Low-Speed Sensorless Control of SynRM Drives Using Adaptive High-Frequency Injection

Abstract

This paper presents a sensorless control strategy for low-speed Synchronous Reluctance Motor (SynRM) drives based on High-Frequency Injection (HFI). The approach accounts for magnetic saturation effects and introduces an optimization framework based on a cost function to determine the injection voltage amplitude and frequency. A Sliding-Mode Controller (SMC) is employed to generate the torque reference, while a Maximum Torque per Ampere (MTPA) strategy provides the $d q$ current references by explicitly considering magnetic saturation. The effectiveness of the proposed strategy is validated through simulation results for SynRM drives. The comparative analysis demonstrates improved rotor-position tracking accuracy, reduced stator current levels, and lower HFI power consumption. Compared with the benchmark strategy, the proposed method reduces the speed-tracking root mean square error (RMSE) by approximately 22%, decreases HFI power consumption by about 23%, and limits the worst-case error to approximately 9.4%.