Robust AC Voltage Regulation of Microgrids in Islanded Mode with Sinusoidal Internal Model

Abstract

This paper shows that the H∞ control is an effective tool for electric voltage regulation. We here consider robust AC voltage regulation of microgrids in an islanded mode. When a microgrid is disconnected from a utility grid, it automatically switches to an islanded mode to provide necessary power using a battery system until the grid is recovered. In the islanded mode, it is important to regulate the electric voltage generated in the grid to track a predetermined AC voltage reference. A difficulty is that there exits unmodeled dynamics in the grid that may cause large power fluctuations. To resolve this problem, we adapt the H∞ control with a sinusoidal internal model to robust AC voltage regulation in microgrids. Simulation and experimental results confirm that the proposed H∞ control can achieve robust tracking performance.