两级结构在高效大功率+DC_DC+变换器中的研究与应用

工学硕士学位论文两级结构在高效大功率DC/DC变换器中的研究与应用王振哈尔滨工业大学2007年6月国内图书分类号：TM151.3国际图书分类号：621.3工学硕士学位论文两级结构在高效大功率DC/DC变换器中的研究与应用硕士研究生：王振导师：张东来教授副 导 师：王智勇高级工程师申 请 学 位：工学硕士学科、专业：电气工程所在单位：深圳研究生院答辩日期：2007年6月授予学位单位：哈尔滨工业大学Classified Index: TM151.3U.D.C: 621.3Dissertation for the Master Degree of Engineering THE RESEARCH AND APPLICATION OF TWO-STAGE TOPOLOGY IN HIGHEFFICIENCY&POWER DC/DCCONVERTERCandidate:Wang ZhenSupervisor:Prof. Zhang Donglai Associate Supervisor:Advanced EngineerWang ZhiyongAcademic Degree Applied for:Master of Engineering Specialty: Electrical Engineering Affiliation: Shenzhen Graduate School Date of Defence:June, 2007Degree-Conferring-Institution:Harbin Institute of Technology哈尔滨工业大学工学硕士学位论文摘要论文主要研究了两级结构在高效大功率DC/DC变换器中的应用。

此种变换器主要应用于3G通信基站电源，具有很大的应用价值，初步预计需求量为2K/年，市场潜力巨大。

两级变换器最大的特点就是能很好与同步整流拓扑配合，提高变换器效率，很适合用于低压大电流情况下；电路拓扑简洁，控制电路简单；前级电路可以在高频下工作，滤波器很小；适应大范围电压波动。

本文研究的目的是为两级变换结构中的Buck+Pushpull这种两级结构提供理论分析依据，以及为今后进一步深入研究和开发高效大功率DC/DC 两级变换器提供了借鉴和参考依据。

本文主要研究内容分为以下几个方面：(1)通过对应用于高效大功率DC/DC变换器的各种拓扑技术比较，引出两级变换结构。

并在此基础上详细分析了两级变换器拓扑的稳态运行原理。

本文所做的Buck+Pushpull这种两级结构的详细稳态电路分析在目前国内外的资料中较少见到。

(2)借助SABER仿真工具，对一些与开关应力有关的关键参数进行了选取，并且通过实际原理样机上的调试证实了参数选择的正确性。

通过对几种同步整流管驱动电路比较，提出了一种适合两级结构同步整流的驱动电路，不仅得到了符合输出要求的驱动波形，驱动时序合理，电路内所有MOSFET 管应力均不超标，同时还极大地提高了变换器的效率。

(3)应用两种数学建模方法对变换器的主拓扑进行了数学建模，并配合Matlab的SISO tool 对系统传递函数进行了校正，设计出合适的控制器，对实际环路的设计提供了很大的帮助。

(4)对整个变换器的主功率电路和控制、保护电路进行了设计和参数优化，极大地提高了DC/DC 变换器的效率等各项关键性能，对系统的电路设计有较强的实践指导意义。

经过对两级变换器拓扑的理论分析和研究，解决了本课题的开关管应力及热损耗难题，最后设计并制作了原理样机。

本文后面章节所示的实验结果显示变换器各个综合性能指标均达到预设规格，各个关键点波形较好，效率高达94%，纹波噪声较低，动态也得到了较好的均衡设计，变换器散热较好。

关键词两级结构；同步整流；建模分析；热损耗- I -哈尔滨工业大学工学硕士学位论文AbstractThe application of two-stage structure in high efficiency&power DC/DC converter was researched in this paper. The converter was mainly used as 3G corresponding stand power supply. It has a huge value in the applying aspect, and has a large market. According to the statistic, the demand of the converter will be 2K/year. Two-stage converter have these characteristics: It can match with sychronous rectificative technology properly in improving efficiency. It is suitable for low voltage high current circs; Simpleness structure and control circuit; First stage can work in high frequency and output filter can be smaller; It can adapt great-range fluctuation of input voltage。

