JPH0951604A - Power supplying device of electric car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lock out of an inverter even when a short-circuit occurs across a load. SOLUTION: A device has an inverter 1 which converts DC to AC, a contactor 2 connected to the inverter 1, breakers for distribution 41, 42, and 43 which are connected to the contactor 2, loads which are connected to the breakers for distribution, and a controller 6 which, being connected to the inverter 1, controls the contactor 2 on a start-up output signal from the inverter 1. Due to this structure, the contactor 2 can be kept continuously turned on when the inverter 1 is re-started after an overcurrent protective circuit is started because a short occurs across a load. When the inverter 1 is re-started, only the breaker for distribution related to the short trouble performs a cut-off operation and therefore the start-up operation is continued and there is no stoppage of the entire system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a power supply device for an electric vehicle that supplies an inverter output to a load.

[0002]

2. Description of the Related Art A conventional electric vehicle power supply apparatus is constructed as shown in FIG. That is, the output of the inverter 1 is supplied to the contactor 2 and an AC low voltage detector (ACLVD) 3 which is an AC voltage detector. The output power from the inverter 1 supplied to the contactor 2 is supplied to the load 5 via the wiring breaker 4. The inverter 1 has a conduction ratio (a) and an output voltage (b) after the startup, which is referred to as a soft start, and has a gradual characteristic that gradually rises with time as shown in FIG.

On the other hand, the AC low voltage detector 3 is an inverter 1
The output voltage (b) after the start-up is detected, and it is detected that the specified voltage value (V) indicating that the operation is established is reached (time T1), and the closing signal is supplied to the contactor 2. When the contactor 2 receiving the closing signal enters the closing operation (time T2), the inverter 1 is connected to the load 5 via the circuit breaker 4 for wiring. The output current (c) as shown is supplied.

Therefore, if the load 5 has a short-circuit fault or a ground fault at the time of turning on the contactor 2 (T2), as shown in FIG. 5, a short-circuit load commensurate with the conduction ratio (a). An electric current (2) flows. When the value of the short-circuit load current (d) exceeds the overcurrent setting level (I), an overcurrent protection circuit (not shown) is activated and the inverter 1 is controlled to be in an operation stop state. The circuit breaker 4 for wiring has an overcurrent fuse. When a current exceeding a rated value flows for a certain period of time, the fuse is blown and the breaking operation is activated.

In any case, the AC low voltage detector (ACLVD) 3 is operated until the inverter 1 is once stopped and then restarted until the output voltage reaches the specified voltage value (V).
Does not derive the closing signal, the output of the inverter 1 is not supplied to the circuit breaker 4 for wiring and the load 5.

[0006]

As described above, in the power supply device for an electric vehicle, the overcurrent protection circuit operates and the inverter 1 stops operating when a short-circuit failure occurs in the load 5. However, in the conventional device, when the inverter 1 is restarted, the AC low voltage detector 3 detects that the inverter output has reached the specified voltage value (V), and supplies the closing operation signal to the contactor 2. The output of the inverter 1 is connected to the load 5 having the short-circuit fault, the overcurrent protection circuit operates again, and the inverter 1 is stopped again.

As described above, although the inverter 1 itself has not failed, once a short-circuit current flows due to a short-circuit failure of the load 5 or the like, normal operation cannot be performed thereafter, and lockout (rockout) is performed. out). In particular, in a system configuration in which the inverter 1 supplies electric power to a plurality of parallel-connected loads, a short-circuit accident in one load immediately causes a normal electric power supply to another load, which leads to an inoperability of the entire vehicle system. Therefore, improvement was requested.

[0008]

SUMMARY OF THE INVENTION A power supply device for an electric vehicle according to the present invention solves the above-mentioned problems of the prior art. An inverter for converting direct current into alternating current, a contactor connected to the inverter, and A circuit breaker connected to the contactor, a load connected to the circuit breaker, and a controller for introducing an output signal from the inverter and supplying a closing operation control signal for the contactor during operation of the inverter. And is provided.

As described above, in the electric vehicle power supply device according to the present invention, the controller is newly provided, and the controller introduces the output signal from the inverter and supplies it to the contactor.
The contactor can be kept on even when the inverter is restarting. Therefore, if a short-circuit accident occurs and the inverter restarts, the contactor will remain in the closed state, so the inverter output current will be a fault current commensurate with the current flow rate with the short-circuit fault load connected. Supplied to the load.

When the inverter is started, it gradually rises at a low conduction ratio. Therefore, since the fault current (c) also rises with a slope corresponding to it, the breaking operation of the wiring breaker corresponding to the short-circuit load operates before the overcurrent detection value (I) is reached,
The inverter is cut off from the short-circuit load, and the normal starting operation can be continued.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a power supply device for an electric vehicle according to the present invention will be described in detail below with reference to the drawings. The same components as those of the conventional electric vehicle power supply device are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a circuit diagram showing an embodiment of a power supply device for an electric vehicle according to the present invention. That is, a power supply device for an electric vehicle according to an embodiment includes an inverter 1 for converting direct current into alternating current, a contactor 2 connected to the inverter, and a plurality of wiring breakers connected to the contactor 2. 41, 42, 43 and the circuit breakers 41, 4 for these wirings
Loads 51, 52, 5 connected to 2, 43 respectively
3, an AC voltage detector connected to the inverter 1, that is, an AC low voltage detector (ACLVD) 3, an output from the AC low voltage detector 3 connected to the AC low voltage detector 3 and the inverter 1. A controller 6 which introduces a signal and an output signal from the inverter 1 and supplies a control signal derived by an OR operation to the contactor 2.

