Experimental study on robust non‐fragile control of DC‐DC buck converter

Abstract

AbstractThe presence of uncertainty in the converter model and controller parameters affects the system's stability and dynamic performance. This paper presents a comparative analysis of robust non‐fragile control based on (i) the Kharitonov method and (ii) the linear matrix inequality (LMI) technique so that the controller can cope with the effect of both uncertainties. The first approach based on Kharitonov theorem determines the robust performance region with guaranteed gain margin and phase margin under parametric uncertainty. The second approach (LMI technique) is based on devising a control law that can quadratically stabilize the closed‐loop system subject to uncertainties and satisfy the H∞ norm bound constraint on disturbance attenuation. Based on these two approaches, a robust non‐fragile PI controller is designed for voltage mode control of dc‐dc buck converter. The effectiveness of the control approaches is evaluated based on (i) robustness against large plant parameter perturbations and load disturbance and (ii) fragility against controller parameter perturbations. The performance of the designed controllers (using the Kharitonov method and the LMI technique) has been thoroughly evaluated and validated through simulation and experimental results.