Analysis, Design, and Experimental Results of the Semidual-Active-Bridge Converter

A new soft-switching circuit topology derived from the popular dual-active-bridge converter (DAB) topology is proposed for applications requiring only unidirectional power flow such as the dc-dc stage of a photovoltaic power converter, and battery charger for electric vehicles. The topology named as the semidual active bridge (S-DAB) is obtained by replacing the fully active (four switches) bridge on the load side of a DAB by a semiactive (two switches and two diodes) bridge. In addition to the reduced number of active switches, the topology offers several other advantages including extended zero-voltage switching (ZVS), and smaller output filter requirement. The operating principles, waveforms in different intervals and expression for power transfer, which differ significantly from the basic DAB topology, are presented in detail. The ZVS characteristics and requirements are analyzed in detail and compared to those of DAB. A small-signal model of the new configuration is also derived. The analysis and performance of S-DAB are validated through extensive simulation and experimental results from a 1-kW hardware prototype.