A Novel Three-port Bi-directional DC-DC Converter

Multi-port bidirectional DC-DC converters have attracted special interest in applications where multiple energy sources are used. In this paper, a three-port converter with two active full bridges, a active half bridge, and a three-winding high-frequency transformer is proposed. It uses a single power conversion stage with high-frequency link to control power flow between batteries, supercapacitors, and load. The converter has capabilities of bidirectional power flow in the battery, the supercapacitor, and the load port. The converter has the advantages of reduced sized, low input current ripple. This paper presents the steady state analysis and dynamic model of this converter. An equivalent circuit based small singnal model is developed. A control strategy with the decoupled network is implemented to obtain fast dynamic response. Steady state and dynamic analysis of the converter is presented along with simulation results. Finally, a prototype is built in the laboratory and tested.