Charging / discharging system for electric vehicle

Abstract

To provide a charging / discharging system for an electric vehicle, in which a power supply circuit can be reliably activated by using an auxiliary battery on a vehicle side in an emergency such as a power failure.SOLUTION: In an EVPS 100, when an auxiliary battery 1 of a vehicle is connected to a connection cable 2, a microcomputer 10 is activated by a power supplied from the auxiliary battery 1 via the connection cable 2, a limiting resistor 3, and a bypass circuit 11. After a load starting current is stabilized, the microcomputer 10 turns on a switch 5 by a switch driving signal S1 to short-circuit both ends of a limiting resistor 4. After a power supplied from a load start current limiting circuit 20 to the EVPS power supply circuit 6 is stabilized, the microcomputer 10 starts the EVPS power supply circuit 6 by an EN / DIS signal S2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a charging and discharging system for an electric vehicle. [Background technology]

[0002] As one way to reduce carbon dioxide emissions from automobiles, vehicles equipped with storage batteries and generators for drive, such as electric vehicles, plug-in hybrid vehicles, and fuel cell vehicles, are becoming more common. However, due to grid power shortages caused by the Great East Japan Earthquake and the widespread use of renewable energy sources such as solar power generation, there is an increasing demand for peak power shifting / cutting using storage batteries. Furthermore, from the perspective of power supply security, there is also a growing demand for emergency power supply. Under these circumstances, a movement to utilize electric vehicles and other vehicles has begun.

[0003] The Electric Vehicle Power Supply System Council has established the Electric Vehicle Charging and Discharging System Guidelines (V2H DC Edition) to ensure electrical safety and compatibility between vehicles and connected devices for V2H (Vehicle to Home), which utilizes the storage and generation capabilities of electric vehicles and other devices to supply power to indoor wiring, and V2L (Vehicle to Load), which directly supplies power to electrical devices.The guidelines stipulate system specifications and requirements for vehicles and EVPS (Electric Vehicle Power System) that use direct current (DC) power to charge and / or discharge power between vehicles (electric vehicles, plug-in hybrid vehicles, fuel cell vehicles, etc.) equipped with on-board batteries and / or generators for driving and the distribution system within a home, which is a general-purpose electrical facility.

[0004] Patent Document 1 discloses a charging system that uses an interface configuration between a charger and an electric vehicle that complies with the CHAdeM0 (registered trademark) specification. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-85898 A (Fig. 2,

[0037] ) Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 discloses a configuration related to optional functions selectively added to an interface configuration conforming to the CHAdeM0 standard. Specifically, a 12V line of a charge / discharge connector is connected to an auxiliary storage battery mounted on a vehicle via a switch. For example, during a power outage, power stored in the auxiliary storage battery is supplied to a charging / discharging device via the 12V line of the charge / discharge connector.

[0007] Figure 4 shows the circuit configuration that realizes the optional function described above. The circuit configuration in Figure 4 is a circuit that starts the EVPS power supply circuit using the vehicle's auxiliary battery (equivalent to the auxiliary storage battery in Patent Document 1).

[0008] The guidelines specify a wide voltage range for auxiliary batteries, from 8 to 16 V, taking into account deterioration and variations in the auxiliary battery. The guidelines also specify the maximum current drawn from the auxiliary battery, which typically requires a limiting resistor on the input side of the EVPS power supply circuit to limit the load startup current.

[0009] However, with this configuration, when the auxiliary battery voltage is low, sufficient power cannot be extracted due to voltage drops caused by the limiting resistor and impedance of the connecting cable, and voltage drops caused by the forward voltage of the diode, and this may prevent the EVPS power circuit from starting.

[0010] The present invention aims to provide a charging / discharging system for an electric vehicle that can reliably start up a power supply circuit using an auxiliary battery on the vehicle side in an emergency such as a power outage. [Means for solving the problem]

[0011] In one aspect of the present invention, a charging / discharging system for an electric vehicle includes a connection cable for connecting an auxiliary battery of the vehicle, a power supply circuit configured to be start / stop controllable in accordance with an EN / DIS signal, a limiting resistor provided in a power supply path from the connection cable to the power supply circuit, and a switch connected in parallel to the limiting resistor and configured to be switchable on / off in accordance with a switch drive signal, the switch shorting both ends of the limiting resistor when on, but not shorting both ends of the limiting resistor when off, and a load starting current. limit a control circuit for outputting the EN / DIS signal and the switch drive signal; and a load starting current limit and a bypass circuit for bypassing the power supplied from the auxiliary battery to the power supply circuit to the control circuit, wherein before the auxiliary battery is connected to the connection cable, the power supply circuit is stopped and the switch is off, and when the auxiliary battery is connected to the connection cable, the control circuit is started by the power supplied from the auxiliary battery via the connection cable, the limiting resistor, and the bypass circuit, and after a load starting current has stabilized, the switch is turned on by the switch drive signal to short-circuit both ends of the limiting resistor, and the load starting current limit After the power supplied from the circuit to the power supply circuit is stabilized, the power supply circuit is started by the EN / DIS signal.

