JPH0787608A - High voltage circuit breaker for electric automobile - Google Patents

Abstract

PURPOSE:To provide a circuit for interrupting high voltage by blowing out a fuse in which a switching element is opened positively after the circuit is interrupted. CONSTITUTION:A power supply battery 4 is connected i series with a load 5, e.g. a running motor, and a fuse 1 and a relay circuit 8 are connected in series between them. The relay circuit 8 comprises a main relay contact 2a, a main relay exciting coil 2b, a subrelay 3a, a subrelay exciting coil 3b, driving transistors 2c, 3c, an OR circuit 2d, and an auxiliary battery 9 for driving relay. A control circuit 6 is driven by the auxiliary battery 9 to control the loads 5 and delivers a signal for feeding power thereto and a current detecting circuit 7a detects load current I thus detecting the operating state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle high voltage circuit breaker for breaking a high voltage circuit of an electric vehicle or the like.

[0002]

2. Description of the Related Art Conventionally, when an overcurrent continues to flow due to a failure of a control circuit of a traveling motor,
There is known a circuit for forcibly short-circuiting the fuse to blow the fuse to prevent the wire from being burned and the traveling motor from being damaged. FIG. 5 shows a motor drive device disclosed in Japanese Unexamined Patent Publication No. 2-114489. In the motor drive device having such a configuration, when an overcurrent flows in the main circuit due to an abnormality in the motor 3 or the like, the switching element 6 is turned on to cause a short-circuit current to flow in the fuse resistor 5, and the fuse resistor 5 is melted. The operating point of the semiconductor driver is controlled within its safe operating area.

[0003]

However, in the motor drive device as shown in FIG. 8, the switching element 6 is used.
The power source of the semiconductor driver element 1 that controls the DC power source 2
Therefore, after the overcurrent is detected and the fuse resistor 5 is blown, the semiconductor driver element 1 does not work and cannot be controlled.

The present invention has been made in view of the above problems. As a first invention, the state of a main circuit including a load is detected by an operating state detecting means provided with an auxiliary power source different from the main power source,
When the operating condition of the main circuit or load is above the first set value, close the sub relay to blow the fuse, and then detect that the main circuit or load state is below the first set value and turn on the sub relay. A second aspect of the present invention provides a high-voltage circuit breaker for an electric vehicle to be opened, which comprises, as a second invention, first and second control means having an auxiliary power source and supplying electric power to the load while the load is being driven. Detecting the state of the main circuit including, the power supply to the load when the operating state of the main circuit or the load is in a state of the second set value smaller than the first set value, further the first set value or more. When it is in the state, the sub-relay is closed and the fuse is blown, and then it is detected that the state of the main circuit or the load becomes less than the first set value and that the signals from the first and second control means disappear. Then main And its object is to provide an electric vehicle high voltage circuit interruption device to open the chromatography.

[0005]

According to a first aspect of the present invention, there is provided an electric vehicle high voltage circuit breaker configured to achieve the above object, wherein a main power source, a fuse, a first switching element and a load are connected in series. A main circuit in which a second switching element is connected in parallel so as to form a short circuit with respect to the main power supply and the fuse, bypassing one switching element and the load, and an auxiliary power supply different from the main power supply. Driven by the first control means for generating a drive signal while driving the load, and driven by the auxiliary power source, receiving a drive signal from the first control means, and driving the first switching element while driving the load. A second control means for applying a signal to the main circuit to close the main circuit to supply electric power to the load, and the auxiliary power source to detect the operating state of the main circuit or the load to operate. Operating state detecting means for generating an operating signal according to the state, and the second switching when driven by the auxiliary power source and receiving the operating signal of the operating state detecting means and the operating signal exceeds the first set value. And a third control means for supplying a signal to the element to short-circuit the main power source to blow the fuse to cut off the electric power supplied to the load.

The electric vehicle high voltage circuit breaker of the second aspect of the invention configured to achieve the above object is, in the first aspect of the invention, driven by the auxiliary power source and receiving an actuation signal of the actuation state detecting means, Fourth control means for applying a signal to the first switching element and closing the main circuit to continue supplying power to the load when the operation signal exceeds a second setting value smaller than the first setting value; It is characterized by having.

[0007]

According to the invention described in claim 1, while the load is being driven, the drive signal is sent from the first control means to the second control means, and the second control means closes the first switching element. By this, electric power is supplied to the load, and the load is driven. When the drive output of the load rises, the operating state detecting means issues an operating signal corresponding to the operating state of the main circuit or the load (for example, the current flowing through the main circuit, or the temperature or the rotation speed of the load). The third control means receives this operation signal, and the operation signal is equal to or higher than an arbitrary first set value (for example, overcurrent, overload).
Then, a signal is given to the second switching element to close it. As a result, the main power supply is short-circuited, the fuse is blown, and the power supplied to the load is cut off. When the fuse is blown and current does not flow in the main circuit and the operating state returns to less than the first set value, the third control means stops emitting a signal and the second switching means is opened. Then, after the drive signal is not issued from the first control means, the first switching element is opened. Since the first, second and third control means and the operating state detection means have the auxiliary power source different from the main power source, they can be driven even after the fuse is blown.

