Harmonics Analysis of Sliding Mode Controlled Boost Converters with Unmodelled Dynamics

The inevitable existence of harmonics in sliding mode (SM) controlled DC-DC boost converters with sensor unmodeled dynamics is investigated in this paper. A singular perturbation model of unmodeled dynamics is proposed by choosing the rise time of sensor as a perturbed parameter. The guaranteed stability conditions of SM controller and sensor output are deduced respectively, following an equivalent model transformation of the whole closed-loop system for convenient analysis. A Lyapunov-like function is further designed to prove the harmonics exist in a vicinity concerning the rise time of sensor. Simulation results validate the proposed scheme.