Filter-less Single-Stage Resonant AC/DC Converter Employing Push-Pull Transformer

Abstract

In this article, we present filterless single-stage resonant ac/dc converter. By using the push-pull transformer itself, with the primary-side switching modulation fixed at 0.5, the proposed ac/dc converter accomplishes theoretically zero input-current ripple and so does not need the extra input filter. Semi-bridgeless configuration reduces the conduction loss associated with an input full-bridge diode rectifier. The resonant neutral-point-clamped (NPC) structure much reduces the voltage stress at secondary-side active power components; this aspect enables use of inexpensive low-voltage-rated active power components. Therefore, the proposed converter features low cost, high power density, and high efficiency. A prototype with 1-kW output power is implemented to verify the superior properties of the proposed ac/dc converter. © 2023 The Korean Institute of Power Electronics.