STEP-OUT DETECTION METHOD AND POWER CONVERSION DEVICE

摘要

Provided is a highly reliable step-out detection method which can be unaffected by noise without use of a position detector in a power conversion device for controlling the drive of a synchronous motor. A power conversion device comprises: a switching circuit for converting DC power to AC power; a PWM controller for outputting a switching control signal to control turning the switching circuit on and off on the basis of a voltage command; a current detector for detecting a current flowing in the synchronous motor; an axis error estimator for estimating the axis error between a control axis and the rotor pole axis of the synchronous motor on the basis of the voltage command and the current detected by the current detector; a frequency component extractor for extracting any frequency component of the axis error estimated by the axis error estimator; and a step-out determination unit for determining whether or not there is step-out on the basis of the frequency component extracted by the frequency component extractor.