Zero Transition Pwm Soft-switching Dc / Dc Converter

This paper discusses the history and status of all kindsof soft-switching technology comprehensively andsystematically, especially zero-transition soft-switchingPWM technology.In this paper, with the Buck circuit topology as the exampleof zero-transition soft-switching PWM DC/DC converters, theoperation principle and characteristics of the conventionalZVT-PWM converter and a novel two phase ZVT-PWM converter areanalyzed in-depth respectively. It is shown by analysis thatthe conventional ZVT-PWM converter has inner circulatingcurrent, which increases the switches' loses and decreasesthe efficiency of the whole converter. To deal with the problem,an improved circuit is proposed. In the course of analysisand design, the powerful computing capacity of the PSPICE7. 1is used to finish simulations and parameter optimization ofthe systems.Hardware, such as control circuits, drive circuits and theover-current safeguard of switch elements of the conventionalZVT-PWM Buck converter, the improved ZVT-PWM Buck converterand the two-phase ZVT-PWM Buck converter, is designed, doneand debugged successively. On this base, a large amount ofsimulations and experiments are done. It is provenby simulationand experiment results that the parameter designing is feasible,theoretical analyzing are correct and improved circuit iseffective.