Robust observer-based DC-DC converter control

Abstract

This paper develops a novel robust control strategy for DC-DC buck converter subjected to varying load and parameter uncertainty. The proposal exploits the robustness of the sliding mode control (SMC) incorporated with proportional-proportional-integral-observer (PPIO) to assure tight reference voltage tracking under a wide range of load change scenarios. Within this framework, an integral sliding mode surface based SMC (ISMC) is designed to guarantee closed-loop robustness against the matched and mismatched disturbance components of the load uncertainty. Subsequently, a novel control structure comprises ISMC and PPIO is presented to overcome the design constraints and to mitigate the undesired transient response accompany the response of the closed-loop system based ISMC. Stability analysis has clearly demonstrated using linear matrix inequality (LMI) and Lyapunov approach. To illustrate the effectiveness of the proposal, a comparison between the closed-loop system responses of SMC, ISMC, and the combined ISMC and PPIO are presented in the simulation results.