JPH09284902A - Short circuit detection circuit for electric vehicles - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To reliably detect the occurrence of a short circuit even when the output current of a main battery is reduced. A motor 10 for running a vehicle, a main battery 1 that supplies a current to the motor 10, and a controller 9 that controls the amount of current supplied from the main battery 1 to the motor 10 in accordance with the amount of accelerator depression. A first fuse 2 for detecting a short circuit, which is installed in an electric vehicle equipped with and is connected between a main battery 1 and a motor 10.
Having. In addition, the second fuse 4 having a smaller rated value than the first fuse 2 for detecting a short circuit is connected in parallel, and when the accelerator is depressed, the main battery 1 and the motor 10 are connected. The first fuse 2 is selectively connected between them, and when the accelerator is not depressed, the second fuse is connected between the main battery 1 and the motor 10.
The relay 14 and the relay contacts 3 and 5 for selectively connecting the fuse 4 of FIG.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short circuit detection circuit for an electric vehicle, and more particularly to a short circuit detection circuit for a main battery which is a power source of the electric vehicle.

[0002]

2. Description of the Related Art FIG. 3 is a schematic diagram of a conventional general electric vehicle. The battery box 50 is installed outdoors because the plurality of batteries mounted inside have a high voltage. Further, a motor 70 that supplies power from the battery box 50 to rotate the wheels and a controller 60 that controls the rotation of the motor 70 are provided in the front hood.

FIG. 4 is a block diagram of the inside of the battery box 50. Inside the battery box 50, a plurality of batteries are connected in series between the positive and negative connectors 53, 53 to form a main battery 51. Here, reference numeral 5
Reference numeral 2 indicates a connection cable. In addition, the positive and negative connectors 5
A main fuse 54 is connected between 3 and 53. The main fuse 54 is provided especially on the positive electrode side.

FIG. 5 is a block diagram of a drive control system including a battery box 50, a controller 60, and a motor 70. The controller 60 provided between the battery box 50 and the motor 70 is provided with an accelerator 61 that inputs an accelerator signal corresponding to the amount of accelerator depression to the controller 60. Controller 60
Is the main battery 5 depending on the input accelerator signal.
The amount of current flowing from 1 to the motor 70 is controlled. here,
Reference numeral 62 indicates an ignition switch that sets the drive control system to an operating state.

The main fuse 54 is a controller 60.
It is also provided for circuit protection when an overcurrent or short circuit occurs in the motor 70. If a short circuit occurs when the capacity of the main battery 51 is full, a short-circuit current flows to the drive control system infinitely, and the main fuse 54 is blown.

[0006]

However, in the above-mentioned conventional example, since the current value at the time of short circuit decreases when the main battery 51 reaches the end of discharge, the main fuse 54
The rated current of may not be reached. Even in such a case, the main battery 51 is an assembled battery and therefore has a high voltage, but the occurrence of a short circuit cannot be detected.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a short-circuit detection circuit for an electric vehicle, which is capable of remedying the disadvantages of the prior art and, more particularly, capable of reliably detecting the occurrence of a short-circuit even when the output current of the main battery is reduced. , And its purpose.

[0008]

In order to achieve the above object, the invention according to claim 1 provides a motor for driving a vehicle, a main battery for supplying a current to the motor, and a main battery for supplying the motor to the motor. The electric vehicle is equipped with a controller that controls the amount of current flowing according to the amount of depression of the accelerator, and has a first fuse for detecting a short circuit connected between the main battery and the motor. Also, a second fuse having a smaller rated value than the first fuse for short circuit detection is connected in parallel to the first fuse for short circuit detection, and when the accelerator is depressed, the first fuse is connected between the main battery and the motor. Selectively connect fuses,
When the accelerator is not depressed, a relay and a relay contact for selectively connecting the second fuse are provided between the main battery and the motor.

According to the present invention, even when the main battery is in the final stage of discharge and the current flowing when a short circuit occurs does not reach the point where the first fuse is blown out, the accelerator is not depressed and the main battery and the motor have the second fuse. If it is in a state of being connected through, the fuse small 4 is blown by the current at the time of short circuit.

According to a second aspect of the present invention, there is provided a short circuit detection circuit for an electric vehicle according to the first aspect, wherein a contact for cutting off the power source for operating the controller is provided together with the melting of the second fuse.

According to the present invention, when the second fuse is blown, the power supply for operation of the controller is cut off, the accelerator is then depressed, and even if the first fuse is connected between the main battery and the motor, the main fuse is connected. No current is supplied to the motor from the battery.

[0012] With these, the above-mentioned object is to be achieved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
It will be described with reference to FIG.

