基于同步整流技术的有源钳位正激变换器的研究

发布时间：2018-03-16 04:22

本文选题：有源钳位　切入点：正激变换器　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着超大规模集成电路的快速发展,计算机、通信系统的供电电源也有了新的发展趋势:输出电压越来越低,输出电流越来越大,同时功率密度也不断提升。因此,低电压、大电流输出、高功率密度的DC/DC电源的研究在最近几年受到广泛的关注。正激变换器由于其电路结构简单,输出纹波电压小等特点,在中小功率应用场合扮演着非常重要的角色。本文通过采用有源钳位复位技术,克服了传统单端正激变换器中磁芯工作在第一象限,磁芯利用率不高的缺点。利用有源钳位复位技术还降低了开关管的电压应力,并且能将励磁电感和漏感中的能量循环利用,提高了变换器的效率。同时,在低压大电流输出的应用中,由肖特基二极管正向压降产生的损耗占总损耗比例越来越大,限制了效率的提高,本文通过采用同步整流技术有效的解决了这个问题。文中首先分析了传统单端正激变换器的工作原理,根据正激变换器的特点对常用的几种复位方式进行了分析。然后深入分析了有源钳位复位的正激变换器的工作过程。其中包括主开关管实现零电压开通的条件,漏感延迟的影响,钳位电路对励磁电感和漏感中能量循环利用。再结合实际应用中的两种钳位方式进行了详细的对比。其次,为了提高效率,文中对同步整流技术做了相关研究。分析了常用的电压型和电流型同步整流驱动方式,考虑到有源钳位复位技术的特点和本课题的输入输出电压范围,文中采用变压器绕组自驱动同步整流方式。另外,为了减小电源体积,满足工业标准半砖结构,采用了平面变压器取代传统的变压器,有效的提高了电源功率密度。最后,详细介绍了电路的设计过程,制作实验样机并完成测试。最大效率达到88%,功率密度达36.5W/in3,纹波电压小于50 mV,满足设计要求。
[Abstract]:With the rapid development of VLSI, the power supply of computer and communication system has a new trend: the output voltage is getting lower and lower, the output current is increasing, and the power density is increasing. The research of DC/DC power supply with high current output and high power density has attracted extensive attention in recent years. Due to its simple circuit structure and low output ripple voltage, the forward converter has many advantages such as low output ripple voltage and so on. It plays a very important role in medium and small power applications. By adopting active clamp reset technique, this paper overcomes the fact that the core of the traditional single-terminal forward converter works in the first quadrant. The use of active clamp reset technology also reduces the voltage stress of the switch tube, and can recycle the energy in the excitation inductance and leakage inductance, thus improving the efficiency of the converter. In the application of low-voltage and high-current output, the loss caused by forward voltage drop of Schottky diode is increasing in the total loss, which limits the improvement of efficiency. In this paper, this problem is effectively solved by using synchronous rectifier technology. Firstly, the working principle of traditional single-terminal forward converter is analyzed. According to the characteristics of forward converter, several common reset methods are analyzed. Then, the working process of active clamp reset forward converter is analyzed in depth. Because of the effect of leakage inductance delay, the clamping circuit makes a detailed comparison between the excitation inductance and the energy recycle in leakage inductance. Then, the two clamping modes in practical application are compared in detail. Secondly, in order to improve the efficiency, In this paper, the synchronous rectifier technology is studied. The common voltage mode and current mode drive mode are analyzed. Considering the characteristics of active clamp reset technology and the input and output voltage range of this subject, In addition, in order to reduce the power supply volume and meet the industrial standard semi-brick structure, a plane transformer is used to replace the traditional transformer, which effectively improves the power density of the power supply. The design process of the circuit is introduced in detail, the experimental prototype is made and the test is completed. The maximum efficiency is 88, the power density is 36.5 W / in 3, and the ripple voltage is less than 50 MV, which meets the design requirements.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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