Nonsmooth Observer-Based Sensorless Speed Control for Permanent Magnet Synchronous Motor

The sensorless speed-regulation problem for a surface-mount permanent magnet synchronous motor (PMSM) system is studied in this paper. Firstly, a new nonsmooth observer scheme is proposed to estimate the rotor position, speed, and lumped disturbance of the system. Based on the estimated information, a composite speed controller is then designed in which the nonsmooth control technique is employed in the feedback design, and the estimated value of disturbance is used in the feed-forward compensation. By Lyapunov theory, rigorous analysis guarantees the stability of the closed-loop system and shows that the proposed method can enhance the disturbance rejection property of the system. Finally, simulation tests and experiment results are given to verify the effectiveness of the proposed method. IEEE