Soft sensor design for mechanical fault detection in PMSM at variable speed

This paper presents a soft sensor (SS) used to localize mechanical faults in a Permanent Magnet Synchronous Machine (PMSM) at variable speed. The speed contains crucial information about the fault and the characteristic frequencies sought can be amplified by a proper observer design to improve the detection procedure. On the other hand, all the measurements are expressed as a function of estimated position in order to obtain a speed independent signature. An original experimental setup based on a mechanical fault emulator is proposed to validate the simulation results. Simulations and experimental results show that the proposed method is effective to amplify the single fault signatures and calculate fault indicator at variable speed.