Microgrid control based on a grid-forming inverter operating as virtual synchronous generator with enhanced dynamic response capability

This paper focuses on improving the dynamic response of autonomous microgrids (MGs) by proposing a grid-forming inverter controlled as a virtual synchronous generator (VSG), in combination with a supercapacitor (SC)-based energy storage system (ESS). By this arrangement, the MG-forming VSG is designed to react only in transitory regimes, the steady-state load being distributed to other MG-supporting inverters spread within the MG. In this way, the MG-forming VSG can maintain its full power reserve capacity for dynamic response. The paper details the control solution for the MG-forming inverter, including the VSG and SC-ESS control. The control method for the MG-supporting inverters that allow achieving the proposed control approach is also described. To prove the concept, the paper includes simulation results and experiments accomplished on a complex laboratory MG system based on three parallel inverters, one being controlled as MG-forming VSG, while the others operating as MG-supporting inverters.