【作者】 王士超；

【导师】 白瑞祥；

【作者基本信息】 天津科技大学 ， 检测技术与自动化装置， 2008， 硕士

【摘要】 取暖锅炉是重要的民用设备。目前,我国北方地区取暖锅炉的使用非常广泛,但是其中大部分自动控制水平很低,且存在燃烧不彻底、排烟热损大等问题,导致锅炉热效率低下和能量的浪费,同时也造成了对环境的污染。锅炉系统是一个典型的非线性时变多变量耦合系统,系统存在惯性滞后,难以建立精确的数学模型,用常规的控制手段如PID控制难以得到理想的控制效果。而目前智能控制理论及智能控制方法的发展为锅炉控制提供了更多解决方案,以实现锅炉有效控制。其中,模糊控制技术作为一种较成熟的方法已越来越多地被应用于锅炉控制系统中。同时,随着自动化技术和计算机技术的发展,出现了以PLC为代表、以程序控制取代人工控制的智能控制器。本文在模糊智能控制技术理论研究的基础上,以丹东稳压给水设备厂供暖锅炉为对象,对供暖锅炉控制的关键技术进行了研究。通过对供暖锅炉实际运行工况的分析,对这种非线性大时滞系统的控制,提出了一种控制方案,主要包括三个控制回路：给粉量控制回路、燃烧最优控制回路和炉膛负压控制回路。根据不同的控制回路的特点,采用模糊PID复合控制方法控制给煤量,采用模糊自寻优方法控制最优风煤比,采用前馈-反馈方法控制炉膛负压。并通过对锅炉热平衡的分析,找出影响锅炉运行的主要因素,在线计算锅炉热效率,为锅炉有效控制提供了理论基础。该项目的现场控制系统采用的是德国SIEMENS公司的S7-300系列PLC做主站,分布式I/O ET200M做从站,构成的PROFIBUS-DP二级总线控制系统。运用与之相配套的STEP7编程软件进行编程和组态。上位机选用性能稳定、抗干扰性能好的工控机。同样采用了德国SIEMENS公司的工控组态软件WINCC对上位机的人机界面进行设计和组态,实现各种现场数据的实时监控、显示和记录。人机界面包括导航画面、锅炉运行画面、记录查询画面、报警画面、报表打印画面、参数设定画面、实时曲线显示画面等操作显示画面。更多还原

【Abstract】 Heat boiler is very important for civil applications. Nowadays, it is widely used in the north region of China. But the automation technology of most of the boilers’ control systems are undeveloped, and there are a lot of problems, such as burning incompleteness, big expense quantity of heat. The result is energy wasting, low thermal efficiency and environmental pollution.The boiler system is a typical nonlinear, time varying, multivariable coupling system. The system has big inertia delay, and it is difficult to set up accurate mathematics model. So we could not get ideal control result by using PID controller. Fortunately, the development of the intellectual control theory and intellectual control method has offered more solutions for boiler systems, and make sure that the boiler is controlled effectively. As a proven technique the fuzzy control technology has already been applied in the control system of the boiler more and more widely. At the same time, with the development of Computer and Automation technology, PLC systems are introduced, which are intellectual systems and can be used to take place of human control.In this thesis, based on the research about fuzzy control technology, a heat boiler of one factory region is considered. Some key control technology to control the heat boiler is researched. By analyzing the running status of the boiler a control program is presented for the nonlinear, long delay system. In the program control system is consisted by three loops that is the fuel quantity control loop, the optimal ratio of blast-coal control loop and the hearth pressure control loop. Different loop has different character, so we use different control strategy. We use a FUZZY-PID controller to control the fuel quantity and a fuzzy self-seeking optimal point strategy is used to obtain the optimal ratio of blast and fuel. Finally a feed forward and feed back strategy is applied to control the hearth’s pressure. By analyzing the boiler’s heat balance, we can find the major factor about boiler’s running and compute the boiler’s combustion efficiency on-line. And this theory can be used in boiler control system effectively.The field control system is composed by the PROFIBUS-DP field-bus control system with the SIEMENS S7-300 PLC as the master station and the ET200M distributed I/O as the slave station. The system is programmed by the corresponding program software——STEP 7.The industrial personal computer (IPC), with high stabilization and anti-jamming performance, has been selected as upper computer. The Human Machine Interface (HMI) has been designed by SIEMENS WINCC to supervise, log and control the real time data. The HMI includes guide, running of the boilers, records checking, alarming, reporting, parameters setting, real time trend curve, and so on.更多还原