JPS5857041B2 - Electric vehicle control device protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protection device for an electric vehicle control device that protects an electric vehicle control device constituted by a chopper control device or the like using a refrigerant such as fluorocarbon.

Chopper control devices for electric vehicles have various advantages such as not wasting electricity with resistance during startup unlike conventional resistance control vehicles, and can perform electric power regeneration braking when braking, so they are currently gaining significant popularity. It has been put into practical use.

High-power semiconductor devices are used in this chopper control device, but the recent trend in high-power semiconductor devices is toward larger capacities, and the amount of heat generated per unit area is also increasing. This method has reached its limit, so
A method is adopted in which Freon, which has good insulating properties, is used as a cooling medium, and semiconductor elements are cooled by the latent heat of vaporization when it changes from a liquid state.

By the way, the semiconductor element used in the chopper control device is
Due to its characteristics, the temperature of the semiconductor element is a specified value, for example 125°C.
If the temperature exceeds 125, the characteristics will rapidly deteriorate or even break down, so it is recommended that the junction temperature of the semiconductor device be 125.
It is necessary to provide a protective device to prevent the temperature from exceeding ℃.

Conventional protection devices for electric vehicle control equipment detect the temperature of the fluorocarbon refrigerant and keep the junction temperature of the semiconductor element at 125°C during operation because it is difficult to detect the temperature of the semiconductor element itself under high voltage. The temperature of the freon liquid when it reaches a slightly lower temperature (for example, TH°C).

), the chopper device is configured to stop operating altogether.

Therefore, when the temperature of the fluorocarbon liquid reaches Tu° C. and the protection device is activated, the operation of the electric vehicle must be immediately stopped, and it becomes impossible to continue operation until the temperature of the fluorocarbon liquid drops.

This invention was made in view of these points, and it is an object of the present invention to provide a protection device for an electric vehicle control device that does not have the above-mentioned drawbacks, focusing on the fact that electric braking such as regeneration is backed up by an air brake or the like. That is.

A protection device for an electric vehicle control device according to an embodiment of the present invention shown in FIGS. 1 to 3 will be described below.

In the figure, 1 is a semiconductor element that forms the main thyristor of the chopper device, and 2 is a fluorocarbon cooling device that cools the semiconductor element 1. It is composed of a condenser 5 that condenses vaporized Freon.

Reference numeral 6 shown in FIG.
9 is a brake command device provided in the driver's cab 7; 9 is a chopper gate control circuit that applies a gate signal to the semiconductor element 1 in response to signals sent through the car row command line 10 and the brake command line 11; Turn on and off, semiconductor element 1
control the current.

12 is immersed in the fluorocarbon liquid 3, and the temperature of the fluorocarbon liquid 3 is T.
A temperature sensor 13 is immersed in the fluorocarbon solution 3 and operates to close the contact 13A when the temperature of the fluorocarbon solution 3 reaches TH'C.

Note that TH'C is set slightly lower than the temperature at which the semiconductor element 1 deteriorates (for example, 125° C.).

Further, T2C is set slightly lower than TH'C.

14 is the first relay, which is activated when the contact 12A closes, opens the auxiliary contact 14A, releases the brake command line 11, closes the auxiliary contact 14B, and lights up the indicator light 15 provided on the driver's cab 7. let

16 is a second relay, which operates when the contact 13A closes, and connects to the auxiliary contact 16A.

Open '16B and brake command line 11 and power line command line 10
At the same time, the auxiliary contact 16c is closed and the indicator light 17 provided on the driver's cab 7 is turned on.

18 is a power source.

FIG. 4 is a block diagram showing a braking system for an electric vehicle control device provided with a protection device for an electric vehicle control device according to an embodiment of the present invention.

In FIG. 4, reference numeral 19 denotes an electric braking device that brakes the electric vehicle using regenerative current, and brakes the electric vehicle with a braking force according to a braking command.

That is, when a braking signal is issued from the braking command device 8 and a gate pulse corresponding to the braking signal is given to the semiconductor element 1 to cause a braking current to flow through the semiconductor element 1, the electric braking device 19 generates a braking signal corresponding to this braking current. It is configured to generate power.

20 is a calculation device that calculates and outputs the shortfall in the braking force of the electric braking device 19 relative to the command value of the brake command device 80.

