Charging device

Abstract

To provide a charging device capable of safely performing rapid charging by a charging connector when an electric power of a high voltage and a large current is used in an electric vehicle even when an abnormality occurs in a discharge control.SOLUTION: A charging device includes: a discharge circuit that includes a charge / discharge relay configured to charge / discharge DC power charged in a first electrolytic capacitor, a discharge resistor and a discharge switch disposed in parallel with a first electrolytic capacitor configured to discharge the DC power; a voltage detection part configured to detect a voltage value applied to the discharge resistor when the discharge switch is turned on; and a charge / discharge control part configured to control the discharge circuit based on the detected voltage value. The charging device includes a discharge determination part that causes the discharge circuit to perform a preliminary discharge in which the discharge circuit is preliminarily discharged for a predetermined period of time, and determines whether or not to start an actual discharge performed after the preliminary discharge according to the presence or absence of a change in the voltage value before and after the start of the preliminary discharge or a change state of the voltage value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a charging device that connects a charging connector of a dedicated charging station to an electric vehicle for rapid charging. [Background technology]

[0002] In recent years, charging devices that rapidly charge electric vehicles at dedicated charging stations have become popular in response to V2H, which allows users to use the onboard storage batteries of electric vehicles during disasters, etc. In addition to grid power sources, there has also been an increase in the use of renewable energy sources such as solar cells as the supply power source for these charging devices.

[0003] A known conventional device for performing the above-mentioned rapid charging is a charging / discharging device (for example, Patent Document 1) that includes a charger / discharger (charging stand) that performs rapid charging of an electric vehicle and a charging connector with a cable, and the charger / discharger and the electric vehicle are connected via the charging connector by power lines, control lines, and communication lines to control charging and discharging.

[0004] However, because fast charging uses high voltage and current, it must be safe for users. This safety requirement is stipulated in the CHAdeMO standard, which is a standard for fast charging electric vehicles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5642226 Summary of the Invention [Problem to be solved by the invention]

[0006] Within this charging station, DC power is supplied from a grid power source or renewable energy source, etc., and charged in an electrolytic capacitor, which is then supplied to the charging connector as power source. To ensure safe charging and discharging using the charging connector, a charge / discharge relay and discharge switch are installed within the charging station, and when the charging connector is disconnected, the discharge switch is turned on to control the discharge of the electrolytic capacitor, reducing the connector connection part of the charging connector, which has a normally open (NO) contactor, to a safe voltage and current.

[0007] However, when the charging connector is disconnected, noise may be generated in the communication lines connected inside the electric vehicle, causing the discharge control to malfunction. As a result, when discharge begins when the contactor is turned ON, an inrush current will flow, preventing the voltage and current from decreasing to a safe level, making it impossible to stop the discharge, and causing high voltage and current to flow through the connector connection, compromising safety.

[0008] Furthermore, based on the CHAdeMO standard, a protocol tester (CPT) may be connected to the charging connector to check operation when installing or inspecting a charging station. This CPT includes a normally open (NO) contactor, a control unit (CPU), and an electrolytic capacitor. It simulates the charging mechanism of an electric vehicle, and the CPU opens and closes the contactor to conduct tests such as charging tests for a specified period of time to determine whether the charging station is functioning properly. If the CPT malfunctions, for example, causing the CPU to go out of control and keep the contactor ON, the contactor may not open. As a result, the discharge control may not function properly, as described above, and the discharge may not be stopped. This could result in high voltage and current flowing through the connector connection, potentially compromising safety.