[0012] According to this configuration, in the charging / discharging system for an electric vehicle, when the auxiliary battery of the vehicle is connected to the connection cable, the control circuit is started by power supplied from the auxiliary battery via the connection cable, the limiting resistor, and the bypass circuit. Then, after the load starting current has stabilized, the control circuit turns on the switch using a switch drive signal to short-circuit both ends of the limiting resistor. This eliminates the voltage drop due to the limiting resistor in the power supply path from the auxiliary battery to the power supply circuit. Then, the control circuit controls the load starting current limitAfter the power supplied from the circuit to the power supply circuit has stabilized, the power supply circuit is started by the EN / DIS signal. This allows the power supply circuit to start up normally. Therefore, in an emergency such as a power outage, the power supply circuit can be reliably started up using the vehicle's auxiliary battery.

[0013] In the above aspect, the control circuit may turn on the switch using the switch drive signal after a predetermined time has elapsed since startup, and may start up the power supply circuit using the EN / DIS signal after a second predetermined time has elapsed since turning on the switch.

[0014] This allows the control circuit to reliably turn on the switch at the desired timing, and also allows the power supply circuit to reliably turn on at the desired timing.

[0015] In the above aspect, a backflow prevention diode may be provided in a power supply path from the power supply circuit to the control circuit, with the forward direction being from the power supply circuit to the control circuit.

[0016] This makes it possible to prevent a reverse flow of power from the control circuit to the power supply circuit. [Effects of the Invention]

[0017] According to the present invention, in an electric vehicle charging / discharging system, in an emergency such as a power outage, the power supply circuit can be reliably started up using the vehicle's auxiliary battery. [Brief explanation of the drawings]

[0018] [Figure 1] System configuration example of EVPS according to the embodiment [Figure 2] A time chart showing an example of the operation of the comparative example [Figure 3] 1 is a time chart showing an example of an operation of an embodiment; [Figure 4] Circuit configuration extracted from the guidelines DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its scope of application, or its uses.

[0020] (Embodiment) FIG. 1 shows an example of the configuration of an EVPS (Electric Vehicle Power System), which is an example of a charging / discharging system for an electric vehicle according to an embodiment. As described above, an EVPS is a system that charges and / or discharges power using direct current (DC) power or alternating current (AC) power between a vehicle (such as an electric vehicle, plug-in hybrid vehicle, or fuel cell vehicle) that has an onboard battery and / or generator for driving and a home power distribution system, which is a general-purpose electrical facility. Note that FIG. 1 shows only the configuration according to the embodiment, and does not show other configurations.

[0021] <Configuration> 1, auxiliary battery 1 is mounted on a vehicle and supplies power to auxiliary devices provided in the vehicle. Auxiliary battery 1 is connected to EVPS 100 via connection cable 2 only during autonomous operation in emergencies such as power outages. Connection cable 2 uses, for example, an EVPS power terminal line that is input from the on-board cigarette lighter socket and a 12V charge / discharge connector line.

[0022] In the EVPS 100, the sneak current prevention circuit 3 is a circuit for preventing a reverse flow of power to the auxiliary battery 1, and is realized by, for example, a diode.

[0023] The load starting current limiting circuit 20 includes a limiting resistor 4 and a switch 5. The limiting resistor 4 is provided to suppress excessive load starting current. The switch 5 switches between on and off states in accordance with a switch drive signal S1; when on (closed state), it shorts both ends of the limiting resistor 4, and when off (open state), it does not short both ends of the limiting resistor 4. The switch 5 is configured by, for example, a semiconductor relay or a mechanical relay. The output of the load starting current limiting circuit 20 is supplied to the EVPS power supply circuit 6 as the EVPS power supply input Vb.

[0024] The EVPS power supply circuit 6 generates an EVPS power output Vc from an EVPS power input Vb. The power supply voltage is, for example, 12 V. The EVPS power supply circuit 6 is configured, for example, by connecting a step-up converter and a step-down converter in series. Alternatively, it may be configured using a step-up / step-down converter. The EVPS power output Vc is supplied to a load 7. The EVPS power supply circuit 6 is also configured to be controllable so that it receives an EN / DIS signal S2 and operates when the EN / DIS signal S2 is on (EN) and does not operate when the EN / DIS signal S2 is off (DIS).

[0025] The microcomputer power supply circuit 9 is a circuit that generates a microcomputer power output Ve from a microcomputer power input Vd. The microcomputer power output Ve is, for example, 5 V and is supplied to the microcomputer 10. The microcomputer power supply circuit 9 is configured, for example, by a step-down converter. Alternatively, it may be configured by a linear regulator, or by a resistor and a Zener diode.

