Voltage-follower control in zero-current-switched quasi-resonant power factor preregulators

In this paper, we propose to study the use of several zero-current-switched (ZCS) quasi-resonant converters (QRC's) (buck-boost, flyback, SEPIC, Cuk, boost, and buck) with a halfwave switch, working as power factor preregulators (PFP's) with voltage-follower control. The analysis carried out demonstrates that these converters show excellent characteristics to obtain a high power factor (PF) without using any input-current feedback loop, and they also allow high switching frequency to operate because they integrate transformer and rectifier diode parasitics into the power topology.