Abstract:It provides technical support for the future large-scale energy Internet formation and the access of various new energy sources, the topology structure of DC micro grid is designed, this paper proposes a four port ring DC grid topology, realization of AC power grid, the energy storage unit, DC load, wind power and photovoltaic power and DC power grid interconnection. Firstly, the interface mode and related technical parameters for AC power grid and DC power grid are studied, and the technical configuration of the interface such as photovoltaic power generation, wind power generation and energy storage unit is proposed. Secondly, the start-stop timing sequence of the whole DC micro grid is studied, the DC power grid connection mode , the voltage level and capacity is designed, Finally, the simulation model of DC park system is built based on MATLAB Simulink platform, and then the typical working conditions are simulated and analyzed: (1) the energy storage unit by the discharge to the point of zero energy; (2) the energy storage unit is charged to full energy; (3) power reversal of VSC1 converter; (4) load jump; (5) the energy storage unit is discharged to charge. These conditions basically contain the possible running state of DC micro grid, which has a higher reference value for the operation and management of DC micro grid.