This paper is to supply an academic analysis of Buck+Pushpull of two-stage structure, take a reference for impoldering the high effiency&high power two-stage converter deeply.Totally speaking, the thesis includes the following parts:(1)The two-stage structure is introduced in detail after comparing of several topology applied in high efficiency&power DC/DC converter. The working principle analysis of steady states is made on the basis of foregoing introduction. Now the analysis of the two-stage topology of Buck+Pushpull in this paper is seldom found on the domestic and overseas information.(2)The SABER simulation is made to choose proper key parameters which respect to switching voltage stress of MOSFET. The debugging on a practical converter validate the correctness of parameters choosing. Comparing of several synchronous rectificative drives prompt a suitable drive which fit two-stage synchronous rectification. It bring demanded drive waveform. The stresses of all MOSFETs are under the maximal voltages. The efficiencies are also increased by this kind of drive.(3)Two mathematical modeling methods are used in modeling main topology of converter. Paper use SISO tool of Matlab in revising system transfer function and designing proper controller. That is helpful in practical closed-loop design.(4) The parameters of the whole converter are optimized. The main- II -哈尔滨工业大学工学硕士学位论文power circuit, control circuit and protection circuit are designed in detail. The key performances of the converter are improved as efficiency and so on. This paper has practical directions of the system circuit designs.The difficult of the switching voltage stress of MOSFET and heat losses are overcome by the analysis and researches of the two-stage structure in high efficiency&power DC/DC converter. At last, a principle sample converter is designed. The results show that the whole performance indexes of the converter can be up to par. The waveforms of all key points of the converter are better. The efficiency is up to 94%. The ripples and noises are low. The dynamic and thermal performances of the converter are good.Keywords two-stage structure, sychronous rectificative technology, modeling analysis, heat losses- III -哈尔滨工业大学工学硕士学位论文目 录摘要 (I)Abstract (II)第1章绪论 (1)1.1课题来源与研究目的及意义 (1)1.2国内外的研究现状及分析 (2)1.2.1 高效大功率DC/DC模块电源国内外研究现状 (2)1.2.2 两级变换结构国内外研究现状 (3)1.2.3 同步整流技术国内外研究现状 (4)1.3本文的主要研究工作 (6)第2章高效大功率隔离型DC/DC变换器原理研究 (7)2.1引言 (7)2.2变换器的拓扑选择 (7)2.3主电路拓扑工作状态分析 (12)2.4两级变换器的仿真研究 (17)2.5关键参数的分析设计 (20)2.5.1 中间电容值 (21)2.5.2 前后级死区时间 (23)2.5.3 输出滤波电感前加电容 (24)2.5.4 变压器开气隙 (25)2.6本章小结 (27)第3章变换器同步整流驱动电路及环路研究 (28)3.1引言 (28)3.2同步整流技术 (28)3.2.1 同步整流技术概述及其驱动问题 (28)3.2.2 几种同步整流方案的仿真对比 (29)3.2.3 外驱动控制驱动电路的芯片选择 (33)3.3热仿真测试 (38)3.3.1 损耗计算 (38)3.3.2 用Flotherm软件进行热仿真 (39)3.4主拓扑的小信号分析 (42)- IV -哈尔滨工业大学工学硕士学位论文3.4.1 Buck级数学模型建立 (44)3.4.2 Pushpull级数学模型建立 (46)3.4.3 两级变换器传递函数分析 (50)3.5本章小结 (53)第4章变换器样机的设计 (54)4.1引言 (54)4.2变换器设计说明 (54)4.3主功率电路设计 (55)4.3.1 高频变压器的设计 (56)4.3.2 Buck级输出电感设计 (58)4.3.3 输出电感电容的设计 (60)4.4控制及保护电路设计 (61)4.4.1 辅助电源的设计 (61)4.4.2 电流采样电路设计 (62)4.4.3 过压保护电路设计 (66)4.5两级变换器电路原理图 (67)4.6本章小结 (67)第5章两级变换器调试与实验结果 (69)5.1引言 (69)5.2各种性能指标测试及分析 (69)5.2.1 效率指标测试 (69)5.2.2 纹波、噪声指标测试 (70)5.2.3 动态及开关机测试 (71)5.3测试环境及实物照片 (74)5.4本章小结 (75)结论 (76)参考文献 (77)攻读学位期间发表的学术论文 (80)哈尔滨工业大学硕士学位论文原创性声明 (81)哈尔滨工业大学硕士学位论文使用授权书 (81)哈尔滨工业大学硕士学位涉密论文管理 (81)致谢 (82)- V -哈尔滨工业大学工学硕士学位论文第1章绪论1.1 课题来源与研究目的及意义近年，由于新型逻辑电路技术不断向前发展，造成工作电压不断下降。