The cost-efficient, full ZVS range hybrid full-bridge-half-bridge family with shared lagging leg: Topology derivation, optimization design and experimental results

This paper focuses on a new dc-dc family, in which the lagging leg of a phase-shifted full bridge (PSFB) converter is also used to structure a new half bridge (HB) branch. Such a shared-lagging-leg (SLL) concept not only extends the ZVS range of lagging leg, but also provides another energy path for possible function extension, such as efficiency improvement and dynamical enhancement. In this paper, the existent SLL converters are reviewed and the general derivation of the SLL family is given, the ZVS feature in the SLL is analyzed and the possible improvements are presented. Finally, a new SLL converter integrating a current-driven PSFB and a LC resonant half bridge structures are proposed. The proposed SLL converter preserves all the advantages of its PSFB and HB counterparts, but eliminates their drawbacks, i.e., it has the minimal component amount, achieves the full ZVS range in the legs, eliminates the circle current and gets fully regulation in the output. The aforementioned analysis and design are also verified by the experimental results.