锅炉水位控制系统的设计说明书.doc

学 号： 毕业设计说明书 GRADUATE DESIGN 设计题目：锅炉水位控制系统的设计 学生姓名： 专业班级： 学 院： 指导教师： 河北理工大学信息学院 摘 要 摘 要 锅炉是多数工业过程中常用的热能动力设备，工业锅炉控制系统是复杂的控制系统。由于设备分散、管理不善或技术原因，使多数锅炉难以处于良好的工况，增加了锅炉的燃料消耗，降低了效率。为确保安全，稳定生产，对锅炉的自动控制十分重要，其中汽包水位是一个非常重要的被控变量。由于锅炉的水位调节过程具有非线性、不稳定性、时滞性等特点，对锅炉汽包水位的控制提出了更高的要求。 锅炉汽包水位控制系统的设计方案主要有三种，即单冲量、双冲量、三冲量：前两种方案有系统结构简单，成本低，不能有效的控制“虚假水位”现象等特点；与前两种方案相比，最后一种方案有系统结构复杂，成本高但能抑制“虚假水位”现象，控制效果好等特点。本文在三种汽包水位控制系统方案的基础上较为系统地分析了PID控制、前馈控制和串级控制的基本原理、理论和实现，并且在串级三冲量汽包水位控制系统中做了三种控制算法的MATLAB仿真，最后对以上三种控制算法做了比较。 关键词：锅炉汽包水位；虚假液位；PID控制；MATLAB； Abstract Abstract Abstract Boiler is thermal power plant usually used in most industrial processes and Industrial boiler’s control system is a complex control system. Because of scattered equipment, poor management or technical reason, it is difficult to work in good condition for the majority of boilers and increased their fuel consumption and reduced the work efficiency. It is very important to control boiler automatically in safety and stabilization, and boiler’s drum water-level is an important variable to be controlled. Boiler’s water adjusting process has nonlinearity, instability and delay characters, so it makes higher demand for boiler’ s drum water-level control system. Designing models of boiler drum water-level control system mainly includes single-impulse, double-impulse and three-impulse: two former models of which have the features of simplicity and low-cost, but can not control false-water-level; last model of which has the features of complexity and high-cost compared with the two former models, but can control false-water-level and can reach good effective control. The author analyses the principle, theory and realization of the algorithms of PID control, feed forward control and cascade control systematically based on the model of three-impulse boilers drum water-level control system and ; These algorithms in cascade three-impulse boilers drum water-level control system are simulated with Simulink; Finally, above-mentioned thre