A Multi-port Photovoltaic DC-DC Converter Suitable for Medium and Low Voltage DC Distribution Network and Control Strategy

The traditional photovoltaic (PV) system has a serious phenomenon of of low utilization of PV power generation due to the randomness and fluctuation of PV power generation system. Distributed PV generation system is considered as an effective way to solve the problems. This paper presents a system architecture that is Easy to expand, configurable, and prone to fault isolation. In addition, the proposed topology has a strong capability of distributed access and can be applied to different power levels and application scenarios. Using low-voltage DC as power decoupling bus of the pre-stage and last-stage of the converter, a multi-port control strategy is proposed to coordinate the power flow of PV, energy storage and output ports in both island mode and grid-connected mode. It will be of great significance to the research and promotion of PV multi-port DC distribution network.