Finite-time disturbance observer based non-singular terminal sliding-mode control for pulse width modulation based DC-DC buck converters with mismatched load disturbances

This study investigates a finite-time disturbance observer (FTDO) based non-singular terminal sliding-mode control (NTSMC) approach for pulse width modulation based DC-DC buck converters subject to matched/mismatched resistance load disturbances. Considering the mismatched resistance load disturbance which does not act in the same channel as the control input, a novel non-singular terminal sliding-mode manifold incorporating with a disturbance estimation technique is designed. A FTDO-based NTSMC method is introduced for DC-DC buck converter systems. A rigorous finite-time stability analysis is also presented. As compared with the nominal NTSMC and existed SMC+ extended stated observer (ESO) method, the proposed method obtains a better disturbance rejection ability no matter the disturbances satisfy the so-called matching condition or not. Simulation and experimental comparison results are implemented to verify the effectiveness of the proposed control method.