JPS58123386A - Speed controller for motor - Google Patents

Abstract

PURPOSE:To accurately control the speed of a motor over a wide range without hunting by constructing to control a gain of a system inversely proportionally to the speed information of the motor. CONSTITUTION:Gain regulating means 8 which varies a gain inversely proportionally to the speed information detected by speed detecting means 3 is provided between a feedback control circuit 6 as control means and a motor driver 7. Accordingly, the gain decreases as the rotating speed of the motor 2 is accelerated, and the gain increases as the rotating speed of the motor 2 is, on the contrary, decelerated. Therefore, the speed of the motor 2 can be always accurately controlled over a wide range without causing hunting.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor speed control device that controls the rotational speed of a motor to a set speed.

Conventionally, as this type of speed control device, one shown in FIG. 1 is known. This is motor 2 with load 1 connected.
For example, the rotational speed of the tacho generator is detected by the speed detecting means 3, and the speed information detected by the speed detecting means 3 and the speed information set by the speed setting means 4 are added by the adder 5. Based on the result, that is, the difference between the two, the feedback control circuit 6 controls the motor drive device 7 that drives the motor.

Incidentally, although a rotating machine serving as a load is generally rigid, it is subject to torsional vibration and necessarily has primary backlash. When such torsional vibration or backlash occurs, hunting occurs in the above-mentioned automatic control system, resulting in so-called whining noise or vibration noise.

Therefore, one possible countermeasure to this problem is to slow down the response of the system. However, if the response of the system is slowed down, speed control is possible when the rotation speed of motor 1 is high, but when the rotation speed of motor 1 is low, it will pulsate and accurate speed control will not be possible. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor speed control device that can always accurately control the motor speed over a wide range without causing hunting.

To solve this problem, the present invention includes a motor to which a load is connected, a motor drive device for driving the motor, a speed detection means for detecting the speed of the motor, a speed setting means, and a speed set by the speed setting means. Based on the difference between the speed information and the speed information detected by the speed detection means, the motor drive device i
In a system equipped with a control means for controlling t, by providing a gain adjustment means for controlling the gain of the system in inverse proportion to the speed information detected by the speed detection means, that is, the rotational speed of the motor can be increased to a high speed. By controlling the system gain to decrease as the motor rotation speed decreases, and conversely increase the system gain as the motor rotation speed decreases,
This aims to achieve the above objectives.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a first embodiment of the invention, and FIG. 3 shows a second embodiment of the invention. In addition, in these figures,
Components that are the same as those in FIG. 1 are given the same reference numerals and their explanations will be omitted.

In the first embodiment, a gain adjustment means 8 is provided between a feedback control circuit 6 serving as a control means and a motor drive device 7, and the gain adjustment means 8 changes the gain in inverse proportion to the speed information detected by the speed detection means 3. It is something. Therefore,
In this embodiment, the gain decreases as the rotational speed of the motor 2 increases, and conversely, the gain increases as the rotational speed of the motor 2 decreases, so the speed of the motor 2 can be varied over a wide range without causing hunting. can be controlled accurately at all times.

In the second embodiment, the feedback control circuit 6 is an operational amplifier 6A, and the operational amplifier 6A is provided with a gain adjustment means 9 that changes the gain in inverse proportion to the speed information detected by the speed detection means 3. be. Therefore, in this embodiment as well, the gains 1' and 1° are lowered as the rotational speed of the motor 2 becomes higher, and conversely, the gains are increased as the rotational speed of the motor 2 becomes lower, so hunting does not occur. , the speed of the motor 2 can always be accurately controlled over a wide range. In particular, in this embodiment, the operational amplifier 6
Since the configuration is such that the gain of A is controlled in inverse proportion to the speed information detected by the speed detection means 3, there is an advantage that the configuration can be simplified.

Incidentally, the Kutani embodiment described above is effective when the load 1 is a machine that requires smooth rotation, such as a printing press. In particular, printing presses have long shafts and are required to rotate slowly and smoothly, so the use of the device according to the above-mentioned embodiments ensures constant stability without any vibration noise. You can get leather products.

As explained above, according to the present invention, in an automatic control system for a motor, the speed information of the motor is inversely proportional to the speed information of the motor. Since the system is configured to control the gain of the system, it is possible to provide a motor speed control device that can always accurately control the motor speed over a wide range without causing knocking.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional motor speed control device, FIG. 2 is a block diagram showing a first embodiment of the present invention, and FIG. 3 is a block diagram showing a second embodiment of the present invention. be. 1... Load, 2... Motor, 3... Speed detection means, 4... Speed setting means, 6... Feedback control circuit as control means, γ°... Motor drive device, 8. 9...Gain adjustment means. Agent Patent attorney Minoru Kinoshita (and 1 other person) Figure 1 4 Figure 3

Claims (1)

[Claims] (1) A companion motor to which a load is connected, a motor drive device for driving the motor, a speed detection means for detecting the speed of the motor, a speed setting means, the speed information set by the speed setting means, and the and a control means for controlling the drive of the motor drive device based on the difference between the speed information detected by the speed detection means, and the gain of the system is set to the reciprocal of the speed information detected by the speed detection means. A speed control device for a motor, characterized in that a gain adjustment means for proportional control has a gold film.