JPH0413921B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric vehicle, and more particularly to a travel control device for an electric vehicle such as a battery forklift.

In electric vehicles such as battery lifts, electric motors are used as drive sources. Further, a DC series motor is generally used as the electric motor, and a chopper circuit is used to control the DC series motor.

Fig. 1 shows an electric circuit of a conventional chopper-controlled electric car using a DC series-wound motor, where 1 is a battery, 2 is a DC motor having an armature 2a, a field winding 2b, and armature diodes 3a, 3b. It is a series motor. 4 is a chopper circuit connected in series to the motor 2, and 5 is a plugging detection circuit.

Electric vehicles with chopper control using such DC series-wound motors have conventionally used plugging brakes, but when braking the armature current 1a
flows, and the braking energy is consumed as heat in the armature 2a and the diode 3a (3b). Therefore, it was necessary to increase the heat capacity of the armature 2a and the heat capacity of the armature diodes 3a and 3b. Furthermore, since the armature current becomes excessive at this time, a resistor is sometimes inserted between the armature and the armature diode to suppress the current.

In this way, when reversing an electric car by applying the electric brake without applying the mechanical brake, the above consideration is required, but after stopping by applying the mechanical brake, In the case of advanced technology, the heat capacity of each member is not required, and the armature diode circuit and plugging detection circuit are also not required. However, if the amateur diode circuit and the plugging detection circuit are eliminated, a field current will flow during reversing, causing the motor to go into a self-excitation state and generating a huge brake torque, potentially damaging the running system.

The present invention has been made in view of the above points, and its purpose is to detect that the electric vehicle is traveling in reverse and stop the stopper circuit, so that plugging is not applied and strong brake torque is not generated. An object of the present invention is to provide a highly safe traveling control device for an electric vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A traveling control device for an electric vehicle according to an embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, reference numeral 6 denotes a one-shot vibrator which is a pulse signal generating circuit and inputs the detection signal of the plugging detection circuit 5. 7 is a reset circuit which inputs the output signal of the one-shot vibrator 6; 8 is an accelerator circuit which emits an output signal according to the amount of depression of the accelerator (not shown); It will be reset. Reference numeral 9 denotes an oscillation circuit. This oscillation circuit 9 receives the output signal of the accelerator circuit 8 and the output signal of the reset circuit 7 as input, and changes the on time according to the output signal of the accelerator circuit 8, and also outputs the signal from the reset circuit 7. The oscillation is stopped by Reference numeral 10 denotes a gate firing circuit which inputs the oscillation output signal of the oscillation circuit 9 and supplies a gate signal to a switching element of the chopper circuit 4, such as a thyristor.

In the electric vehicle travel control device shown in FIG.
A drive circuit 30 is constituted by the DC series motor 2 and the chopper circuit 4, a drive control circuit 40 is constituted by the accelerator circuit 8, the oscillation circuit 9, and the gate firing circuit 10, and the plugging detection circuit 5, The one-shot vibrator 6 and the reset circuit 7 constitute a brake control circuit 50.

FIG. 3 shows a specific circuit configuration of the brake control circuit 50 consisting of the plugging circuit 5, one-shot vibrator 6 and reset circuit 7 shown in FIG. 2, and the accelerator circuit 8 in the drive control circuit 40.

As shown in FIG. 3, in the plugging detection circuit 5 of the brake control circuit, the emitter terminal and base terminal of the transistor 11 are connected to an armature diode 3.
connected to b. Further, a parallel circuit including a resistor 12a, a capacitor 13a, and a diode 14a is connected between the emitter and base of the transistor 11. A constant voltage circuit is connected to the collector terminal of the transistor 11 via a diode 14b, a resistor 12b, and a diode 14c.
This constant voltage circuit is composed of Zener diodes 15a, 15b, which are constant voltage elements, a resistor 12c, and a capacitor 12b. Comparator 16
One input terminal 16a is connected to the connection point between the anode of the diode 14c and the resistor 12c, and the other input terminal 16b is connected to the connection point between the anode of the diode 14c and the resistor 12c.
It is connected to the connection point with b. A resistor 12b and a diode 1 are connected between the output terminal of the comparator 16 and the positive potential.
4d and a resistor 12e are connected.

The one-shot multivibrator 6 is composed of a flip-flop 17, resistors 18a to 18c, and capacitors 19a and 19b.

The reset circuit 7 includes a first inverting amplifier 20, a second
It is composed of an inverting amplifier 21, diodes 22a to 22b, and resistors 23a and 23b.
One terminal (negative terminal) of the first inverting amplifier 20
is connected to the output terminal of flip-flop 17,
The other terminal (positive terminal) is the plugging detection circuit 5
is connected to the connection point of Zener diodes 15a and 15b. Further, the output terminal of the flip-flop 17 is connected to the oscillation circuit 9 of the drive control circuit via a diode 22a and a resistor 23a. Second
One input terminal (negative terminal) of the inverting amplifier 21 of
is connected to the output terminal of the first inverting amplifier 20,
The other terminal (positive terminal) is a Zener diode 15
It is connected to the connection point between a and 15b. The output terminal of the second inverting amplifier 21 supplies a reset signal to the accelerator circuit 8 via a diode 22d.
The accelerator circuit 8 is composed of resistors 24a, 24b, a diode 25, and a transistor 26.

