Magnet temperature estimating system for synchronous electric motor

Abstract

A magnet temperature estimating system for a synchronous electric motor having a permanent magnet includes: a superimposing unit configured to superimpose a voltage or current of a frequency different from a frequency of a fundamental wave driving the synchronous electric motor on at least a d-axis of the synchronous electric motor; a calculator configured to calculate an impedance of the synchronous electric motor from the superimposed voltage or current and a current or voltage obtained by the superimposing; and a magnet temperature estimating unit configured to estimate a temperature of the permanent magnet on the basis of the calculated impedance.

Dependencies are inferred from the claim text.