The goal of developing AC-DC converters with Isolation and Power Factor Correction feature in a single power processing stage and without a mandatory full-bridge rectifier has for years eluded Power Electronics researchers. Present AC-DC converters operated from a single-phase ac line are based on conventional PWM switching method and process the power through at least three distinct power processing stages: full-bridge rectifier followed by Boost PFC converter and another cascaded isolated Full-Bridge DC-DC converter stage, which together use a total of 14 switches and three magnetic components resulting in corresponding efficiency, size and cost limitations. The new Hybrid Switching Method enables new Single-Stage AC-DC converter topology, the True Bridgeless PFC Converter* consisting of just three switches and a single magnetic component albeit at a much higher efficiency approaching 98% and having a 0.999 power factor and 1.7% total harmonic distortion. Three-Phase Rectifier* consisting of three such Single-Phase Rectifiers* takes for the first time a full advantage of Tesla’s three-phase transmission system to convert constant instantaneous input power of a three-phase system directly to a constant DC output power, albeit isolated at high switching frequency, with near unity power factor (0.999), low total harmonic distortion (1.7%), smaller size and lower cost but at ultra high efficiency of 98%.
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