Supervision based Smart Microgrid Systems: Grid Connected, Island Mode and Seamless Transition

The uninterruptible power supply and the seamless transition between operation modes, are the principal aims in microgrid systems. During the grid-connection mode, the inverter regulates the active and reactive power transferred with the grid. On the other hand, during the grid-forming mode, the inverter emulates the grid by imposing the voltage and frequency. In order to guarantee a seamless transition, the transferred power and the phase synchronization have to be taken into account. This paper proposes a smart inverter solution which fulfills the requirements working in both operating modes, and ensuring a seamless transition by regulating the power and phase before the mode transition. The operation of the proposed microgrid system is based on the installation of a Supervisor Unit, which manages the references generation and the mode operation. Simulation results are presented in order to validate the proposed approach.