JPH0444481B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric vehicle control device, and more particularly to an electric vehicle control device equipped with a main control circuit commutation failure detection protection device suitable for use in a battery lift truck.

A commutation failure detection protection device is installed in a vertical lift truck, and if the main control circuit fails to commutate, or if the order of the key switch and forward/reverse switch set for safety is incorrect, it will be detected as an erroneous operation and a commutation failure will occur. The detection protection circuit was activated to prevent the forward and reverse contactors from being turned on.

However, in the past, once the commutation failure detection protection device was activated due to any of the above reasons, it was released by turning off the key switch. The drawback was that the next operation could not be performed unless the key switch was turned on after the switch was turned on. In addition, examples of commutation failure detection and protection circuits are also disclosed in Japanese Patent Application Laid-Open No. 125007/1983.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric vehicle control device that can easily cancel the operation of a commutation failure detection protection circuit using a forward or reverse switch.

In the present invention, before connecting a differentiating circuit between the anode and cathode of the thyristor of the commutation failure detection protection circuit,
The operation of the commutation failure detection protection circuit is canceled by outputting a differential signal when the reverse switch is set to neutral.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention. In the figure, between the (+) wire 2 and the (-) wire 3 of the battery 1, a forward contactor 4, a reverse contactor 5, a traveling motor 6, a current detector 7,
Chopper circuits 8 are connected in series. The cathodes of diodes D1 and D2, whose anodes are commonly connected to the current detector 7, are connected to the output ends of the forward and backward contactors 4 and 5, respectively. Also, a key switch 9 connected to the (+) line 2
Between one end and (-) wire 3, there is a forward switch FSW,
Front and reverse switch 1 consisting of reverse switch RSW
0, a forward contactor excitation coil FC, a reverse contactor excitation coil RC, and a control transistor TR1 connected in series are connected. Forward switch FSW, reverse switch RSW
The output end of the inverter 11 is connected to a trigger circuit 13 via an oscillation stop circuit 12, respectively, through diodes D3 and D4. Further, the output terminal of the trigger circuit 13 is connected to a chopper circuit 8.
and is connected to the commutation failure detection protection circuit 14.

A differentiating circuit 15 whose input end is connected to the output end of the inverter 11 and whose output end is connected to the commutation failure detection protection circuit 14 includes a control transistor 15TR.
and a capacitor 15C and resistors 15R1 and 15R2 connected in series to the gate of the transistor,
It consists of a transistor malfunction prevention resistor 15R3 connected between the base and emitter and a diode 15D forming a discharge circuit. Here, the commutation failure detection protection circuit 14 and the differentiation circuit 15 form a commutation failure protection device 30.

The commutation failure detection protection circuit 14 connects the chopper circuit 8 to the point A and the (+) line 2 via a base resistor 14R2, a diode 14D3, a Zener diode 14Z, and a backflow blocking diode 14D2.
a control transistor TR4 whose base is connected to the transistor TR4 through a resistor R8, and whose gate is connected to the transistor TR4 through a resistor R8.
The thyristor SCR is connected to the output side of the inverter 11 via a diode 14D1 and a capacitor 14C2, which are connected in parallel between the collector and emitter of the inverter 14. the thyristor
The anode of SCR is resistor R1, diode D5,
It is connected to the (+) line 2 via a key switch 9. Furthermore, the Zener diode ZD1 connected to the base of the control transistor TR1 is
Control transistor 1 constituting the differentiating circuit 15
The collector of 5TR is commonly connected to the emitter of the thyristor SCR.

Pilot lamp PL connected between the power supplies
The gate of the transistor TR2 in a series circuit consisting of a resistor R4, a switching transistor TR2, and a switching transistor TR2 is connected to one end of the key switch 9 via resistors R2 and R3, and its voltage dividing point is connected to the output side of the resistor R1. An alarm display circuit 40 is formed.

