An Improved Sliding Mode Control for PMSM Considering Sliding Mode Chattering and Disturbance Compensation

An improved sliding mode control strategy for permanent magnet synchronous motor (PMSM) using novel reaching law and improved extended state observer is proposed to solve problems of sliding mode chattering, load disturbances and poor control accuracy in traditional sliding mode control system for PMSM. Firstly, a novel reaching law is proposed to solve the problem of sliding mode chattering, and an integral sliding mode controller based on the novel reaching law is designed in speed loop. The chattering suppression effect of the novel reaching law is analyzed by a difference equation. Secondly, a sliding mode control law is added to the extended state observer to solve the problem of disturbance compensation and to improve the adaptive ability of observer, and an improved extended state observer is designed to estimate disturbance torque. Then, the estimated disturbance torque value is served as a feedforward signal to compensate sliding mode controller in speed loop. The stability of the proposed control strategy is proved by Lyapunov criterion. Simulation results, and a comparison with the traditional sliding mode control show that the proposed controller obtains very nice system respond, effectively suppresses the sliding mode chattering and improves the estimation accuracy of torque and the control accuracy of system when the motor starts and is subjected to load disturbances. © 2020, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.