Smooth Switching Control Strategy for Microgrid Off-grid and Grid-connected Based on Droop Control

In order to reduce the impact on grid and micro-grid when the micro-grid changes operating mode, synchronization control strategy is proposed. To enable a smooth switching between the island and grid-connected mode of micro-grid, this paper makes the voltage magnitude difference, frequency difference and phase angle difference between grid and micro-grid to meet the grid-connecting requirements by adjusting their output voltage. Finally, a simulation model was established using Matlab/Simulink, and the simulation results showed that the proposed method can achieve smooth switching between the two modes of the microgrid.