Sliding Mode Control Based on Linear Extended State Observer for DC-to-DC Buck–Boost Power Converter System With Mismatched Disturbances

This article presents a new control strategy merging a sliding mode control (SMC) with a linear extended state observer (LESO) to regulate the output voltage of the buck–boost power converter system affected by matched and mismatched disturbances. The SMC–LESO schema uses the input–output linearization approach and the equivalent control method to determine the boundary layer around the sliding surface. This boundary layer depends on the sliding surface and the equivalent control value, depending on the estimated variables obtained through a LESO. With this schema, the unknown matched, and mismatched disturbances are observed and compensated by an adaptation of the SMC. The proposed approach minimizes the sliding surface chattering and improves the performance against sudden static and dynamic load changes as well as voltage variations on the power supply input. An experimental comparison with traditional sliding mode control and classical proportional–integral–derivative control is performed, confirming the proposal's effectiveness. The closed-loop stability (observer-controller-plant) is guaranteed in the input-to-state stability framework.