Region-based Stability Analysis on DC MGs with Consensus-Based Secondary Control and Communication Delay

Distributed control algorithms have been frequently adopted in coordinating multiple power electronics interfaced distributed generators (DGs). This work analyzes how the communication delay effects would degrade the performance of distributed secondary controllers in DC microgrids (MGs). Two types of consensus-based controllers are under study: one is the conventional dynamic consensus-based controller and the other is a novel controller based on the surplus consensus algorithm. The steady-state performance of both controllers is analytically derived with considerations of communication delays. The delay-dependent stability regions of both controllers are analyzed, respectively. As the selected system parameter vary, the corresponding marginal delay that transits the stable system to an unstable one is quantified, and the delay dependent-stability boundary is identified using Kernel Ridge Regression (KRR) algorithm. At last, the proposed work is validated with simulation tests and experimental verification.