Motor control device, motor magnetic flux estimating device, and magnetic flux estimating method

Abstract

The present invention provides a motor control device, a magnetic flux estimation device for a motor, and a magnetic flux estimation method, which can detect stator magnetic flux with high accuracy. The motor control device in the embodiment includes a magnetic flux estimator for estimating the vector of the stator magnetic flux of the motor based on the difference between the output voltage from the power converter to the motor and the amount of voltage drop caused by the winding resistance of the motor. The magnetic flux estimator includes a variable low-pass filter and a phase adjuster. The variable low-pass filter performs low-pass filtering processing on the difference at a cutoff frequency corresponding to the frequency of the output voltage. The phase adjuster delays the output phase of the variable low-pass filter or the phase of the difference before input to the variable low-pass filter.

Description

technical field [0001] The disclosed embodiments relate to a motor control device, a magnetic flux estimating device for a motor, and a magnetic flux estimating method. Background technique [0002] There is known a control device that drives a motor such as a synchronous machine or an induction machine without using a position sensor. For example, there is known a technique of estimating the stator magnetic flux of the motor from the current and voltage of the motor, and controlling the motor based on the estimated stator magnetic flux (for example, refer to Patent Document 1). [0003] Patent Document 1: Japanese Patent Laid-Open No. 2012-228083 [0004] However, when an integrator is used to estimate the stator magnetic flux, if there is an offset error in a current detector that detects the current of the motor, an offset may occur in the estimated value of the stator magnetic flux. Therefore, vibrations corresponding to the drive frequency of the motor may be included...

AI Technical Summary

Problems solved by technology

[0004] However, in the case of stator flux estimation using an integrator, when there is an offset error in the current detector that detects the current of the motor, an offset may occur in the estimated value of the stator flux

Therefore, vibration corresponding to the driving frequency of the motor may be included in the speed or phase obtained from the estimated value of the stator magnetic flux, and the motor may not be controlled with high precision.

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