Unified control based seamless transfer of microgrids

The microgrid must be able to transfer from grid-connected mode into islanding operation mode seamlessly to guarantee the power reliability for the critical local load. In the grid-tied mode, the power exchanged with the main grid should be smoothed to reduce the disturbance to the main grid, while the quality of the bus voltage in the islanding operation mode is significant. This paper presents a unified control strategy for microgrid to achieve above goals, where the microgrid is configured by a master distributed generator (DG) and several slave DGs and the control structures of them are not switched during the transfer of the operation mode. The control strategy is verified by the experimental results.