Composite Adaptive Observer-Based Anti-Windup Integral Predefined-Time Sliding Mode Control for Sensorless PMSM

In the operation of sensorless permanent magnet synchronous motor (PMSM), parameter uncertainty and rapidly varying loads are frequently encountered, which pose significant challenges to sensorless drive system. To address this issue, this paper proposes a unified control framework that integrates a Composite Adaptive Predefined-Time Observer (CAPTO) and an Anti-Windup Integral Predefined-Time Sliding Mode Controller (AIPTSMC). The CAPTO consists of a predefined-time back electromotive force (BEMF) observer and a nonsingular disturbance observer, enabling decoupled and independently optimized estimation of rotor states and external disturbances with high accuracy and speed, while significantly reducing phase delay and without requiring prior disturbance bounds. AIPTSMC is designed to enhance dynamic response and steady-state performance by combining predefined-time convergence and integral sliding mode surfaces, while incorporating an anti-windup strategy to suppress overshoot. This control scheme guarantees fast, robust, and stable closed-loop operation within a predefined time under strong uncertainties and load fluctuations. Experiment results verify the effectiveness and superiority of the proposed control scheme.