Disturbance Observer-Based Sliding Mode Control of PMSM via Highorder Fully Actuated System Approaches

In this paper, a sliding mode control enhancement strategy for permanent magnet synchronous motor (PMSM) based on the high-order fully-actuated system (HOFAS) theory is proposed, combined with a nonlinear disturbance observer (NDO), aiming to address the limitations of the traditional dual closed-loop control structure in terms of accuracy and anti-disturbance capability. The research method starts with the construction of a HOFAS model of the PMSM to lay the foundation for the control design. The HOFA control law is derived through parameterization to ensure the stability of the closed-loop system. A global sliding mode controller is developed to enhance the system's robustness to uncertainties and disturbances. A nonlinear disturbance observer is introduced to estimate and compensate for external disturbances and load changes in real time. Simulink simulation verifies the effectiveness of the proposed strategy, which shows better transient response, steady-state accuracy, and anti-disturbance performance compared to the traditional dual closed-loop PI control and sliding mode speed control. The results highlight the advantages of this approach in high-performance PMSM applications.