Virtual Inertia Based Control of Two-stage Photovoltaic Inverters for Frequency Regulation in Islanded Micro-grid

Abstract

This paper presents a virtual inertia frequency control (VIFC) strategy for two-stage photovoltaic (PV) systems in an islanded micro-grid. By adjusting capacitor voltage and PV output power simultaneously, sufficient energy can be guaranteed for inertia synthesis from PV systems directly. Meanwhile, primary and secondary frequency regulation can also be emulated with fast dynamic response. High performance and reliability can be ensured since all the control signals are based on local measurements and no extra phase locked loop (PLL) is needed. Analysis is confirmed via small signal models and simulation studies demonstrate the effectiveness of the proposed method.