Medium-to-High Speed Range Sensorless Control of SRM Drives Based on Unaligned Rotor Position Estimation

This article proposes a sensorless control strategy for medium-to-high speed range operation of switched reluctancemotors (SRMs) based on the unaligned rotor position estimation. By leveraging reluctance characteristics, the unaligned rotor position is estimated during each phase excitation period by detecting the negative zero-crossing point of the phase reluctance slope, enabling accurate rotor speed and position estimation. Under the current chopping control (CCC) mode, high-frequency pulse injection is used to compensate for the phase reluctance curve. Under angle position control (APC) mode, the advancement of the TURN-ON angle allows the negative zero-crossing point of the phase reluctance slope to be directly detected. A mode-switching strategy is proposed to ensure smooth transitions between the two modes, enabling dynamic switching between CCC and APC modes within the sensorless control framework. Additionally, a remedial measure based on fault phase skipping (FPS) is introduced to address phase failure, enabling the SRM to operate normally under phase failure conditions and improving its fault tolerance. Finally, the proposed position sensorless control strategy is validated experimentally on a six-phase SRM.