Improved Transient Frequency Stabilization of Grid Feeding Distributed Generation Systems Using Active Damping Control

A shortage of energy reserves in power electronic based (active) microgrids (distributed generation) is not able to accommodate the load dynamics and is a major cause for the frequency stability problem. The work proposed in this paper aims to efficiently stabilize the frequency of grid feeding active distributed generators (GF-ADG) by controlling the stored energy in the dc link capacitor. In particular, an active damping control method is proposed to help GF-ADG to withstand larger power disturbances. The proposed method increases the stability margins by reducing frequency overshoot and improves the frequency profile when the system interfaces a weak grid. The method uses enhanced capabilities of dc link synthetic inertia controlled by the instantaneous energy mismatch between the supply and the load. The proposed method is verified with the simulation results developed for a PV connected microgrid system.