Control device for electric vehicles

Abstract

To prevent power from flowing back from the electric vehicle to the external power source while AC charging is in progress. [Solution] A control device for an electric vehicle comprising a battery, a charging circuit connected to the battery that is capable of both AC and DC charging and has some power lines common to both the AC charging circuit and the DC charging circuit, and a single inlet connected to the charging circuit with a detachable charging connector for an external power supply that is common to both AC and DC charging, wherein when AC charging control is being performed with the charging connector connected to the inlet, if it is determined that voltage is being applied to the AC charging circuit and there is no voltage frequency, the AC charging control is stopped.

Description

Technical Field

[0001] The present invention relates to a control device for an electric vehicle.

Background Art

[0002] Patent Document 1 discloses performing external charging using electric power supplied from an external power source in an electric vehicle that includes a battery, an inlet, a charging circuit, and a control device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] As an electric vehicle capable of external charging, an electric vehicle including a shared charging circuit in which an AC charging circuit and a DC charging circuit are shared, and a shared inlet in which an AC charging inlet and a DC charging inlet are shared is known. However, in this electric vehicle, if the energization path of the DC charging circuit is formed during execution of AC charging, there is a risk that power will flow backward from the battery to the external power source via the DC charging circuit.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device for an electric vehicle that can prevent power from flowing backward from the electric vehicle to an external power source during execution of AC charging.

Means for Solving the Problem

[0006] The present invention relates to a control device for an electric vehicle, comprising: a battery; a charging circuit connected to the battery, capable of both AC charging and DC charging, with some power lines common to both the AC charging circuit and the DC charging circuit; and a single inlet connected to the charging circuit, with a detachable charging connector for an external power supply, which is common to both the AC charging and the DC charging, characterized in that, while AC charging control is being performed with the charging connector connected to the inlet, if it is determined that a voltage is being applied to the AC charging circuit and that there is no frequency for the voltage, the AC charging control is stopped. [Effects of the Invention]

[0007] This invention makes it possible to prevent power from flowing back from the electric vehicle to an external power source while AC charging is being performed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing an electric vehicle in an embodiment. [Figure 2] This diagram illustrates the flow of electricity during AC charging. [Figure 3] This is a diagram illustrating how to check the status of the system. [Figure 4] This is a flowchart illustrating the processing flow of AC charging control. [Modes for carrying out the invention]

[0009] The following describes in detail the control device for an electric vehicle in an embodiment of the present invention. However, the present invention is not limited to the embodiments described below.

[0010] Figure 1 is a schematic diagram showing an electric vehicle in an embodiment. The electric vehicle 1 is an electric vehicle that can be externally charged using power supplied from an external power source. The electric vehicle 1 comprises a battery 2, a charging circuit 3, an inlet 4, and a control device 5.

[0011] Battery 2 is a secondary battery that stores power to supply to the motor for driving. Battery 2 is a DC power source installed in the electric vehicle 1. Battery 2 can be charged with power supplied from an external power source.

[0012] The charging circuit 3 is connected to the battery 2 and converts power supplied from an external power source into power suitable for charging and supplies it to the battery 2. An SMR6 is provided between the charging circuit 3 and the battery 2. When the SMR6 is closed, the battery 2 and the charging circuit 3 are electrically connected. When the SMR6 is open, the battery 2 and the charging circuit 3 are electrically disconnected. The SMR6 is controlled by the control device 5.

[0013] The charging circuit 3 is capable of both AC charging and DC charging. The charging circuit 3 includes an AC charging circuit 7 and a DC charging circuit 8. In the charging circuit 3, some power lines are shared between the AC charging circuit 7 and the DC charging circuit 8. The AC charging circuit 7 has an AC charger 9. The AC charger 9 is a power converter that converts AC power supplied from an external power source into DC power and outputs it to the battery 2. The AC charger 9 has an AC / DC converter that converts AC power supplied from the power grid into power suitable for charging the battery 2. The DC charging circuit 8 has a DCR 10. The DCR 10 is a charging relay that is controlled to be closed during external charging. The DCR 10 is controlled by the control device 5.