According to the second aspect of the present invention, while the load is being driven, the drive signal is sent from the first control means to the second control means, and the second control means closes the first switching element. By this, electric power is supplied to the load, and the load is driven. When the drive output of the load rises, an operating signal according to the operating state of the main circuit or the load is emitted from the operating state detecting means. The fourth control means sends a signal to the first switching element when the actuation signal reaches or exceeds an arbitrary second set value that is smaller than the first set value. In this state, the first switching element receives a signal from both the second control means and the fourth control means, and thereby power is supplied to the load. When the drive output of the load further rises and an actuation signal corresponding to the actuation state is issued, and the actuation signal exceeds an arbitrary first set value, the third control means gives a signal to the second switching element to close it. Let As a result, the main power supply is short-circuited, the fuse is blown, and the power supplied to the load is cut off. When the fuse is blown and current does not flow in the main circuit and the operating state returns to less than the first set value, the third control means does not emit a signal and the second switching means is opened. The first switching element is opened when the operating state returns below the first set value and the drive signal is no longer issued from the first control means. Further, since the fourth control means has the auxiliary power supply different from the main power supply, it can be driven even after the fuse is blown.

[0009]

According to the first aspect of the present invention, when the drive output of the load rises and the operating signal emitted from the operating state detecting means exceeds the arbitrary first set value, a signal is given to the second switching element. Let it close. As a result, the main power supply is short-circuited, the fuse is blown, and the power supplied to the load is cut off. When the fuse is blown and the current stops flowing in the main circuit and the operating state returns to less than the first set value, the third control means stops emitting a signal and the second switching means is opened. The first switching element is opened when the operating state returns below the first set value and the drive signal is no longer issued from the first control means. Since the first, second and third control means and the operating state detection means have the auxiliary power source different from the main power source, they can be driven even after the fuse is blown.

According to the second aspect of the present invention, during driving of the load, the first switching element receives a signal from both the second control means and the fourth control means, whereby electric power is supplied to the load. Therefore, by setting the second set value to a value such that the first switching element operates at a current value equal to or less than the breaking capacity thereof, in addition to the effect of the invention according to claim 1, the first switching element is inexpensive and compact. It can also be an element.

[0011]