[0009] The present invention aims to provide a charging device that can safely perform rapid charging using a charging connector when high-voltage, large-current power is used for an electric vehicle, even if an abnormality occurs in the discharge control. [Means for solving the problem]

[0010] In order to achieve the above object, one embodiment of the present invention provides a charging device installed in a charging station for rapid charging an on-board battery of an electric vehicle, the charging device comprising: a charge / discharge relay for charging and discharging DC power of a first electrolytic capacitor charged from a power supply; a discharge circuit including a discharge resistor and a discharge switch arranged in parallel with the first electrolytic capacitor for discharging the DC power; a voltage detection unit for detecting a voltage value applied to the discharge resistor when the discharge switch is on; and a charge / discharge control unit for controlling the discharge circuit based on the detected voltage value; The charge / discharge control unit performs a preliminary discharge in which the discharge circuit discharges preliminarily for a predetermined period of time, and includes a discharge determination unit that determines whether or not actual discharge can be started after the preliminary discharge based on whether or not there is a change in the voltage value before and after the start of the preliminary discharge or the state of change in the voltage value.

[0011] According to this configuration, the charge / discharge control unit controls the discharge circuit based on the voltage value applied to the discharge resistor when the discharge switch is turned on, and also performs a preliminary discharge in which the discharge circuit discharges preliminarily for a predetermined period of time, and determines whether or not actual discharge can be started after the preliminary discharge based on whether or not there is a change in the voltage value before and after the start of the preliminary discharge or the state of change in the voltage value.Therefore, even if an abnormality in the discharge control occurs during an operational test of the charging station, rapid charging using high-voltage, high-current power for an electric vehicle and performed via a charging connector can be performed safely because preliminary discharge is performed to determine whether actual discharge can be continued.

[0012] Preferably, the charge / discharge control unit stops the actual discharge even before the end of the duration if the voltage value exceeds an upper threshold based on a predetermined duration of the actual discharge and an upper threshold that defines an allowable limit for an increase in the voltage value. Therefore, quick charging performed via the charge connector can be performed more safely even if an abnormality occurs in the discharge control.

[0013] Preferably, the voltage detection unit also detects the voltage during discharge of the second electrolytic capacitor connected to a protocol tester (CPT) simulating a charging mechanism for an electric vehicle. Therefore, even if an abnormality occurs in the discharge control of the protocol tester during an operational test of the charging station simulating a charging mechanism for an electric vehicle, the test can be performed more safely.

[0014] In another embodiment of the present invention, a charging device provided in a charging station for rapid charging an on-board battery of an electric vehicle includes: a charge / discharge relay for charging and discharging DC power of a first electrolytic capacitor charged from a power supply; a discharge circuit including a discharge resistor and a discharge switch arranged in parallel with the first electrolytic capacitor for discharging the DC power; a voltage detection unit for detecting a voltage value applied to the discharge resistor when the discharge switch is on; and a discharge control unit for controlling the discharge circuit based on the detected voltage value; The discharge control unit includes a discharge determination unit that determines whether or not actual discharge can be continued based on whether or not there is a change in the voltage value before and after the start of actual discharge in the discharge circuit, or based on the state of change in the voltage value.

[0015] According to this configuration, the discharge control unit controls the discharge circuit based on the voltage value applied to the discharge resistor when the discharge switch is turned on, and determines whether or not actual discharge can be continued based on whether or not there is a change in the voltage value before and after the start of actual discharge in the discharge circuit, or the state of change in the voltage value.Therefore, even if an abnormality in the discharge control occurs during actual discharge, rapid charging using high-voltage, high-current power and performed via a charging connector can be performed safely, as it can determine whether or not actual discharge can be continued.

[0016] Preferably, the discharge control unit stops the actual discharge even before the end of the duration if the voltage value exceeds an upper threshold based on a predetermined duration of the actual discharge and an upper threshold that defines an allowable limit for an increase in the voltage value. Therefore, quick charging performed using the charge connector can be performed more safely even if an abnormality occurs in the discharge control. [Effects of the Invention]

