JPH0759377A - Motor driver - Google Patents

Abstract

PURPOSE:To suppress the speed ripple at changeover of magnification by adding corrective speed to a speed command when changing over the magnification of an operating means converting commands into speed commands. CONSTITUTION:A gain changeover signal 3 is inputted into a position loop gain multiplier 2 and a speed control computing element 6 so as to change over each gain. And, when a position command 1 is inputted into the position loop gain multiplier 2, the position command 1 becomes a speed command, being increased by position loop gain after gain changeover times. At the time of this gain changeover, the gain of a gain multiplier 2 and a speed command being operation results and the gain of a speed control computing element 6 change into step shape. At the same time with it, corrective speed commands in saw shape are outputted from a corrective speed command generator 4. And, the speed command of the output of the position loop gain multiplier 2 and the corrective speed command of the output of the corrective speed command generator 4 become smooth waveforms, being added to each other in an adder 5, and those are inputted into a speed control computing element 6, and are increased by speed loop gain after gain changeover times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive device used in industrial machines and the like.

[0002]

2. Description of the Related Art Conventionally, a motor drive device has a gain switching function for switching a loop gain according to a position deviation or the like.

A conventional motor drive device will be described below. FIG. 3 is a block diagram of a conventional three-phase synchronous motor drive device. In FIG. 3, 1 is a position command for driving the motor 12 to a certain position, 2 is a position loop gain multiplier that multiplies the position command 1 by a position loop gain, and converts it into a speed command, and 6 is a position loop gain multiplier. A speed control calculator that multiplies the speed command that is the output of 2 by a speed loop gain and converts it into a torque command. Reference numeral 3 represents a plurality of gains of the position loop gain multiplier 2 and a plurality of gains of the speed control calculator 6. A gain switching signal for switching according to the position deviation between the command 1 and the position of the motor 12, 7 is a magnetic pole detector for detecting the magnetic pole of the motor 12 from the encoder 11, and 8 is a torque command and magnetic pole output from the speed control calculator 6. A multiplier for multiplying the magnetic pole data detected by the detector 7, 9 is a D / A converter for D / A converting the current command output from the multiplier 8, and 10 is D / A. Amplifies the current command which is D / A converted current amplifier for supplying current to the motor by inverter 9, 13 is a speed detector for performing speed detection by the signal from the encoder 11.

The operation of the motor drive device configured as described above will be described below. First, according to the position deviation, the gain switching signal 3 as shown in FIG.
When is input to the position loop gain multiplier 2 and the speed control calculator 6, the position loop gain multiplier 2 and the speed control calculator 6 switch the gains. When the position command 1 is input to the position loop gain multiplier 2, the position command 1
Is multiplied by the position loop gain after gain switching, and becomes a speed command, which is input to the speed control calculator 6. Further, the speed control calculator 6 receives the speed command output from the position loop gain multiplier 2, and the speed command is multiplied by the speed loop gain after the gain switching to be a torque command, which is input to the multiplier 8. The multiplier 8 multiplies the torque command output from the speed control calculator 6 by the magnetic pole data detected by the magnetic pole detector 7 and outputs it as a current command to the D / A converter 9. The D / A converter 9 D / A converts the current command output from the multiplier 8 and outputs it to the current amplifier 10 in the subsequent stage. In the current amplifier 10, the D / A converter 9
The A-converted current command is amplified to supply current to the motor 12 to drive the motor 12.

[0005]

However, in the above-mentioned conventional configuration, the gain switching signal 3 as shown in FIG.
When the position command 1 is input to the position loop gain multiplier 2, the position command 1 is input to the position loop gain multiplier 2 and the speed control calculator 6 when the position command 1 is input to the position loop gain multiplier 2. The position loop gain after gain switching is multiplied to become a speed command, and this speed command is multiplied by the speed loop gain after gain switching at the speed control calculator 6 to become a torque command. At this time, since the position loop gain multiplier 2 and the speed control calculator 6 switch the loop gain from a large gain to a small gain or from a small gain to a large gain, the loop gains of the position loop gain multiplier 2 and the speed control calculator 6 are There is a stepwise change, and accordingly, the speed command, which is the calculation result of the position loop gain multiplier 2, changes in a stepwise manner. Further, the torque command, which is the calculation result of the speed control calculator 6 to which the step speed command is input, also changes stepwise. The stepwise torque command is input to the multiplier 8 and multiplied by the magnetic pole data detected by the magnetic pole detector 7, and the multiplication result becomes a stepwise current command, which is input to the D / A converter 9. The stepwise current command is D / A converted by the D / A converter 9 and transmitted to the current amplifier 10 in the subsequent stage. And
The current amplifier 10 amplifies the stepwise current command D / A converted by the D / A converter 9 and supplies a current to the motor 12 to drive the motor 12, but the operation of the motor 12 is affected by gain switching. There is a problem that it cannot follow the stepwise current command and has a velocity ripple as shown in FIG. 4 (b).

[0006]

In order to solve the above-mentioned problems, the present invention increases the magnification of the calculation means for multiplying the difference between the control command input from the outside and the rotational position of the motor by a predetermined value and converting it into a speed command. It is provided with an output means for outputting a sawtooth speed command when switched, and an addition means for adding the output of the output means to the output of the arithmetic means.

