On the effect of component mismatches in inverter interfaced microgrids

In droop-controlled inverter-based microgrids, component mismatches and parameter drifts may have a significant effect on system stability. Analyzing this practical and important problem, it is shown that droop control is sensitive to such drifts and certain conditions have to be satisfied to maintain stability. Furthermore, these mismatches lead to a deviation in power sharing between the droop-controlled inverters even in the stable case. A central supervisory control that uses very low bandwidth communication is proposed to correct the resulting deviations. Simulation results of a simple microgrid example demonstrate the problem and the proposed solution.