A quasi single-stage power factor correction converter based on a three-level boost converter

A quasi single-stage power factor correction converter, which is composed of a three-level (TL) Boost converter and a DC-DC transformer (DCX), is presented and analyzed in this paper. The DC output load is connected to one of the dividing capacitors of the TL Boost converter, so that the load voltage can be lower than the peak amplitude of the AC line voltage and part of the AC input power can be processed within only single conversion stage. Power factor correction and output voltage regulation are realized by adopting a dual-carrier-based modulation strategy. Voltage and power balance between the two dividing capacitors of the TL Boost converter is implemented by the open-loop controlled DCX. Smooth mode transition between single-stage mode and two-stage mode is achieved. The operation principles, characteristics and design considerations of the converter are analyzed and verified with simulation experimental results.