JPH0729682Y2 - Electric vehicle speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a speed control device for an electric vehicle that changes the characteristics of an accelerator signal to enable soft start / stop.

(Prior Art) FIG. 6 is a circuit diagram showing an example of a conventional speed control device for an electric vehicle, and FIG. 7 is a waveform diagram for explaining the operation of the conventional device.

In FIG. 6, 1 is an accelerator, 2 is a reference wave oscillation circuit, 3 is a motor drive signal generation circuit, 4 is a motor drive circuit, 5 is a battery, and 6 is a motor.

The accelerator 1 outputs an accelerator signal (FIG. 7 (a)) proportional to the operation amount of the accelerator lever or the like. The reference wave oscillating circuit 2 is a reference wave such as a sawtooth waveform (Fig. 7 (b)).
Is a circuit for outputting. The motor drive signal generation circuit 3 is
From the output of the accelerator 1 and the output of the reference wave oscillating circuit 2, a motor drive signal having a pulse width proportional to the accelerator signal (7th
This is a circuit for generating the diagram (c)). Motor drive circuit 4
Is a circuit for intermittently connecting the voltage of the battery 5 to the motor 6 according to the output of the motor drive signal generation circuit 3.
The motor 6 is a motor that drives the drive wheels of the electric vehicle.

In such a speed control device, the speed of the electric vehicle is controlled by changing the pulse width of the motor drive signal according to the change in the accelerator signal. For this reason, electric towing vehicles, especially
When applied to a small and lightweight electric tow vehicle, the load on the towed vehicle is much larger.Therefore, unless the accelerator operation is carefully performed, the towed vehicle will collapse when accelerated or decelerated. There was a problem that it would end up.

To solve this problem, the accelerator signal is controlled by a resistance method, or the accelerator signal (FIG. 8 (a)) is integrated (FIG. 8 (b)) and then the motor drive signal is generated. Was being done.

(Problems to be solved by the invention) However, in the case of the former, especially in the case of heavy goods,
I can't expect much effect.

On the other hand, in the latter case, as shown in FIG. 8 (b), although the signal is somewhat soft, in reality, there is a rapid change at the starting point (A, B) of the change. The problem remains. In order to eliminate this, it is sufficient to make the integration constant large (FIG. 8 (c)), but this causes poor response and a new problem that work efficiency decreases.

An object of the present invention is to provide a speed control device for an electric vehicle that has a simple structure and can prevent a load from slipping on a towed vehicle even when the accelerator is rapidly accelerated and decelerated.

(Means for Solving the Problems) In order to achieve the above object, a speed control device for an electric vehicle according to the present invention is an accelerator that outputs an accelerator signal proportional to an accelerator operation amount, and a reference wave that generates a reference oscillation wave. An oscillator circuit, a motor drive signal generation circuit that generates a motor drive signal proportional to the accelerator signal from the accelerator signal and the reference oscillation wave, and a motor drive circuit that intermittently connects a power source to the motor according to the motor drive signal. A speed control device for an electric vehicle comprising: an integrating circuit for integrating the accelerator signal; a differentiating circuit for differentiating the accelerator signal; and a differential amplifying circuit for differentially amplifying the output of the integrating circuit and the output of the differentiating circuit. An accelerator signal processing circuit consisting of is provided to smooth changes in the accelerator signal so that the acceleration applied to the vehicle becomes substantially constant. ing.

Embodiment Hereinafter, the present invention will be described in detail with reference to the drawings and the like.

FIG. 1 is a block diagram showing an embodiment of a speed control device for an electric vehicle according to the present invention, and FIGS. 2 and 3 are waveform diagrams for explaining the operation of the device of the embodiment.

The parts that perform the same functions as those of the above-mentioned conventional example are designated by the same reference numerals.

In the present invention, an accelerator signal processing circuit 7 is further added.

FIG. 2A shows an accelerator signal V, which is connected to the accelerator signal processing circuit 7. Second
FIG. 6B shows a signal waveform V ′ processed by the accelerator signal processing circuit 7, which has a waveform that gradually increases with time and finally increases rapidly. The power supply current I at this time has a substantially constant rising characteristic as shown in FIG. 2 (c), and a substantially constant regenerative current is obtained when the processed signal waveform V'falls.

