Design of frequency shift acceleration control for anti-islanding of an inverter-based DG

The paper proposes frequency shift acceleration control (FSAC) for anti-islanding of an inverter-based distributed generator. The key concept is to disturb an islanded system frequency by controlling reactive current output in d-q frame, and accelerate the resulting frequency shift using an acceleration gain. Design method of the acceleration gain is proposed using analytical approaches, based on small-signal stability and step input response. Simulation and experimental results are presented.