Power factor correction using quasi-resonant SEPIC converter with three-phase input

A new combination of a `unity power factor three-phase rectifier stage´ with a quasi-resonant SEPIC converter, provides high quality input currents of a transformer isolated three-phase AC-DC converter. Analysis of the converter, including analysis of the three-phase input current waveforms, has been performed and a design procedure developed. Results of a transformer isolated 1.0 kW/35 kHz prototype converter, utilising a single 1200 V IGBT as the active switching device and operating direct off-line from a 415 V three-phase mains supply, are presented to verify theoretical predictions. The measured input current waveforms, drawn from the three-phase supply, approach unity power factor with little harmonic content