基于DSP的BUCK数字控制器设计

基于DSP的BUCK数字控制器设计(论文12000字)
摘要：随着电力电子技术的快速发展，开关电源技术普遍运用开关功率转换器来控制电能。本文主要以DC/DC开关变换器为例，进行数字模型的建立、分析、控制与DSP控制等工作。Buck变换器就是其中一种典型的DC/DC变换器，具有降压的功能，其输出电压极性与输入电压的极性相同。与其他变换器相比，Buck变换器具有体积小、效率高的优点。
在实际工程应用中，DC/DC变换器的控制器通常都是用模拟电路实现。由于数字控制芯片价格的不断下降，数字控制技术比重越来越大。数字控制技术具有抗噪声能力、实时调节控制器参数、可编程性、对环境因素变化不敏感等优点。
结合电力电子的相关知识，本文阐述了基于DSP的Buck数字控制技术。首先介绍Buck变换器的基本原理及其稳态分析；然后推导出等效交流小信号模型,并设计相关参数，在Mathcad中进行电感元件的设计，求出其控制-输出和输入-输出传递函数，用Matlab绘制出系统的Bode图分析频率特性，结合传递函数与Bode图对Buck变换器进行闭环控制器的设计；将设计出的模拟控制器进行数字化，并对数字控制器进行仿真，校验系统对阶跃扰动的响应，得出数字控制器的差分方程，以便算法实现；最后完成基于DSP28335数字控制器设计，主要包括软件流程图、主要DSP模块的设置方法和主要数字代码的解读。
关键词：Buck；DSP；小信号建模；补偿网络；数字控制器

Design of BUCK Digital Controller Based on DSP
Abstract :With the rapid development of power electronics technology, Switching power supply technology generally uses switching power converters to control electrical energy.This paper mainly takes the DC/DC switching converter as an example to carry out the work of establishing, analyzing, controlling and controlling the digital model. The Buck converter is one of the typical DC/DC converters with a buck function, and its output voltage polarity is the same as the input voltage. Compared with other converters, Buck converters have the advantages of small size and high efficiency.
In practical engineering applications, the controllers of DC/DC converters are usually implemented in analog circuits. Due to the continuous decline in the price of digital control chips, the proportion of digital control technology is growing.Digital control technology has the advantages of anti-noise ability, real-time adjustment of controller parameters, programmability, and insensitivity to environmental factors.
Combining with the knowledge of power electronics, this paper expounds the Buck digital control technology based on DSP.Firstly, the basic principle of Buck converter and its steadystate analysis are introduced. Then derive the equivalent AC small-signal modeland designedthe relevant parameters. The design of inductance component is carried out in Mathcad. The control-output and input-output transfer functions are derived. Using Matlab to plot the frequency characteristics of the Bode diagram of the system.The closed-loop controller of the Buck converter is designed by combining the transfer function and the Bode diagram. The designed analog controller is digitized. The digital controller is simulated to verify the response of the system to the step disturbance, and the difference equation of the digital controller is obtained for algorithm implementation.Finally, the digital controller based on DSP28335 is designed, including software flow chart, setting method of main DSP module and interpretation of main digital code.
Key words：Buck；DSP；Small signal modeling；Compensation network；Digital controller
 

目录
第1章 绪论    1
1.1本课题的目的及研究意义    1
1.2国内外研究现状    1
第2章 Buck变换器工作原理    1
2.1Buck变换器电路图    1
2.2Buck变换器工作原理    2
2.2.1 Buck变换器工作模态    2
2.2.2 CCM模式下Buck变换器工作原理    2
第3章 理想Buck电路的小信号模型及其闭环控制器的设计    4
3.1 CCM模式下Buck变换器的交流小信号模型    4
3.1.1 非线性模型    4
3.1.2 小信号线性模型    6
3.1.3 小信号等效电路    9
3.1.4 滤波电容等效串联电阻的影响    11
3.2 Buck变换器闭环控制器设计    12
3.2.1 Buck闭环反馈控制网络    13
3.2.2 闭环控制器设计    13
第4章 数字控制器的设计    18
4.1 数字控制器结构概述    18
4.2 连续系统设计的离散等效    19
4.2.1 近似z型代换离散法    19
4.2.2 零极点匹配法    22
4.3 模拟控制器的数字化    23
4.3.1 采样周期的选择    24
4.3.2 计算离散等效传递函数     24
4.3.3 闭环系统的计算机仿真    25
4.3.4 差分方程    27
第5章 Buck变换器数字控制器的DSP实现    27
5.1数字控制器主体程序框架    28
5.2 主要功能子函数介绍    28
5.2.1 ADC中断函数    28
5.2.2 PID计算函数    29
5.2.3 更新ePWM比较值函数    29
总结    30
参考文献    30
致谢    32