[0017] In the present invention, the discharge control unit controls the discharge circuit based on the voltage value applied to the discharge resistor when the discharge switch is turned on, and determines whether or not discharge can be started based on whether or not there is a change in the voltage value before and after discharge by the discharge circuit begins, or the state of change in the voltage value.Therefore, when high-voltage, high-current power is used in an electric vehicle, rapid charging using a charging connector can be performed safely even if an abnormality occurs in the discharge control. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a block diagram showing a charging device according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a characteristic diagram showing the operation of the device. [Figure 3] FIG. 4 is a characteristic diagram showing the operation of the device. [Figure 4] FIG. 4 is a characteristic diagram showing the operation of the device. [Figure 5] FIG. 10 is a block diagram showing a charging device according to a second embodiment. [Figure 6] (A) and (B) are characteristic diagrams showing the operation of this device. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a charging device 1 according to a first embodiment of the present invention. This charging device 1 uses power from a grid power supply (not shown) or a renewable energy power supply such as a solar cell, and fast charges an electric vehicle by connecting a charging connector to the charging device. The power from the grid power supply or renewable energy power supply is converted by a power conditioner (not shown), and the input and output sides are separated by an isolation transformer (transformer) 2 (only the output side is shown), and the desired DC power is supplied to a charging stand 3. The DC power charged in a first electrolytic capacitor 5 in this charging stand 3 is supplied as power supply power to an onboard battery 7 of the electric vehicle 4 via a charging connector 6.

[0020] Within the charging stand 3, a charge / discharge relay 10 that charges and discharges DC power from the first electrolytic capacitor 5 and a parallel circuit consisting of a resistor R2 and an inrush current prevention relay 11 are connected in series to the positive electrode side of the first electrolytic capacitor 5. Also provided in parallel with the first electrolytic capacitor 5 is a discharge circuit 14 that has a discharge resistor R1 and a discharge switch 13 and discharges DC power. Furthermore, the charging stand 3 is provided with a voltage detection unit 15 that detects the voltage value applied to the discharge resistor R1 when the discharge switch 13 is on, and a charge / discharge control unit 16 that controls the discharge circuit 14 based on the detected voltage value.

[0021] When the charge / discharge relay 10 is turned on and the discharge switch 13 of the discharge circuit 14 is turned off, the charge / discharge control unit 16 charges the on-board battery 7 of the electric vehicle 4 via the charge connector 6, as shown by arrow α. When the charge / discharge relay 10 is turned on and the discharge switch 13 of the discharge circuit 14 is turned on to pass current, the charge / discharge control unit 16 has a discharge function of discharging charge from the first electrolytic capacitor 5, as shown by arrow β.

[0022] The charge / discharge control unit 16 has a discharge determination unit 17 that causes the discharge circuit 14 to perform a preliminary discharge by using the discharge function to discharge for a certain period of time, and determines whether or not actual discharge can be started after the preliminary discharge based on whether or not there is a change in the voltage value before and after the start of the preliminary discharge, or the state of change in the voltage value.

[0023] In this charge / discharge control unit 16, if the voltage value exceeds the upper threshold based on a predetermined duration of actual discharge and an upper threshold that defines the allowable limit for voltage value increase, the charge / discharge control unit 16 stops actual discharge in the discharge circuit 14 even before the end of the duration, thereby ensuring safety.

[0024] In this embodiment, a protocol tester (CPT) 12 is connected to the charging connector 6 to check the operation of the charging stand 3 based on the CHAdeMO standard. The CPT 12 includes normally open (NO) contactors 18, 18 and a CPT control unit (CPU) 19, and is equipped with a second electrolytic capacitor (external capacitance element) 20 that simulates the first electrolytic capacitor 5 of the charging stand 3. When testing the CPT 12, the electric vehicle 4 is generally not connected (indicated by the dashed line). If the CPT 12 malfunctions and the contactors 18, 18 remain ON due to, for example, a runaway of the CPU 19, the contactors 18, 18 may not open, causing a high voltage and current to flow through the connector connection, potentially compromising safety. In this embodiment, to ensure safety, a preliminary discharge is performed to check whether the CPT 12 is operating normally.

