Frequency regulation and enhanced power sharing in microgrids including modified droop coefficients and virtual resistances

In this paper, a design of the control system for parallel distributed sources is proposed. These sources are connected together using inverters in an isolated low voltage microgrid. The inverters have been used to connect distributed power sources to microgrid with the capability of modification of the voltage amplitude and frequency. Also for the first time in IEEE publications, an automatic frequency regulator for the microgrids working with droop system has been proposed which preserves the good power sharing while controls the reactance of the system elements. Also the modified droop control is used providing better reactive power sharing between the sources even if the line impedances are unbalanced or the sources have different power ratings. The other papers have not addressed these issues.