Novel Buck-Type Active Power-Decoupling Control Strategy for Single-Phase Converter

The active power decoupling is an effective solution to deal with the inherent dc-link power fluctuation of single-phase converter. The available control strategies are facing the challenge of low power decoupling accuracy and complicate controller design because the reference usually include plenty of harmonics. In this paper, a buck-type active power decoupling circuit is employed to absorb the ripple power. The system model with the control object of the square of the auxiliary capacitance voltage is creatively established. Thanks to this, the reference of control object only contains a double-frequency ac component and a dc offset, the controller design could be greatly simplified and the power decoupling accuracy would increase. For the control scheme, a second order filter is used to accurately extract the double-frequency ripple power to further construct the reference. And the dual closed-loop control structure is employed to tune the control object. The effectiveness of the proposed active power decoupling strategy is verified by the simulation results.