A three-port bidirectional DC-DC converter with zero-ripple terminal currents for PV/microgrid applications

A three-port converter (TPC) based on the Ćuk topology is proposed in this paper. The proposed converter interfaces one unidirectional input power port (envisioned to be a DC power source such as PV, or fuel cell) and two bidirectional output ports, representing the grid-tied inverter dc bus and a storage port respectively. This converter utilizes a single integrated magnetic core on which all the inductor and the transformer windings are wound. The proposed structure utilizes only three power switches, and does not require output capacitors on the output ports on account of the zero-ripple property. Depending on utilization state of the battery, three different power operation modes are defined for the converter. The features of the proposed converter are analyzed and then verified by means of simulation results for different operation conditions.