Event-triggered adaptive fixed-time sliding mode control for voltage regulation of spacecraft DC microgrids

Abstract

This paper presents an event triggered adaptive fixed-time sliding mode control (ETAFTSMC) strategy for robust voltage regulation of a spacecraft DC microgrid characterized by low inertia and high sensitivity to load variations due to converter-dominated renewable energy sources integration. The proposed controller integrates nonlinear fixed-time (FT) convergence dynamics, adaptive disturbance estimation, hyperbolic tangent-based chattering suppression and robust damping enhancement within a unified control framework. An event-triggered update mechanism is incorporated to reduce unnecessary controller updates and computational burden while preserving closed-loop stability. A nonlinear sliding surface is developed to assure FT convergence of the voltage tracking error independent of initial operating conditions to deal with abrupt disturbances that are not predefined. Existing control strategies often fail to ensure rapid and robust stabilization under uncertain operating conditions. The proposed controller shows improved transient response, reduced control ripple, enhanced robustness, practical implementation feasibility and lower computational burden compared to other conventional controllers. The numerical and statistical analysis are verified using MATLAB and Monte Carlo analysis respectively. The closed-loop stability is proved using Lyapunov analysis.