Low-speed Sensorless Control of SPMSM based on Pulsated High Frequency Current Signal Injection and Detection Coils

Sensorless control of permanent magnet synchronous motor (PMSM) is important for its system integration and cost reduction, for which the high frequency (HF) voltage injection method is generally utilized for its low speed performance. However, the bandwidth limitation and estimation error respectively due to additional filters and HF impedance variation still need improvement for the voltage injection method. In this paper, a novel HF current injection method is proposed to cope with the problems mentioned above for the surface permanent magnet synchronous motor (SPMSM). The reduction of filter requirement and enhanced impedance robustness are analyzed theoretically, contributing to improved dynamic performance and estimation accuracy. which are also validated through simulations.