[0025] As shown in FIG. 2, first, the charge / discharge relay 10 in the charging station 3 is turned on, and the contactors 18, 18 of the CPT 12 are closed to charge the second electrolytic capacitor 20. Next, as a preliminary discharge, with the discharge switch 13 turned on, discharge of the first electrolytic capacitor 5 and the second electrolytic capacitor 20 begins for, for example, 19 to 20 msec, and the voltage detection unit 15 detects the voltage value across the discharge resistor R1 (acquired voltage value (a)). Thereafter, the charge / discharge relay 10 is turned off, and the contactors 18, 18 of the CPT 12 are opened, and the average voltage value over 100 msec is detected (acquired voltage value (b)). For example, this is determined by averaging 10 times every 10 msec.

[0026] At this time, the upper limit threshold that determines the allowable limit of the voltage value increase is set to the acquired voltage value (a) × 0.9. When the following equation holds: Obtained voltage value (a) x 0.9 > Obtained voltage value (b)...(1), For example, if the acquired voltage value (a) is 350 V and the acquired voltage value (b) is 300 V (less than 315 V), it is determined that the voltage value of the discharge circuit 14 has dropped sufficiently, the charge / discharge relay 10 is turned on, the contactors 18, 18 are also closed, and actual discharge is carried out for the duration, for example, 3 seconds.

[0027] At this time, it is determined that the discharge circuit 14 of the charging stand 3 is operating properly and that the contactor 18 of the CPT 12 is not continuing to be ON, and the discharge determination unit 17 determines that the discharge control is operating normally, so actual discharge begins and various tests of the CPT 12 are performed.

[0028] As shown in FIG. 3, in the voltage detection, When the following equation is true: Obtained voltage value (a) × 0.9 ≦ Obtained voltage value (b) ... (2) For example, if the acquired voltage value (a) is 350V and the acquired voltage value (b) is 346V (315V or more), it is determined that the voltage value of the discharge circuit 14 has not dropped sufficiently, that is, the contactor 18 of the CPT 12 has welded and is running out of control, and the discharge determination unit 17 determines that the discharge control is not operating normally, the charge / discharge relay 10 remains off, no actual discharge is performed, and various tests of the CPT 12 are not performed.

[0029] As shown in Figure 4, in the voltage detection, Even if the formula (1) holds, the voltage value (a) × 0.9 > the voltage value (b) may be too high due to noise. When the following equation holds: Acquired voltage value (a) × 0.9 ≦ Acquired voltage value (c) ... (3) The discharge determination unit 17 determines that an abnormality has occurred in the discharge control, the charge / discharge relay 10 remains off, actual discharge is not performed, and various tests of the CPT 12 are not performed.

[0030] As a result, even if an abnormality in the discharge control occurs during the operational test of the charging stand 3 by the CPT 12, rapid charging using high-voltage, large-current electricity for the electric vehicle 4 via the charging connector 6 can be carried out safely because a preliminary discharge is performed to determine whether or not actual discharge can continue.

[0031] It is also possible to perform various tests on the CPT 12 while the electric vehicle 4 is connected to the CPT 12 connected to the charging connector 6 of the charging stand 3.

[0032] 5 is a block diagram showing a charging device 1A according to a second embodiment. In this example, a charging connector 6 having a normally open (NO) contactor (not shown) is directly connected to an electric vehicle 4, without connecting a CPT 12 to a charging stand 3. A voltage detection unit 15 detects the voltage value across the discharge resistor R1 when the first electrolytic capacitor 5 is discharged when the discharge switch 13 is turned on. Unlike the first embodiment, the operation of the discharge circuit 14 is checked during actual discharge, without performing preliminary discharge.