FIG. 1 is a block circuit diagram of a drive control system including an embodiment of the present invention. In FIG. 1, the output of the main battery 1 is connected to a motor 10 via a controller 9. Between the positive electrode of the main battery 1 and the controller 9, a large fuse 2 and a relay contact 3 are provided.
(RYA) is connected in series, and in parallel with these, the fuse small 4 and the relay contact 5 (RYA) are connected in series.

Reference numeral 12 indicates a battery for operating the controller 9 and the accelerator 8. At the output stage of the battery 12, a short warning lamp 18, a relay 15 (RY
B) and the relay 14 (RYA) are connected in parallel. Also, the battery 12 and the short-circuit warning lamp 1
8, the relay contact 17 (RYB) is connected to the battery 1
A limit switch 6 is provided between the battery 2 and the relay 15 (RYB), and a relay contact 16 (RYB), an ignition switch 13, and a switching transistor 21 are provided between the battery 12 and the relay 14 (RYA). There is.

Here, relay contacts 3 and 5 (RYA), small fuse 4, relay contact 5 (RYA), limit switch 6, relay 14 (RYA), relay 15 (RYB),
The relay contacts 16 and 17 (RYB) and the short-circuit warning lamp 18 form a short-circuit detection circuit 19 for the main battery 1.

More specifically, in this embodiment, the main battery 1 is configured as an assembled battery of a plurality of batteries as in the conventional example. The large fuse 2 has a predetermined rated value corresponding to that of the main fuse 54 of the conventional example. On the other hand, the small fuse 4 is set to a relatively smaller rated value than the large fuse. Each fuse 2, 4
In determining the rated value of, the large fuse 2 is set to a rated value larger than the maximum current amount supplied to the motor 10 in a normal running state, and the small fuse 4 is supplied to the motor 10 in a normal running state. It is preferable to set a rated value smaller than the maximum current amount.

The relay contacts 3 and 5 are respectively the relay 14
It is opened and closed by (RYA). In particular, relay 14 (RY
At the time of energization of A), the relay contact 3 is short-circuited and the relay contact 5 is opened. Conversely, while the relay 14 (RYA) is not energized, the relay contact 3 is opened and the relay contact 5 is short-circuited. It is supposed to be done. The small fuse 4 and the limit switch 6 function as a conventional general warning fuse 7 that interacts with each other. Specifically, a spring is fixed around the fuse small 4 in a compressed state, and when the fuse small 4 is blown, one end of the spring extends and the limit switch 6
Is designed to be short-circuited.

The accelerator 8 inputs an accelerator signal corresponding to the accelerator depression amount to the controller 9. Further, the accelerator 8 turns on the switching transistor 21 when the accelerator is depressed and turns off the switching transistor 21 when the accelerator is not depressed. The operation power supply terminal of the accelerator 8 is connected to the negative electrode side of the battery 12 with respect to the ignition switch 13 and the relay contact 16. The controller 9 controls the amount of current flowing from the main battery 1 to the motor 10 according to the accelerator signal input from the accelerator 8. This controller 9
The power supply terminal for operation is connected to the negative side of the battery 12 with respect to the ignition switch 13 and the relay contact 16. The motor 10 is a running motor for an electric vehicle. The battery 12 is, for example, a DC power source of 12V.
The ignition switch 13 turns on / off the controller 9, the accelerator 8, and the relay 14 (RYA).

The relay 14 controls opening / closing of the relay contacts 3 and 5. This relay 14 is an ignition switch 1
When the switching transistor 21 is turned on in the state where the switch 3 and the relay contact 16 (RYB) are connected, the conduction is released, and when the switching transistor 21 is turned off, the conduction state is released. Relay 1
5 (RYB) controls opening / closing of the relay contacts 16 and 17. This relay 15 (RYB) is a limit switch 6
The connection is energized and is not energized while the limit switch 6 is open. Relay contacts 16 and 17 (RY
B) is controlled to be opened / closed by a relay 15 (RYB).
When the relay 15 (RYB) is not energized, the relay contact 16 is connected and the relay contact 17 is opened. On the contrary, when the relay 15 (RYB) is conducted, the relay contact 16 is opened and the relay contact 17 is connected. It is supposed to be done. The short warning lamp 18 is provided in the driver's seat.

Next, the overall operation of the above embodiment will be described with reference to FIG.

When the ignition switch 13 is off,
The relay 14 (RYA) is not energized, the relay contact 3 is open, and the relay contact 5 is in the connected state (step S1,
S2, S4). That is, the main battery 1 and the motor 10 are connected via the small fuse 4. Here, when a short circuit occurs in the main battery 1, the small fuse 4 is blown and the limit switch 6 is connected (step S
2) Since the relay 15 (RYB) is energized, the relay contact 16 is opened and the relay contact 17 is in the connected state,
The short-circuit warning lamp 18 is turned on, and thereafter, even if the ignition switch 13 is connected, the controller 9 and the accelerator 8 are not conducted, and the vehicle cannot run (step S3).

