Fixed-Time Disturbance Rejection Control for PMSM Drives via Estimation-Error Compensation and a Fuzzy Event-Triggering Mechanism

Disturbance observers are cornerstone techniques for enhancing the robustness of permanent magnet synchronous motor drives. However, restricted observer bandwidth and time varying external disturbances often result in inevitable estimation errors, thereby compromising high-precision tracking performance. Existing estimation-error compensation methods often rely on discontinuous switching terms, which inevitably lead to severe chattering and require prior knowledge of disturbance bounds that is difficult to obtain. To overcome this limitation, this paper proposes a fixed-time disturbance rejection control strategy featuring an active estimation-error compensation mechanism without prior knowledge. First, a fixed-time disturbance observer is constructed to rapidly reconstruct system disturbances. Unlike conventional asymptotic or finite-time observers, the proposed observer guarantees a deterministic settling time, regardless of initial estimation errors, ensuring its applicability in all situations. To counteract the detrimental effects of observation residues on tracking precision, an active compensation mechanism is incorporated into the control law. Furthermore, a fuzzy hybrid event triggering mechanism is introduced to optimize communication resource utilization. By dynamically adjusting the triggering threshold based on system states, the computational burden is significantly reduced while maintaining satisfactory control performance. Theoretically, the closed-loop system is proven to be practically fixed-time stable via Lyapunov analysis. Extensive comparative experiments have demonstrated that the proposed approach is superior to other state-of-the-art approaches in terms of both disturbance rejection and dynamic response.