Fully Symmetrical CLLC Converter Design for Plugin Electric Vehicles (PEV)

This paper proposes a design method with fully symmetrical parameters for the CLLC bidirectional converter used in plug-in electric vehicles, which obtains more consistent forward and backward characteristics. Based on the three-stage charging strategy, the half-bridge (HB) and full-bridge (FB) hybrid operating modes are adopted. The converter can work in the discontinuous region under light load to solve the problem of insufficient step-down gain. Finally, design a planar transformer with integrated leakage inductor, and a 1.2kW experimental prototype is built.