An unity power factor operation symmetrical power supply

This paper presents an AC/DC power converter which can operate as a symmetrical power supply. The AC input voltage and current waveforms are closely in phase and present a very low harmonic distortion. Consequently, the proposed power converter is able to work with unity power factor. A symmetrical output voltage source was obtained by associating Cuk and SEPIC converters using a common input stage. A 500 watts prototype operating at 100 kHz fixed switching frequency was implemented. PSPICE simulation and a laboratory prototype operating with open and closed loops was realized and the results have proved the operating principles of the structure and the implemented control strategy.