ESO-based Backstepping Control of DC-DC Buck Converter Under Mismatched load Disturbance

The DC–DC power converter play a critical role to provide stable DC output voltage, however which is subject to various uncertainties and disturbance in supplying the sensitive loads. This paper propose a composite backstepping control strategy with extended state observer (ESO) for buck converter. Firstly, a backstepping control function is constructed to derive an inner current loop reference assuming load disturbance is known, which renders global stability of the system. An ESO is designed to estimate the mismatched load current and feedforward it to the backstepping controller to obtain disturbance rejection. Quantitative selection of control and observer gains are provided under highly nonlinear relationship of system dynamics. Rigorous stability of proposed scheme are poved with analysis of robustness. Finally, simulation results illustrate the effectiveness of the proposed control scheme in the presence of load disturbance and uncertainties