Characteristics of Interior Permanent Magnet Synchronous Motor with Imperfect Magnets

Abstract

This paper investigates the effect of permanent magnet demagnetization on the performance of interior permanent magnet synchronous motors (IPMSMs). In our study, magnetic demagnetization was imitated by decrease in magnet volume. The demagnetization level in our study is less than that in previous research studies, that is, the volume of PMs is reduced in the radial and axial directions by 2.5, 5.0, and 7.5%. Simulation results show that the stator current is useful for fault detection of a PMSM with a demagnetized PM under constant V/f open-loop control. Further, for detecting a demagnetized PM within a PMSM under vector control, stator voltage is useful except in the middle torque range: the stator current is useful in a large torque range. The simulated results are verified through experiments.