Fully Distributed Cooperative Secondary Frequency and Voltage Control of Islanded Microgrids

Abstract

This paper proposes a new distributed cooperative secondary control for both frequency and voltage restoration of an islanded microgrid with droop-controlled, inverter-based distributed generations (DGs). Existing distributed methods commonly design secondary control based on the minimum real part of the nonzero Laplacian matrix eigenvalues related to the microgrid communication graph, which, however, is global information. In contrast to the existing distributed methods, in this paper we design a fully distributed adaptive control based on the dynamic model of DG units and on information from neighboring units. Therefore, the proposed control scheme increases the system reliability, decreases its sensitivity to failures, and eliminates the need for a central processing unit. The fully distributed controllers restore the islanded microgrid frequency and voltage magnitudes to their reference values for all DG units irrespective of parametric uncertainties and disturbances while providing accurate real power sharing. Furthermore, the proposed method considers the coupling between the islanded microgrid frequency and voltages. Finally, we have conducted comprehensive simulation studies in the MATLAB/SimPowerSystems toolbox to verify the proposed control strategy performance.