A Study on Resonance Suppression Control Based on Virtual Resistance Concept for Parallel Inverters in Islanded Microgrid

This paper studies a resonance suppression control based on virtual resistance concept for parallel inverters in islanded microgrids. At the inverter systems with LC output filters, resonances often occur due to various reasons. To suppress the resonances, additional resistances are often used to dampen the system (passive damping). However, additional resistance inevitably causes additional losses. On the other hand, many active damping approaches have also been studied. In this paper, we study one of the active damping methods, the resonance suppression control based on virtual resistance concept. In particular, the resonance suppression control implemented at the current-controlled inverter and that implemented at the voltage-controlled inverter in islanded microgrids are comparatively studied. The effectiveness is evaluated by analyses of frequency characteristics, simulation studies, and experimental results in the case of two parallel inverters in islanded microgrids.