When the ignition switch 13 is turned on in the normal state (step S4), the initial state is maintained until the accelerator is depressed (steps S5, S).
1, S2, S4). Here, when the main battery 1 is short-circuited and the small fuse 4 is blown (step S2), the short-circuit warning lamp 18 is turned on and the vehicle becomes inoperable (step S3), as described above.

When the accelerator is depressed in the normal state (step S5), an accelerator signal corresponding to the amount of depression is input from the accelerator 8 to the controller 9 and a predetermined voltage is applied to the base terminal of the switching transistor 21 to cause the relay 14 to operate. (RYA) is energized. As a result, the relay contact 3 is connected and the relay contact 5 is opened (step S6). That is, the main battery 1 and the motor 1
0 is in a state of being connected via the large fuse 2.

Further, the controller 9 is the accelerator 8
Main battery 1 according to the accelerator signal input from
Supplies a predetermined amount of current to the motor 10 to rotate the motor 10 to drive the vehicle. This state is maintained by continuing to depress the accelerator (steps S7 and S9). Here, when the main battery 1 is short-circuited and the large fuse 2 is blown (step S7), no electric current is supplied from the main battery 1 to the motor 10 and the vehicle cannot run (step S8). The normal driver is
Stopping the vehicle as you notice that you are no longer able to drive.

On the other hand, when the accelerator pedal is no longer depressed during normal running (step S9), the accelerator 8 turns off the switching transistor 21.
The relay 14 (RYA) is de-energized, the relay contact 3 is opened, the relay contact 5 is connected, and the initial state is restored (step S1).

In the above operation, the main battery 1 is in the final stage of discharge, and the current flowing when a short circuit occurs causes the fuse to be large.
Even if it does not reach the point where it melts, the relay contact 5 (R
YA) is closed and the main battery 1 and the motor 10 are connected via the small fuse 4, the small fuse 4 is blown by the short-circuit current, and the vehicle cannot run (steps S2 and S3). ), The occurrence of a short circuit can be reliably detected even at the end of discharge of the main battery 1.

Further, since the operation power supply Vcc of the controller 9 is cut by the blow of the small fuse 4, even if the accelerator is subsequently depressed and the large fuse 2 is connected between the main battery 1 and the motor 10, No current is supplied from the main battery 1 to the motor 10, and it is possible to reliably prevent the vehicle from traveling in a short-circuited state.

In addition to this, since the short-circuit warning lamp 18 is turned on only when the fuse 4 is blown, it is possible to easily determine which fuse has been blown, and quick and appropriate maintenance can be performed. .

Here, the specific circuit configuration for realizing the present invention does not have to be the circuit configuration of this embodiment.

[0031]

Since the present invention is constructed and functions as described above, even when the main battery is in the final stage of discharge and the current flowing at the time of occurrence of a short circuit does not blow the first fuse. If the main battery and the motor are connected via the second fuse, the second fuse is melted by the short-circuit current, and the vehicle cannot run. Therefore, even in the final stage of discharging the main battery, It is possible to reliably detect the occurrence of a short circuit.

According to the second aspect of the present invention, since the power supply for operating the controller is cut off by blowing the second fuse, the accelerator is stepped on after that and the first fuse is connected between the main battery and the motor. However, the electric current is not supplied from the main battery to the motor, and it is possible to reliably prevent the vehicle from traveling in the short-circuited state.
It is possible to provide an unprecedented excellent short circuit detection circuit for an electric vehicle.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an overall operation of the embodiment shown in FIG. 1;

FIG. 3 is a schematic configuration diagram showing a drive system mounted on an electric vehicle.

FIG. 4 is a configuration diagram showing internal connection of a battery box.

FIG. 5 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 1 Main Battery 2 Fuse Large (First Fuse) 3,5 Relay Contact 4 Fuse Small (Second Fuse) 9 Controller 10 Motor 12 Battery 14 Relay 16 Relay Contact (Contact) 19 Short Circuit Detection Circuit Vcc Controller Operation Power Supply

Claims (2)

[Claims] 1. A motor for driving a vehicle, a main battery for supplying current to the motor, and a controller for controlling the amount of current supplied from the main battery to the motor according to the amount of depression of an accelerator. A short-circuit detection circuit for an electric vehicle, which is installed in an electric vehicle and has a first fuse for short-circuit detection connected between the main battery and the motor, wherein the first fuse for short-circuit detection is Also connects a second fuse having a small rated value in parallel, and selectively connects the first fuse between the main battery and the motor when the accelerator is stepped on. And the relay connection for selectively connecting the second fuse between the main battery and the motor when the switch is not depressed. A short-circuit detection circuit for an electric vehicle, which is provided with dots. 2. The short-circuit detection circuit for an electric vehicle according to claim 1, further comprising a contact for cutting off the power supply for operating the controller when the second fuse is blown.