Design and analysis of a five-phase flux-intensifying fault-tolerant permanent-magnet motor with active sensorless strategy under multimode operation

In this paper, a new flux-intensifying fault-tolerant permanent magnet synchronous motor (FI-FTPMSM) is proposed to improve sensorless operating capacity under multimode operation including fault conditions. Most previous studies regarding fault-tolerant motors aim to improve fault-tolerant capability but suffer the saliency characteristic problem, which is unfavorable for sensorless control. In this study, an active sensorless strategy is developed by considering the sensorless operating capability under multimode operation in the motor design stage. Based on this novel idea, a new FI-FTPMSM with a high inverse saliency ratio is designed. By carefully choosing slot-pole combination, subtly setting q-axis magnetic barrier shape, and improving air gap waveform, the superior inverse saliency characteristic is obtained, which effectively improves the dynamic and steady-state sensorless operating performance. Through simulation analysis and experimental tests, the rationality and validity of the proposed strategy are verified.