Improved Sensorless Control of Permanent Magnet Synchronous Motor Based on Two-stage Filter

In order to improve the performance of sensorless control system of permanent magnet synchronous motor using sliding mode observer and solve the problems of chattering and phase delay when observing rotor position, an improved sensorless control strategy of permanent magnet synchronous motor using sliding mode observer was proposed. Firstly, a hyperbolic tangent function is used to replace the traditional switching function to construct an improved sliding mode observer, and Lyapunov criterion is used to verify the stability of the system. Secondly, an adaptive low-pass filter and a Kalman filter cascade filter are designed to remove harmonics and noise in the estimated value of the back Electric Motive Force (EMF) signal. Finally, the rotor position is calculated by the arctangent function method. The simulation results show that the proposed strategy can suppress chattering and improve the dynamic and static performance of the system.