A three-level converter and its applicationto power factor correction

The first part of this paper introduces a novel three-level dc-dc converter topology. It is shown that a floating capacitor connected across the clamping diodes of a conventional three-level converter enables phase-shift control while retaining zero voltage switching. Design constraints and experimental results are shown for a 6-kW, 100-kHz dc-dc prototype. The second part of the paper discusses the same three-level topology operated as a single-stage front-end converter. In this application, the converter realizes power factor correction and dc output voltage regulation. To ensure low harmonic distortion, the input currents are operated in discontinuous conduction mode, and the performance, including soft switching, is also verified on a 3-kW, 50-kHz ac-dc converter.