Implementation of full-bridge three-port converters with wide input voltage range for renewable energy systems

Future renewable energy systems will need to interface several energy sources such as fuel cells, photovoltaic (PV) array with the load along with battery backup. A three-port energy management system can accommodate a primary source and storage, and combines their advantages by utilizing a single power stage that has multiple interfacing ports. A systematic method for deriving three-port converters (TPCs) from the full-bridge converter (FBC) is proposed in this paper. The proposed method splits the two switching legs of the FBC into two switching cells with different sources and allows a dc bias current in the transformer. By using this systematic method, a novel full-bridge TPC (FB-TPC) is developed for renewable power system applications which feature simple topologies and control, a reduced number of devices, and single-stage power conversion between any two of the three ports. The proposed FB-TPC consists of two bidirectional ports and an isolated output port. The primary circuit of the converter functions as a buck-boost converter and provides a power flow path between the ports on the primary side. The FB-TPC is analyzed in detail with operational principles and design considerations.