Robust control design and implementation for a quadratic buck converter

A robust controller for a quadratic buck converter is designed using Kharitonov´s theorem. Then, the controller is implemented and experimental results are given for a low power switching quadratic buck converter. The robust D-stability concept is used to achieve robust performance by clustering the roots of closed loop system characteristic polynomial equation in a specified angular region. The obtained results demonstrate a desirable reference voltage tracking, line disturbance rejection and show that the designed controller guarantees the robust stability and robust performance for a wide range of line voltage and load variation.