Study of aControl Methodof FuelcellInverters ConnectedinParallel and Verification TestResult ofan Isolated Micro grid

The"NewEnergyPlant" hadbeenbuilt atthe Aichi EXPO.2005site aspartofthe"Demonstrative Project ofRegional PowerGridwithVarious NewEnergies". The plant includes three types offuel cells, aphotovoltaic power generation system andaSodiumSulfur (NaS)battery. One ofthepurposes ofthedemonstrative project istoachieve isolated operation of a microgridwithoutrotating generators. Thesenewenergy generators andbattery are connected tothemicrogridviainverters. Inisolated operation, thesystem voltage andfrequency aredetermined byfourfuel cell inverters connected inparallel. Thispaper presents thecontrol strategies, especially loadshare between inverters, forisolated operation ofamicrogridconfigured withsomenewenergy generators. Simulation results and verification test results arealso showninthis paper. IndexTerms-Micro grid, Isolated operation, Loadshare, Autonomouscontrol, New energygenerator, Inverter, Simulation, Verification test, FuelCell, NaS battery, Photovoltaic