Robust control of DC-DC converters: the buck converter

Under different input voltage and output load conditions, the dynamics of the buck converter changes. In this paper, we use a structured uncertainty model to describe the dynamic behavior of the buck converter for voltage mode control. For the current mode control case, we use an unstructured multiplicative uncertainty model to capture the family of perturbed small signal dynamics of the buck converter. The powerful Kharitonov´s theorem and the LQG/LTR technique are then utilized to design robust controllers to achieve robust stability and performance for the voltage mode controlled and current model controlled buck converters respectively