Reduced-Order Extended State Observer Based Quasi-Sliding Mode Predictive Control for DC-DC Buck Converter System

Based on estimated values of reduced-order extended state observer (RESO), a quasi-sliding mode predictive control (QSMPC) method is designed to reject the disturbances, keep high robustness and great steady state performance in the DC-DC buck converter system. First, a novel state space model for tracking error of buck converter is introduced in order to define the matched and mismatched disturbances as a total disturbance. Second, a reduced-order extended state observer is designed to estimate the system states and total disturbances, including load resistance changes and input voltage variation. Third, a QSMPC is designed combining MPC and SMC for better steady state performance and higher robustness. Fourth, the stability analysis of the RESO and closed-loop system are completed using characteristic equation and input-to-state stable correlation theorem. Finally, simulations show that the proposed control scheme have better performance in steady state or facing input and load disturbances and have higher robustness than the RESO-SMC and RESO-MPC.