Smooth switching between grid and island mode of microgrid is the key to improve the power quality and reliability. In this paper

the energy storage unit as the power damping device in the switching period is proposed on the basis of analyzing four types of operation modes of microgrid

and its control strategy between such two operation mode as grid and island is analyzed

and such problem as change of control strategy or remarkable adjustment of output power caused by micro power supply due to the switching of microgrid mode is solved

the influence of switching process on the load is reduced so to assure smooth transition between the grid-connection and island. The effectiveness of the control strategy is verified in the laboratory platform.