Distributed secondary control based on cluster consensus of inhibitory coupling with power limit for isolated multi‐microgrid

Abstract

Multiple nearby isolated microgrids (MGs) can be interconnected to become multi-MGs (MMGs) and meet larger bulk power demands, thus improving reliability/security of MMGs and reducing the power supply investment costs. However, a multi-layer control structure and complex communication network are inevitable, which increase communication delays and complicate the control structure. To solve this problem, this article introduces a distributed secondary control (DSC) based on cluster consensus of inhibitory coupling with a power limit scheme. Compared with an inter-cluster communication coupling structure, the communication channels of the proposed scheme are minimised to simplify network topology, decrease the communication delays and control dimensions. The proposed control strategy reaches multi-valued consensus states for accurate active/reactive power sharing in different MGs. Furthermore, active/reactive power overloading in a MG cluster is discussed under an inhibitory coupling configuration. Based on the power limit scheme, each distributed generator (DG) of the overloaded MG is controlled to generate power within the rated power range for high local autonomy. In addition, an adaptive virtual impedance control is introduced to decrease voltage deviations between DGs. The analytical results are verified by a simulation in MATLAB/Simulink.