A constant voltage circuit 16 connected to one end of the key switch 9 is configured to be able to supply a constant voltage to a constant voltage line 17 even if the voltage of the battery 1 fluctuates. This constant voltage line 17 is used as a power source for the control circuit. An output line that is output in accordance with the amount of depression of the accelerator 18 is connected to the duty ratio control circuit 20 via an accelerator command current amplification circuit 19 connected to the constant voltage line. The output line is connected from the conduction rate control circuit 20 to the trigger circuit 13.
On the other hand, the starting protection circuit 50 includes a series circuit connected from the constant voltage line 17 to the (-) line 3 via the capacitor C1 and the diode D6, and a resistor R5 connected at one end to the connection point between the capacitor C1 and the diode D6. through the resistor R, and one end connected to the (-) line 3
and a transistor TR3 having a base 2 connected through one end of the transistor TR3. the transistor
TR3 connects the collector to constant voltage line 17 via resistor R7.
Zener diode 14Z of commutation failure detection protection circuit 14 is connected to
connected to the anode of

Next, the operation of the control circuit having such a configuration will be explained.

First, we will explain the case where the key switch 9 and the FR switch 10 are operated normally in this order. When the key switch 9 is turned on, the transistor TR2 becomes conductive via the diode D5 and the resistors R1 and R3, and the pilot lamp of the alarm display circuit 40 is turned on.
PL lights up to indicate normal operation. (At this time, the thyristor SCR of the commutation failure detection protection circuit
(is non-conducting) Next, when the forward switch FSW (or reverse switch RSW) of the FR switch 10 is turned on, the control transistor TR1 is turned on by the base current applied via the diode D5, resistor R1, and Zener diode ZD1. Then, conduction is established, the forward contactor excitation coil FC (or the reverse contactor excitation coil RC) is energized, and the contacts of the forward contactor 4 (or reverse contactor 5) are connected in the opposite direction to that shown in the figure. On the other hand, forward and reverse FR
The output signals of the forward switch FSW and reverse switch RSW of the switch 10 are inverted by the inverter 11 via diodes D3 and D4 and supplied to the oscillation stop circuit 12, which releases the oscillation stop circuit and turns the chopper circuit 8 on and off. The driving motor 6 is driven and rotated. Next, when the accelerator 18 is depressed to increase the accelerator output, the accelerator command current amplification circuit 19 operates, the amount of conduction changes depending on the amount of accelerator depression, and the output is applied to the conduction rate control circuit 20. This amount of conduction is applied from the conduction rate control circuit 20 to the trigger circuit 13, and the chopper circuit 8 repeats conduction and non-conduction to control the ratio of the conduction time to the chopper period, that is, the conduction rate, and the speed of the traveling motor is adjusted. controlled.

Next, when the chopper circuit 8 fails in commutation and remains conductive, the voltage at point A of the chopper circuit 8 decreases, so that the transistor TR4 of the commutation failure detection protection circuit 14 becomes non-conductive.

Here, the commutation failure detection protection circuit 14 detects the difference between the off signal of the chopper circuit 8 and the on signal of the trigger circuit 13.
An AND is taken and the transistor TR4 is kept on at all times.If the chopper circuit 8 remains on, the AND signal may be low, which turns off the transistor TR4. At this time, since the voltage at point A remains at a low level, the voltage of the capacitor 14C1 may be at a low level.

At this time, the base current of transistor TR4 is turned off, and diode D3 (or D4) resistor 1
5R1 and the capacitor 14C2 is charged through the diode 14D1, the gate voltage of the thyristor SCR increases, and the thyristor is turned on.

When the thyristor SCR fires, the base current of the control transistor TR1 flows from the diode D5 to the resistor R1 to the thyristor SCR, so the control transistor TR1 becomes non-conductive, the forward contactor 4 (or the backward contactor 5) is opened, and the chopper circuit 8 becomes non-conductive. On the other hand, the pilot lamp PL also goes out because the transistor TR2 becomes non-conductive, indicating that the commutation failure detection protection circuit 14 has operated.

Next, the case where the forward and reverse switches 10 and the key switch 9 are operated in this order will be explained.

