JPH06335116A - Speed controller for motor operated vehicle - Google Patents

Abstract

PURPOSE:To provide a speed controller for a motor operated vehicle in which brake at the time of decelerating, etc., can be effectively conducted while reducing power consumption. CONSTITUTION:A speed controller for a motor operated vehicle is constructed to control to drive a traveling motor 3 according to a pulse width modulation signal, and comprises brake means 20 for outputting a brake signal for braking the motor 3 at the time of outputting a non-drive signal at the modulation signal only at the time of decelerating to drive or stopping the motor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control device for an electric vehicle configured to drive and control a traveling electric motor with a pulse width modulation signal.

[0002]

2. Description of the Related Art Conventionally, in a speed control device for an electric vehicle of this type, for example, an electric motor is always braked when the drive pulse for driving the electric motor in the pulse width modulation signal is in the off state. The terminals of the electric motor are short-circuited, and the electromotive force generated by the rotation of the motor causes the electric motor to generate a braking force for the rotation at that time, thereby braking the electric motor.

[0003]

However, if the electric motor is constantly braked when the drive pulse for driving the electric motor is in the off state as in the above-mentioned conventional technique, the braking is performed when the vehicle is traveling while maintaining a predetermined speed. Since it is necessary to drive the electric motor at a high speed that can offset the deceleration amount due to, the electric power consumed by the electric motor to reach the desired speed becomes large and the battery capacity etc. becomes large. Otherwise, there was a drawback that it could not be used for a long time. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a speed control device for an electric vehicle that can reliably perform braking during deceleration or the like while reducing power consumption.

[0004]

In order to achieve the above-mentioned object, a speed control device for an electric vehicle according to the present invention has the above-mentioned structure, and has the pulse signal only when driving and decelerating the electric motor. Braking means for outputting a braking signal for braking the electric motor when a non-driving signal in the width modulation signal is output is provided. The operation and effect of this characteristic configuration are as follows.

[0005]

In other words, since the braking signal for braking the electric motor is output when the non-driving signal in the pulse width modulation signal is output only when the electric motor is driven to decelerate or stop, the normal constant speed running or the increase is performed. At the time of high speed, a braking signal for braking the electric motor is not output, and therefore the vehicle is not braked, so that power is not consumed more than necessary to compensate for the deceleration caused by the braking. Further, at the time of driving deceleration and at the time of stopping, the electric motor is braked by the braking signal at the time of outputting the non-driving signal, whereby the speed can be quickly decelerated and stopped.

[0006]

As a result, the power consumption can be reduced, and therefore the travelable distance per power consumption becomes long, which enables long-distance travel and long-time use.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows a scooter type small electric vehicle as an example of the electric vehicle. This small electric vehicle is equipped with a battery 6, a steering wheel, a rear portion of a vehicle body frame 5 supported by a front wheel 2 steered by a steering wheel 1, and a pair of left and right rear wheels 4, 4 driven by an electric motor 3. Seat 7 and control device 8
Etc. are equipped and configured.

