Minimizing PFP converters [power factor preregulators]

The basic DC-DC power converters (boost, buck, flyback, Zeta, Sepic and Cuk converters) can work as power factor preregulators (PFP) using many types of control methods. These converters can work in continuous conduction mode (CCM), in discontinuous conduction mode (DCM) or in critical conduction mode (C_riCM), and can be designed to obtain unity or near unity power factor (PF) values. A method for high frequency electromagnetic interference reduction using the frequency modulation (FM) approach that is a particular case of the C _riCM was described previously. In this paper, a study of the effect of the control method on the power converter size is presented. As one of the main responsible for the size of the PFP converters is the size of the inductors. This article presents a full description of the behaviour of the size of the inductor as a function of the operating modes. So, it will be possible to know which converters have a minimized size