Contactless charging system

Abstract

To provide a contactless charging system that can suppress welding caused by opening the charging relay while power is being transmitted from the power transmission unit to the power reception unit. [Solution] The contactless charging system of the present invention is a contactless charging system that charges a power storage device by non-contact power transmission from the power transmission unit of a power transmission device to the power receiving unit of a power receiving device installed on a vehicle, wherein the power transmission device is equipped with an inverter, and the vehicle is equipped with a charging relay that electrically connects and disconnects the power receiving device and the power storage device, and a control device that, when it receives an inverter stop signal from the power transmission device via wireless communication, opens the charging relay to electrically disconnect the power receiving device and the power storage device and executes control to terminate the charging of the power storage device, wherein the control device opens the charging relay to terminate the charging of the power storage device when it cannot receive an inverter stop signal and when the charge effective counter that is counted up during charging does not count up.

Description

Technical Field

[0001] The present invention relates to a non-contact charging system.

Background Art

[0002] Patent Document 1 discloses a power transmission system that transmits power for charging a battery provided in a vehicle in a non-contact manner from a power transmission unit of a power transmission device provided outside the vehicle to a power reception unit of a power reception device provided in the vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When charging is terminated due to full charge or the like, after stopping power transmission from the power transmission unit to the power reception unit, in other words, by receiving an inverter stop signal from the power transmission device, the charging relay is opened to electrically disconnect the power reception unit and the battery. However, if an abnormality occurs where the inverter stop signal cannot be received, since the charging relay has to be opened to end charging while the state of power transmission is unknown, if the charging relay is opened during power transmission, there is a risk that the charging relay will weld.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a non-contact charging system capable of suppressing welding caused by opening a charging relay during power transmission from a power transmission unit to a power reception unit. [[ID= forty]]

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, the contactless charging system according to the present invention is a contactless charging system that charges a power storage device installed in a vehicle by non-contact power transmission from a power transmission unit of a power transmission device installed outside the vehicle to a power receiving unit of a power receiving device installed in the vehicle, wherein the power transmission device is equipped with an inverter that converts the power supplied from a power source to the power transmission unit into AC power of a predetermined frequency, and the vehicle is equipped with a charging relay that switches between a closed state and an open state to electrically connect and disconnect the power receiving device and the power storage device, and a control device that, when it receives an inverter stop signal from the power transmission device via wireless communication, opens the charging relay to electrically disconnect the power receiving device and the power storage device and executes control to terminate the charging of the power storage device, wherein the control device is characterized in that, when it cannot receive the inverter stop signal and there is no count-up of the charging effective counter that is counted up during charging, it opens the charging relay to electrically disconnect the power receiving device and the power storage device and executes control to terminate the charging of the power storage device. [Effects of the Invention]

[0007] The contactless charging system according to the present invention uses a charging active counter to open and close the charging relay when an inverter stop signal cannot be received, thereby suppressing welding caused by opening the charging relay while power is being transmitted from the power transmission unit to the power reception unit. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of a schematic configuration of a contactless charging system according to an embodiment. [Figure 2] Figure 2 is a timing chart showing an example of control related to contactless charging performed by the vehicle ECU and the power transmission ECU. [Figure 3] Figure 3 is a flowchart showing an example of control related to contactless charging performed by the vehicle's ECU. [Figure 4]Figure 4 is a flowchart showing an example of control related to contactless charging performed by the power transmission ECU. [Modes for carrying out the invention]

[0009] The following describes embodiments of the contactless charging system according to the present invention. However, the present invention is not limited to these embodiments.

[0010] Figure 1 is a diagram showing an example of a schematic configuration of a contactless charging system 1 according to an embodiment.

[0011] The contactless charging system 1 according to this embodiment comprises a power transmission device 2 and a power receiving device 40 provided on a vehicle 4. The power transmission device 2 is, for example, provided on the ground. The power receiving device 40 is, for example, located on the underside of the floor panel of the vehicle 4. The power transmission device 2 transmits power to the power receiving device 40 provided on the vehicle 4 in a contactless manner, and the transmitted power is used to charge a battery 43, which is a power storage device provided on the vehicle 4.

[0012] The power transmission device 2 includes a power transmission unit 20, a power transmission ECU 21, and a communication device 22. The power transmission unit 20 includes a PFC (Power Factor Correction) circuit 201, an inverter (INV) 202, a filter circuit 203, and a power transmission section 204. The power transmission section 204 is also equipped with a power transmission coil 205. The PFC circuit 201 rectifies and boosts the AC power supplied from the AC power source 3 and supplies that power to the inverter 202. The inverter 202 converts the power rectified by the PFC circuit 201 into AC power of a predetermined frequency and outputs it. The AC power output from the inverter 202 is supplied to the power transmission section 204 through the filter circuit 203. Each of the power transmission section 204 and the power receiving section 401 has a resonant circuit and is designed to resonate at the frequency of the transmitted power. Then, when AC power is supplied from the inverter 202 to the power transmission unit 204 through the filter circuit 203, a magnetic field is formed between the power transmission coil 205 of the power transmission unit 204 and the power receiving coil 402 of the power receiving unit 401. Power is transmitted from the power transmission coil 205 to the power receiving coil 402 through this magnetic field.

