Sensorless Control of Permanent Magnet Synchronous Motor Based on Improved SMO

Aiming at the vector control of permanent magnet synchronous motor (PMSM), a position sensorless control strategy with improved sliding mode observer (SMO) is proposed by taking advantage of the advantages of SMO, such as insensitivity to motor parameters and disturbances, fast response speed and strong robustness. In order to improve the error caused by high-frequency chattering in estimating rotor speed and rotor position of traditional SMO, the symbol function is replaced by a new saturation function to reduce the chattering with high frequency in the system; Meanwhile, the phase locked loop (PLL) is used to replace the inverse tangent function for rotor position estimation, and adopt the improved PLL, the traditional PI is replaced by the fraction-order PI, later, Lyapunov stability criterion was used to prove the stability of the improved SMO. Finally, an improved SMO positionless sensor control strategy model based on PMSM was built through MATLAB/Simulink for simulation analysis, and the program code was configured through the built model and the motor was used for experimental verification.