The controller 6 is composed of an OR circuit, which introduces the output signal from the AC low voltage detector 4 and the output signal from the inverter 1 and performs a logical OR operation to introduce either one of the signals. If so, the control signal is derived so as to turn on (ON) the contactor 2.

Therefore, in the electric vehicle power supply device having the configuration shown in FIG. 1, if the load 51 is short-circuited and an abnormal short-circuit current due to the accident is indicated by a dotted line (e),
If the load is supplied from the inverter 1 to the load 51 via the contactor 2 and the circuit breaker 51 for wiring, an unillustrated overcurrent protection circuit is activated and the inverter 1 is controlled to stop as in the conventional case. Therefore, the inverter 1 is temporarily stopped and the contactor 2 is also turned off. afterwards,
The inverter 1 is restarted and its output signal is supplied to the controller 6 composed of an OR circuit, but one AC low voltage detector (ACLVD) 3 output is not derived before the specified voltage value (V) is reached, Since the activation output signal from the inverter 1 is supplied to the controller 6, the contactor 2 is switched to the ON state by the output signal of the controller 6.

Therefore, the output current of the inverter 1 at the time of restart is supplied to the loads 51, 52, 53 in the state where the load 51 having the short-circuit fault is connected and the fault current corresponding to the current flow rate at that time is supplied. By the way, as shown in FIG. 2, since the conduction ratio at the time of starting the inverter gradually rises at a low level, the short-circuit load current (d) also rises with a slope corresponding to it. At this time, the amount of current flowing through the short circuit load 51 blows off the built-in fuse of the corresponding circuit breaker 41 to cut off the circuit. Therefore, before the output current of the inverter 1 reaches the overcurrent detection value (I), It is cut off from the short-circuit load 51.

That is, FIG. 2 shows that the duty factor (a), output voltage (b) and output current (c, d) when the inverter 1 is restarted.
The characteristics of Now, the inverter 1 starts restarting with the short-circuit load 51 connected, and the inverter 1 derives a short-circuit load current (d) commensurate with the conduction ratio (a) under the short-circuit load 51 connection condition. The short-circuit load current (d) is a trigger for starting the breaking operation of the circuit breaker 41 for the wiring, and the time T
After the progress of 3, the built-in fuse is blown. The elapsed time from the start-up of the inverter 1 to the time T3 is before the elapsed time until the overcurrent protection circuit (not shown) detects the overcurrent detection value (I) (time T4), and the disconnection for wiring is performed at the time T3. Vessel 41 trips.

Therefore, after the time T3, the faulty load 51 is cut off, and the restarting operation of the inverter 1 is changed with only the other normal loads 52 and 53 connected, and the characteristic curve of the output current (c) is shown. Enter rated operation along the line.

As described above, in the power supply device for an electric vehicle of the present invention, when one of the loads causes a short circuit accident or a ground fault and the inverter is restarted by the overcurrent protection circuit, the wiring of the defective load is generated. Since only the circuit breaker operates and other circuits continue to operate smoothly, lockout and system down of the inverter are avoided.

[0019]

The present invention provides a power supply device for an electric vehicle in which the inverter does not fall into lockout even if the overcurrent protection circuit operates, and a remarkable effect can be obtained in practical use. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a power supply device for an electric vehicle according to the present invention.

FIG. 2 is a characteristic curve diagram showing inverter operating characteristics of the electric vehicle power supply device shown in FIG.

FIG. 3 is a block diagram showing a conventional electric vehicle power supply device.

FIG. 4 is a characteristic curve diagram showing inverter operating characteristics when the electric vehicle power supply device shown in FIG. 3 operates normally.

5 is a characteristic curve diagram showing inverter operating characteristics when the power supply device for the electric vehicle shown in FIG. 3 has a load short-circuit accident.

[Explanation of symbols]

 1 Inverter 2 Load contactor 3 AC low voltage detector 4, 41, 42, 43 Wiring circuit breaker 5, 51, 52, 53 Load 6 Controller

Claims (3)

[Claims] 1. An inverter for converting direct current into alternating current, a contactor connected to the inverter, a circuit breaker connected to the contactor, a load connected to the circuit breaker, and A controller for introducing an output signal from an inverter and supplying a closing operation control signal for the contactor during the operation of the inverter. 2. The power supply device for an electric vehicle according to claim 1, wherein a plurality of the circuit breakers for wiring and loads corresponding to the circuit breakers for wiring are connected to the contactors. . 3. The closing operation when the controller comprises an OR circuit and outputs at least one of an output signal from the inverter and a specified output signal from an AC voltage detector connected to the inverter. The power supply device for an electric vehicle according to claim 2, wherein the contactor is controlled so as to operate.