Nonlinear Automatic Power-Decoupling Control of a Differential Buck Grid-Tied DC'AC Converter

Abstract

A nonlinear automatic power-decoupling (APD) control strategy for a single-phase grid-tied differential buck dc?ac converter is proposed in this work. The proposal implements a full-state feedback resonant controller for grid current regulation, while a feedback linearization-based control strategy is used for dc-bus voltage regulation. The approach offers good system robustness and achieves excellent dynamic response of the system, particularly in the dc-bus control loop. In addition, the proposal enables the placement of all closed-loop poles of the system at arbitrary positions, allowing precise adjustment of the dynamic response for both the grid current injection control loop and the dc-bus voltage control loop. Experimental and simulation results are presented to demonstrate the validity and effectiveness of the proposal, including the excellent control performance in the presence of mismatched storage capacitors.