一种单管正激式开关电源的设计

发布时间：2018-06-30 17:37

本文选题：开关电源 + 正激式　；参考：《湖南大学》2014年硕士论文

【摘要】：随着电力电子技术的高速发展,电力电子设备与人们的工作、生活的关系日益密切,而电子设备都离不开稳定可靠的电源。直流稳压电源主要分为开关电源和线性电源两大类。从成本来说,开关电源和线性电源的成本都是随着输出功率的增加而增长,但二者增长速度不同。在某一输出功率点上,线性电源成本反而要高于开关电源,这就是成本反转点。在目前中国建设资源节约型、环保示范型社会的大背景下,具有安全环保、高效节能、短小轻薄等优点的开关电源已经成为本学科一个重要的研究热点。单管正激式开关稳压电源由于采用了较新的电路结构,并采取了一系列措施来降低输出纹波,能在输出过流、过压、过热和电路工作异常时进行自我保护,因此具有一定的先进性和创新性。本课题来源于某公司项目,通过设计一个具体型号的工业产品,来掌握单管正激式开关电源设计的一些基本理论如：正激变换器拓扑、变压器、反馈环路和补偿网络的设计、PWM开关变换器的基本原理与设计等。在学习设计流程的基础上,进一步掌握产品设计的要求规范,从而形成严密谨慎的科学思维,培养认真务实的科学态度。因此具有较高的实用价值和良好的工程应用前景,也为开发和设计其它开关电源提供了借鉴和参考作用。本文设计了一个单管正激式开关电源,直流输入范围是36V-75V,标称输入电压为48V,输出电压18V,输出电流1120mA,输出功率20W。该电源主要采用控制芯片UC3842、光电耦合器PC357与可调式精密并联稳压器TL431等集成芯片,能同时实现输入欠压保护、过压保护、过流保护、降低最大占空比等功能。在设计过程中,做了如下对比实验：不同匝比的变压器性能比较,不同型号的MOS管损耗比较,不同反馈补偿环路的效率比较。通过以上的对比实验,找到了一种最优设计方案。通过对样机进行的黑盒、白盒及余量测试得出的数据和波形表明,电源输出电压稳定,电压精度小于±2%；电压调节率接近±0.5%；负载调节率小于±1%；输出纹波电压不高于50mV/150mV(峰-峰值),纹波较小。电源各项指标均达到或接近设计指标,性能良好。本文主要创新点：1、采用电压反馈和电流反馈双闭环串级结构,使输出电压能够很好地稳定；2、利用光耦H11A1和三端可调稳压管TL431配合控制大大提高了瞬态响应速度；3、很好地设计了RCD吸收回路和开关管保护电路,能有效地消除漏感,使元件能稳定可靠地工作。
[Abstract]:With the rapid development of power electronics technology, the relationship between power electronic equipment and people's work and life is increasingly close, and electronic equipment can not be separated from stable and reliable power supply. DC power supply is mainly divided into switching power supply and linear power supply. In terms of cost, the cost of switching power supply and linear power supply increase with the increase of output power, but the growth rate is different between them. At a certain output power point, the cost of linear power supply is higher than that of switching power supply, which is the cost reversal point. Under the background of constructing resource-saving and environmental protection demonstration society in China, switching power supply with the advantages of safe and environmental protection, high efficiency and energy saving, short and light and so on, has become an important research hotspot in this subject. Because of the new circuit structure and a series of measures to reduce the output ripple, the single-transistor forward switching stabilized power supply can protect itself when the output overcurrent, overvoltage, overheating and abnormal operation of the circuit. Therefore, it has a certain advanced and innovative. This topic comes from a company project, through the design of a specific type of industrial products, to master the single transistor forward switching power supply design of some basic theory such as: forward converter topology, transformer, Design of feedback loop and compensation network the basic principle and design of PWM switching converter. On the basis of studying the design process, the author further grasps the requirements and norms of product design, so as to form a strict and cautious scientific thinking and cultivate a serious and pragmatic scientific attitude. Therefore, it has high practical value and good engineering application prospect, and also provides reference and reference for the development and design of other switching power supply. In this paper, a single transistor forward switching power supply is designed. The DC input range is 36V-75V, the nominal input voltage is 48V, the output voltage is 18V, the output current is 1120mAand the output power is 20W. This power supply mainly uses integrated chips such as control chip UC3842, optoelectronic coupler PC357 and adjustable precision parallel voltage regulator TL431, which can simultaneously realize the functions of input under-voltage protection, over-current protection and reduction of maximum duty cycle. In the process of design, the following comparative experiments are done: the performance comparison of transformer with different turn ratio, the comparison of loss of MOS transistor of different types, and the comparison of efficiency of different feedback compensation loop. Through the above contrast experiment, we find an optimal design scheme. The data and waveform obtained from the test of black box, white box and margin of the prototype show that the output voltage of the power supply is stable, the voltage accuracy is less than 卤2, the voltage regulation rate is close to 卤0.5 and the load adjustment rate is less than 卤1. The output ripple voltage is not higher than 50 MV / 150 MV (peak-peak), and the ripple is smaller. All the indexes of the power supply are up to or close to the design target, and the performance is good. In this paper, the main innovation point: 1, using voltage feedback and current feedback double closed loop cascade structure, the output voltage can be very good stability, the use of optocoupler H11A1 and three-terminal adjustable voltage regulator TL431 control greatly improve the transient response speed; 3. The RCD absorption circuit and the switch protection circuit are well designed, which can effectively eliminate the leakage inductance and make the elements work stably and reliably.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN86

【相似文献】