Research On Phase-Shifted Full-Bridge ZVS Converter With24V/20A

The phase-shifted full-bridge (PS FB) pulse-width-modulated (PWM) DC/DC converterswith zero-voltage switching (ZVS) or zero-current switching (ZCS) have many advantages,such as low switching stresses, low switching losses and high frequency. So they are widelyused in high input voltage and middle-to-high power DC/DC converters.Therefore, it is ofgreat significance for its research and design.Firstly, the thesis has expounded the soft-switching technology of PWM DC/DCconverter, and then it has based a circuit topology of phase-shifted control PWM full-bridgeconverter, the main circuit topology and operating principle of the PS FB ZVS PWM DC/DCconverter are analyzed, and the realization of zero-voltage switching, the duty ratio loss,clamping diode and other related issues are discussed; Secondly, the thesis has designed themain circuit topology which we selected, and gave the methods of parameters designing andcalculation for main circuit, including parameters’ designing with high—frequencytransformer and the resonant inductor, output rectifying filter circuit; further the selection ofpower devices, output retifying diodes and clamping diode.Then, the formation of the phase-shifted control circuit is discussed, and thephase-shifted control chip UC3879is sufficiently analysed and designed. The simulation andexperiments are made on a prototype of PS FB PWM DC/DC converter, the simulation andexperiments results are in positive to the analysis showing the feasibility of the proposedmethods.