Half-Bridge Type Soft-Switching AC-DC Converter with High Power-factor

Abstract

This paper presents an improvement circuit of the high power-factor of AC-DC converter by employing a half-bridge system that enables a soft-switching in step-up converter.
In this circuit the improvement of power-factor will be facilitated, under critical conduction mode, with the half-bridge type converter, and such power-factor improvement can be achieved without using multiplier, and larger voltage than the peak value of stepped up AC voltage will be charged in an electrolytic capacitor. Analysis of the performance of circuit proposed was carried out, and a converter having 97% high power-factor could be developed by identifying the relation of parameter of step-up factor (alpha) and selecting the reactor appropriately. We also have introduced, as one of the applications, a low cost one-converter that making the main switch part common by connecting the half-bridge type converter to the post-stage