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

TL;DR

This paper introduces a dissipativity-based distributed control and topology co-design method for nonlinear DC microgrids, effectively handling CPL and VSC nonlinearities for voltage regulation and current sharing.

Contribution

It develops a one-shot co-design framework using LMIs that jointly optimizes controllers and communication topology, addressing nonlinearities directly.

Findings

The proposed method achieves robust voltage regulation and current sharing.

Simulation results demonstrate superior performance over traditional control methods.

The framework effectively manages nonlinearities from CPLs and VSC saturation.

Abstract

This paper presents a dissipativity-based distributed droop-free control and communication topology co-design framework for voltage regulation and current sharing in DC microgrids (MGs), where constant-power loads (CPLs) and voltage-source converter (VSC) input saturation introduce significant nonlinearities. In particular, CPLs introduce an inherently destabilizing nonlinearity, while VSC input saturation imposes hard amplitude constraints on applicable control input at each distributed generator (DG), collectively making the DC MG control system design extremely challenging. To this end, the DC MG is modeled as a networked system of DGs, transmission lines, and loads coupled through a static interconnection matrix. Each DG is equipped with a local PI-based controller with an anti-windup compensator and a distributed consensus-based global controller, from which a nonlinear networked error dynamics model is derived. The CPL nonlinearity is characterized via sector-boundedness with the S-procedure applied directly to yield tight LMI conditions, while the VSC input saturation is handled via a dead-zone decomposition and sector-boundedness, with both nonlinearities simultaneously absorbed into the dissipativity analysis. Both nonlinearities are simultaneously absorbed into the dissipativity analysis using the S-procedure. Subsequently, local controller gains and passivity indices, and distributed controller gains and the communication topology are co-designed by solving a sequence of local and global Linear Matrix Inequality (LMI) problems, enabling a one-shot co-design process that avoids iterative procedures. The effectiveness of the proposed framework is validated through simulation of an islanded DC MG under multiple operating scenarios, demonstrating robust performance superior to conventional control approaches.