Research on the Control Strategy of Inverters in the Micro-Grid

This paper proposes an appropriate control systems aiming at the control demands of distributed generation (DG) unit in the micro-grid. When the micro-grid is connected to the main grid, PQ control with droop characteristic is adopted for the inverter; When micro-grid separates from the main grid, Vf control with droop characteristic is used. Also, the controller can make the conversion between different modes seamless. The grid-connected mode, islanding mode and transition from grid-connected to an islanding operation are simulation by PSIM software. The simulation results verify that the proposed control strategy is right and feasible.