Periodic gain feedback control of power converters

Although periodic feedback offers more flexibility than constant gain feedback, there has been no demonstration that this control can be practically implemented. This paper presents a practical implementation of periodic feedback control applied to a switching DC/DC buck/boost power converter. Stability of the closed-loop discrete system is analyzed for capacitor voltage and inductor current feedbacks. It is found that feedback of the inductor current through periodically varying gains results in a more stable power converter than periodic feedback of the capacitor voltage. Simulation and experimental results of both feedback systems are presented and discussed.