Optimization of Disturbance Rejection Performance for AC--DC--AC Converters Based on Proportional Voltage Feedforward

Abstract

To address the need for enhanced dynamic response of the DC-bus voltage and improved load power observation accuracy, this article proposes a direct capacitor power control (DCPC) strategy combined with proportional voltage feedforward. First, by introducing a proportional voltage feedforward loop, the strategy effectively suppresses the DC-bus voltage fluctuations in conventional DCPC. Simultaneously, a high-order linear extended state observer (H-LESO) is employed to achieve accurate observation of the load power, thereby enhancing the overall control performance of the system. Second, theoretical analysis based on small-signal modeling verifies the feasibility of the proposed method. Finally, experimental comparisons under three operating conditions validate the effectiveness and superiority of the proposed approach.