发布时间 : 星期三 文章毕业论文 开关电源设计更新完毕开始阅读44b7e426cfc789eb172dc8c1
兰州交通大学毕业设计（论文）
摘 要
开关电源因其具有稳压输入范围宽、效率高、功耗低、体积小、重量轻等显著特点而得到了越来越广泛的应用，从家用电器设备到通信设施、数据处理设备、交通设施、仪器仪表以及工业设备等都有较多应用，尤其是作为便携式产品的电池提供高性能电源输出，比其他结构具有不可超越的优势。
开关电源的稳定性直接影响着电子产品的工作性能,误差放大器是直流开关电源系统中电压控制环路的核心部分，其性能优劣直接影响着整个直流开关电源系统的稳定性，因而对高性能误差放大器的分析是本论文的主要研究目标。本文误差放大器的分析基于Buck型DC-DC转换器，从系统稳定性、负载调整率及响应速度要求的角度出发，首先对该款Buck型DC-DC转换器的系统电压控制环路进行小信号分析,并对控制环路进行了零极点分布分析，确定环路补偿策略。最后基于系统级来分析误差放大器。
关键词：开关电源；Buck型DC-DC转换器；误差放大器。
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兰州交通大学毕业设计（论文）
Abstract
Due to their merits of wide input range, high efficiency, small in size and light in weight ect, switching power supplies are gaining more and more application areas in today’s modern world, ranging from domestic equipments to sophisticated communication and data handling systems, especially in portable devices, they have unsurpassable advantages.
The rapid development of products in corresponding application areas requires the power supplies to have better performances. The robustness of switch—mode power supplies directly affect the performance of electronic devices. As one of the most important parts of switched mode DC to DC converters, error amplifier has significant influences on the voltage control loop’s stability. Thus this paper focuses on the design of high performance error amplifier for DC-DC converters based on system requirements analysis. A buck DC-DC converter was concerned, an error amplifier for the buck converter was designed from the points of view of system stability, load regulation and response speed requirements. At the first place, the Buck DC-DC converter’s voltage control loop stability and pole-zero analysis was done based on a small signal model of the voltage control loop, the compensation scheme was proposed. At last, according to the system level to analysis the error amplifier.
Key words：Switching power; Buck DC-DC Converter; Error Amplifier.
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兰州交通大学毕业设计（论文）
目 录
摘 要 ........................................................................................................................................... I Abstract ...................................................................................................................................... II 1. 诸 论 ................................................................................................................................... 1 1.1 引言 ............................................................................................................................. 1 1.2 本文研究的目的与意义 ............................................................................................. 1 1.3 本论文主要研究内容 ................................................................................................. 1 2. 开关电源基础及其类型 ..................................................................................................... 2 2.1 开关电源基础理论 ..................................................................................................... 2 2.1.1开关电源基本工作原理 ....................................................................................... 2 2.1.2开关电源的组成 ................................................................................................... 2 2.1.3开关电源的各种分类 ........................................................................................... 3 2.2 开关电源典型结构[6] .................................................................................................. 4 2.3 DC-DC变换器 ............................................................................................................ 7 2.3.1Buck变换器 ........................................................................................................... 8 3.3.2Boost变换器 ........................................................................................................ 10 3. Buck型DC-DC转换器及其控制方式分析 ................................................................... 12 3.1 Buck型DC-DC转换器 ........................................................................................... 12 3.2 Buck型DC-DC转换器及其控制方式 ................................................................... 13 3.2.1Buck型DC-DC转换器工作原理 ...................................................................... 13 3.2.2Buck型DC-DC转换器的控制方式 .................................................................. 14 3.2.3Buck型DC-DC转换器工作模式 ...................................................................... 18 3.3 环路控制中误差放大器的重要作用 ....................................................................... 18 4. 开关电源管理电路系统分析 ........................................................................................... 19 4.1 Buck型DC-DC转换器 ........................................................................................... 19 4.2 开关电源控制环路的分析研究 ............................................................................... 20 4.2.1Buck型DC-DC转换器稳定性分析 .................................................................. 20 4.2.2Buck型转换器电压环路控制模型 ..................................................................... 21 5. 误差放大频率特性及其补偿策略 ................................................................................... 27 5.1 控制电路的频率响应分析 ....................................................................................... 27
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兰州交通大学毕业设计（论文）
5.1.1频率响应 ............................................................................................................. 27 5.1.2开关电源输出滤波电路分析 ............................................................................. 28 5.2 开关电源中负反馈及自激振荡分析 ....................................................................... 30 5.2.1负反馈自激振荡 ................................................................................................. 30 5.2.2误差放大电路稳定分析 ..................................................................................... 30 5.3 补偿误差放大器及频率校正策略 ........................................................................... 32 5.3.1I类补偿误差放大器 ............................................................................................ 32 5.3.2Ⅱ类补偿误差放大器 .......................................................................................... 32 5.3.3Ⅲ型补偿误差放大器 .......................................................................................... 34 6. 闭环设计中误差放大器的分析与研究 ........................................................................... 36 6.1 闭环控制系统中的误差放大分析 ........................................................................... 36 6.2 环路增益 ................................................................................................................... 38 6.2.1带有LC滤波电路的环路增益 .......................................................................... 38 6.2.2PWM增益 ............................................................................................................ 39 6.2.3取样增益－反馈系数 ......................................................................................... 40 6.2.4输出LC滤波器的总增益 .................................................................................. 40 6.3 误差放大器的特性分析 ........................................................................................... 40 6.3.1误差放大器的幅频特性整形 ............................................................................. 40 6.3.2误差放大器的传递函数、极点和零点 ............................................................. 42 6.3.3零点、极点和频率增益斜率变化 ..................................................................... 43 6.4 误差放大器零点、极点的分析与计算 ................................................................... 43 6.4.1Ⅱ型误差放大器零点和极点分析 ...................................................................... 43 6.4.2采用Ⅲ型误差放大器及其传递函数 ................................................................. 45 6.4.3Ⅲ型误差放大器的相位滞后分析 ...................................................................... 45 6.4.4Ⅲ型误差放大器零点和极点计算 ...................................................................... 46 6.5 反馈环路条件稳定探讨 ........................................................................................... 47 结 论 ........................................................................................................................................ 49 致 谢 ........................................................................................................................................ 50 参考文献 .................................................................................................................................. 51
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