Robust Distributed Disturbance-Resilient H∞-Based Control of Off-Grid Microgrids with Uncertain Communications

Abstract

In this article, a novel robust distributed cooperative control (RDCC) scheme is proposed to be used in the secondary layer of off-grid (autonomous) ac microgrids (MG). The MG, including heterogeneous units such as distributed generation and battery energy storage systems. Most of the reported studies have assumed the ideal conditions to communicate among units. They have not considered any uncertainties or disturbances in the network, whereas the communications are already subjected to uncertainties or disturbances. To tackle these concerns, we give an RDCC scheme based on the H∞ control theory for MGs in the present external disturbances and uncertain communication links. The proposed method is extended for a time-varying topology network (that can be considered as an unreliable network which makes the problem more challenging). The theoretical concepts of the proposed control strategy, including the mathematical modeling of MG, graph theory, fundamental lemma, and controller design procedure, are outlined. Sufficient conditions are also derived by using the H∞ control theory, which leads to a set of linear matrix inequalities. Finally, to evaluate the performance of the proposed control strategy, offline digital time-domain simulation studies are carried out on a test MG system in MATLAB/Simulink environment. The results are compared with several previously reported methods. Simulation results and comparison with previous works reveal the effectiveness, efficiency, authenticity, and accuracy of the proposed method in regulating MG voltage and frequency, state of charge (SoC) balancing, and providing accurate proportional active power-sharing.