Barrier Adaptive Nonlinear Finite Time Control Strategy for Resilient Voltage Stabilization in DC Microgrids

This paper introduces a novel non-linear control strategy to enhance the voltage regulation performance of Medium Voltage DC (MVDC) converters operating under significant external disturbances and parameter uncertainties. The proposed controller synergistically improves the performance of MVDC microgrid by proposing a Barrier Adaptive Super Twisting Sliding Mode Control (BA-STSMC) employing a novel non-singular finite time proportional integral derivative (PID)-type terminal surface. The proposed work collectively provides a rapid transient response and finite-time error convergence, robust disturbance rejection and eliminate steady-state errors using continuous control signal that effectively mitigating chattering. This composite design inherently avoids the singularity issues common in conventional terminal SMC. The barrier adaptivity mechanism dynamically adjusts the control effort by constraining state trajectories within a predefined invariant domain, thereby guaranteeing that control signals remain within safe operational limits while enhancing the finite-time convergence properties. The stability and finite-time reachability of the closed-loop system are rigorously established via Lyapunov analysis. Comprehensive simulation and experimental validations demonstrate the proposed controller's superior ability to restore Distributed Generator (DG) current and voltage during severe events including abrupt load variations and communication failures outperforming conventional PI, standard SMC, and adaptive STSMC methods in terms of robustness, convergence speed, and control signal quality.