A Fully-Isolated Triple-Ports Bidirectional DC-DC Converter Based on Integration of Dual-Activebridge and LLC Resonant Converter

A fully-isolated triple-ports bidirectional DC-DC converter based on integration of dual-active-bridge and LLC resonant converter is proposed for energy storage applications in this paper. The proposed topology stems from integrating the dual-active-bridge (DAB) converter and LLC resonant converter; therefore, the proposed converter has both the performance from both of the two kinds of converters. The power flow of the proposed topology is directional inherits from the DAB converter; what's more, all of the power switches can achieve zero-voltage switching turn on (ZVS) over the full load range which inherits from the LLC resonant converter. Furthermore, the triple ports in the proposed topology are isolated from each other by the high frequency transformer. Therefore, the proposed topology can provide triple ports with high efficiency and small size. Finally, a 1.2 kW experimental prototype is built to verify the feasibility and effectiveness of the proposed topology. Both of the forward and backward experimental waveforms under full load are presented to demonstrate the feasibility of the proposed topology. Efficiency curves are measured to demonstrate the effectiveness, the efficiency is above 90 % over the full load range, and the maximum efficiency is as high as <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{9 6. 5 \%}$</tex>.