Adaptive Fixed-Time Control for Permanent Magnet Synchronous Motors With Unknown Disturbances

This paper proposes an improved deadbeat predictive current control (DPCC) method and an adaptive fixed-time speed controller to enhance the current and speed tracking performance of permanent magnet synchronous motors. First, a theoretical analysis is conducted to examine the limitations of conventional DPCC in maintaining control accuracy under conditions of parameter mismatches. To address this, a fixed-time disturbance observer is designed to estimate and compensate for lumped disturbance caused by motor parameter mismatches and unknown dynamic uncertainties. Then, an adaptive fixed-time sliding mode speed controller is proposed. This controller employs a second-order integral sliding manifold, which reduces system chattering. Moreover, the designed adaptive law does not require prior knowledge of disturbance bounds, thereby reducing the over-conservatism of the controller. The stability of the system is demonstrated through Lyapunov's stability theorem. Finally, experimental results validate the effectiveness and superiority of the proposed method, demonstrating enhanced robustness, reduced overshoot, and shorter response times.