De-coupled PQ control for operation of islanded microgrid

Operating an islanded microgrid is a challenge. In this paper a new approach is adopted to tackle this problem. The microgrid under study is formed by one grid-forming generator DG1 which is powered by DC source, two renewable energy powered generators and a number of loads. The basic control methodology is to de-couple PQ control for the grid-forming DG1. By doing so, accurate control of its real power becomes feasible so long its reactive power is kept at low value. The real power reference of DG1 is generated by voltage variation at its terminal. A multiplying factor is introduced to expedite the realtime real power reference generation. The reactive power is taken over by instantaneous var compensator which accompanies DG1. The system operates at constant 50Hz and the voltage variation can be kept within limit.