QFT based robust controller design for a DC-DC switching power converter

In this paper, a quantitative feedback theory (QFT) was applied successfully to design a robust controller for a DC-DC buck converter operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The controller is designed to provide optimum attenuation of the load disturbances in spite of practical limitations on the achievable closed-loop performance and in the presence of other design constraints including closed-loop tracking and robust stability. The derived analytical results are verified by computer simulation of a voltage-mode (VM) controlled buck converter.