Non-Cascade Fast Nonsingular Terminal Sliding Mode Control of Permanent Magnet Synchronous Motor Based on Disturbance Observers

This paper proposes a new non-cascade fast nonsingular terminal sliding mode control algorithm based on disturbance observers for the speed control of permanent magnet synchronous motor (PMSM). To ensure the high precision control and fast finite-time convergence, a fast nonsingular terminal sliding mode controller is designed for PMSM. The novel controller adopts the single-loop non-cascade control structure. Then, to improve the anti-disturbance ability, a nonlinear disturbance observer and a dual disturbance observer are respectively designed to estimate the disturbances during motor operation, which are used for the feed-forward compensation control. The composite control method can effectively alleviate the larger chattering caused by the high sliding mode gain. Finally, the stability is proved based on Lyapunov stability theory. Simulation and experimental results show that the proposed method has the advantages of fast convergence and strong robustness against parameter variations and external disturbances.