Adaptive Integral-Type NTSMC for DC–DC Buck Converters With Zero-Crossing Gain Under Matched and Mismatched Uncertainties

This paper presents an adaptive integral-type non-singular terminal sliding mode (AINTSM) control strategy with zero-crossing control gain for DC-DC buck converters operating under both matched and mismatched uncertainties, which can be widely utilized to ensure the continuous stability and rapid response of various systems. By integrating adaptive gain and zero-crossing for adapting to system uncertain states, adjusting the control direction, and suppressing chattering. The advantages of integral-type NTSM help eliminate singularity issues during global convergence, further compensate steady-state errors through an integral control architecture, the proposed method overcomes key limitations of conventional sliding mode approaches. Compared to linear sliding mode (LSM) and fixed-gain NTSM controllers, AINTSM achieves enhanced output accuracy and dynamic stability while preserving structural simplicity. The global finite-time convergence is rigorously established through Lyapunov-based analysis, supported by phase trajectory studies that define stability boundaries for control parameter selection. Experimental validation under comprehensive parameter perturbations demonstrates the controller’s effectiveness in suppressing chattering phenomena and improving transient response, confirming its superior robustness in practical power conversion applications with complex operating conditions.