Three-Phase AC-DC Converter with Algorithm based Adaptive Direct Power Control Technique and Backstepping Controller

In this work, a backstepping controller for the regulation of dc bus voltage is presented for a three-phase AC-DC power converter with an algorithm based adaptive direct power control (ADDPC) technique. This controller is employed in the outer voltage control loop and the AADPC scheme is utilized in the inner control loop. The presented approach is providing better voltage regulation of the outer loop and improving the dynamic response of the ac-dc converter. Two cases are considered, in the first case the load is increased, and in the second case the load is decreased across the dc bus. Laboratory experiments are performed and from obtained results, it is observed that with the backstepping controller dc bus voltage dip and rise are also decreased as compared to the PI controller-based AADPC approach for increase and decrease of load respectively. Power ripples and percentage THD content in the supply side line current is nearly comparable under steady-state. The introduced controller with AADPC can suppress the fluctuations in the dc bus faster as compared to the conventional PI-based approach which is enhancing the system's dynamic performance.