锅炉蒸汽温度模糊控制器的设计.doc

PAGE I 锅炉蒸汽温度模糊控制器的设计 摘要 电厂实现热力过程自动化，能使机组安全、可靠、经济地运行。锅炉是火力发电厂最重要的生产设备，过热蒸汽温度控制是锅炉控制系统中的重要环节。 随着控制对象变得复杂，应用常规PID控制，精度和鲁棒性降低。锅炉过热汽温具有大惯性、大滞后的特点，并且动态特性随机组负载变化而变化，运行过程中扰动多、难控制。当控制对象很复杂的情况下，常规PID控制器已经不太能满足控制要求了，为提高对复杂系统的控制性能，本文介绍了一种模糊PID控制器。文章针对这种情况，研究了模糊-PID复合控制算法,并针对某火电厂燃煤锅炉过热蒸汽温度进行了仿真研究。在分析蒸汽温度系统工作过程、调节对象及其动态特性的基础上,构建了系统的结构模型；在对火电厂过热汽温控制对象特点分析的基础上，结合模糊控制动态特性好的特点，提出了一种模糊-PID控制设计方法。它将PID控制与模糊控制的简便性、灵活性以及鲁棒性融为一体，构造了一个自适应模糊PID控制器。此控制器的比例系数、积分系数、微分系数可根据模糊推理规则进行在线调整。本文比较了PID控制和模糊控制的异同，结合两者各自在控制方面的优点，设计出符合整套控制系统的模糊-PID控制器。 本文以误差和误差变化率为输入，利用模糊推理的方法实现了对参数的在线自动整定， 并且在MATLAB环境下对该控制器进行了设计和仿真。从仿真结果可以看出, 参数自整定模糊控制器控制效果优于传统控制器, 提高了系统的动态性能。 关键词：过热蒸汽温度；传统PID控制器；模糊-PID控制器；仿真  Abstract Power plants perform thermal process automation, which makes machine run safely, steadily and economically. Boilers are the most important production equipment in the power plants. The overheating steam temperature is one of the important quality standards. When the controlled objects become complicate, the control accuracy and robustness of the normal PID decrease. This paper design a fuzzy PID control in order to improve the system performance for complex systems in which the normal PID controller is not suitable in such case. The paper studied the integrated control arithmetic of Fuzzy-PID for the above problems and made a simulation in over-heated steam temperature system of a thermal power station. On the basis of analyzing the operating process, adjusted-object and their dynamic characteristics of the over-heated steam temperature system, the system’s structure models were established. A design scheme of integrated fuzzy serial control system was presented the good dynamic characteristic of fuzzy control based on the analysis of the characteristic of over-heated steam temperature of thermal power station. A self-adjusting PID controller, which has simpler structure and higher robustness, is built when Fuzzy logic controller and PID controller are combined together appropriately. The proportional,