[0013] The power transmission ECU 21 has a CPU, memory, and input / output ports for inputting and outputting various signals, and controls various devices in the power transmission device 2, such as the inverter 202. For example, the power transmission ECU 21 operates the PFC circuit 201 and the inverter 202 to supply power in response to a power supply request from the vehicle 4, thereby forming a magnetic field around the power transmission coil 205. The communication device 22 is configured to enable bidirectional wireless communication with the communication device 45 of the vehicle 4.

[0014] Vehicle 4 is equipped with a power receiving device 40, a charging relay 41, a DC / DC converter 42, a battery 43, a vehicle ECU 44, and a communication device 45. The power receiving device 40 includes a power receiving section 401, a filter circuit 403, and a rectifier section 404. The power receiving section 401 is also provided with a power receiving coil 402. Power transmitted from the power transmitting coil 205 of the power transmitting device 2 to the power receiving coil 402 is filtered for noise by the filter circuit 403 and converted from AC power to DC power by the rectifier section 404. This DC power is then supplied to the DC / DC converter 42 via the charging relay 41.

[0015] The charging relay 41 is a relay for electrically connecting / disconnecting the power receiving device 40 and the battery 43 (DC / DC converter 42). The charging relay 41 is configured to physically disconnect the electrical circuit and switches between a closed state and an open state according to a control signal from the vehicle ECU 44. The DC / DC converter 42 is electrically connected to the power receiving device 40. The DC / DC converter 42 converts the voltage of the DC power received from the power receiving device 40 to a voltage for charging the battery 43 mounted on the vehicle 4, according to a control signal from the vehicle ECU 44. The battery 43 is mounted as the drive power source (power source) of the vehicle 4. The battery 43 is composed of a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The vehicle ECU 44 has a CPU, memory (ROM and RAM), and input / output ports to which various signals are input and output. The vehicle ECU 44 receives signals from various sensors and outputs control signals to various devices, and also controls each device.

[0016] The vehicle ECU 44 is configured to calculate the State of Charge (SOC) of the battery 43. Furthermore, the communication device 45 is configured to enable bidirectional wireless communication with the communication device 22 of the power transmission device 2.

[0017] Figure 2 is a timing chart showing an example of control related to contactless charging performed by the vehicle ECU 44 and the power transmission ECU 21.

[0018] In the non-contact charging system 1 according to the embodiment, when the power receiving device 40 receives an inverter stop signal from the power transmission device 2, the charging relay 41 of the vehicle 4 is opened to end the charging of the battery 43. Further, in the non-contact charging system 1 according to the embodiment, the vehicle ECU 44 counts up a charging valid counter during the charging of the battery 43. Further, when the vehicle ECU 44 determines that charging has ended (with a charging end request), it stops counting up the charging valid counter. Then, when the vehicle ECU 44 cannot receive the inverter stop signal from the power transmission device 2 and there is no counting up of the charging valid counter, it executes control to electrically cut off the power receiving device 40 and the battery 43 and end the charging of the battery 43.

[0019] Further, in the non-contact charging system 1 according to the embodiment, a signal related to the charging valid counter (the count value of the charging valid counter) is transmitted to the power transmission device 2 by wireless communication. The power transmission ECU 21 determines (detects) whether there is an abnormality in the charging valid counter based on the received signal related to the charging valid counter, and when it determines (detects) that there is an abnormality in the charging valid counter, it executes control to stop the inverter 202. Further, for example, as shown in FIG. 2, the power transmission ECU 21 determines that there is no abnormality detection (no abnormality in the charging valid counter) if the charging valid counter is within a preset threshold range (between the threshold of the normal upper limit of the charging valid counter and the threshold of the normal lower limit of the charging valid counter), and determines that there is an abnormality detection (abnormality in the charging valid counter) if it is outside the threshold range. Note that the method for determining (detecting) whether there is an abnormality in the charging valid counter by the power transmission ECU 21 is not limited to the above method, and for example, as will be described later, the determination (detection) of whether there is an abnormality in the charging valid counter may be performed based on whether the charging valid counter is in an abnormal range.

[0020] FIG. 3 is a flowchart showing an example of control related to non-contact charging executed by the vehicle ECU 44.

[0021] First, the vehicle ECU 44 determines whether there is a determination of charging completion (step S1). When the vehicle ECU 44 determines that there is no determination of charging completion (No in step S1), it increments the charging valid counter such that charging valid counter = previous value + 1 (step S2). Next, the vehicle ECU 44 sets the inverter stop waiting time = 0 (step S3). After that, the vehicle ECU 44 proceeds to step S7. On the other hand, when the vehicle ECU 44 determines that there is a determination of charging completion (Yes in step S1), it stops incrementing the charging valid counter and sets the charging valid counter = previous value (step S4). Next, the vehicle ECU 44 determines whether the inverter has stopped (step S5). When the vehicle ECU 44 determines that the inverter has not stopped (No in step S5), it sets the inverter stop waiting time = previous value + 1 (step S6). After that, the vehicle ECU 44 proceeds to step S7.

