Self-tuned dither control of buck converter

In this paper, general relationships are established using dither control strategies and self-tuning control schemes leading to sliding modes in nonlinear systems. The results are applied to the design of a sliding regime for the regulation of a DC/DC switching mode buck converter. The converter's parameters may vary during its operation and therefore the design of the dither control depends on the extreme values of these parameters, which in turn introduces stress on the converters. To alleviate this stress, the parameters of the converter are estimated using the ARMAX model technique which is used with variable structure control to determine the optimum switching instants. The produced switching pattern grantees the stability and closed-loop robustness for buck converters. As a practical application, a self-tuning controller for a buck converter is designed and tested by both computer simulation and online implementation. Simulation and experimental results for the buck converter are shown to verify the applicability of the proposed controller.