[0014] Inlet 4 is connected to the charging circuit 3 and is a single charging inlet common to both AC and DC charging. Inlet 4 is electrically connected to the battery 2 via the charging circuit 3 and SMR 6. Inlet 4 is a common inlet that functions as both an AC charging inlet and a DC charging inlet. Both an AC charging connector and a DC charging connector are detachable from inlet 4.

[0015] A charging connector 22, provided on the charging stand 21, is detachably attached to the inlet 4. The charging stand 21 is installed on the power supply equipment 20 and connected to an external power source. The charging connector 22 is connected to the charging stand 21 via a cable 23. The charging stand 21 includes both an AC charging stand and a DC charging stand. The charging connector 22 includes both an AC charging connector and a DC charging connector. The AC charging connector is connected to the AC charging stand via a cable 23. The DC charging connector is connected to the DC charging stand via a cable 23. The AC charging stand and AC charging connector are included in a power system that supplies alternating current power. The DC charging stand and DC charging connector are included in a power system that supplies direct current power.

[0016] The control device 5 is an electronic control device that controls the power supply device and the charging device. The power supply device includes the battery 2 and the SMR 6. The charging device includes the charging circuit 3 and the inlet 4. When external charging is performed, the control device 5 performs charging control to control the charging circuit 3. The control device 5 performs charging control and outputs a command signal to the SMR 6, controlling the SMR 6 to a closed state. While charging control is being performed, the SMR 6 is in a closed state, and the battery 2 and the charging circuit 3 are electrically connected. Charging control includes AC charging control and DC charging control.

[0017] AC charging control, as shown in Figure 2, is a charging control method in which AC power supplied from an external power source via the inlet 4 is converted to DC power by the AC charging circuit 7 and then supplied to the battery 2. DC charging control is a charging control method in which DC power supplied from an external power source via the inlet 4 is supplied to the battery 2 from the DC charging circuit 8.

[0018] In the electric vehicle 1 configured as described above, part of the power line of the AC charging circuit 7 and part of the power line of the DC charging circuit 8 in the charging circuit 3 are shared. Therefore, if the current-carrying path of the DC charging circuit 8 is erroneously formed during AC charging, the voltage of the power system becomes lower than the voltage of the battery 2, causing the power of the battery 2 to flow backward into the power system. Accordingly, the control device 5 is configured to correctly detect that AC charging is in progress, and to prevent the current-carrying path of the DC charging circuit 8 from being formed during AC charging.

[0019] The control device 5 executes a process of checking the state of the system connected to the inlet 4. The control device 5 checks the state of the system using a voltage sensor provided in the AC charger 9. The voltage sensor detects the voltage applied to the AC charger 9. The voltage sensor outputs a signal related to the detected voltage to the control device 5. As shown in FIG. 3, the control device 5 determines the voltage state and the presence or absence of a frequency based on the signal input from the voltage sensor, and determines the state of the system.

[0020] As shown in FIG. 3, when checking the voltage state, the control device 5 determines whether the voltage is equal to or higher than a predetermined value. If the voltage is equal to or higher than the predetermined value, it is determined that a voltage is present. If the voltage is less than the predetermined value, it is determined that no voltage is present. The case of no voltage includes the case of a low voltage less than the predetermined value.

[0021] Further, when checking the presence or absence of a frequency, the control device 5 determines the presence or absence of the frequency of the voltage. When the control device 5 detects the frequency of the voltage, it is determined that a frequency is present. When the control device 5 cannot detect the frequency of the voltage, it is determined that no frequency is present.

