Sampled-Data Control for Buck-Boost Converter Using a Switched Affine Systems Approach

This paper focuses on the sampled-data control for a DC-DC buck-boost converter, which is modeled as a class of continuous-time switched affine systems (SASs). The controller of the closed-loop system, in which both the control inputs and switching signals are sampled-data-dependent, is designed to ensure convergence of the system state to a specified region. This region comprises multiple ellipsoids centered around some shifted points that need to be determined, which can better characterize the convergence region under non-uniform sampling intervals. By introducing a switching multi-shifted-point-dependent Lyapunov functional, sufficient conditions are derived to ensure practical stability of the presented SASs. The proposed design scheme generalizes the switching quadratic Lyapunov function based method, and provides a smaller and more accurate invariant set. Moreover, the method is extended to SASs with uncertainties, and the corresponding robust stability conditions are provided. Finally, the superiority of the proposed approach is demonstrated through a case study of a DC motor driven by a buck-boost converter.