Robust Control of Power System Frequency Regulation in Islanded Microgrids

Abstract

This paper reviews the work in the areas of robust control strategies for power system frequency regulation in islanded microgrids. One study delves into the challenges of accurate power sharing and voltage regulation in multi-feeder microgrid systems. It introduces an enhanced resilient control strategy that views the regulation and power balancing as a quadratic optimization problem. This strategy employs an impedance estimator and an optimal controller, focusing on voltage magnitude information transfer at each inverter’s controller. The approach is designed to be computationally efficient, especially for micro-networks with a large number of load feeders. Another area of focus is the development of a generalized central power management system and a decentralized, robust control strategy for autonomous operation of microgrids with multiple distributed energy resource (DER) units. These DER units, categorized into voltage-controlled and power-controlled units, operate based on independent internal oscillators synchronized by a GPS-based timereference signal. The power management system sets power and voltage points for each DER unit’s local controllers. A robust decentralized control system ensures fast tracking, zero steady-state error, and resilience against microgrid uncertainties. The performance of these strategies is validated through various simulation platforms and hardware-in-the-loop studies.