Abstract
This article proposes an improved adaptive sliding mode control (IASMC) based on a predefined-time disturbance observer (PTDO) to ensure the anti-disturbance capability and the accuracy of speed control for a permanent magnet synchronous motor (PMSM). The current control design is based on an improved sliding mode approach law, which can adjust the control current according to the change of PMSM state and mitigates system chattering. At the same time, the PTDO is introduced as a compensator to counteract interference and reduce control gain. The characteristic of the pre-defined time sliding mode enables the interference observer to complete the disturbance estimation in the pre-specified time. The closed-loop stability analysis is rigorously given by Lyapunov stability theory. The numerical simulation results confirm the validity of the proposed method.