Motor control device, motor control method, and motor control system

Abstract

The motor control apparatus according to the present invention has a plurality of motor control units each controlling a shaft on the basis of an operation command from a host apparatus, and synchronizes and controls two or more motor shafts. Each of the motor control units is provided with: a control unit for controlling the operation of a motor; a command-signal generating unit for generating a command signal; a PWM-signal generating unit for generating a PWM control signal in which the pulse-width thereof is modulated on the basis of the command signal; and an inverter for generating a driving signal by switching a switching element using the PWM control signal. Also, each of the PWM-signal generating units is provided with: a superimposing-signal generating unit for generating a superimposing signal to be superimposed on the command signal; a carrier-signal generating unit for generating a carrier signal, which is a triangular wave; an adding unit for adding the command signal and the superimposing signal; and a comparing unit for comparing the superimposed command signal output from the adding unit with the carrier signal to generate a PWM control signal. The superimposing signals are signals that are different for each of the shafts controlled by the plurality of motor control units.

Description

technical field [0001] The present invention relates to a motor control device, a motor control method, and a motor control system for synchronously controlling a plurality of shafts by applying a voltage for PWM control to windings of a motor, and in particular to a motor control system with A motor control device, a motor control method, and a motor control system with a function of controlling the timing of switching operations of an inverter. Background technique [0002] In the servo motor used in FA (FACTORY AUTOMATION: factory automation), the position, speed, and torque of the motor are controlled so that the position, speed, and torque of the motor follow the drive command from the upper device (superior controller) (position command). And, as the control calculation device, digital control using a microcomputer is widely used. In the PWM (PULSE WIDTH MODULATION: Pulse Width Modulation) control method generally used to control the torque of the motor, the current ...

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Problems solved by technology

[0006] However, the noise caused by the switching operation in the inverter as described above has a great influence especially during no rotation (servo lock), low speed rotation, and low torque operation where the switching timings of the phases tend to overlap.

Furthermore, in the conventional method of superimposing the AC superimposed signal on the command signal, there is a problem that the switching timings of the U-phase to W-phase overlap during servo lock, low-speed rotation, and low-torque operation. Cannot be a solution to phenomena that generate loud noise

However, if according to Figure 12 As can be clearly seen, the timing of the switching operations of U-phase to W-phase is, for example, Figure 12 Like rising timing tr and falling timing tf in Figure 11 Similarly, overlapping between phases results in large conduction noise and radiation noise at each moment

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