Active Power Decoupling Method based on Dual Active Bridge Converter without additional components

This paper proposed an active power decoupling method using a Dual Active Bridge (DAB) converter to minimize the energy buffer in single-phase AC-DC converter applications. Single-phase converters commonly require bulky electrolytic capacitors due to their power pulsation at twice the grid frequency. However, the electrolytic capacitor often decreases the power density and lifetime of the power converter. Active power decoupling is one of the solutions to this problem by using a firm or ceramic capacitor as the energy buffer. However, the additional circuit decreases the conversion efficiency and power density.This paper proposes the active power decoupling method using a DAB converter without additional components. The Proposed method applies the feed-forward control to determine the phase shift angle for the power decoupling capability. In addition, the ZVS condition with the proposed method is considered to clarify the design of the small DC-link capacitor. The validity of the proposed method is demonstrated by the experimental result. As the experimental result, it was confirmed that the second harmonic component of the output voltage was reduced by 91.2%.