitted from a power transmitting coil included in a power transmitting unit of power supply equipment provided outside a vehicle is wirelessly received by a power receiving coil included in a power receiving unit provided in the vehicle, and an electricity storage device mounted on the vehicle is charged, A contactless charging system characterized by having a control device that controls charging to be performed when, when the vehicle's READY-OFF state is reached, a position determination has not been completed as to whether the relative position of the power transmitting coil and the power receiving coil is in a position where charging is possible, and when the vehicle is stopped after a predetermined time has elapsed since the READY-OFF state and the position determination has determined that the relative position is in a position where charging is possible.

2. The contactless charging system according to claim 1, characterized in that after READY-OFF, a position detection function is activated to detect whether the relative positions of the transmitting coil and the receiving coil are in a position where charging is possible, and if the position information detected by the position detection function is valid, the vehicle is stopped, and the position information is equal to or less than a predetermined threshold, the control device determines that the position determination is OK and performs charging.

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

4. 4. The wireless charging system according to claim 1, wherein the control device is provided in the vehicle.

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