[0007]

With the above structure, the present invention can suppress the speed ripple at the time of switching the magnification by adding the correction speed to the speed command when switching the magnification of the calculating means.

[0008]

1 is a block diagram of a three-phase synchronous motor drive device according to an embodiment of the present invention. In FIG. 1, 1 is a position command for driving the motor 12 to a certain position, 2 is a position loop gain multiplier that multiplies the position command 1 by a position loop gain and converts it into a speed command, and 4 is a gain switching signal 3 A correction speed command generator that generates a correction speed command when the value is switched is an adder 5 that calculates the speed command that is the output of the position loop gain multiplier 2 and the output of the correction speed command generator 4, Is a speed control calculator that multiplies the speed command output from the adder 5 by a speed loop gain and converts it into a torque command. Reference numeral 3 is a plurality of gains of the position loop gain multiplier 2 and a plurality of speed control calculators 6. A gain switching signal for switching the gain according to the position deviation between the position command 1 and the position of the motor 12, 7 is a magnetic pole detector for detecting the magnetic pole of the motor 12 from the encoder 11, and 8 is a speed control. Multiplier for multiplying the pole data detected by the torque command and the pole detector 7 which is the output of the arithmetic unit 6, 9
Is D / A that converts the current command output from the multiplier 8 into a D / A signal.
A / D converter 10 is D / A by D / A converter 9.
A current amplifier that amplifies the converted current command and supplies a current to the motor 12, and a speed detector 13 that detects a speed by a signal from the encoder 11.

The operation of the motor drive device of the present invention constructed as above will be described below.

First, when a gain switching signal 3 as shown in FIG. 2A is input to the position loop gain multiplier 2 and the speed control calculator 6 according to the position deviation, the position loop gain multiplier 2 and the speed control signal 6 are input. The control calculator 6 switches the gain. Then, the position command 1 is the position loop gain multiplier 2
Is input to the position command 1, the position command 1 is multiplied by the position loop gain after the gain switching to become the speed command. In this gain switching, the position loop gain multiplier 2 and the speed control calculator 6 switch the gain from a large gain to a small gain, so that the gains of the position loop gain multiplier 2 and the speed control calculator 6 change in steps. do. Along with this, the speed command which is the calculation result of the position loop gain multiplier 2 also changes stepwise as shown in FIG. At the same time, when the gain switching signal 3 is input from the correction speed command generator 4, a sawtooth correction speed command as shown in FIG. 2C is output. Then, the stepped speed command output from the position loop gain multiplier 2 and the sawtooth corrected speed command output from the corrected speed command generator 4 are added by the adder 5 and are added as shown in FIG. It becomes a smooth waveform and is input to the speed control calculator 6 and multiplied by the speed loop gain after gain switching. The torque command as the calculation result of the speed control calculator 6 also changes smoothly as shown in FIG. This torque command is input to the multiplier 8 and multiplied by the magnetic pole data detected by the magnetic pole detector 7, and the multiplication result becomes a current command, which is input to the D / A converter 9. This current command is D / A converted by the D / A converter 9 and transmitted to the current amplifier 10 in the subsequent stage. Then, the current amplifier 10 amplifies the current command D / A converted by the D / A converter 9 to amplify the current command.
The electric current is supplied to 2 to drive the motor 12. The operation of the motor 12 is driven by the smooth current command even if the position loop gain multiplier 2 and the speed control calculator 6 switch the gain from the large gain to the small gain or from the small gain to the large gain. Since the motor 12 can follow a smooth current command without being affected by the gain switching, the speed fluctuation due to the gain switching becomes small, and the speed of the motor 12 after the gain switching is shown in FIG.
As shown in, the speed ripple becomes smaller.

[0011]

As described above, in the motor drive device according to the present invention, the difference between the control command input from the outside and the rotational position of the motor is multiplied by a predetermined value, and the magnification of the calculation means for converting into the speed command is switched. In this case, by providing the output means for outputting the sawtooth speed command and the adding means for adding the output of this output means to the output of the calculating means, the correction speed is added to the speed command when the magnification of the calculating means is switched. By doing so, the speed ripple at the time of switching the magnification can be suppressed, and stable motor control with good settling becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram of a three-phase synchronous motor drive device according to an embodiment of the present invention.

FIG. 2 is a timing chart of a three-phase synchronous motor drive device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a conventional three-phase synchronous motor drive device.

FIG. 4 is a timing chart of a conventional three-phase synchronous motor drive device.

[Explanation of symbols]

 1 Position command 2 Position loop gain multiplier 3 Gain switching signal 4 Correction speed command generator 5 Adder 6 Speed control calculator 7 Magnetic pole detector 8 Multiplier 9 D / A converter 10 Current amplifier 11 Encoder 12 Motor 13 Speed detector

Claims (1)

[Claims] 1. A position detection means for detecting a difference between a control command for controlling a rotational position of a motor inputted from the outside and a rotational position of the motor, and a signal from the position detecting means multiplied by a predetermined value to obtain a speed command. Calculation means for switching the magnification to be converted according to the position deviation, speed detection means for detecting the difference between the speed command from the calculation means and the speed of the motor, and the speed of the motor is controlled by the signal from the speed detection means. And output means for outputting a sawtooth speed command when the magnification of the arithmetic means is switched, and addition means for adding the output of the output means to the output of the arithmetic means. A motor drive device characterized in that