[0022] When the control device 5 determines that voltage is present and frequency is present, it determines that the state of the power grid is an AC power grid, that is, AC charging. When the control device 5 determines that voltage is present and frequency is absent, it determines that the state of the power grid is a DC power grid, that is, DC charging. When the control device 5 determines that voltage is absent and frequency is present, it determines that the state of the power grid is an AC power grid, that is, AC charging, and the voltage of the power grid is a low voltage. When the control device 5 determines that voltage is absent and frequency is absent, it determines that the charging connector 22 is not connected to the inlet 4.

[0023] Then, the control device 5 compares the state of the power grid obtained from this determination result with the charging state recognized by the control device 5. When the state of the power grid and the charging state match, the control device 5 continues charging. When the state of the power grid and the charging state do not match, there is a possibility that power flows backward from the battery 2 to the external power supply side, so the control device 5 terminates charging.

[0024] Figure 4 is a flowchart showing the processing flow of AC charging control. The control shown in Figure 4 is executed by the control device 5.

[0025] The control device 5 detects that the AC charging connector is connected to the inlet 4 (step S1). In step S1, the AC charging connector is connected to the inlet 4. The control device 5 detects the connection of the AC charging connector based on signals output from the inlet 4 and the like.

[0026] The control device 5 executes AC charging control (step S2). In step S2, AC charging is started.

[0027] The control device 5 checks the state of the power grid during AC charging (step S3). In step S3, the state of the power grid is determined as shown in Figure 3. While executing the AC charging control, the control device 5 determines whether a voltage is applied to the AC charger 9 based on the signal input from the voltage sensor of the AC charger 9, and also determines the presence or absence of the frequency of the voltage.

[0028] The control device 5 determines whether the system state and the control content match (step S4). In step S4, it is determined whether the system state confirmed in step S3 matches the AC charging control being executed by the control device 5. In other words, in step S4, it is determined whether the system state confirmed in step S3 corresponds to AC charging.

[0029] If it is determined that the system state and the control content match (Step S4: Yes), the control device 5 continues AC charging control (Step S5). In this case, AC charging continues. After the process in Step S5 is completed, this control routine terminates.

[0030] If it is determined that the system status and the control content do not match (Step S4: No), the control device 5 terminates the AC charging control (Step S6). In this case, AC charging is stopped. After the process in Step S6 is performed, this control routine terminates.

[0031] As described above, according to this embodiment, the control device 5 can correctly detect that AC charging is in progress, and a power path for the DC charging circuit 8 can not be formed during AC charging. This prevents power from the battery 2 from flowing back into the power grid during AC charging.

[0032] Furthermore, the control device 5 may acquire information from other ECUs as needed to improve the accuracy of its determination of the grid state. For example, when the control device 5 installed in the electric vehicle 1 determines the grid state, it may also take into account the charging decision made by the HLC-ECU, which communicates with the charging station 21. [Explanation of symbols]

[0033] 1. Electric Vehicle 2 batteries 3 Charging circuit 4 Inlets 5 Control device 6 SMR 7 AC charging circuit 8 DC charging circuit 9 AC charger 10 DCR 20 Power supply equipment 21 Charging Stand 22 charging connectors

Claims

1. Batteries and A charging circuit connected to the aforementioned battery, capable of both AC and DC charging, and in which some power lines are common between the AC charging circuit and the DC charging circuit, The external power supply's charging connector is detachable and connected to the charging circuit, and has a single inlet common to both AC charging and DC charging, A control device for an electric vehicle, comprising: If, while AC charging control is being performed with the charging connector connected to the inlet, it is determined that a voltage is being applied to the AC charging circuit and that there is no frequency for that voltage, the AC charging control is stopped. A control device for electric vehicles characterized by the following features.

2. The AC charging circuit includes an AC charger equipped with a voltage sensor. While the AC charging control is being performed, it is determined whether or not voltage is being applied to the AC charger based on the signal input from the voltage sensor, and whether or not the voltage has a frequency. The control device for an electric vehicle according to feature 1.

3. The DC charging circuit is electrically connected to the charging connector and to the battery while AC charging is being performed. A control device for an electric vehicle according to claim 1 or 2.

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