Comparative Analysis of Magnet Thermal and Magnetization State Monitoring in PMSMs Based on High-Frequency Signal Injection

Thermal and magnetization state monitoring of permanent magnet synchronous machines (PMSMs) is important for reliability purposes. Use of magnet high-frequency (HF) resistance has been proposed both for thermal and magnetization state monitoring, as it directly depends on PM temperature and magnetization state. Machine d-axis HF inductance has been recently proposed for thermal state monitoring, though its use for magnetization state estimation remains to be explored yet. This article reviews the use of HF-signal-injection-based methods for thermal and magnetization state monitoring on PMSMs, including the use of the HF inductance for magnetization state monitoring.