Distributed LMI-based control of heterogeneous microgrids considering fixed time-delays and switching topologies

Abstract

In this study, a distributed cooperative control protocol for inverter-based islanded microgrids (MGs) is presented. The MG consists of distributed generation units and battery energy storage systems (BESSs). Despite most of the reported works which assumed the ideal conditions and did not considered any delay in information exchange between local controllers, the authors design a controller for the restoration of voltage and frequency fluctuations, achieving accurate active power-sharing and state of charge (SoC) balancing of BESS in the presence of fixed communication time-delay and changing topology of the network. The stability analysis is performed based on the Lyapunov-Krasovskii method, and sufficient conditions are presented based on linear matrix inequalities (LMIs) to guarantee the system stability and to reach consensus under arbitrary switching topologies. The upper bound of communication delay that the system can tolerate is given, too. Finally, to evaluate the performance of the control laws, offline digital time-domain simulation studies are performed on a test MG system in MATLAB/ Simulink, and simulation results reveal the effectiveness, efficiency, authenticity and accuracy of the proposed method in regulating MG voltage and frequency and providing accurate proportional active power-sharing and SoC balancing.