A Comprehensive Review of Integrated Three-Port DC-DC Converters With Key Performance Indices

Integrated three-port DC-DC converters (TPCs) exhibit obvious advantages in achieving flexible power flow regulation among photovoltaic (PV) module port, battery port, and load/grid port in distributed PV power generating systems. In the past three to five years, many new TPC schemes have been proposed, exhibiting unique characteristics, including isolation performance, number of components, and efficiency, which cannot be accurately described using traditional TPC classification methods. Moreover, there has been a lack of comparison of key performance indicators for a large number of TPC schemes in previous studies. Therefore, a comprehensive review on circuit topologies and control techniques of TPCs by properly defining key performance indicators becomes essential for converting high fluctuation solar energy into reliable and stable power while maintaining high efficiency and small footprint. This article is just to fill this gap by a comparative analysis and overview of classical and recently reported TPC schemes with key performance indexes. After introducing main operation modes of TPCs during one day, four topological structures of TPCs composed of two or three two-port DC-DC converters are classified and comparatively analyzed. Four important indexes of TPCs, namely voltage gain, control coupling, soft switching and high-stress working, are used for a fair and comprehensive performance comparison. The advantages and disadvantages of various TPC schemes are featured, leading to a guidance for the selection of TPCs under different scenarios and valuable suggestions for the future development of TPCs.