Full-Bridge DC-DC Converter Using Asymmetric Phase-Shifted PWMControl

Abstract

A novel zero-voltage and zero-current switching (ZVZCS) Full-bridge converter is proposed using Asymmetric Phase-shifted PWM Control, Current in primary winding during the freewheeling period is reduced to zero by adding a blocking capacitor and a saturable inductor, realizing ZCS turn-on and ZVS turn-off for chopping-leg switches as well as ZCS turn-on and turn-off for lagging-leg switches. The control method is easy digital realization, overcomes control precision and flexibility of the traditional phase-shifting control special chip. The operation processes and characteristics of the converter are analyzed, and a prototype is built. Experimental results verify the proposed DC-DC converter with low freewheeling energy, low switching loss and high efficiency.