The Design And Development Of Phase-shifting Controlled PWM Full-bridge Soft-switch DC/DC Converter

Therapid development of power electronics is regarded as the second electronic revolution in the human society.Switch power supply is involved in power electronics,intelligent IC, new circuit technology and other technical fields,in which the technology of soft-switching power electronic transformation is a hot subject in recent years.Phase-shifted zero-voltageswitching PWMDC/DC full-bridge converter is a hot spot being researched on converters,a lot of the oretical problems are in urgent need of research,such as high-performance,high efficiency,low noise,low pollution and so on.Soft-switching is a device that adds some auxiliary devices on the main circuit of the hard-switching to soften switching devices and achieves ZVS or ZCS.This paper bases on the analysis of the circuit,control principle and conversion mode of the switch of the basic phase-shifted control of ZVS PWM DC /DC full-bridge converter,analyzes the conditions and strategies for switching devices achieving zero-voltage-switching and the causes and solutions for both sides of duty cycle and loss; elaborates the reasons for the lagging leg of the full-bridge converter achieving ZVS harder than the leading leg;The basic PS ZVS PWMDC/DC FB converter has some disadvantages.In order to solve these problems,a corresponding improvement has been made for the circuit of the basic phase-shifted control of ZVS PWM DC/DC full-bridge converter,through strict theory inferential reasoning,increase the clamping diode on the leading leg,and increase the auxiliary circuit on the lagging leg,thus PS ZVS PWM DC/DC FB converter is designed,which has a belt-assisted circuit,so that the good switch effect of the ZVS converter can be gained and the loss of duty cycle of output voltage of secondary winding can be reduced.On the basis of the above-mentioned analysis this paper designs a 48V/20A soft switching power supply,and gives a circuit simulation based on ORCAD PSPICE 10.5 software.In the paper,control circuits,driver circuits,and protection circuits are designed.And PI regulator is used to realize voltage closed-loop control to enhance the stability and the Precision of the circuits,and the circuitry diagram is drawn and the prototype is developed finally.