Nonlinear feedback control of compound active-clamp soft-switching three-phase PFC converter base on load observer

Abstract

The compound active-clamp zero-voltage switching (CAC-ZVS) three-phase power factor correction (PFC) converter is a kind of improved topology converter used for high efficiency and high power factor applications. The load of the converter varies with the working condition. The conventional control methods cannot adapt to such variation and lead to the degraded performance. To solve this problem, we proposed a nonlinear feedback control method with the sliding-mode observer. The sliding mode observer is developed to estimate the uncertain load online, and then the load estimation is used in nonlinear feedback controller to regulate the output voltage. This method does not need the load information in the controller design process, avoiding the difficulty faced with many existing methods. Comparison results of the proposed method to the conventional PI control and the feedback linearization control methods show the priority of the proposed method.