Analysis of magnet defect faults in permanent magnet synchronous motors through fluxgate sensors

This paper presents magnet defect faults detection through fluxgate sensors simply by monitoring the leakage flux content around permanent magnet synchronous motors (PMSMs). As known, flux spectrums of electric machines contain most critical and direct fault related information to monitor and characterize various faults and their progressions. In this paper, a remote/on case fault monitoring prototype is prepared which includes fluxgate sensor, signal sensing/conditioning circuit, and a microcontroller for leakage flux data streaming. In order to identify magnet defect faults in PMSMs, faults patterns in the leakage flux spectrum are exhaustively analyzed at different torque-speed profiles. Simulation and experimental results show that deployment of fluxgate sensor in magnet defect fault detection yields better results than the classical stator current analysis in PMSMs both in time and frequency domains.