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Dissipativity-Based Distributed Control and Communication Topology Co-Design for Voltage Regulation and Current Sharing in DC Microgrids

Mohammad Javad Najafirad, Shirantha Welikala

TL;DR

This work tackles voltage regulation and proportional current sharing in DC microgrids by formulating a dissipativity-based, droop-free distributed control framework and a simultaneous co-design of local/global controllers and communication topology. It builds a networked-system model with a static interconnection matrix, derives error dynamics around an equilibrium, and enforces stability through X-EID/LMI-based design. The main contributions include a unified co-design procedure that optimizes both controller parameters and topology, a droop-free consensus-based current sharing mechanism, and a convex optimization pathway for scalable synthesis with stability guarantees. Simulation validates robustness to load changes and disturbances, and demonstrates advantages over conventional droop control in terms of performance, control effort, and scalability, with practical implications for adaptive and reconfigurable MG operation.

Abstract

This paper presents a novel dissipativity-based distributed droop-free control approach for voltage regulation and current sharing 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 DGs and lines (i.e., subsystems) are interconnected via a static interconnection matrix. This interconnection matrix demonstrates how the inputs, outputs, and disturbances of DGs and lines are connected in a DC MG. Each DG is equipped with a local controller for voltage regulation and a distributed global controller for current sharing, where the local controllers ensure individual voltage tracking while the global controllers coordinate among DGs to achieve proportional current sharing. 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 problem, we identify a set of necessary local and global conditions to 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 using existing convex optimization tools. The effectiveness of the proposed solution 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 the droop control algorithm.

Dissipativity-Based Distributed Control and Communication Topology Co-Design for Voltage Regulation and Current Sharing in DC Microgrids

TL;DR

This work tackles voltage regulation and proportional current sharing in DC microgrids by formulating a dissipativity-based, droop-free distributed control framework and a simultaneous co-design of local/global controllers and communication topology. It builds a networked-system model with a static interconnection matrix, derives error dynamics around an equilibrium, and enforces stability through X-EID/LMI-based design. The main contributions include a unified co-design procedure that optimizes both controller parameters and topology, a droop-free consensus-based current sharing mechanism, and a convex optimization pathway for scalable synthesis with stability guarantees. Simulation validates robustness to load changes and disturbances, and demonstrates advantages over conventional droop control in terms of performance, control effort, and scalability, with practical implications for adaptive and reconfigurable MG operation.

Abstract

This paper presents a novel dissipativity-based distributed droop-free control approach for voltage regulation and current sharing 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 DGs and lines (i.e., subsystems) are interconnected via a static interconnection matrix. This interconnection matrix demonstrates how the inputs, outputs, and disturbances of DGs and lines are connected in a DC MG. Each DG is equipped with a local controller for voltage regulation and a distributed global controller for current sharing, where the local controllers ensure individual voltage tracking while the global controllers coordinate among DGs to achieve proportional current sharing. 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 problem, we identify a set of necessary local and global conditions to 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 using existing convex optimization tools. The effectiveness of the proposed solution 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 the droop control algorithm.

Paper Structure

This paper contains 31 sections, 11 theorems, 88 equations, 18 figures, 1 table.

Table of Contents

  1. Introduction
  2. Preliminaries
  3. Dissipativity
  4. Networked Systems
  5. System Modeling
  6. DC MG Physical Interconnection Topology
  7. Dynamic Model of a Distributed Generator (DG)
  8. Dynamic Model of a Transmission Line
  9. Dynamic Model of a Load
  10. Proposed Controller
  11. Local Voltage Controller
  12. Distributed Global Controller
  13. Closed-Loop Dynamics of the DC MG
  14. Networked System Model
  15. Networked Error Dynamics
  16. ...and 16 more sections

Key Result

Proposition 1

welikala2023platoon The LTI system is $X$-EID if and only if there exists $P>0$ such that

Figures (18)

  • Figure 1: The impact of communication links on DC MG performance: (a) average voltage and current sharing error for different numbers of communication links and (b) corresponding communication network topology.
  • Figure 2: A generic networked system $\Sigma$.
  • Figure 3: A simplified diagram of a DC MG network.
  • Figure 4: The electrical schematic of DG-$i$, load-$i$, $i\in\mathbb{N}_N$, local controller, steady-state controller, distributed global controller, and line-$l$, $l\in\mathbb{N}_L$.
  • Figure 5: DC MG dynamics as a networked system configuration.
  • ...and 13 more figures

Theorems & Definitions (25)

  • Definition 1
  • Definition 2
  • Remark 1
  • Proposition 1
  • Corollary 1
  • Remark 2
  • Remark 3
  • Proposition 2
  • Lemma 1
  • Remark 4
  • ...and 15 more