A Robust Deadbeat Predictive Power Control with Sliding Mode Disturbance Observer for PWM Rectifiers

This paper presents a robust deadbeat predictive power control (DBPC) for PWM rectifiers with consideration of parameter mismatches. To achieve accurate power control with crude estimations of the grid-side impedance, the system disturbance caused by inaccurate parameter is analyzed. Then, a complex power based sliding-mode disturbance observer (SMDO) is proposed. Both DBPC and SMDO are implemented in the stationary alpha-beta frame without coordinate transformation. Unlike the observer designed in the synchronous reference frame, the disturbance in stationary frame is not a DC component but varies at the frequency of grid voltage. Due to the coupling between alpha- and beta- axis components, it is not a easy task to analyze system performance using scalar notation. For compact representation and to facilitate the analysis of tracking error in terms of phase angle and magnitude, the proposed SMDO is designed based on complex state variables. Theory analysis confirms that the proposed SMDO can track the system disturbance without phase lag or magnitude error. Both simulation and experimental results validate the effectiveness of the proposed scheme.