JPH06245582A - AC servo motor drive - Google Patents

Abstract

(57) [Summary] [Object] To provide an AC servo motor drive device that reduces torque due to phase delay of the phase current when the AC servo motor rotates at high speed, and reduces current (torque) ripple when switching the excitation phase. . [Composition] The phase of the commutator is calculated from the position data and the speed data detected by the position detecting means 8 and the speed detecting means 9, the phase delay at the time of high speed rotation is compensated, and at the same time, the phase change is detected, so that the high speed Suppresses torque reduction during rotation and reduces torque ripple during excitation phase change A
Obtain the C servo motor controller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC servo motor driving device for performing digital current control, and particularly for compensating for a phase delay of a phase current at a high speed rotation of an AC servo motor and a torque ripple when an exciting phase changes.

[0002]

2. Description of the Related Art In recent years, servo motor control devices have taken advantage of improved performance and maintenance free, and have been able to perform analog control instead of digital control and DC servo motor to AC control.
It has been moved to a servo motor. An example of a conventional servo motor control device will be described below with reference to the drawings.

FIG. 3 shows a drive unit of a conventional digitally controlled AC servo motor controller. In FIG. 3, 1 is a current detection means for detecting a current flowing in the motor, 2 is a commutation signal for detecting the phase of the commutator of the AC servomotor, and 3 is an excitation phase for outputting an excitation command 4 from the commutation signal 2. Determination means,
Reference numeral 5 is a drive means for converting the torque command into a PWM signal and driving the servo motor based on the excitation command, 6 is an AC servo motor, and 7 is an encoder.

The operation of the AC servo motor driving device constructed as described above will be described below.

The drive means 5 has a torque command and an excitation command 4
Based on the above, the AC servomotor 6 is driven, but the current flowing in the AC servomotor 6 is fed back by the current detection means 1 and the difference from the torque command is input to the drive means 4 to drive the AC servomotor.

[0006]

However, in the above control method, high-speed and high-precision current detection means is required for digital control, and the feedback is delayed due to the calculation speed. Therefore, there is a problem that it is not possible to compensate for a decrease in torque output due to a phase delay of a phase current at high rotation and a torque ripple generated when the excitation phase of the AC servo motor changes.

The problem will be described below with reference to the drawings. FIG. 4 shows a commutation signal of an AC servomotor according to the conventional control method and a current waveform / composite current waveform of each phase. When the excitation phase changes, the falling speed of the current of the phase in which the current flows and The current ripple (torque ripple) occurs when the exciting phase is switched because the rising speed of the current of the next flowing phase is different. Also, the excitation command 4 is delayed due to the calculation time in digital control,
The phase delay of the phase current at the time of high speed rotation becomes large, and the torque decreases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a servo motor driving device that reduces the phase delay of the phase current during high speed rotation and the torque ripple generated when the excitation phase of the AC servo motor changes.

[0009]

In order to achieve the above object, the AC servo motor drive device of the present invention comprises an excitation phase determining means for inputting position data / speed data and a commutation signal and outputting an excitation command. I have it.

[0010]

According to the present invention, with the above configuration, the phase delay of the phase current is compensated by the position data and the speed data, and at the same time, the change of the excitation phase is detected by the position data and the speed data, and the combination with the commutation signal is performed. As a result, the torque ripple when switching the excitation phase is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a drive unit of a control device for an AC servomotor according to the present invention. Members having the same purpose as those of the conventional example shown in FIG. In FIG. 1, 3
Is an excitation phase determining means for outputting an excitation command 4 based on position data / speed data and a commutation signal, 8 is a position detecting means for detecting a current position, and 9 is a speed detecting means for detecting a rotation speed.

The operation of the AC servomotor control device configured as described above will be described with reference to FIGS. 1, 2, and 4.

FIG. 4 shows a commutation signal of an AC servomotor according to a conventional control method and a current waveform / composite current waveform of each phase. When the excitation phase changes, the current of the phase in which the current is flowing rises. A current ripple (torque ripple) occurs when the exciting phase is switched because the falling speed and the rising speed of the current of the next flowing phase are different. Further, due to the calculation time in the digital control, a phase delay of the phase current at the time of high speed rotation occurs, and a torque decrease occurs.
Therefore, the excitation phase determining means 4 calculates the phase of the commutator based on the position data and the speed data and compensates for the delay, thereby suppressing the torque reduction due to the phase delay of the phase current during high-speed rotation, and at the same time, confirming the excitation phase. By detecting the switching and combining with the commutation signal, the torque ripple at the switching of the excitation phase can be reduced.
(Fig. 2 shows the calculated phase of the commutator at that time, the commutation signal, and the current waveform and combined current waveform of each phase.)

[0015]

As described above, according to the present invention, by providing the excitation phase determining means for inputting the position data, the velocity data and the commutation signal and outputting the excitation command, the phase current causes a phase delay during the high speed rotation. Compensate for torque reduction,
At the same time, the torque ripple generated when the excitation phase changes can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an AC servo motor drive device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between control signals in the AC servo motor drive device according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional AC servo motor drive device.

FIG. 4 is an explanatory diagram showing a relationship between control signals in a conventional AC servo motor drive device.

[Explanation of symbols]

 1 Current Detection Means 2 Commutation Signal 3 Excitation Phase Determining Means 4 Excitation Command 5 Driving Means 6 AC Servo Motor 7 Encoder 8 Position Detecting Means 9 Speed Detecting Means

Claims (1)

[Claims] 1. A current detecting means for detecting a current flowing through an AC servo motor, a position detecting means for detecting a current position, a speed detecting means for detecting a rotation speed, and a commutation indicating a phase of a commutator of the AC servo motor. An AC servo having an excitation phase determining means configured to output an excitation command to the AC servomotor based on the signal, the speed data detected by the speed detecting means, and the position data detected by the position detecting means. Motor drive device.