Robust Distributed Optimal Secondary Voltage Control in Islanded Microgrids with Time-Varying Multiple Delays

This paper focuses on solving the problem of voltage restoration in droop-controlled inverter-based islanded micro-grids (MGs) under communication delays. To this aim, we propose a novel robust distributed secondary controller which is the combination between an integral sliding mode controller and a linear consensus scheme with constant weights. Lyapunov analysis and Linear Matrix Inequalities (LMI) are employed together to demonstrate the associated stability and convergence features. The allowable upper bound for communication delays is also estimated by linear matrix inequalities. Regulating the MG’s voltages to the associated reference values additionally taken into account by developing an optimization algorithm to find the optimal constant control gains. Finally, simulation results show the effectiveness of the proposed solution.