Resilient Composite Control for Stability Enhancement in EV Integrated DC Microgrids

TL;DR

This paper proposes a resilient composite control strategy for EV integrated DC microgrids to enhance stability by addressing low-inertia and negative impedance issues, demonstrating significant improvements in dynamic response.

Contribution

It introduces a novel composite controller combining sliding mode and backstepping techniques with a virtual capacitor and fractional power law for improved stability in EV DC microgrids.

Findings

Significant reduction in overshoot and undershoot during transients.

Enhanced stability verified through Lyapunov-based analysis.

Simulation results show faster settling times and improved dynamic performance.

Abstract

When electric vehicles (EVs) are integrated into standalone DC microgrids (DCMGs), stability issues arise due to their constant power load (CPL) behavior, which provides negative incremental impedance (NII). In addition, the microgrids suffer from an inherent low-inertia problem. Therefore, this study presents a composite controller incorporating a global integral terminal sliding mode controller with a backstepping controller. A virtual capacitor is employed to mitigate the low-inertia issue and strengthen the DC-bus response. An improved fractional power-based reaching law decreases chattering and accelerates convergence. Exact feedback linearization converts the nonlinear boost converter model into Brunovsky's canonical form, mitigating NII effects and non-minimum phase issues. The entire system stability is verified using Lyapunov control theory. Simulation outcomes confirm superior performance, with 34.4-53.3% reduction in overshoot, 52.9-74.9% in undershoot, and 12-47.4% in settling time compared to the existing controller.