Reference numeral 21 denotes a mechanical braking device that brakes the electric vehicle with a braking force according to the output of the arithmetic device 20 to compensate for the lack of the electric braking device 19, and is constituted by an air brake.

Next, the operation of one embodiment of the present invention will be explained.

Now, if the temperature of the fluorocarbon liquid 3 begins to rise abnormally due to an abnormal rise in ambient temperature in the control device of the electric vehicle, the temperature detector 12 will be activated when the fluorocarbon liquid 3 reaches T2C and the contact will be activated. Close 12A.

When the contact 12A closes, the relay 14 is activated to open the auxiliary contact 14A to release the brake command line 11, and close the auxiliary contact 14B to turn on the indicator light 15.

Even if a braking command is issued by opening the braking command line 11, the gate control circuit 9 will no longer operate, and no braking current will flow through the semiconductor element 1.

As a result, even if a braking command is issued, the electric braking does not work, but in this case, the mechanical braking device 21 brakes the electric vehicle with a braking force according to the command value.

In addition, the Rin-14 releases the brake command line 11 but does not release the power line command line 10, so even if the fluorocarbon fluid 3 reaches T2C, if the power line command is issued, the electric car will run in the car direction. .

In this state where the fluorocarbon liquid 3 reaches TL'C, the electric vehicle can continue to operate normally.

On the other hand, the temperature of the fluorocarbon liquid 3 that has risen abnormally and reached T2C will not rise any further because the brake command line is disconnected and the braking current stops flowing among the currents flowing through the semiconductor element 1, and the amount of heat generated by the semiconductor element 10 decreases. It disappears.

When the cause of the temperature rise disappears and the temperature falls below 71° C., the temperature detector 13 is activated to open the contact 12A, and electric braking is performed normally.

Furthermore, when the temperature rises rapidly and the Chiron liquid 3 reaches TH'C, the temperature detector 13 is activated and the contact 13A is closed, and the relay 16 is activated to close the auxiliary contact 16c and turn on the indicator light 17. The auxiliary contacts 16A and 16B are opened to release the power line instruction line 10 and the brake instruction line 11.

As a result, both the power and braking command lines are disconnected, so they are not executed (and no current flows through the semiconductor element 1).

Therefore, the junction temperature of semiconductor element 1 is 125°C.
There is no possibility that the characteristics of the semiconductor element 1 will deteriorate due to reaching this point.

As described above, the protection device for the electric vehicle control device of the present invention has the following features:
When the temperature of the refrigerant that cools the semiconductor device reaches a predetermined value, it becomes impossible to carry out continuous operation (only electric braking is disabled; if a braking command is issued, mechanical braking is applied). Since the electric car is configured to be braked, it is possible to suppress the temperature rise of the semiconductor elements without stopping the operation of the electric car.

[Brief explanation of the drawing]

1 to 3 show a protection device for an electric vehicle control device according to an embodiment of the present invention, FIG. 1 is a simplified diagram showing the arrangement of a temperature sensor, and FIG. 2 is a circuit of the temperature sensor. FIG. 3 is a circuit diagram showing the main parts thereof. FIG. 4 is a block diagram showing a braking system for an electric vehicle control device in which a protection device for an electric vehicle control device according to an embodiment of the present invention is used. In the figure, 1 is the main thyristor, 2 is the Freon cooling device,
3 is a fluorocarbon liquid, 6 is a power line command device, 8 is a brake command device, 9 is a chopper gate control circuit, 12.13 is a temperature sensor, 1
4 and 16 are relays, 19 is an electric control device, and 21 is a mechanical braking device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 Semiconductor elements are used in the power and braking control circuits of electric vehicles, and the semiconductor devices are configured to conduct electrically conductive operation or electrical control of the electric vehicle, and to prevent insufficient braking force due to the electric braking. A control device for an electric vehicle supplemented by mechanical braking includes a temperature detector that detects the temperature of a refrigerant that cools the semiconductor element and outputs a signal when the temperature of the refrigerant reaches a predetermined value; A protection device for an electric vehicle control device, characterized in that a relay is provided which operates in response to the signal and operates to disable only the electric braking without disabling forward driving of the electric vehicle.