Linear fractional order control of a DC-DC buck converter

The aim of this paper is the application of Fractional Order Control (FOC) to the control of a Buck converter. This work deals with the design of a linear controller for a DC-DC Buck power converter. In order to achieve this goal, several design methods are proposed and experimentally validated. Bode's ideal function will be used as reference system in all of them. The employ of this design technique requires the obtention of a continuous linearized model of the dc-dc converter (LC filter + PWM actuator). The resultant pseudo-continuous system is a non-minimum phase system with a Right-Hand-Side (RHS) zero. In this work, two methods are proposed for the design of fractional order controllers in systems that exhibit this behavior. As well, a technique based on the discrete linearized model is applied. In all the cases, discrete approximations of the fractional controllers are obtained.