Abstract:Traditional PI speed control and traditional sliding mode control (SMC) lead to poor speed regulation during the surface permanent magnet synchronous motor (SPMSM) operation. When the load changes and the speed changes suddenly, traditional controllers cannot well control the system and the chattering is large. To solve these problems, a new non-singular fast terminal (NSFT) sliding mode surface combined with fuzzy control is proposed to design the speed controller, which can realize SPMSM speed sensorless control. Using the continuous function υ(s) to replace the switching function in the approaching law can effectively suppress chattering. The newly designed fuzzy control rules and fuzzy parameter adaptation law can adaptively adjust the parameters in the approaching law. Meanwhile, a Lyapunov function is designed to prove the stability of the new SMC controller. The simulation results of MATLAB show that the designed NSFT-fuzzy-SMC controller has faster adjustment speed and better adjustment effect when the system state changes, the system is more robust, and the chattering is smaller during stable operation. Compared with the general SMC, it has better control performance and anti-disturbance ability.