Multi mode Operation Control of DC Microgrid System

9 kinds of operation modes are designed after detailed analyzing the grid connected and islanded operation condition. For each operation mode, a coordinated control scheme for whole system based on local information is proposed to coordinate working modes between PV interface, battery energy storage interface and the netside interface, which can guarantee the DC bus voltage maintain constant, thus to ensure reliable power supply for critical loads that are sensitive to voltage changes (such as constant power load (CPL)) and the operation stability and power balance of system. Such local information as the state of power grid, the relationship between DG power output and loads demand and the SOC of battery decides the operation modes and conversion between different modes of the system. The proposed control scheme can maintain the DC bus voltage constant effectively, which realizes reliable operation of the DC microgrid system. In the end, simulations are carried out in Matlab/Simulink simulation environment, and the results verify the effectiveness of proposed scheme.