Electrolytic capacitor-less single-phase AC/DC converter using T-type NPC circuit

This paper discusses a control method for an electrolytic capacitor-less single-phase AC/DC converter with PFC capability and with constant dc-output voltage. Generally, single-phase AC/DC converters employ bulky electrolytic capacitors in order to smoothen the ripple power with twice the utility frequency. The proposed control method uses a T-type NPC circuit with a small film capacitor and decouple the ripple-power with neutral point voltage control. The basic operation was confirmed by the simulation and the experiment.