Characterization of conducted noise generation for Sepic, Cuk and Boost converters working as power factor preregulators

The influence of the electromagnetic interference in the electronic design is becoming more and more important. The current and future regulations limit the generation of conducted and radiated noise. These regulations also limit the minimum power factor for the equipment connected to the AC line. All these facts show the importance of the analysis of power converters working as power factor preregulators (PFP). In this paper the authors present a characterization of conducted noise generated by Sepic and Cuk converters as PFP in the discontinuous conduction mode (DCM). A comparison of conducted noise generated between Sepic and Cuk converters as PFP in DCM, and a Boost converter as PFP in continuous conduction mode (CCM) and DCM is made. The results show that the conducted noise generated by Sepic and Cuk converters in DCM is lower than the conducted noise generated by the Boost converter in DCM and CCM, for the same input inductor. This fact has important influence in the selection of the optimum topology for PFP