Inductance measuring device and measuring method for synchronous motor

摘要

[Problem];For measuring the inductance of a synchronous motor, a high-speed and convenient inductance measuring device for a synchronous motor is provided.;[Solution];A three-phase high-frequency rotation voltage is applied to a synchronous motor, thereby calculating the inductance from the same frequency component as that of the high-frequency voltage included in a motor current.

主权项

1. An inductance measuring device for a synchronous motor comprising:
a voltage signal generator for generating a high-frequency voltage signal to be inputted to a voltage converter; a voltage converter for converting the high-frequency voltage signal to apply to the synchronous motor; a current detector for detecting a current of the synchronous motor; a coordinate converter for converting the current detected by the current detector into a current on an orthogonal biaxial coordinate system positioned in an arbitrary phase with respect to a fixed coordinate system, to output a current in one axis of the orthogonal biaxial coordinate system; a fundamental wave component extractor for extracting the same frequency component as that of the high-frequency voltage included in the current in the one axis of the orthogonal biaxial coordinate system; and an inductance calculator for calculating an inductance from a root-mean-square value and a frequency of the high-frequency voltage, and an output from the fundamental wave component extractor, wherein, in the generating the high-frequency voltage signal, the voltage signal generator generates a variable voltage root-mean-square value, and a three-phase high-frequency rotation voltage signal having a frequency, as a fundamental frequency, sufficiently higher compared with the maximum value of a rotation frequency at which the synchronous motor can synchronously rotate, and outputs the variable voltage root-mean-square value and the three-phase high-frequency rotation voltage signal to the voltage converter as the high-frequency voltage signal.