Single-stage near-unity power factor AC/DC converter with both regulated bus and output voltages

摘要

Recently a single-stage AC/DC converter configuration which combines a boost power factor correction (PFC) circuit with a two-transistor DC/DC converter is presented. The converter achieves high power factor (PF), bus voltage regulation and output voltage regulation simultaneously that are hardly achieved in conventional single-stage power-factor-corrected (S~2PFC) converters. The converter is also able to work in stand-by mode to reduce power loss. To improve the converter performance further, this letter introduces a dual current-mode pulse-width modulation controller for this converter configuration to optimise the PF. Experimental results of a 24 VDC/100 W hardware prototype on a boost converter integrated with a two-switch forward converter are presented. The measured PF is above 0.99 at full load. The conversion efficiency is above 87% throughout the entire input AC line voltage range (100-240) V_(rms) and output load range (0.5-4.5) A.