Dissipativity-Based Distributed Droop-Free Control and Communication Topology Co-Design for DC Microgrids

This paper presents a novel dissipativity-based distributed droop-free control approach for voltage regulation in DC microgrids (MGs) comprised of an interconnected set of distributed generators (DGs), loads, and power lines. First, we describe the closed-loop DC MG as a networked system where the sets of DGs and lines (i.e., subsystems) are interconnected via a static interconnection matrix. This interconnection matrix demonstrates how the disturbances, inputs, and outputs of DGs and lines are connected with each other. Each DG has a local controller and a distributed global controller. To design the latter, we use the dissipativity properties of the subsystems and formulate a linear matrix inequality (LMI) problem. To support the feasibility of this problem, we next identify a set of necessary local conditions, which we then enforce in a specifically developed LMI-based local controller design process. In contrast to existing DC MG control solutions, our approach proposes a unified framework for co-designing the distributed controller and communication topology. As the co-design process is LMI-based, it can be efficiently implemented and evaluated. The proposed solution's effectiveness in terms of voltage regulation and current sharing is verified by simulating an islanded DC MG in a MATLAB/Simulink environment under different scenarios, such as load changes and topological constraint changes, and then comparing the performance with a recent droop control solution.