Power factor preregulators employing the flyback and zeta converters in FM mode

The flyback and zeta converters can work as power factor preregulators (PFP). These converters can be designed to obtain unitary power factor, that is, they are resistance emulators. In this paper, a method for high frequency electromagnetic interference reduction using the frequency modulation (FM) approach is described for these converters. Results show that a reduction of conducted electromagnetic interferences (EMI) generated by these converters is possible using the FM technique. The price for this EMI reduction is a small reduction in the power factor (PF).