Mode-Adaptive Decentralized Control for Renewable DC Microgrid With Enhanced Reliability and Flexibility

TLDR

The study proposes a mode‑adaptive decentralized control strategy for power management in a DC microgrid with renewable generators and storage, and introduces a novel mode definition criterion distinguishing DC from AC microgrids. The approach uses the DC bus voltage to enable power sharing, designate operation modes, and facilitate seamless transitions, with three typical operation conditions defined based on the dominant source type. The mode‑adaptive mechanism delivers greater control freedom than conventional DC voltage droop control, provides fully self‑disciplined regulation of distributed converters without an extra control center or communication link, enhances reliability and flexibility, and its effectiveness was verified experimentally on a composite DC microgrid test system.

Abstract

A mode-adaptive decentralized control strategy is proposed for the power management of a dc microgrid with multiple renewable distributed generators and energy storage systems. In the presented solution, the dc bus voltage signal is used not only to enable power sharing among different sources, but also to designate microgrid operation modes and facilitate seamless mode transitions. With this mode-adaptive operation mechanism, a greater control freedom can be achieved than the conventional dc voltage droop control scheme. More importantly, this approach features fully self-disciplined regulation of distributed converters without an extra control center or communication link. Therefore, both reliability and flexibility can be enhanced. Meanwhile, a novel mode definition criterion is also provided to highlight the special characteristics of the dc microgrid which is different from an ac one. Three typical operation conditions are summarized according to which type of sources are dominating the power balance. Finally, the effectiveness of the proposed technique is verified experimentally based on a composite dc microgrid test system.