A Full-Bridge Three-Port Converter for Renewable Energy Application

Multi-port DC/DC converters have been widely employed in stand-alone renewable power systems to provide stable and continuous power to the electrical loads. A full-bridge three-port converter (FB-TPC) interfacing a renewable source, a storage battery, and a load is proposed. The proposed FB-TPC integrates two Buck-boost converters into the primary side of the full-bridge topology, and the magnetizing inductor of the transformer functions as an inductor. Single stage power conversion between any two of the three ports is achieved, and zero-voltage-switching for all the primary switches are achieved. As a result, high power density and high efficiency can be implemented with the proposed converter. The duty cycle of the buck-boost converter is adopted to realize the maximum power point tracking of the PV cell and the charging control of the battery, while the phase angle between the two switching legs is employed as another control freedom to achieve the output voltage regulation. The operational principles of the proposed converter are analyzed in detail and verified with experimental results.