| With the development of power electronics technology, Pulse Width Modulation DC-DC converters get more and more application. Nowadays, high performance, high efficiency and light weight are the most important performance figure of all kinds of PWM DC-DC converters. In order to increase the power density and output efficiency, the soft switching techniques is the key. And it has been attracted more and more attentions.A soft-switching converter circuit is discussed on the basis of analysis of the hard-switching power converter circuit's shortcoming in the paper. The definition, classification, development and the control strategy of the soft-switching have been summarized. On the base of the analysis and the study mentioned above, an improved full-bridge zero current transition resonant DC/DC converter is designed in this paper.The circuit topology, principle of operation and the circuit features have been analyzed detailed. This converter not only achieves zero current switching for the main switches and auxiliary switch in the load ranges, but it also realizes soft commutation of the secondary rectifier diodes. So it guarantees high efficiency over wide load range. Then the design of main circuit and control circuit are developed, the parameters of main circuit are given. The phase-shift control is implemented with UC3875.Furthermore, a simulation is performed successfully to analyze the converter's working characteristics using the famous CAD simulation software Pspice9.2. The simulation results show the circuit topology is right. |
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