JPH07110148B2 - DC motor controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for a DC electric motor.

[Conventional technology]

FIG. 2 is a circuit configuration diagram of the thyristor Leonard device shown in P.787 of the electrical engineering handbook, the new edition, issued on February 28, 1988, for example, in which 1 is an input transformer of a power source and 2 is an input transformer. The main circuit of the thyristor converter as the AC / DC power conversion means converts AC power to DC power. 3 is a DC motor connected to the thyristor converter main circuit 2;
Is a pulse generator (PLG) such as a rotary encoder, 5
Is a roll of load, 6 is a field input transformer of the DC motor 3,
Reference numeral 7 is a field main circuit, 8 is a field winding of the DC motor 3, 9 is a speed sensor for detecting the speed from the output of the pulse generator 4, and 10
Is a speed reference signal generation circuit for generating a speed reference signal, 11 is an operational amplifier for amplifying the deviation between the signal N ^* of the speed reference signal generation circuit 10 and the actual speed N of the speed sensor 9, and 13 is an armature of the DC motor 3. Current transformer for detecting current, 14 is a current sensor for detecting current from output of current transformer 13, 15 is armature current reference (output of operational amplifier 11) Ia ^* Deviation from actual armature current Ia Operational amplifier for amplification, 16 is a thyristor converter main circuit 2
Gate pulse generator (GPG) that generates a signal to fire the gate of, field current reference generator 17 and field current If
A current sensor connected to the current transformer 18, 20 is an operational amplifier for amplifying the deviation between the output If ^{* of the} field current reference generation circuit 17 and the actual field current If, Reference numeral 21 is a gate pulse generator, 22 is a DC motor speed control device, and 23 is a DC motor drive device.

Next, the operation will be described. First, when the speed control of the DC motor 3 is performed, the field current reference generating circuit 17 generates a field current reference If ^* , and a constant real field current If is supplied to the field winding 8 and the speed reference is applied. A speed reference N ^* is generated by the signal generating circuit 10, a speed deviation between the speed reference N ^* and the speed feedback (actual speed) N is amplified by an operational amplifier 11, and the speed deviation is used as an armature current reference Ia ^* . To do. The amplification factor of the operational amplifier 11 at this time is determined by the flywheel effect (hereinafter referred to as GD ² ) of the DC motor 3 and the roll 5 so as to obtain a predetermined speed response. The current deviation between the armature current reference Ia ^* and the actual armature current Ia (output of the current sensor 14) is amplified by the operational amplifier 15, and the output is amplified by the gate pulse generator (GP
G) 16 to control the output of the thyristor of the main circuit 2 of the thyristor converter, that is, the DC voltage to control the DC motor 3
The speed is controlled.

[Problems to be Solved by the Invention]

Since the conventional DC motor controller is configured as described above, when the roll is driven via the gear, GD ² of the load (DC motor 3 and roll 5) changes due to the backlash of the gear. (Because the DC motor GD ² and the roll GD ² are the apparent DC motor GD ^2. ) Here, if the amplification factor of the operational amplifier 11 is constant, the GD of the load is
There is a problem that the speed response changes due to the change of ^{2 and} the speed response of the DC motor changes as a result, which may cause disturbance and lose the stability of the control system.

This invention was made in order to solve the above problems, GD ² of the load due to gear backlash,
The purpose of the present invention is to obtain a control device for a DC motor that configures a control system so that speed control is switched from speed feedback control to voltage control when there is a change, and that speed fluctuation disturbance is prevented and stable control is possible. To do.

[Means for Solving the Problems]

The control device for the DC motor according to the present invention is a voltage detector that obtains a voltage signal by detecting the armature current of the DC motor, and the speed feedback signal when the fluctuation of the flywheel effect GD ² applied to the DC motor is a predetermined value or less. Is taken into the operational amplifier via a normally-closed contact, and an operational unit that amplifies the speed feedback signal, and the operational unit detects the fluctuation when the fluctuation of GD ² exceeds a predetermined value, and the operational unit And a normally open contact for inputting the voltage signal of the voltage detector to the operational amplifier.

