High Frequency Torque Pulsation Suppression Strategy for Dual Winding Permanent Magnet Synchronous Motor Sensorless Control Based on Dual High Frequency Square Wave Injection Method

To address the problem of high frequency torque pulsation in the zero-low-speed permanent magnet synchronous motor (PMSM) sensorless control by the high frequency square wave injection method, a torque pulsation suppression strategy based on the dual high frequency square wave injection method for the dual-winding permanent magnet synchronous motor (DW-PMSM) sensorless control is proposed. A high-frequency mathematical model of the PMSM is established, and the analytical relationship between the torque pulsation and the injection signal is analyzed. For a surface mounted DW-PMSM with two windings differing in γ electrical angle, the general form of the square wave signal that should be injected into the second winding is derived based on the position relationship between the two windings when the first winding is injected with a high-frequency square wave, with the objective of minimizing the equivalent high-frequency torque generated. The rotor position estimation error contained in the high-frequency signals of the two windings is extracted, and the rotor position estimation accuracy is improved by tracking the rotor position using a luenberger observer with the goal of minimizing the error. Simulation and experimental results show that the method is able to reduce torque pulsation by more than 50% and improve rotor position estimation accuracy by more than 4 times.