Single-Phase PFC Boost Converter Operating in CCM with Active Input Filter Using Linear Regulator Assistance

Hard switching (PWM) converters with input or output smoothing inductors provide small current ripple at CCM. PFC stages need additionally a passive input filter usually formed by LC-Filter. This passive filter was replaced by an active filter, formed by a linear regulator, that compensates the input current ripple by draining the inductor current ripple to ground potential [1]. A 150 Watts PFC boost converter for line voltage input of 230 V was designed and built using CCM operation mode to minimize the current ripple. The remaining peak inductor current ripple of about 77.4 mA was reduced by linear regulator compensation to 12.0 mA peak input current ripple, what means 84.5 % ripple reduction, while input filter inductors and input filter capacitors were avoided. The power factor was 0.991 and the efficiency of the boost converter with the presented linear regulator assistance was 91.1%.