Discrete‐time robust voltage controller for buck converters based on the coefficient ratio method with open‐loop feed‐forward control

Abstract

Summary In this study, a hybrid controller based on the discrete‐time characteristic ratio controller and an open‐loop feed‐forward controller is presented for voltage control of the buck converters used in many different applications. The presented controller is designed using a standard‐form characteristic ratio. The designed controller is supported by the open‐loop duty ratio as a feed‐forward term to improve its robustness against the disturbance, especially to changes in the input voltage. The performance of the designed controller to follow the change in the output‐voltage reference is investigated by simulation and real‐time experimental studies. By designing the presented controller for three different generalized time‐constants, it has been validated that the transient regime of the closed‐loop system can be adjusted without disrupting the general wave structure of the system response. The robustness of the designed controller for various disturbances such as the input‐voltage and load variations and parameter uncertainties has also been thoroughly investigated. The results of comparative simulation and real‐time experimental studies realized by the PID and CR method without FF term clearly demonstrated the superiority of the presented method.