FIG. 1 shows a schematic circuit diagram for driving the electric motor 3. That is, the control device 8 has
A controller 9 composed of a microcomputer and the like,
The motor drive circuit unit 10 converts the pulse signal P for driving the electric motor 3 output from the controller 9 into a signal for driving the electric motor 3. More specifically, the pulse signal P output from the controller 9 is a pulse width modulation signal having a pulse width w1 corresponding to the drive speed of the electric motor 3, as shown in FIG. That is, the amount of swing of the accelerator lever 11 provided on the steering wheel 1 is detected by the potentiometer 12, and the detection signal is input to the controller 9, and the amount of swing of the accelerator lever 11 is large according to this detection signal. That is, the modulation is performed so that the pulse width w1 becomes larger as the value becomes. Then, the pulse signal P output from the controller 9 is input to the drive signal generation circuit 13 in the motor drive circuit unit 10, and the drive signal generation circuit 1
The output signal from 3 is output to the base of the first transistor 14 connected in series with the electric motor 3. In addition, the pulse signal P output from the controller 9 is applied to the inverting circuit 15
It is also input to the braking signal generation circuit 16 via. In the inverting circuit 15, as shown in FIG. 2, the drive pulse signal in the pulse signal P is inverted to a low level and the non-drive signal is inverted to a high level. Then, a braking signal having the same phase as the inverted signal is output from the braking signal generation circuit 16, and the braking signal is input to the base of the second transistor 17 connected in parallel with the electric motor 3. Further, the controller 9 is provided with a differentiating circuit 18 which measures the amount of rocking operation of the accelerator lever 11 detected by the potentiometer 12 with time and differentiates the measured value. When the differential value obtained by the differentiating circuit 18 is zero or positive, the braking signal generating circuit 16 outputs a braking inhibiting signal for preventing the braking signal from being output to the second transistor 17, and the differential signal is generated. When the differential value in the circuit 18 is negative, the brake lever 19 of the steering wheel 1
When the brake operation signal obtained by the brake operation is input to the controller 9 or the accelerator lever non-operation signal is input to the controller 9, the braking signal is output to the second transistor 17 to the braking signal generation circuit 16. A braking permission signal for permitting the operation is output. Here, the braking signal generation circuit 16 outputs only a zero level signal to the base of the second transistor 17 when the braking inhibition signal is input, and the second transistor when the braking permission signal is input. A signal corresponding to the inverted signal Q inverted by the inversion circuit 15 is output to the base of 17. The differentiating circuit 18, the controller 9, the braking signal generating circuit 16, the inverting circuit 15 and the second transistor 17 form a braking means 20.

Therefore, according to the above configuration, when the accelerator lever 11 is operated to increase the speed or the vehicle speed is maintained at a constant speed, the detection signal in the differentiating circuit 18 is positive or zero. Therefore, a braking inhibition signal is output from the controller 9 to the braking signal generation circuit 16, and a braking signal for turning on the second transistor 17 is prevented from being output. Therefore, at this time, only the first transistor 14 is turned on based on the pulse signal P from the controller 9, whereby the electric motor 3 is intermittently driven, and the electric motor is driven even in the cycle in which the first transistor 14 is not turned on. 3 is never braked. Then, when the accelerator lever 11 is operated to decelerate, when the brake lever 19 is operated to brake, or when the accelerator lever 11 is not operated at all, the detection signal in the differentiation circuit 18 is negative. As a result, the controller 9 outputs a braking permission signal to the braking signal generation circuit 16 and inverts the pulse signal P so as to turn on the second transistor 17 when the first transistor 14 is off. The signal corresponding to the inverted signal Q is output to the base of the second transistor 17. When the second transistor 17 is turned on, the collector-emitter of the second transistor 17 connected to both terminals of the electric motor 3 is short-circuited, so that both terminals of the electric motor 3 are short-circuited. The electromotive force generated by the electromotive force generated in the short-circuited circuit
Electrically brake to reduce the rotation speed of. It should be noted that the pulse signal 3 for driving the electric motor 3 is not output when the accelerator lever 11 is not operated at all, but the signal inverted by the inversion circuit 15 at that time is a direct current of a constant value. Since it is a signal, the second transistor 17 continues to be in the ON state based on the signal, and the two terminals of the electric motor 3 remain short-circuited. Since the controller 9 is configured to perform the control based on the brake operation signal of the brake lever 19 in preference to the operation signal of the accelerator lever 11, the brake operation is performed regardless of the operation state of the accelerator lever 11. At this time, the electric motor 3 is braked.

In the present invention, the functions of the controller 9 and the motor drive circuit section 10 in the above embodiment, that is, the function of the braking means 20 can be realized by a digital control software system using a microcomputer. You may carry out in.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a speed control device for an electric vehicle.

FIG. 2 is a time chart showing a pulse signal for driving an electric motor and its inversion signal.

FIG. 3 is a plan view showing a steering handle portion.

FIG. 4 is an overall side view showing a small electric vehicle

[Explanation of symbols]

 3 Electric motor 20 Braking means

Claims (1)

[Claims] 1. A speed control device for an electric vehicle, configured to drive and control a traveling electric motor (3) by a pulse width modulation signal, wherein the electric motor (3) is driven only during deceleration and stop. A speed control device for an electric vehicle, comprising braking means (20) for outputting a braking signal for braking the electric motor (3) when a non-driving signal in the pulse width modulation signal is output.