Research on Control Strategy of Grid-Connected Inverter in Microgrid System

In microgrid system, the grid-connected inverter is the important interface between the system and the grid, and the control of grid-connected inverter allows the microgrid system to connect or disconnect in any time, achieving plug-and play function. This paper adopts the control strategy of grid-connected inverter. This strategy can meet the requirements of micro-grid when it is in the grid-connected and independent modes. The strategy uses PQ control mode when it is in grid-connected mode, choosing the best grid-connected time by the same period grid-connected control part. And it uses droop control for running independently. Simulation results for the two modes of switching verify the feasibility and correctness.