Sensorless Control of Synchronous Reluctance Motors via Sliding Mode Disturbance Observer Compensation

Synchronous reluctance motors (SynRMs) have gained significant attention in industrial and automotive applications due to their cost-effectiveness.However, the practical implementation of sensorless control for SynRMs faces critical challenges. Existing sensorless control strategies employ high-frequency signal injection (HFSI) methods at low speeds and hybrid flux observers at medium-high speeds. Nevertheless, model-based hybrid flux observers are severely affected by internal and external disturbances, leading to degraded observation accuracy and compromised control stability. This paper proposes a novel control framework incorporating a sliding mode disturbance observer (SMDO) for compensation. The SMDO theoretically achieves finite-time convergence to the sliding manifold, enabling zero-error disturbance estimation. A unified disturbance modeling approach is introduced to systematically characterize total disturbances, which are then actively estimated and compensated by the SMDO. Simulation results demonstrate that the proposed algorithm significantly enhances control accuracy and robustness.