A single-stage power factor correction switched mode power supply

This paper presents a single-stage power factor corrected ac-dc converter based on a half-bridge topology. The proposed converter make use of the charge-pump and interleaving techniques resulting in near unity power factor and ripple free input current, meeting the IEC 61000-3-2 regulations for wide-load ranges. It is also a cost effective and competitive solution for 100 - 600 W applications where a two stage approach is costly and passive filters are not recommended. It works with zero voltage switching (ZVS) for a reasonable load variation range, achieving higher efficiency at higher load conditions. To overcome the excessive elevation of the Dc-link voltage in lower load situations, a common problem of single-stage PFC solutions, frequency variation and PWM control are used simultaneously.