[0022] In step S7, the vehicle ECU 44 determines whether the inverter stop waiting time > charging valid counter anomaly detection time + a. In other words, when there is no increment of the charging valid counter, the vehicle ECU 44 presumes that the power transmission ECU 21 of the power transmission device 2 has detected an anomaly in the charging valid counter and has stopped the inverter 202. When the vehicle ECU 44 determines that the inverter stop waiting time > charging valid counter anomaly detection time + a is not true (No in step S7), in other words, when it presumes that the power transmission ECU 21 has not detected an anomaly in the charging valid counter and has not stopped the inverter 202, it ends the series of controls. On the other hand, when the vehicle ECU 44 determines that the inverter stop waiting time > charging valid counter anomaly detection time + a is true (Yes in step S7), in other words, when it presumes that the power transmission ECU 21 has detected an anomaly in the charging valid counter and has stopped the inverter 202, as a charging relay open request, it opens the charging relay 41 to end the charging of the battery 43 (step S9). After that, the vehicle ECU 44 ends the series of controls.

[0023] Furthermore, in step S5, if the vehicle ECU 44 receives an inverter stop signal from the power transmission device 2 and determines that the inverter is stopped (Yes in step S5), it sets the inverter stop waiting time to 0 (step S8). Next, the vehicle ECU 44 requests the charging relay to open, opens the charging relay 41, and ends the charging of the battery 43 (step S9). After that, the vehicle ECU 44 ends the series of controls.

[0024] Figure 4 is a flowchart showing an example of control related to contactless charging performed by the power transmission ECU 21.

[0025] First, the power transmission ECU 21 determines whether the charge valid counter is within the abnormal range (step S11). If the power transmission ECU 21 determines that the charge valid counter is not within the abnormal range (No in step S11), it sets the abnormal counter to 0 (step S12). After that, the power transmission ECU 21 proceeds to step S14. On the other hand, if the power transmission ECU 21 determines that the charge valid counter is within the abnormal range (Yes in step S11), it sets the abnormal counter to the previous value + 1 (step S13). After that, the power transmission ECU 21 proceeds to step S14.

[0026] In step S14, the power transmission ECU 21 determines whether the abnormal counter > the charging valid counter abnormality determination threshold. If the power transmission ECU 21 determines that the abnormal counter > the charging valid counter abnormality determination threshold is not met (No in step S14), the charging valid counter abnormality determination is set to "no determination" (step S15). The power transmission ECU 21 then proceeds to step S17. On the other hand, if the power transmission ECU 21 determines that the abnormal counter > the charging valid counter abnormality determination threshold is met (Yes in step S14), the charging valid counter abnormality determination is set to "determined" (step S16). The power transmission ECU 21 then proceeds to step S17.

[0027] In step S17, the power transmission ECU 21 determines whether or not there is a charge valid counter abnormality. If the power transmission ECU 21 determines that there is no charge valid counter abnormality (No in step S17), it terminates the series of controls. On the other hand, if the power transmission ECU 21 determines that there is a charge valid counter abnormality (Yes in step S17), it stops the inverter 202 (step S18). After that, the power transmission ECU 21 terminates the series of controls.

[0028] In the contactless charging system 1 according to the embodiment described above, if the vehicle ECU 44 cannot receive an inverter stop signal from the power transmission device 2, the charging relay 41 is opened and closed using the charging active counter signal. As a result, in the contactless charging system 1 according to the embodiment, welding caused by opening the charging relay 41 while power is being transmitted from the power transmission device 2 to the power receiving device 40, without knowing whether the inverter 202 of the power transmission device 2 has stopped, can be suppressed. [Explanation of Symbols]

[0029] 1. Contactless charging system 2 Power transmission equipment 20 Power transmission units 21 Power Transmission ECU 22,45 Communication equipment 40 Power receiving device 41 Charging relay 43 batteries 44 Vehicle ECU 202 Inverter 204 Power Transmission Section 205 Power transmission coil 401 Power Receiving Unit 402 Power receiving coil

Claims

[Claim 1] A contactless charging system that charges a power storage device installed in a vehicle by non-contact power transmission from a power transmission unit installed on the outside of the vehicle to a power receiving unit installed on the vehicle, The aforementioned power transmission device is It is equipped with an inverter that converts the power supplied from the power source to the power transmission unit into AC power of a predetermined frequency. The aforementioned vehicle is A charging relay that switches between a closed state and an open state to electrically connect and disconnect the power receiving device and the energy storage device, A control device that, upon receiving an inverter stop signal from the power transmission device via wireless communication, opens the charging relay to electrically disconnect the power receiving device and the energy storage device, thereby terminating the charging of the energy storage device. It is equipped with, If the control device cannot receive the inverter stop signal and the charge valid counter, which is counted up during charging, does not count up, it opens the charging relay to electrically disconnect the power receiving device and the energy storage device, and executes control to terminate the charging of the energy storage device. A contactless charging system characterized by the following features.

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