[0026] The bypass circuit 11 is a circuit for bypassing the EVPS power supply input Vb, which is the output of the load starting current limiting circuit 20, to the microcomputer power supply circuit 9 as the microcomputer power supply input Vd.

[0027] The microcomputer 10 operates by receiving the microcomputer power output Ve and controls the functions of the EVPS 100. The microcomputer 10 generates and outputs a switch drive signal S1 for controlling the switching of the switch 5. The microcomputer 10 also generates and outputs an EN / DIS signal S2 for controlling the operation / stop of the EVPS power supply circuit 6. The microcomputer power supply circuit 9 and the microcomputer 10 are an example of a control circuit in the present disclosure.

[0028] Additionally, backflow prevention diode 8 is provided in the power supply path from EVPS power supply circuit 6 to microcomputer power supply circuit 9, with the forward direction being from EVPS power supply circuit 6 to microcomputer power supply circuit 9. Backflow prevention diode 8 prevents microcomputer power supply input Vd from flowing back into EVPS power supply circuit 6. Note that backflow prevention diode 8 may be omitted.

[0029] <Operation> First, the operation of a comparative example of this embodiment will be described. In this comparative example, the bypass circuit 11 is not provided in the configuration of Fig. 1, and the microcomputer 10 does not have the function of outputting the EN / DIS signal S2. Fig. 2 is a time chart showing an example of the operation of the comparative example.

[0030] When the vehicle's auxiliary battery 1 is connected to the EVPS 100, power from the auxiliary battery 1 is supplied to the EVPS power supply circuit 6 via the connection cable 2, the sneak current prevention circuit 3, and the limiting resistor 4. When the EVPS power supply circuit 6 is started, a current for charging the load 7 flows in the following path: auxiliary battery 1 → connection cable 2 → sneak current prevention circuit 3 → limiting resistor 4 → EVPS power supply circuit 6 → load 7.

[0031] However, the EVPS power input Vb supplied to the EVPS power supply circuit 6 falls below the auxiliary battery voltage Va due to voltage drops in the connection cable 2 and limiting resistor 4, and voltage drops due to the forward voltage of the diodes that make up the sneak current prevention circuit 3. For this reason, when the voltage of the auxiliary battery 1 is low, it may not be possible to extract sufficient power, and the EVPS power supply circuit 6 may not be able to start.

[0032] That is, as shown in FIG. 2, when the vehicle's auxiliary battery 1 is connected to the EVPS 100, the load start current Ia increases rapidly and then gradually decreases (1). When the EVPS power input Vb increases and exceeds the operable voltage, the EVPS power supply circuit 6 starts. Then, the load start current Ia increases rapidly again (2). As the load start current increases rapidly, the voltage drop across the limiting resistor 4 also increases rapidly. When the EVPS power input Vb decreases and falls below the operable voltage, the EVPS power supply circuit 6 stops (3). With the EVPS power supply circuit 6 stopped, the load start current Ia decreases. As a result, the EVPS power supply input Vb increases again (4). Thereafter, the operations of (2) to (4) are repeated. That is, the EVPS power supply circuit 6 repeats the cycle of start → stop → restart → stop → restart → stop, and is unable to start normally.

[0033] Next, the operation of the embodiment will be described with reference to Fig. 3, which is a time chart showing an example of the operation of the embodiment.

[0034] When the vehicle's auxiliary battery 1 is connected to the EVPS 100, the load starting current Ia increases sharply and then gradually decreases (1). Power is supplied from the auxiliary battery 1 to the microcomputer power supply circuit 9 via the connection cable 2, sneak current prevention circuit 3, limiting resistor 4, and bypass circuit 11. When the microcomputer power input Vd exceeds the operating voltage, the microcomputer 10 starts up (2). Note that the operating voltage of the microcomputer 10 is lower than the operating voltage of the EVPS power supply circuit 6. The backflow prevention diode 8 also functions as a backflow prevention element for the EVPS power supply circuit 6. At this time, power is also supplied to the EVPS power supply circuit 6 from the auxiliary battery 1 via the connection cable 2, sneak current prevention circuit 3, and limiting resistor 4. However, because the microcomputer 10 sets the EN / DIS signal S2 to DIS (off), the EVPS power supply circuit 6 does not start up.

[0035] The microcomputer 10 turns on the switch drive signal S1 at a predetermined timing after the load startup current Ia has stabilized (3), which turns on the switch 5 (closed state) and shorts both ends of the limiting resistor 4. As a result, the voltage drop caused by the limiting resistor 4 in the power supply path from the auxiliary battery 1 to the EVPS power supply circuit 6 is eliminated, and the EVPS power input Vb increases.

