Research On Boost-Half-Bridge PFC Circuit

Power Factor Correction(PFC) technique based on boost-half-bridgetopology is studied in this paper. Firstly, origin and history of PFC technique is introduced. Thepassive PFC approach and the active single-stage PFC approach and theactive two-stage PFC approach are summarized. Theory of two-stageboost-half-bridge PFC rectifier is studied in detail include that theoryand basic relation of boost-PFC in DCM and constant duty cycle are studiedin theory. Research demonstrates that high power factor costs highvoltage stress. Modes and basic relation of CDR half-bridge converterworking in five different modes are analyzed. Condition being ZVS is given.By utilizing energy of current-doubler inductor the converter can makeZVS into reality. When current doubler inductors designed work on CCM2,the converter can realize ZVS within whole load range. Exactness ofanalysis is verified by 100W prototype. Principle and basic relation ofsingle-stage boost-half-bridge PFC rectifier in different modes arestudied in detail. Design criteria of key parameters and circuit stressare given. Simulations of the converter in detail are carried out. Therange of soft switching influenced by change of circuit parameters isanalyzed. Research demonstrates in single-stage boost-half-bridge PFCrectifier,because a switch is commonly used by boost converter andhalf-bridge converter,two switches in same leg work asymmetrically.Being ZVS is even easier top switch than bottom switch. Because boostconverter works in DCM, output voltage is changed by load. Range of ZVSof two switch is more narrow than two-stage's. Lastly, 100W prototype isdesigned and manufactured based on theory discussed above. Exactness ofthe theory is verified by experiment.