A novel multi-port DC-DC converter for hybrid renewable energy distributed generation systems connected to power grid

Multi-port power converters are promising in applications such as renewable power generation systems and distributed generation systems (DGS). In this paper a novel multi-port DC-DC converter with a high-frequency isolation transformer is presented for a grid-connected hybrid renewable energy DG system without battery storage. Full-bridge power converters are employed to realize bi-directional power flow between renewable generators, load and grid. Detailed analysis is provided for a four-directional power converter in a wind-photovoltaic distributed generation system. In addition, a two loop PI control scheme is proposed to achieve constant output voltage and exact power flow management. Theoretical analyses are verified by simulations in PSPICE and MATLAB.