Inverter-based microgrid control and stable islanding transition

A hybrid microgrid control architecture is proposed, which combines centralized control and distributed control to achieve a fully-functional microgrid control strategy. A complete model of the microgrid has been built. Coordination and power sharing strategies have been developed for the inverters and microgrid controller, and the microgrid can be operated in on-grid mode and islanding mode, and is able to transition between the two modes smoothly with minimum load disruption and shedding during transitions. A multi-input proportional-integral control is proposed to eliminate the transients caused by the inverter control mode transition. In islanding mode, secondary frequency and voltage control strategies are proposed besides droop control methods. Assisted with the microgrid controller and the communication between the microgrid controller and the individual source and load, the microgrid can achieve optimized power flow and energy utilization, and the system efficiency can also be improved.