[Work]

The control device of the DC motor in this invention is a voltage reference signal of the speed reference signal generation circuit and the voltage detected armature current by the voltage detector against the unstable phenomenon of the speed control system due to the GD ² change of the load of the DC motor. In order to obtain the stability of the control system, the instability phenomenon of the control system caused by the velocity disturbance is eliminated by switching to the voltage control system that returns the deviation of the above.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as those in FIG. 2 are shown with the same reference numerals. In FIG. 1, 24 is a voltage detector for detecting the DC voltage of the thyristor converter main circuit 2, and 25 is the rate of change of the speed feedback signal N. , A calculator for operating the normally closed contact 26b and the normally closed contact 26a so as to switch the feedback signal given to the operational amplifier 11 from the output of the speed sensor 9 to the output of the voltage detector 24 when the value is faster than a certain value, and 27 is a direct current A motor controller, 28 is a DC motor driver.

Next, the operation of the present invention will be described. First, the operation when the speed control of the DC motor 3 is performed is the same as that of the conventional device, but if the speed control system becomes unstable due to speed disturbance, or if there is a possibility of becoming unstable, the speed control is performed. The feedback control signal is switched from the control system to the voltage control system for control. That is, it operates as follows.

For example, the roll 5 is a GD ² and the load of the DC motor 3 GD ²
When the ratio between the speed sensor 9 and the speed controller reaches about 1; 60, the speed feedback signal N output from the speed sensor 9 changes abruptly. Then, the speed feedback signal N overshoots the speed reference signal N ^* output from the speed reference signal generation circuit 10, resulting in loss of stability of the speed control system. That is, a hunting phenomenon occurs in the speed of the DC motor 3. Therefore, the speed feedback signal N
If the rate of change of is higher than a predetermined value, the computing unit 25 monitors its state and operates immediately, turning the normally closed contact 26b off and the normally open contact 26a on from the speed control system to the voltage control system. Switch.

The speed reference signal N ^* of the speed reference signal generation circuit 10 outputs the value as it is. If the field current If is constant,
This is because the speed feedback signal N and the voltage V are proportional to each other.
Then, the control system operates so that the voltage V is stably suppressed so as not to be easily affected by the speed disturbance, and the overshoot is reduced.

Further, in the above-described embodiment, the case where the armature current reference Ia ^* of the thyristor converter main circuit is controlled has been described, but another converter main circuit electronic switch may be used and the same effect as that of the above-described embodiment can be obtained. Play.

〔The invention's effect〕

As described above, according to the present invention, when the rate of change of the speed of the DC motor is not larger than the predetermined value, the armature current reference signal is set according to the deviation between the speed of the DC motor and the speed reference signal. When the speed and the rate of change of the DC motor are larger than the predetermined values, the armature current reference signal is set according to the deviation between the DC voltage of the AC / DC power conversion means and the speed reference signal. Even if the flywheel effect of the load fluctuates due to backlash, etc., the stability of the control system can be maintained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a DC motor controller according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional DC motor controller. In the figure, 2 is a thyristor converter main circuit (AC / DC power converter), 3 is a DC motor, 9 is a speed sensor, 10 is a speed reference signal generating circuit, 11 is an operational amplifier, 20 is an operational amplifier,
24 is a voltage detector and 25 is a calculator. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An inverter for converting AC power output from an AC power supply into DC power and supplying the DC power to a DC motor.
Direct power conversion means, speed detection means for detecting the speed of the DC motor, armature current detection means for detecting the armature current of the DC motor, and voltage for detecting the DC voltage of the AC / DC power conversion means. A detection unit, a determination unit that monitors the rate of change of speed detected by the speed detection unit and determines whether the rate of change is greater than a predetermined value, and the rate of change of the speed is a predetermined value by the determination unit. If it is determined that it is not larger, the armature current reference signal is set according to the deviation between the speed detected by the speed detection means and the speed reference signal, while the speed change rate is set to a predetermined value by the judgment means. If it is determined that the armature current reference signal is greater than the above, the armature current reference signal is set according to the deviation between the DC voltage detected by the voltage detection means and the speed reference signal, and the set armature current reference signal and the above-mentioned Control device for a DC motor and a control means for controlling the gate of the exchange-linear power conversion means based on the deviation of the armature current detected by the armature current detecting means.