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

TL;DR

The paper tackles voltage regulation and current sharing in DC microgrids by coupling dissipativity-based control with topology co-design. It models the plant as a networked system of DGs and lines interconnected by a static matrix and enforces robust $L_2$-stability via an equilibrium-independent dissipativity (X-EID/Y-EID) framework, solved efficiently as LMIs. A two-tier control scheme is proposed: local controllers ensure feasibility, while a global, droop-free controller (described by a tunable interconnection block $K$) shapes inter-DG communication to achieve desired energy performance and minimal gain from disturbances. Simulations on islanded MGs with 4–6 DGs demonstrate voltage tracking to a reference and proportional current sharing, with soft-topology constraints reducing communication load substantially compared with hard constraints and outperforming conventional droop control in overshoot and regulation quality. The approach offers a scalable, plug-and-play capable pathway for co-designing controllers and communication networks in DC microgrids, with potential extensions to AC systems.

Abstract

This paper presents a novel dissipativity-based distributed droop-free control approach for the voltage regulation problem 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 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 distributed global controllers, we use the dissipativity properties of the subsystems and formulate a linear matrix inequality (LMI) problem. To support the feasibility of this distributed global controller design, we 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 that separate distributed controller and communication topology design problems, our approach proposes a unified framework for distributed controller and communication topology co-design. As the co-design process is LMI-based, it can be efficiently implemented and evaluated using existing software tools. The effectiveness of the proposed solution 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 comparing its performance with the recent droop control approach.

Figures (11)

• Figure 1: A generic networked system $\Sigma$.
• Figure 2: The electrical schematic of DG-$i$, load-$i$, $i\in\mathbb{N}_N$, local controller, distributed global controller, and line-$l$, $l\in\mathbb{N}_L$.
• Figure 3: DC MG dynamics as a networked system configuration.
• Figure 4: Overview of the procedure for designing local and distributed global controllers for the considered DC MG.
• Figure 5: The physical topology of DC MG with 4 DGs and 4 Lines.

Theorems & Definitions (21)

• Definition 1
• Definition 2
• Remark 1
• Proposition 1
• Corollary 1
• Remark 2
• Proposition 2
• Remark 3
• Remark 4
• Proposition 3