JPH0487595A - Speed controller for motor - Google Patents

Abstract

PURPOSE:To stably operate even if invaded by noise by reducing impedance of a torque command signal of torque command modes of a plurality of modes of acceleration torque, deceleration torque, torque holding by impedance reducing means and outputting the signal from torque command means. CONSTITUTION:Even if transistors 6, 7 are together turned OFF, an output PD of torque command means 2 does not become a high impedance by the operation of impedance reducing means 10, but reduced in impedance to parallel impedance of resistors 11, 12. When the output PD becomes a middle level, an output VT of an amplifier 3 is operated to hold a present level. Thus, power is supplied to a motor 1 in response to the output PD of the means 2. As a result, the motor 1 is controlled at a predetermined speed, but the output PD does not become a high impedance. Even in any case, a low impedance is held.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a speed control device for a motor used in equipment such as the OA field and the home appliance field.

Conventional technology In recent years, devices in the OA field and home appliances field have been given various added value, and along with this, the motors used in these devices have been added with highly accurate speed control functions. This is strongly required.

Conventional techniques for motors having such a speed control function include the following.

Hereinafter, a conventional motor speed control device will be described with reference to the drawings.

FIG. 2 is a circuit diagram of a conventional motor speed control device.

In FIG. 2, 1 is a motor. 5 is a torque command mode generator, the output A of the torque command mode generator 5 is input to the base of a transistor 6, and the emitter of the transistor 6 is grounded. The output B of the torque command mode generator 5 is input to the base of a transistor 7, and the emitter of the transistor 7 is connected to the positive feed line. The collectors of the transistor 6 and the transistor 7 are commonly connected. Here, each of the components 5 to 7 constitutes a torque command means 20,
A common connection point between the transistor 6 and the collector of the transistor F constitutes the output PD of the torque command means 20. The output FD of the torque command means 20 is input to the amplifier 3, and the output VT of the amplifier 3 is input to the motor drive means 4. The motor driving means 4 is connected to the motor 1.

The operation of the conventional motor speed control device configured as described above will be described below.

In FIG. 2, the torque command means 20 outputs an acceleration torque command as a torque command signal to the motor 1.

It operates to output command signals in three modes: deceleration torque command and torque holding command.

First, a case where the motor 1 has not reached a predetermined speed will be described.

At this time, the output A of the torque command mode generator 5.

Both transistors B operate to be at the H5gh level, transistor 6 is in the ON state, and transistor 7 is in the OFF state. Therefore, the output PD of the torque command means 20 becomes Low level. When the output FD is at a low level, it means that the torque command means 20 is outputting an acceleration torque command signal.

When the output PD becomes Low level, the output VT increases because the amplifier 3 is configured to perform an inverting amplification operation. When the output VT of the amplifier 3 increases, the motor drive means 4 operates to increase the amount of power supplied to the motor 1 and accelerate the motor 1.

Next, a case where the motor 1 can reach a predetermined speed will be described.

At this time, the output A of the torque command mode generator 5.

Both transistors B operate at a low level, transistor 6 is turned off, and transistor 7 is turned on.

Therefore, the output PD of the torque command means 20 becomes High level. When the output PD is at a High level, it means that the torque command means 20 is outputting a deceleration torque command signal.

When the output PD becomes High level, since the amplifier 3 is configured to perform an inverting amplification operation, its output VT
is descending. When the output VT of the amplifier 3 decreases, the motor drive means 4 operates to reduce the amount of power supplied to the motor 1 and decelerate the motor l.

Finally, a case will be described in which the motor 1 is driven at a predetermined speed.

Here, if a slight deviation from the predetermined speed occurs due to the load torque or torque disturbance of the motor 1, in order to correct this, the torque command means 20 issues an acceleration torque command or a deceleration torque command as described above. Although there is a momentary period during which the output is performed, this period will be ignored in the explanation here.

At this time, the output A of the torque command mode generator 5.

B operates to be at Low level and High level, respectively, and both transistors 6 and 7 are in the OFF state. Therefore, the output PD of the torque command means 2o becomes a high impedance. When the output PD is high impedance, it means that the torque command means 20 is outputting a torque holding command signal.

When the output PD becomes high impedance, the output VT of the amplifier 3 operates to maintain the current level, and therefore the motor driving means 4 maintains the current amount of power supplied to the motor 1 and keeps the motor 1 at a constant speed. Works to keep.

As described above, power is supplied to the motor 1 according to the output PD of the torque command means 20, and as a result, the motor 1
is controlled at a predetermined speed.

Problems to be Solved by the Invention However, in the above-described conventional motor speed control device, when the motor is driven at a predetermined speed,
The output PD of the torque command means has high impedance. If the output PD has a high impedance, if some noise enters from the outside, it will be in a state where it is extremely likely to malfunction, making it difficult to drive and control the motor at a predetermined speed.

