A family of single-phase hybrid step-down PFC converters

The conventional Boost PFC usually suffers from high output voltage and low efficiency at low input condition. Recently, the Buck PFC has attracted a lot of research interests for its low output voltage and high efficiency at low input condition. However, the conventional Buck PFC converter usually has low power factor (PF) and poor harmonic performance due to the inherent dead angle of the input current, especially at low input condition. How to achieve high power factor, low output voltage and high efficiency at the same time is still a big challenge for the PFC converters. This paper proposes a family of hybrid PFC converter topologies combine the advantages of Boost PFC and Buck PFC converters, which feature low output voltage and continuous input current (high PF). The derivation methodology is presented. The experimental results verify the advantages of the proposed topologies.