A Distributed Scalable Architecture using L1 Adaptive Controllers for Primary Voltage Control of DC Microgrids

TL;DR

This paper introduces a scalable distributed control architecture using $$ adaptive controllers for primary voltage regulation in heterogeneous DC microgrids, ensuring stability and robustness during plug-and-play operations and topology changes.

Contribution

It presents a novel distributed control scheme with scalable local controller synthesis and guarantees global stability using Lyapunov functions and Riccati equations.

Findings

Achieves fast, robust voltage stability in microgrids.

Effective in plug-and-play and topology change scenarios.

Validated on heterogeneous and bus-connected microgrids.

Abstract

This paper proposes a new distributed control architecture for distributed generation units in heterogeneous DC islanded microgrids. Each unit is equipped with state-feedback baseline and augmenting $\mathcal{L}_1$ adaptive voltage controllers at the primary level of the microgrid control hierarchy. Local controller synthesis is scalable as it only requires information about corresponding units, couplings, and at most, the addition of state-predictor measurements of neighbouring controllers. Global asymptotic stability of the microgrid is guaranteed in a plug-and-play fashion by exploiting Lyapunov functions and algebraic Riccati equations. The performance of the proposed architecture is evaluated using a heterogeneous DC islanded microgrid that consists of 6 DC-DC boost converters configured in a radial and meshed topology. The use of $\mathcal{L}_1$ adaptive controllers achieves fast and robust microgrid voltage stability in the presence of plug-and-play operations, topology changes and unknown load changes. Finally, the distributed architecture is tested on a bus-connected islanded-microgrid consisting of linear resistive load and non-linear DC motor.