Communication-Based Control for DC Microgrids

Centralized communication-based control is one of the main methods that can be implemented to achieve autonomous advanced energy management capabilities in dc microgrids. However, its major limitation is the fact that communication bandwidth and computation resources are limited in practical applications. This can be often improved by avoiding redundant communications and complex computations. In this paper, an autonomous communication-based hybrid state/event driven control scheme is proposed. This control scheme is hierarchical and heuristic, such that on the primary control level, it encompasses state-driven local controllers, and on the secondary control level, an event-driven microgrid centralized controller is used. This heuristic hybrid control system aims at reducing the communication load and complexity, processor computations, and consequently system cost while maintaining reliable autonomous operation during all possible scenarios. A mathematical model for the proposed control scheme using finite state machines has been developed and used to cover all the possible modes/sub-modes of operation, and assure seamless transitions among them during various events. Results of some case studies involving severe operational scenarios were presented and discussed. Results verify the validity and effectiveness of the proposed communication-based control scheme.