Design criteria for SEPIC and Cuk converters as power factor preregulators in discontinuous conduction mode

SEPIC and Cuk converters present a great advantage over boost and fly-back topologies in discontinuous conduction mode (DCM): an input current with low harmonic content can be obtained by correctly choosing the inductors L₁ and L₂ of the converter with a fixed operation frequency, as is demonstrated here. The authors also discuss the intermedium capacitor C₁ as well as some advantages and disadvantages of the application. Simulation and experimental results support the approach. It is concluded that SEPIC and Cuk converters in DCM seem to be good choices for use as power factor preregulators