QFT based robust controller design for fourth-order boost dc-dc switching power converter

In this paper, a systematic procedure is proposed for robust digital controller design for higher order switching power converters using Quantitative Feedback Theory. A robust voltage mode controller is then directly designed in discrete-time domain for a fourth-order boost dc-dc switching power converter operating in continuous conduction mode. A simplified flowchart that describes the detailed design procedure is developed and based on that controller is designed to ensure stability, robustness, command tracking and disturbance rejection features that are desirable from power supplies. The performance of the designed controller is analyzed through computer simulations and then verified experimentally on a 28 V, 30 W laboratory prototype converter. Simulation and experimental results are in correlation and show that the controller is able to stabilize the system for the predefined range of perturbations in load and source voltage while satisfying all the constraints placed during controller design.