[0033] During actual discharge when the charging connector 6 is connected to the electric vehicle 4, if, for example, the acquired voltage value (a) is 350 V and the acquired voltage value (b) is 200 V (less than 262 V (75%)), as shown in FIG. 6(A), it is determined that the voltage value of the discharge circuit 14 has dropped sufficiently, the contactor of the charging connector 6 does not continue to be ON, the discharge determination unit 17 determines that the discharge control is operating normally, and the charge / discharge relay 10 is turned ON to perform actual discharge for, for example, 1.5 seconds.

[0034] As shown in FIG. 6(B), for example, if the acquired voltage value (a) is 350 V and the acquired voltage value (b) is 346 V (less than 262 V), it is determined that the voltage value of the discharge circuit 14 has not dropped sufficiently, and the discharge determination unit 17 determines that the discharge control is not operating normally, and no actual discharge is performed.

[0035] This allows the electric vehicle 4 to be rapidly charged using high-voltage, high-current power via the charging connector 6, and even if an abnormality occurs in the discharge control during actual discharge, it is possible to determine whether or not actual discharge can be continued, so that it can be carried out safely.

[0036] The present invention is not limited to the above-described embodiments, and various additions, modifications, and omissions are possible without departing from the spirit of the present invention. Therefore, such additions, modifications, and omissions are also included in the scope of the present invention. [Explanation of symbols]

[0037] 1: Charging device 2: Isolation transformer 3: Charging stand 4: Electric vehicles, 5: First electrolytic capacitor 6: Charging connector 7: Vehicle battery 10: Charge / discharge relay 12: CPT (Protocol Tester) 13: Discharge switch 14:Discharge circuit 15: Voltage detection unit 16: Charge / discharge control unit 17:Discharge determination section 18: Contactor 19: CPT control section 20: Second electrolytic capacitor R1: Discharge resistor

Claims

1. A charging device installed in a charging station for rapid charging an on-board battery of an electric vehicle, a charge / discharge relay that charges and discharges DC power from a first electrolytic capacitor charged from a power supply; a discharge circuit including a discharge resistor and a discharge switch arranged in parallel with the first electrolytic capacitor that discharges the DC power; a voltage detection unit that detects a voltage value applied to the discharge resistor when the discharge switch is on; and a charge / discharge control unit that controls the discharge circuit based on the detected voltage value; The charge / discharge control unit A charging device comprising: a discharge determination unit that causes the discharge circuit to perform preliminary discharge for a predetermined period of time, and determines whether or not actual discharge can be started after the preliminary discharge based on whether or not there is a change in the voltage value before and after the start of the preliminary discharge or the state of change in the voltage value.

2. In claim 1, The charge / discharge control unit A charging device that stops the actual discharge even before the end of a predetermined duration of the actual discharge if the voltage value exceeds an upper limit threshold based on a predetermined duration of the actual discharge and an upper limit threshold that defines an allowable limit for an increase in the voltage value.

3. In claim 1 or 2, The charging device, wherein the voltage detection unit also detects the voltage during discharge of a second electrolytic capacitor connected to a protocol tester (CPT) that simulates a charging mechanism for an electric vehicle.

4. A charging device installed in a charging station for rapid charging an on-board battery of an electric vehicle, a charge / discharge relay that charges and discharges DC power from a first electrolytic capacitor charged from a power supply; a discharge circuit including a discharge resistor and a discharge switch arranged in parallel with the first electrolytic capacitor that discharges the DC power; a voltage detection unit that detects a voltage value applied to the discharge resistor when the discharge switch is on; and a charge / discharge control unit that controls the discharge circuit based on the detected voltage value; The charge / discharge control unit A charging device comprising: a discharge determination unit that determines whether or not actual discharge can be continued based on whether or not there is a change in the voltage value before and after the start of actual discharge of the discharge circuit, or based on the state of change in the voltage value.

5. In claim 4, The charge / discharge control unit A charging device that stops the actual discharge even before the end of a predetermined duration of the actual discharge if the voltage value exceeds an upper limit threshold based on a predetermined duration of the actual discharge and an upper limit threshold that defines an allowable limit for an increase in the voltage value.

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