内蒙古科技大学毕业设计说明书（毕业论文）
摘 要
换热器作为一种标准工艺设备已经被广泛应用于动力工程领域和其他过程工业部门。以工业上常用的列管式换热器为例，热流体和冷流体通过对流热传导达到换热的目的，从而使换热器物料出口温度满足工业生产的需求。但是，由于换热系统这种被控对象具有纯滞后、大惯性、参数时变的非线性特点，传统的PID控制往往不能满足其静态、动态特性的要求。控制方式的单一性及目前制造工艺的限制，使换热器普遍存在控制效果差，换热效率低的现象，造成能源的浪费。如何提高换热器的控制效果，提高换热效率，对于缓解我国能源紧张的状况，具有长远的意义。
本课题是针对换热器实验设备温度控制的改进提出的。设计中首先通过对现阶段换热器出口温度控制的特点进行分析，从而发现了制约控制效果进一步提高的瓶颈，为下一步改善换热器的控制效果提供了理论依据。然后根据换热系统组成、控制流程的特点对换热器温度控制系统建立数学模型。再根据所建立的数学模型，联系换热器温度控制的特点，给出了相应的控制策略，即带Smith预估补偿的模糊串级控制方案。主回路采用Smith预估补偿的模糊控制算法，副回路采用模糊PID控制算法，并在理论上验证了其可行性。最后用MATLAB7.0/SIMULINK工具箱进行换热器出口温度的控制仿真，并对仿真结果进行分析，说明所设计的控制算法及方案的优越性。
关键词：换热器温度控制；PID控制；模糊控制；仿真
The heat exchanger based on MATLAB simulation of temperature
control
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内蒙古科技大学毕业设计说明书（毕业论文）
Abstract
Heat exchanger as a standard process equipment has been widely used in the field of power engineering and other process industries. Commonly used in industrial heat exchanger tube as an example, the hot fluid and cold fluid heat transfer through convection heat transfer to achieve the purpose, so that heat exchanger outlet temperature materials to meet the needs of industrial production. However, as the heat exchange system that has a pure time delay plant, large inertia, the parameters of the nonlinear time-varying characteristics of the traditional PID control often can not meet the static and dynamic characteristics of the request. Control the uniformity and the current manufacturing process of the limit, so that the effect of heat exchanger to control the prevalence of poor, low heat transfer efficiency, resulting in waste of energy. How to improve the control of the effect of heat exchangers to improve heat transfer efficiency and ease the tense situation in our country's energy, with a long-term significance.
This issue is heat exchanger for temperature control of laboratory equipment to improve the proposed. first of all , The design stage through the heat exchanger outlet temperature control characteristics of the analysis, which found that the effect of restricting the control to further improve the bottleneck for further improving the control of the effect of heat exchanger provides a theoretical basis. Heat exchange system according to the composition of the characteristics of control flow on the heat exchanger temperature control system mathematical model. Established in accordance with the mathematical model of contact heat exchanger temperature control characteristics of the corresponding control strategy, which Smith estimated compensation with fuzzy cascade control program. Smith estimated the main loop compensation for the use of fuzzy control algorithm, the Vice-loop fuzzy PID control algorithm, and in theory, to verify its feasibility. Toolbox MATLAB7.0/SIMULINK Finally, heat exchanger outlet temperature of the control simulation, and analysis of simulation results to illustrate the design of control algorithms and the advantages of the program. Key words: heat exchanger temperature control; PID control; fuzzy control; simulation
目 录
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内蒙古科技大学毕业设计说明书（毕业论文）
摘 要 ......................................................................................................................................... I Abstract ...................................................................................................................................... II 第一章 绪 论 .......................................................................................................................... 1 1.1 引言 ................................................................................................................................. 1 1.2 选题的背景及意义 ......................................................................................................... 1 1.3换热器的温度控制概述 .................................................................................................. 2 1.3.1 换热器简介 .............................................................................................................. 2 1.3.2换热器运行控制的现状 ........................................................................................... 4 1.4课题的主要任务及意义 .................................................................................................. 5 第二章 换热系统的数学模型 .................................................................................................. 6 2.1 换热器过程控制系统分析 ............................................................................................. 6 2.2 信号的检测及参数关系 ................................................................................................. 7 2.2.1 流量信号的检测 ...................................................................................................... 7 2.2.2 温度信号的检测 ...................................................................................................... 8 2.2.3 执行机构的输入输出关系 ...................................................................................... 8 2.3 换热器特性分析 ............................................................................................................. 9 2.3.1换热器的静态特性分析 ........................................................................................... 9 2.3.2换热器的动态特性 ................................................................................................. 13 2.4离心泵控制模型 ............................................................................................................ 16 2.4.1 系统组成概述 ........................................................................................................ 16 2.4.2离心泵的动态特性 ................................................................................................. 17 第三章 换热器温度控制系统分析及方案设计 .................................................................... 19 3.1 换热器温度控制系统分析 ........................................................................................... 19 3.2 控制模型的选择 ........................................................................................................... 22 3.2.1 副回路控制模型的选择 ........................................................................................ 22 3.2.2主回路控制模型的选择 ......................................................................................... 23 第四章 换热器控制系统控制算法 ........................................................................................ 24 4.1 模糊控制理论 ............................................................................................................... 24 4.1.1 模糊控制概述 ........................................................................................................ 24 4.1.2 模糊控制的原理 .................................................................................................... 25
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内蒙古科技大学毕业设计说明书（毕业论文）
4.2基本模糊控制器的设计 ................................................................................................ 26 4.2.1 模糊化过程 ............................................................................................................ 27 4.2.2 模糊化方法 ............................................................................................................ 28 4.2.3 建立模糊控制器的控制规则 ................................................................................ 30 4.2.4 模糊推理与模糊判决 ............................................................................................ 31 4.3 模糊PID控制算法实现 ............................................................................................. 32 4.3.1 PID控制原理及模糊PID控制原理图 ................................................................. 32 4.3.2模糊参数自整定原则 ............................................................................................. 34 4.3.3 各变量隶属度函数的确定 .................................................................................... 34 4.3.4建立模糊规则表 ..................................................................................................... 35 4.3.5 模糊PID控制器的MATLAB实现 ..................................................................... 37 4.4 Smith—Fuzzy串级控制算法的实现 ............................................................................ 41 4.4.1 Smith预估补偿的原理 ........................................................................................... 41 4.4.2 Smith预估补偿的实现 ........................................................................................... 43 4.4.3换热器出口温度Smith—Fuzzy控制实现 ............................................................ 43 第五章 换热器温度控制系统仿真及结果分析 .................................................................... 46 5.1仿真软件简介 ................................................................................................................ 46 5.2基于换热器出口水温控制系统的仿真 ........................................................................ 48 5.3换热器温度控制系统仿真分析 .................................................................................... 52 第六章 结束语 ........................................................................................................................ 54 参 考 文 献 ............................................................................................................................ 55 致 谢 ........................................................................................................................................ 57
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