When the forward switch FSW (or reverse switch RSW) of the forward/reverse switch 10 is turned on and the key switch 9 is turned on, the voltage of the constant voltage circuit 16 charges the capacitor C1, and the transistor TR3 becomes conductive until it becomes a constant voltage, so the diode Transistor TR of commutation failure detection protection circuit 14 via D7
4 becomes non-conductive. Therefore, the thyristor SCR becomes conductive and the forward contactor 4 (or the backward contactor 5) is not turned on. On the other hand, the pilot lamp PL also does not light up, indicating that it is not operating normally. Next, a control circuit for normal operation in such a state will be described.

First, the forward switch FSW of FR switch 10
When the reverse switch RSW is set to the neutral position (the state shown in the figure), the output of the inverter 11 is supplied to the differentiating circuit 15. Therefore, the differentiating circuit 15 operates and outputs a differential signal, and the thyristor SCR of the commutation failure detection protection circuit 14 is made non-conductive, so that the commutation failure protection circuit device 30 is released. At this time,
The pilot lamp PL lights up to indicate that normal operation has returned. In this state, FR switch 10
If you operate it, it will operate normally. The constants of the differentiating circuit 15 are selected so that the pilot lamp PL will not go out even if the FR switch 10 is set to the neutral position during normal operation. By attaching the Pilot Lamp PL to the vehicle's instrument panel, it can be displayed to the driver at a glance.

Capacitor C1, diode D6, transistor TR3, resistors R5, R6. The starting protection circuit 50 consisting of R7 prevents the travel motor 6 from rotating at high speed if the forward (reverse) switch FSW is turned on and the key switch 9 is turned on and the chopper circuit 8 remains conductive for some reason, causing the travel motor 6 to rotate at high speed. It is.

Therefore, in order to prevent this from happening, the protection circuit 50 turns on the transistor TR3 for a certain specified time (several milliseconds) when the key switch 9 is turned on, and converts the voltage at point A of the chopper circuit 8 into the capacitor 14C1.
block high-level signals.

For this purpose, the thyristor SCR is fired and turned on to cut off the base current of the control transistor TR1, and the control transistor TR1 is turned off to open the contact of the forward contactor 4 (or the backward contactor 5).

As is clear from the above description, according to the embodiment of the present invention, the operation of the commutation failure detection protection circuit can be canceled.
Equipped with a commutation failure protection device that can be performed only with the FR switch, eliminating the hassle of turning on and off the key switch. Also,
By attaching a pilot lamp to the instrument panel of the vehicle when the key switch is turned on, it is effective for the driver to be able to determine at a glance whether or not the key switch is operating normally.

As described above, according to the present invention, it is possible to provide an electric vehicle control device in which the operation of the commutation failure detection protection circuit constituting the commutation failure protection device can be easily canceled using the forward and reverse switches.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. 4...Forward contactor, 5...Reverse contactor, 6...Travel motor, 8...Chiyotsupa circuit,
10...FR switch, 11...Inverter, 1
3... Trigger circuit, 14... Commutation failure detection protection circuit, 15... Differentiation circuit, 20... Commutation rate control circuit, 30... Commutation failure protection device, FSW... Forward switch, RSW... Reverse movement Switch, ZD1...Zena diode, TR1 to TR4...Transistor, SCR...Thyristor, FC...Forward contactor excitation coil, RC...Reverse contactor excitation coil.

Claims (1)

[Scope of Claims] 1. An electric vehicle control device having a commutation failure protection device 30, wherein the electric vehicle is driven by a conduction rate control circuit 20,
It is controlled by a travel motor 6 and a chopper circuit 8 that controls the rotational speed of the travel motor, and the control includes regeneration control and plugging braking, and the commutation failure protection device 30 prevents commutation failure. It has a detection protection circuit 14 and a differentiation circuit 15, and the commutation failure detection protection circuit 14 takes in the signal of the chopper circuit 8 and the signal of the trigger circuit 13, and performs excitation for exciting the forward and reverse contactors 4 and 5. The thyristor SCR for controlling the coils FC and RC is controlled via the transistor TR4, and the differentiating circuit 15 is connected between the anode and the cathode of the thyristor SCR of the commutation failure detection protection circuit 14. , an electric vehicle control device that outputs a differential signal when the reverse switch 10 is in the neutral position, and releases the operation of the commutation failure detection protection circuit 14.