Asymmetric modulation of bridgeless single‐stage full‐bridge AC–DC converter for active power factor correction and zero voltage switching

Abstract

Abstract Singe‐phase single‐stage AC–DC converters exhibit the advantages of lower cost, higher efficiency, and lower power semiconductor device count compared with traditional two‐stage topologies. However, most existing single‐stage AC–DC topologies encounter some or all the following drawbacks: hard‐switching operation, bulky bus or output capacitor, uncontrolled bus voltage, not actively shaped input current, a large amount of power semiconductor devices, etc. The bridgeless single‐stage full‐bridge AC–DC converter can be considered a promising solution for high power capacity and efficiency. However, this topology still suffers from most of the drawbacks. In this paper, a new asymmetric modulation method of bridgeless single‐stage full‐bridge AC–DC converter is proposed to achieve active power factor (PF) correction and zero‐voltage switching. Topology description, the proposed modulation and control methods, theoretical analysis progress, and reference design procedure are presented in detail. Finally, a 2‐kW laboratory prototype is implemented with experimental results presented to validate the principle and design.

Keywords

• modulation
• single‐stage
• soft‐switching