Design of Control System for Smooth Mode Transfer in Smart Microgrid Application

A complete control system of smart microgrid is proposed in this paper, in order to realize the smooth mode transfer of the grid-connected mode (GTM) and islanding mode (ILM). In the system, every DG unit will work as the voltage source and use the same control method of output voltage, whatever in GTM or ILM. The only difference of GTM and ILM is how to regulate of the reference voltage of the voltage control. Meanwhile, a grid-tracking control loop is proposed in order to synchronize the AC bus of microgrid with the grid before microgrid switches from ILM to GTM. Finally, the experiment results are presented, which validates the performance of the smooth mode transfer.