[0036] At a predetermined timing after the EVPS power input Vb has stabilized, the microcomputer 10 sets the EN / DIS signal S2 to EN (ON) (4). This starts the EVPS power supply circuit 6. When the EVPS power supply circuit 6 starts, the load starting current Ia increases, and although the EVPS power input Vb drops slightly, it is still able to maintain a voltage above the operating voltage. This allows the EVPS power supply circuit 6 to start normally. After that, the EVPS power output Vc stabilizes (5).

[0037] As described above, in this embodiment, when the auxiliary battery 1 of the vehicle is connected to the connection cable 2 in the EVPS 100, the microcomputer 10 is started by power supplied from the auxiliary battery 1 via the connection cable 2, the limiting resistor 3, and the bypass circuit 11. After the load starting current has stabilized, the microcomputer 10 turns on the switch 5 using the switch drive signal S1 to short-circuit both ends of the limiting resistor 4. This eliminates the voltage drop caused by the limiting resistor 4 in the power supply path from the auxiliary battery 1 to the EVPS power supply circuit 6. The microcomputer 10 then determines whether the load starting current is stable. limit After the power supplied from circuit 20 to EVPS power supply circuit 6 has stabilized, EN / DIS signal S2 starts EVPS power supply circuit 6. This allows EVPS power supply circuit 6 to start normally. Therefore, in an emergency such as a power outage, even if the power supply voltage of auxiliary battery 1 is low due to deterioration or variations in the vehicle's auxiliary battery 1, EVPS power supply circuit 6 can be reliably started using the vehicle's auxiliary battery 1.

[0038] In this embodiment, the microcomputer 10 sets the timing for turning on the switch drive signal S1 by counting a predetermined time using a timer from the time of startup. That is, the microcomputer 10 turns on the switch 5 using the switch drive signal S1 after the predetermined time has elapsed since startup. However, instead of this, for example, a means for monitoring the load startup current Ia may be provided, and the switch drive signal S1 may be turned on based on the monitoring results.

[0039] Furthermore, the microcomputer 10 sets the timing for turning on the EN / DIS signal S2 by using a timer to count a predetermined time after turning on the switch drive signal S1. That is, the microcomputer 10 starts the EVPS power supply circuit 6 with the EN / DIS signal S2 after the predetermined time has elapsed since turning on the switch drive signal S1. However, instead of this, for example, a means for monitoring the EVPS power supply input Vb may be provided and the EN / DIS signal S2 may be turned on based on the monitoring results. [Industrial Applicability]

[0040] The present invention is useful for reliably starting up a charging / discharging system for an electric vehicle in an emergency such as a power outage. [Explanation of symbols]

[0041] 1. Vehicle auxiliary battery 2 Connection cables 4 limiting resistors 5 Switch 6 EVPS power circuit 8. Reverse current prevention diode 9 Microcomputer power supply circuit 10 Microcomputer 11 Bypass circuit 20 Load starting current limit circuit 100 EVPS (Electric Vehicle Charging and Discharging System)

Claims

1. A charging and discharging system for an electric vehicle, a connection cable for connecting an auxiliary battery of the vehicle; a power supply circuit configured to be able to control start / stop in accordance with an EN / DIS signal; a load startup current limiting circuit provided in a power supply path from the connection cable to the power supply circuit, the load startup current limiting circuit including: a limiting resistor; and a switch connected in parallel to the limiting resistor, configured to be switchable on and off in accordance with a switch drive signal, the switch shorting both ends of the limiting resistor when on, and not shorting both ends of the limiting resistor when off; a control circuit that outputs the EN / DIS signal and the switch drive signal; a bypass circuit for bypassing the power supplied from the load startup current limiting circuit to the power supply circuit to the control circuit, Before the auxiliary battery is connected to the connection cable, the power supply circuit is stopped and the switch is off; When the auxiliary battery is connected to the connection cable, the control circuit The vehicle is started by power supplied from the auxiliary battery via the connection cable, the limiting resistor, and the bypass circuit, After the load starting current is stabilized, the switch is turned on by the switch driving signal to short-circuit both ends of the limiting resistor; After the power supplied from the load startup current limiting circuit to the power supply circuit has stabilized, the power supply circuit is started up by the EN / DIS signal. Charging and discharging system for electric vehicles.

2. 2. The charging / discharging system for an electric vehicle according to claim 1, The control circuit After a predetermined time has elapsed since activation, the switch is turned on by the switch drive signal; After a second predetermined time has elapsed since the switch was turned on, the power supply circuit is started up by the EN / DIS signal. Charging and discharging system for electric vehicles.

3. 3. The charging / discharging system for an electric vehicle according to claim 1, a backflow prevention diode provided in a power supply path from the power supply circuit to the control circuit, the forward direction of which is from the power supply circuit to the control circuit; Charging and discharging system for electric vehicles.

Images