Comparative Analysis and Optimization of Power Loss Based on the Isolated Series/Multi Resonant Three-Port Bidirectional DC-DC Converter

Based on the loss distribution and efficiency analysis, a comparative study between a series resonant three-port bidirectional DC-DC converter (SR-TBC) and a multi-resonant three-port bi-directional DC-DC converter (MR-TBC) is reported here. By using the Fourier equivalent analysis method in hand, the resonant current, switching current expressions, zero voltage soft switching (ZVS) conditions of MR-TBC and SR-TBC are deduced. Besides, in consideration of efficiency and soft switching aspects, the loss models of main power components and resonant elements are integrated and optimized for both topologies. Their loss distributions are established, and the different effects derived from the adoption of SiC MOSFET and Si MOSFET on the converter efficiency are discussed. Finally, to verify the theoretical analyses, comparative experiments under diverse load states are conducted based on the prototypes of the MR-TBC and SR-TBC. The obtained results demonstrate that the MR-TBC successfully broadens the ZVS range and thus achieves higher efficiency along the entire load range.