Current quality and performance tradeoffs under active power factor correction

Active power factor correction provides near unity power factor, at the expense of large filters to handle double-frequency power. When active correction is not used and converter regulation is the main control objective instead, poor power factor results. It is shown that a tradeoff between power factor and filter size can be supported. Through computer analysis, it is found that there is a specific supply current waveform that should be used to achieve a given power factor target with minimum filter size. For reasonable power factors (such as 70% to 100%), the current waveforms meet requirements in IEC 61000-3-2 over a wide range of supply power level. The results point the way to reduced cost power supplies.