Soft-Switched Single Inductor Single Stage Multiport Bidirectional Power Converter for Hybrid Energy Systems

A soft-switched nonisolated multiport bidirectional converter is proposed for hybrid energy system applications. The proposed topology improves the efficiency and expands the applications of the conventional three-port converter (TPC) by adding a soft-switching cell and a bidirectional power flow path from output to charge the energy storage device. Moreover, soft-switching conditions for all TPC switches in all operating modes are achieved. The topology uses one inductor that is shared by all power flow paths. Thus, power conversion in all operating modes is done in a single-stage and the conduction loss is reduced. To implement the soft-switching cell, coupled inductors are used to optimize the magnetic core and volume of the converter. Various converter operating modes are presented, and design considerations are discussed. Moreover, different control system operating modes are explained and designed in detail. Finally, a converter prototype to supply a 250 W–200 V load is implemented, and the theoretical analysis is validated by the experimental results.