Power Quality improvement of microgrids by virtual synchronous generator control

Due to inertia-less feature of inverters, microgrids with high penetration rate of inverter-interfaced distributed generators (DGs) usually suffer from power quality issues such as poor dynamic frequency stability. A promising solution of this issue is to apply virtual synchronous generator (VSG) control concept to inverter-interfaced DGs. In this paper, it is shown that compared to previous microgrid control scheme, e.g. conventional droop control, VSG control can improve microgrid frequency stability during loading transitions and fault events. This conclusion is demonstrated by theoretical time domain response of DG frequency obtained through small-signal analyses, and is verified by simulations performed in PSCAD/EMTDC.