Passivation of Clustered DC Microgrids with Non-Monotone Loads

TL;DR

This paper addresses voltage stability in DC microgrids with uncertain, non-monotone loads by designing controllers that ensure stability and passivity, verified through LMIs and robust to network variations.

Contribution

It introduces a novel control framework guaranteeing voltage regulation and passivity in clustered DC microgrids with uncertain loads, using LMIs and singular perturbation theory.

Findings

Controllers ensure voltage regulation and OS-EIP in controlled buses.

Overall microgrid stability is achieved through interconnection of OS-EIP clusters.

The OS-EIP property is robust against network parameter and topology changes.

Abstract

In this paper, we consider the problem of voltage stability in DC networks containing uncertain loads with non-monotone incremental impedances and where the steady-state power availability is restricted to a subset of the buses in the network. We propose controllers for powered buses that guarantee voltage regulation and output strictly equilibrium independent passivity (OS-EIP) of the controlled buses, while buses without power are equipped with controllers that dampen their transient behaviour. The OS-EIP of a cluster containing both bus types is verified through a linear matrix inequality (LMI) condition, and the asymptotic stability of the overall microgrid with uncertain, non-monotone loads is ensured by interconnecting the OS-EIP clusters. By further employing singular perturbation theory, we show that the OS-EIP property of the clusters is robust against certain network parameter and topology changes.