Robust Deadbeat Predictive Direct Speed Control for PMSM With Dual Second-Order Sliding-Mode Disturbance Observers and Sensitivity Analysis

A novel robust deadbeat predictive direct speed control (RDP-DSC) method for permanent magnet synchronous motor is proposed to improve the speed control bandwidth and eliminate the conventional cascaded speed control structure. First, the basic DP-DSC method with one-step ahead time delay compensation is introduced briefly. Then, the control sensitivity analysis issue on the electrical and mechanical parameter mismatches, and external disturbance and inverter nonlinearity are inspirationally discussed. Further, based on the analysis above, a novel dual second-order sliding-mode disturbance observer (SOSMDO) structure is proposed for both current and speed disturbance suppression. The proposed RDP-DSC equipped with SOSMDO is presented with full control errors completely compensated. Meanwhile, the undesired chattering phenomenon caused by the switching function in the existing popular sliding-mode observers is eliminated by the proposed SOSMDO. Rich experiments are then performed, showing that the proposed method has strong enough robustness to various parameter mismatches and external disturbances while the system still holds the DSC methods' advantages, such as high response speed and satisfying bandwidth.