Sensorless control with two types of pulsating high frequency signal injection methods for SPMSM at low speed

Two types of pulsating high frequency signal injection control of surface mounted permanent magnet synchronous motor (SPMSM) — pulsating high frequency voltage injection method and pulsating high frequency current injection method are studied at zero and very low speeds in the paper. The basic principle of pulsating voltage injection is analyzed in detail, and the rotor position and speed estimation system is designed to make improvements. On this basis, a novel sensorless control method based on pulsating current signal injection is proposed in this paper. The two methods are compared by theoretical analysis and simulation. The simulation results indicate that the rotor position and speed can be obtained exactly at low and zero speed by both of the methods, and the method of pulsating current injection is more simple and stable.