An Isolated Multi-port Forward-Flyback Converter for Integration of PV strings and Battery Storage Systems in Solar Power Plants

In this paper, an isolated multi-port DC-DC converter is proposed for application in solar power plants. The design of the proposed converter combines a forwardflyback topology with an improved SEPIC converter. The proposed converter offers a high voltage gain, bidirectional power flow capability for the battery port, low input current ripple, and galvanic isolation between input and output ports, which make it well-suited for solar systems equipped with battery storage. Additionally, an energy management algorithm is proposed to optimize and stabilize power management through the proposed converter. This algorithm manages power flow between the storage system, solar panels, internal loads of the power plant, and both DC and AC busbars. Finally, the validity of the derived relationships from the analysis of the proposed converter under various operating modes is confirmed through simulation results.