In the traveling control device for an electric vehicle having the above configuration, when the vehicle is traveling forward and current is flowing in the drive circuit 30 in the direction of arrow B shown in FIG. When the armature 2a is excited, a generated current flows from the armature 2a as shown by arrow A. The plugging detection circuit 5 of the brake control circuit 50 detects that current flows through the armature diode 3b and operates the one shot vibrator 6. The one-shot vibrator 6 inputs an output signal to the reset circuit 7, and the reset circuit 7 stops the oscillation of the oscillation circuit 9 in the drive control circuit 40 in response to the input signal from the one-shot vibrator 6, for example, for 0.1 seconds. The gate ignition circuit 10 is stopped for ~1 second, and if the plugging detection circuit 5 receives an input again, this state continues until the car stops moving. As a result, the amateur diode current only flows intermittently for a moment, generating almost no heat, and also does not generate a large amount of torque.

More specifically, as shown in FIG. 3, in the plugging detection circuit 5, when current flows through the amateur diode 3b, the transistor 11 becomes conductive, and the capacitor 13b is charged. A capacitor 1 is connected to one input terminal 16a of the comparator 16.
3b is applied, and the other input terminal 16
A reference voltage is applied to b. When the comparison value of these input voltages is inverted, the signal is input to the flip-flop 17 of the one-shot vibrator 6, and the flip-flop 17 generates a pulse signal. The pulse signal of the flip-flop 17 is input to one input terminal 20a of the first inverting amplifier 20 of the reset circuit 7, and is also input to the diode 22a.
The signal is input as an oscillation stop signal to the oscillation circuit 9 via the oscillation circuit 9. The other input terminal 2 of the first inverting amplifier 20
A reference voltage is applied to 0b, and input terminal 2
When a pulse signal is supplied to 0a, the first inverting amplifier 20 supplies an output signal to the second inverting amplifier 21, and the second inverting amplifier 21 issues an output signal. This output signal also resets the accelerator circuit 8.

When the accelerator circuit 8 and the oscillation circuit 9 are reset, the gate ignition circuit 10 becomes inoperable, the chopper circuit 4 of the drive circuit 30 becomes non-conductive, and the main circuit current shown by B in FIG. 2 is briefly cut off. , As a result, the generator current A also stops flowing. When such a situation occurs, the electric vehicle is braked by the mechanical brake.

In the above explanation, the plugging detection circuit operates with the voltage generated by the amateur diodes 3a and 3b, but as another method, a shunt for current detection is connected in series with the amateur diodes 3a and 3b, respectively, and the plugging detection circuit operates using the voltage generated by the amateur diodes 3a and 3b. Another possible method is to operate by detecting the current.

As explained above, in the present invention, the electric brake is stopped and the mechanical brake is used. Therefore, according to the present invention, it is possible to prevent the generation of heat in the electric circuit and to suppress the generation of large braking torque, thereby providing a highly safe traveling control device for an electric vehicle. Furthermore, there is no need to use a tachogenerator or the like to detect whether or not the car has finished traveling, and the control device itself becomes cheaper, which has great effects.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram of a conventional electric vehicle travel control device, FIG. 2 is a block wiring diagram of an electric vehicle travel control device according to an embodiment of the present invention, and FIG. 3 is a block diagram of the electric vehicle travel control device according to an embodiment of the present invention. It is an electrical circuit diagram of the main part. 1...Battery, 2...DC series motor, 3
a, 3b... amateur diode, 4... chopper circuit, 5... plugging detection circuit, 6...
One-shot vibrator, 7...Reset circuit, 8...Accelerator circuit, 9...Oscillation circuit, 10
...Gate ignition circuit, 30...Drive circuit, 40...
...Brake control circuit, 50...Drive control circuit.

Claims (1)

[Scope of Claims] 1. A drive circuit 30 that drives an electric vehicle by controlling power supplied from a DC power source 1 to an electric motor 2 using a chopper circuit 4, and a drive control circuit that controls the chopper circuit 4 of this drive circuit 30. 40, and a braking control circuit 50 that controls the drive braking circuit 40 when braking the electric vehicle, wherein the drive control circuit 40 includes an accelerator circuit 8 and an accelerator circuit 8. An oscillation circuit 9 that outputs an oscillation signal according to the amount of depression of the accelerator, and this oscillation circuit 9
The braking circuit 50 has a gate circuit 10 that controls the chopper circuit 4 of the drive circuit 30 by inputting the output signal of the plugging detection circuit 5.
, a pulse signal generation circuit 6 , and a reset circuit 7 , the plugging detection circuit 5 detects plugging of the electric vehicle and generates a detection signal, and the pulse signal generation circuit 6 includes a The reset circuit 5 receives the detection signal as an input and generates an output signal, and the reset circuit 5 receives the output signal of the pulse signal generation circuit 6 as an input and resets the accelerator circuit 8 and the oscillation circuit 9 of the drive circuit 40 for a predetermined period of time. A travel control device for electric vehicles featuring: