多路输出反激变换器交叉调整率的改善与实现

发布时间：2018-07-09 15:02

本文选题：多路输出 + 反激变换器　；参考：《西安科技大学》2017年硕士论文

【摘要】：随着电子技术的快速发展,电子设备需要更多不同等级电压源为其供电,有时甚至需要负电压。若采用一个电源仅给一个模块电路供电,则整个系统需要多个模块电源供电,势必会造成设备的重量增加、体积变大、成本变高等不足。反激变换器因其具有拓扑结构简单、输入与输出电气隔离、升压与降压范围宽等优点,在中小功率开关电源中得到了广泛应用,因此通过增加反激变压器绕组组数输出不同等级电压可满足设备的供电需求,为此,本文设计制作了一款+15V/IA,-15V/IA,+5V/1.5A三路输出反激开关电源样机。本文首先对反激变换器拓扑结构和工作原理进行全面分析,针对反激变换器在两种不同工作模式下能量的传输过程进行详细的分析,总结了反激变换器工作在这两种不同工作模式的优缺点,确定出样机所采用的工作模式。在此基础上,引出多路输出开关电源交叉调整率的概念、分析多路输出反激变换器交叉调整率的影响因素以及目前常用的改善方法,采用电压加权控制法、RCD钳位电路、变压器参数和结构的优化以及增加假负载等方法对交叉调整率进行综合改善。在理论分析的基础上,采用UC3845作为主控芯片,设计样机电路原理图及制作反激变压器。在Saber软件环境下对原理图进行仿真实验,验证其可行性。绘制样机电路PCB板,制作实物样机,并对其分别采用电压加权反馈控制法和传统的单环路反馈控制法进行实验测试,测试结果表明,本文所采用的综合改善方法使交叉调整率得到了良好的改善,满足了设计要求。
[Abstract]:With the rapid development of electronic technology, electronic equipment needs more and more different voltage sources to supply it, sometimes even negative voltage. If only one power supply is used to supply one module circuit, the whole system needs more than one module power supply, which will lead to the increase of equipment weight, the bigger volume and the higher cost. Flyback converter has been widely used in medium and small power switching power supply because of its advantages of simple topology, electrical isolation between input and output, wide range of boost and voltage reduction, and so on. Therefore, by increasing the number of windings of flyback transformer, the output voltage of different grades can meet the demand of power supply. Therefore, a 15V / IA-15V / IA-15V / IA, 5V / 1.5A three-way output flyback switching power supply prototype is designed and manufactured in this paper. In this paper, the topology and working principle of flyback converter are analyzed in detail, and the energy transfer process of flyback converter under two different working modes is analyzed in detail. The advantages and disadvantages of flyback converter in these two different operation modes are summarized, and the working modes used in the prototype are determined. On this basis, the concept of crossover adjustment rate of multi-channel output switching power supply is introduced, and the influencing factors of cross-adjustment rate of multi-output flyback converter and the commonly used improvement methods are analyzed. The voltage weighted control method is used to control the RCD clamp circuit. The optimization of transformer parameters and structure and the increase of false load can improve the crossover adjustment rate synthetically. On the basis of theoretical analysis, UC3845 is used as the main control chip to design the circuit schematic diagram of the prototype and to make the flyback transformer. In Saber software environment, the schematic diagram is simulated to verify its feasibility. The PCB board of the prototype circuit is drawn and the physical prototype is made. The voltage weighted feedback control method and the traditional single loop feedback control method are used for the experimental test. The test results show that, The comprehensive improvement method adopted in this paper improves the cross-adjustment rate well and meets the design requirements.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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