Study on influence of switching frequency on sliding mode control performance of permanent magnet synchronous motor

Abstract

Abstract Aiming at the deficiencies of the speed loop PI control algorithm of permanent magnet synchronous motor (PMSM) in variable working conditions, a new fast reaching law sliding mode control algorithm based on double‐power is proposed. Firstly, a new sliding mode reaching law is proposed, and the reaching law includes system state variables and the power function of the terminal attractors. It can reach the sliding mode surface at a faster speed, reduce chattering and improve system performance. Secondly, the reachability and existence of the new reaching law are proved by the Lyapunov function, and a new reaching law sliding mode controller (NRLSMC) is designed. Then, the theoretical analysis of the switching frequency of the system is carried out, and the effects of different switching frequencies on the performance of sliding mode control (SMC) of PMSM are explored. Simulation and experimental results demonstrate that the proposed NRLSMC can effectively attenuate the disadvantages of large overshoot and long transition time under variable working conditions compared with ordinary sliding mode controller (OSMC) and PI controller. Moreover, the relative optimal switching frequency that improves the above performance is obtained, and the existence of the optimal sampling period for stable convergence of the system is proved.