Chattering-Free Robust Terminal Sliding Mode Control for DC Nanogrids

DC nanogrid is an emerging solution for providing affordable electricity to rural areas and homes equipped with solar panels, power converters, and on-site batteries. However, its poor transient response limits its practical application, presenting a significant drawback. This paper proposes a chattering-free robust terminal sliding mode control with finite time stability for the DC nanogrid. The proposed control strategy effectively addresses issues such as poor transient response and chattering, thereby ensuring optimal operation of the DC nanogrid. To achieve robust closed-loop power system operation, advanced nonlinear sliding surfaces and control laws are designed. This work focuses on achieving robustness against dynamic changes and system uncertainties caused by the intermittent nature of the renewable generation unit, instantaneous load variation, and saturation of the control laws. The finite-time stability of the closed-loop system is proved using Lyapunov theory to ensure finite-time convergence for both the reaching and sliding phases. The effectiveness of the proposed nonlinear controller is demonstrated by comparing it with higher-order SMC and conventional asymptotic SMC. System behavior is analyzed through MATLAB/Simulink simulations, and practical applicability is validated experimentally using an IMPERIX hardware setup.