PFC circuits with very low THD

A power factor correction circuit to operate in a discontinuous current mode comprising:

• a three-phase alternating current (AC) power source;
• three capacitors star-connected across the three-phase AC power source;
• a first transformer;
• a second transformer;
• a third transformer;
• respective center taps of primary windings of the respective first, second, and third transformers connected to receive three-phase AC power from the three-phase AC power source;
• anodes of three first diodes connected to respective first ends of the center-tapped primary windings of the respective first, second, and third transformers;
• cathodes of the three first diodes shorted together and denoted as a first short;
• cathodes of three second diodes connected to respective second ends of the center-tapped primary windings of the first, second, and third transformers;
• anodes of the three second diodes shorted together and denoted as a second short;
• a switching device connected between the first short and the second short;
• respective secondary windings of the first, second, and third transformers;
• anodes of three third diodes connected to the respective secondary windings of the first, second, and third transformers;
• cathodes of the three third diodes shorted together as a third short;
• respective other sides of the secondary windings of the respective first, second, and third transformers shorted together as a fourth short;
• a load capacitor connected between the third short and the fourth short;
• wherein widths of fixed frequency pulses applied to a gate of the switching device to turn on and off the switching device are varied to control a load voltage across the load capacitor.