Robust Switched Controller Based on Takagi-Sugeno Fuzzy Model for DC-DC Converters Against Disturbances

Abstract

This paper proposes the application of a robust switched control strategy for dc-dc converters, primarily focuses on the restriction of the H∞ norm improving the dynamic response under disturbances. In order to obtain a accurate model in a local operating sector, the Takagi-Sugeno (T-S) fuzzy model is used to approximate the nonlinear system, thereafter is proposed a control law independent of the membership functions. The H∞ norm constraint is introduced into the switched control in terms of Linear Matrix Inequalities (LMIs) and then the condition is relaxed with the use of the Finsler's Lemma. For the verification of the proposed conditions, the control strategy is applied to a Boost dc-dc converter, obtaining an improvement in the dynamic response against disturbances compared to switched control without H∞ norm restriction.