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an electric vehicle high voltage circuit breaker according to a first embodiment of the present invention.
Schematically, a battery 4 as a power source and a load 5 such as a traveling motor are connected in series, and a fuse 1 and a relay circuit 8 are connected in series between them. Here, in this embodiment, the relay circuit 8 is composed of the third and fourth control means and the first and second switching elements described in claim 1. A control circuit 6 including first and second control means for controlling the load 5, a current detection circuit 7a for detecting an operating state by detecting the load current I, and an auxiliary battery 9 for driving the relay in the relay circuit 8 Is configured as shown in the figure. Further, the relay circuit 8 includes a main relay contact 2a, a main relay exciting coil 2b,
The sub relay 3a, the sub relay exciting coil 3b, the driving transistors 2c and 3c, and the OR circuit 2d are included. The relay contacts 2a and 3a are closed by exciting the exciting coils 2b and 3b. The main relay exciting coil 2b is excited by the signal A from the control circuit 6 and the signal B from the current detecting circuit 7a, and the sub relay exciting coil 3b is excited by the signal C from the current detecting circuit 7a. First, the transistor 2c is driven by the Hi level signal of the signal A to close the contact 2a, and then the load 5 is controlled by the control circuit 6 and the load current I flows. The signal A is maintained at the Hi level while the load current I is flowing, and becomes the Lo level when the load current I becomes 0, and becomes the contact 2a.
Are separated. FIG. 4 shows the relationship between the load current I and the signals A, B, and C. As shown in FIG. 4, when the load current increases and reaches the value of the second set value I1, the signal B becomes Hi level and is supplied to the OR circuit 2d of the relay circuit 8. The value of I1 is set to such a value that, even if the relay contact 2a interrupts the current value I1 for some reason, no injury is caused by a contact arc or the like. Further, when the load current I increases due to a failure of the control circuit 6 or the load 5 to reach the first set value I2, the signal C from the current detection circuit 7a becomes Hi level and is supplied to the transistor 3c to supply the sub relay exciting coil 3b. Is driven, the contact 3a is closed, and the fuse 1 is forcibly blown. Here, the first set value I2 is set to a current value of a magnitude that should not be passed through the load 5 and the main circuit. When the fuse 1 is blown and no current flows in the main circuit and the load current returns to less than the first set value I2, the signal B becomes Lo level, and the sub relay contact 3 is opened. Further, the load current returns to less than I1, and the signal A from the control circuit 6 becomes L.
When it reaches the o level, the main relay contact 2a is opened.
Here, since the control circuit 6, the relay circuit 8 and the current detection circuit 7a have the auxiliary battery 9 different from the power supply 4, they can be driven even after the fuse 1 is blown. Further, while the load 5 is being driven, the main relay 2 receives signals from both the control circuit 6 and the current detection circuit 7a, so that power is supplied to the load 5. Therefore, the second set value I
By setting 1 to a value at which the main relay 2 operates at a current value less than or equal to its breaking capacity, the main relay can be made into an inexpensive and small element. In this embodiment, the current detection is performed in the circuit that constitutes the short circuit as shown in FIG. As a result, the current detection circuit 7a can generate the signal C even during the short circuit, and can surely blow the fuse 1. (Second Embodiment) FIG. 2 is a circuit diagram showing an electric vehicle high voltage circuit breaker according to a second embodiment of the present invention. The operation state is detected by a thermistor installed near the load 5 This circuit is performed by detecting the temperature of. The temperature detection unit 7b detects heat generated while the load 5 is driven, and when the temperature becomes equal to or higher than an arbitrary first set temperature, the OR circuit 2 of the relay circuit 8
If a signal A of Hi level is sent to d and the load 5 is overloaded due to an abnormality in the control circuit 6 or the load 5 and the temperature of the load 5 rises too much, the signal C from the temperature detection unit 7a becomes Hi.
It becomes a level and is supplied to the transistor 3c to drive the sub relay exciting coil 3b to close the contact 3a and forcibly blow the fuse 1. Therefore, also in this circuit, the same effect as that of the first embodiment can be obtained. (Third Embodiment) FIG. 3 is a circuit diagram showing an electric vehicle high voltage circuit breaker according to a sixth embodiment of the present invention. This is the circuit. The rotation speed detection circuit 7c detects the rotation speed of a load such as a drive motor, and when the rotation speed exceeds an arbitrary rotation speed, sends a high level signal A to the OR circuit 2d of the relay circuit 8 to detect an abnormality in the control circuit 6 or the load 5. Load 5
Is overloaded and the speed of the load 5 rises too much,
The signal C from the rotation speed detection circuit 7c becomes Hi level,
The sub relay exciting coil 3 is supplied to the transistor 3c.
b is driven, the contact 3a is closed, and the fuse 1 is forcibly blown. Therefore, also in this circuit, the same effect as that of the first embodiment can be obtained.

In this embodiment, the first and second switching elements are relays, the third and fourth control means are circuits including transistors, and the operating state detection means are current detection, temperature detection and rotation speed detection. The configuration or the detecting means can be arbitrarily changed and implemented without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an electric vehicle high voltage circuit breaker according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of an electric vehicle high voltage circuit breaker according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram of an electric vehicle high voltage circuit breaker according to a third embodiment of the present invention.

FIG. 4 is a diagram showing changes of a signal A, a signal B, and a signal C with respect to a load current.

FIG. 5 is a circuit diagram of a conventional high voltage circuit breaker.

[Explanation of symbols]

 1 Fuse 2 Main relay 2a Main relay contact 2b Main relay excitation coil 2c Main relay drive transistor 2d OR circuit 3a Sub relay contact 3b Sub relay excitation coil 3c Sub relay drive transistor 4 Power supply 5 Load 6 Control circuit 6a First control unit 6b Second control unit 7a Current detection circuit 7b Temperature detection circuit 7c Rotation speed detection circuit 8 Relay circuit 9 Auxiliary battery 10 Accelerator 11 Main switch

Claims (2)

[Claims] 1. A main power supply, a fuse, a first switching element, and a load are connected in series, and a bypass circuit is constructed for the main power supply and the fuse by bypassing the first switching element and the load. A main circuit in which a second switching element is connected in parallel, a first control means that is driven by an auxiliary power source that is different from the main power source, and that generates a drive signal during driving of the load, and that is driven by the auxiliary power source. A second control unit that receives a drive signal from the first control unit and gives a signal to the first switching element during driving of the load to close the main circuit to supply power to the load; An operating state detecting means for driving and detecting an operating state of the main circuit or the load to generate an operating signal according to the operating state; and an operating state driven by the auxiliary power source. When the operation signal of the detection means is received and the operation signal exceeds the first set value, a signal is given to the second switching element to short-circuit the main power source and blow the fuse to cut off the power supplied to the load. An electric vehicle high voltage circuit breaker, comprising: 2. The first switching element when driven by the auxiliary power source, receiving an operation signal of the operation state detecting means, and when the operation signal exceeds a second set value smaller than the first set value in the previous period. The electric vehicle high voltage circuit breaker according to claim 1, further comprising: a fourth control unit that applies a signal to the main circuit to keep the main circuit closed and to continue supplying power to the load.