A time extension of this is shown in FIG. 3, and from the characteristics of the upper limit current suppression circuit of the control device and the motor,
The current I shown in FIG. 3 (b) is obtained from the waveform of FIG. 3 (a). This is as shown in FIG. 3 (c) when viewed at the speed v, and it can be seen that a substantially constant speed is obtained. As a result, it is possible to control the soft start / stop.

FIG. 4 is a circuit diagram showing an accelerator signal processing circuit used in the device of the present invention, and FIG. 5 is a waveform diagram for explaining the operation of the circuit.

In FIG. 4, 71 is an integrating circuit, 72 is an amplifier, 73 is a differentiating circuit, 74 is an amplifier, and 75 is a differential amplifier.

The accelerator signal V from the accelerator 1 (FIG. 5 (a)) is
It is input to the accelerator signal processing circuit 7. In the accelerator signal processing circuit 7, the signal is branched, and one of them is integrated by an integrating circuit 71 and then connected via an amplifier 72 to a non-inverting input terminal of a differential amplifier 75 (see FIG. 5 ( b)). The other is differentiated by the differentiating circuit 73 and then connected to the inverting input terminal of the differential amplifier 75 via the amplifier 74 (FIG. 5 (c)).

The differential amplifier 75 calculates the difference (va-vb) between the signals, and the output is as shown by vc in FIG. 5 (d).

Therefore, if the motor drive signal (Fig. 5 (f)) is generated from the signal from the reference wave oscillation circuit 2 and the corrected accelerator signal V '(Fig. 5 (e)), the acceleration of the accelerator 1 is increased. Smooth speed control is possible during speed and deceleration. Here, FIGS. 5 (e) and (f) are shown enlarged in the time direction.

In the present embodiment, the analog circuit is described as an example,
The signal may be processed digitally, and at this time,
Further precise control becomes possible. Further, although the device according to the present invention enables soft start / stop automatically, it may be manually operated.
In this case, if the accelerator is operated slowly,
Since the differential output vb becomes small and becomes equal to the normal control, there is no sense of discomfort in operation.

(Effects of the Invention) As described in detail above, according to the present invention, since a substantially constant acceleration can be obtained by a simple configuration in which an accelerator signal processing circuit is added, a shock given to a load can be minimized. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a speed control device for an electric vehicle according to the present invention, and FIGS. 2 and 3 are waveform charts for explaining the operation of the embodiment. FIG. 4 is a circuit diagram showing an accelerator signal processing circuit used in the device of the present invention, and FIG. 5 is a waveform diagram for explaining the operation of the circuit. FIG. 6 is a circuit diagram showing an example of a conventional speed control device for an electric vehicle, and FIG. 7 is a waveform diagram for explaining the operation of the conventional device. FIG. 8 is a waveform diagram for explaining the problems of the conventional accelerator signal processing. 1 ... Accelerator, 2 ... Reference wave oscillating circuit 3 ... Motor drive signal generating circuit 4 ... Motor drive circuit, 5 ... Battery 6 ... Motor 7 ... Accelerator signal processing circuit 71 ... Integrating circuit, 72 ... Amplifier 73 ... Differentiating circuit, 74 ... Amplifier 75 ... Differential amplifier

Claims (1)

[Scope of utility model registration request] 1. An accelerator for outputting an accelerator signal proportional to an accelerator operation amount, a reference wave oscillation circuit for generating a reference oscillation wave, a motor drive signal proportional to the accelerator signal from the accelerator signal and the reference oscillation wave. In a speed control device for an electric vehicle, which comprises a motor drive signal generating circuit for generating a motor drive signal and a motor drive circuit for intermittently connecting a power source to the motor according to the motor drive signal, an integrating circuit for integrating the accelerator signal, the accelerator signal An accelerator signal processing circuit including a differentiating circuit that differentiates the output of the integrating circuit and a differential amplifying circuit that differentially amplifies the output of the integrating circuit and the output of the differentiating circuit is provided to smooth the change of the accelerator signal and to reduce the acceleration applied to the vehicle. A speed control device for an electric vehicle, which is configured to be constant.