A Method for Expanding the Operating Range of Variable-structure Multiport Converters

Traditional multi-port converters have problems such as low integration, low efficiency and complex control, while non-isolated converters have become the focus of research due to their simple structure, high efficiency and easy scalability. In this paper, a non-isolated three-port converter with variable port structure is proposed, which realizes flexible switching between Buck, Boost and Buck/Boost modes by controlling the switch, weakens the voltage constraint and expands the operating range. Based on the time scale, the control strategy is divided into three layers: modulation optimization, mode switching and variable structure switching, and the corresponding strategies are designed to optimize the performance, achieve smooth switching, and further expand its operation range.