Conventional motor speed control devices have had such problems.

The present invention has been made to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a motor speed control device that operates stably even when some kind of noise enters from the outside.

Means for Solving the Problems To achieve this object, a motor speed control device of the present invention includes a motor, a torque command means for outputting a command signal of the torque generated by the motor, and an output of the torque command means. and a motor drive means for supplying electric power to the motor according to the output of the amplifier, and the torque command means outputs torque command signals in multiple modes of acceleration torque, deceleration torque, and torque holding. The device is configured to output the impedance at a low impedance using a low impedance means.

With this configuration, even if some noise enters from the outside, the output of the torque command means is made low impedance by the low impedance means, so it will not be affected by the noise, and therefore the motor can be stably controlled. This makes it possible to perform speed control.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a circuit diagram of a motor speed control device according to an embodiment of the present invention.

In FIG. 1, reference numeral 2 denotes torque command means, and the torque command means 2 is configured such that its output section is grounded via a resistor 11 and connected to the positive side feed line via a resistor 12. The circuit configuration diagram of the conventional motor speed control device shown in FIG. 2 is the same as that shown in FIG. Therefore, parts having the same functions as those in the circuit diagram of the conventional motor speed control device shown in FIG. 2 are given the same symbols, and the explanation thereof will be omitted.

Here, the resistor 11 and the resistor 12 constitute impedance lowering means 10.

The operation of the motor speed control device according to the embodiment of the present invention configured as described above will be described below.

In FIG. 1, similar to the torque command means 20 shown in FIG. 2, the torque command means 2 issues commands in three modes as a torque command signal to the motor 1: an acceleration torque command, a deceleration torque command, and a torque holding command. Operates to output a signal.

That is, if the motor 1 has not reached the predetermined speed,
The output PD of the torque command means 2 outputs a low level acceleration torque command signal, and operates to accelerate the motor 1.

When the motor 1 exceeds a predetermined speed, the torque command means 2
The output PD outputs a High level which is a deceleration torque command signal, and operates to decelerate the motor 1.

The operation up to this point is completely the same as the conventional example shown in FIG.
is in the ON state, the impedance of the output PD is low.

Even when the motor 1 is driven at a predetermined speed, the operation is the same as in the conventional example until both transistors 6 and 7 are turned off; however, transistors 6 and 7 are both turned off. Even if this occurs, the output PD of the torque command means 2 does not have a high impedance as in the conventional example, but is reduced to a parallel impedance of the resistors 11 and 12 due to the action of the low impedance reducing means 10.

Note that the output level of the output PD at this time is M i −dd
level le, which means that the torque command means 2 is outputting a torque holding command signal.

When the output FD reaches the M i d d I e level, the output VT of the amplifier 3 operates to maintain the current level,
Thereafter, as in the conventional example, the motor 1 is operated to maintain a constant speed.

In this way, power is supplied to the motor 1 according to the output PD of the torque command means 2, and as a result, the motor 1 is controlled at a predetermined speed, but the output PD is different from that of the conventional example. It never becomes a high impedance, and is kept low impedance in any case.

Therefore, the output PD of the torque command means 2 is not affected by the intrusion of noise from the outside, and stable motor speed control is always possible.

As described above, according to this embodiment, by providing the low impedance means 10 constituted by the resistors 11 and 12 at the output section of the torque command means 2, the output of the torque command means 2 malfunctions due to noise. This makes it possible to stably drive and control the motor at a predetermined speed.

In addition, in this embodiment, the low impedance means 1
0 is configured by the resistors 11 and 12, but it may be configured by, for example, a voltage follower circuit using an operational amplifier or an emitter follower circuit using a transistor.

Effects of the Invention As described above, the present invention is configured such that the torque command signal outputted from the torque command means is outputted with low impedance by the low impedance means, so that even when some kind of noise enters from the outside, It is possible to realize an excellent motor speed control device that is capable of stable motor drive and control without malfunction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit configuration diagram of a motor speed control device in an embodiment of the present invention, and FIG. 2 is a circuit configuration diagram of a motor speed control device in a conventional example. ■...Motor, 2...- Torque command means, 3...Amplifier, 4...Motor drive means, 10...Lower impedance means.

Claims (1)

[Claims] A motor, a torque command means for outputting a command signal of the torque generated by the motor, an amplifier for amplifying the output of the torque command means, and a motor drive means for supplying the motor with electric power according to the output of the amplifier. A speed control device for a motor, wherein the torque command means is configured to output torque command signals in multiple modes of acceleration torque, deceleration torque, and torque holding after being reduced in impedance by a low impedance reduction means.