Abstract:The flexible interconnected distribution network with DC distribution center (DDC) as the core can realize closed-loop operation of multiple feedback lines, which is of great significance for improving the reliability operation level of distribution network and the ability to absorb new energy. Based on DDC, this paper focuses on the DC micro-network access technology with DAB as the core. Firstly, the basic structure and working principle of DAB are analyzed, and the corresponding control strategies are designed. Then, the simple DC micro-grid and related models with photovoltaic and DC loads are introduced. Finally, the four-terminal AC-DC flexible interconnection is built by using PSCAD/MTDC. The power distribution system verifies the technical feasibility of interconnecting the DC microgrid with the DDC through DAB. The result proves that the DC power distribution center system can operate stably, and the DC transformer can realize the technical requirements of DC microgrid access. When the steady state and the disturbance are disturbed, the system can maintain stable operation and the load power supply is not affected.