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.