【作者】 周习祥；

【导师】 彭可；

【作者基本信息】 湖南师范大学 ， 电路与系统， 2008， 硕士

【摘要】 电力电子技术突飞猛进的发展,被视为人类社会的第二次电子革命。开关电源涉及电力电子、智能化IC、新电路技术等诸多技术领域,其中,软开关电力电子变换技术是近年来的一个热门课题。移相控制ZVS PWM DC/DC全桥变换器是变换器的一个研究热点,诸如高性能、高效率、低噪声、低污染等理论问题急需研究。软开关是在硬开关主体电路上增加一些辅助器件来“软化”开关器件,使开关器件实现ZVS或ZCS。本文基于对基本移相控制ZVS PWMDC/DC变换器的电路结构、控制原理及开关转换模式等的分析,得到了开关器件实现零电压开关的条件和策略及副边占空比丢失的原因和解决方法;阐述了全桥变换器的滞后臂比超前臂更难实现ZVS的原因;指出了基本移相控制ZVS PWM DC-DC全桥变换器的不足。为了解决这些问题,对基本移相控制ZVS PWMDC/DC变换器的电路结构作了相应改进,通过严密的理论推导,在其超前臂加箝位二极管,滞后臂加辅助网络,从而设计了一款带辅助电路,使变换器获得良好的ZVS开关效果,并减少副边占空比丢失的移相控制PWM全桥软开关DC/DC变换器。本文在上述分析的基础上,设计了一款48V/20A的软开关电源,并给出了基于ORCAD PSPICE 10.5软件的电路仿真结果。本文还对控制电路、驱动电路、保护电路等进行了设计,采用PI调节器实现电压闭环控制,以提高电路的稳定性和精确度,最后得出了整机电路图,并完成了样机的开发。更多还原

【Abstract】 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.更多还原