New control scheme for AC-DC-AC converter without DC link electrolytic capacitor

Abstract

A novel concept for a static three-phase to three-phase power converter for an AC motor drive with unity power factor and reduced harmonics on the utility line is presented. The power circuit consists of two back-to-back connected six-pulse bridges having only a 5-/spl mu/F ceramic capacitor in the DC link. By controlling the active power balance between two bridges, the DC link voltage can be maintained within a 20-V deviation from the nominal value with the small ceramic capacitor regardless of the load variation.<>