(论文翻译 页数:51 字数:16466)范围极广，过程控制是其中最重要的一个分支。因而，过程控制在国民经济中占有极其重要的地位。工业生产对过程控制的要求是多方面的，最终可以归纳为三项要求，即安全性、经济性和稳定性，其中，安全性是最重要最基本的要求。
锅炉是众多工业部门必不可少的重要动力设备。因此，锅炉往往成了不少工厂不可缺少的一部分。因而，对锅炉设备中的自动控制系统进行分析研究是必要的。锅炉水位控制系统是锅炉生产控制系统中最重要的环节。对锅炉生产操作如果不合理，管理不善，处理不当，往往会引起事故。这些事故中的大部分是由于锅炉水位控制不当引起的，可见锅炉汽包水位控制在锅炉设备控制系统中的重要性。
现代工业锅炉都向着大容量高参数的方向发展，一般锅炉容量越大，汽包的容水量就相对越小，允许波动的蓄水量就更少。这样对汽包水位要求就更高了。而在常规的三冲量控制系统中，由于“虚假液位”的原因使得蒸汽负荷上升和下降时的动态特性曲线不对称，且系统参数具有时变性，不能求出准确的数学模型，也就不能设计出准确的前馈控制器，只能实现静态前馈，能实现稳态无误差，但对动态性能控制不好。这样，就不能很好的满足现代工艺的要求。
考虑到模糊控制器的设计不需要知道该过程的数学模型以及它的其他特点都适合于这种蒸汽前馈控制，所以我们决定在这里用模糊控制器代替了三冲量控制系统中的蒸汽前馈控制中的常规控制器。而给水流量的扰动造成的汽包水位变化这一过程可以通过实验测试和数据处理得到精确的数学模型，这样就能够设计常规控制器来控制，并能达到很好的效果。
于是，应用模糊控制理论，设计出一个锅炉汽包水位模糊控制系统，实现了模糊动态前馈，通过在simulink下仿真，达到了较好的控制效果。主回路采用模糊与PI混合型的控制器，减小了稳态误差。改变对象参数后，模糊控制系统仍能使偏差在工艺允许范围内。证明了模糊控制系统的鲁棒性好，抗干扰能力强等特点。并通过常规三冲量PID仿真与模糊控制仿真进行了一系列对照，结果证明对于那些过程复杂，具有时变性和明显滞后以及难以取得精确的数学模型的系统，模糊控制比传统的三冲量控制更容易实现全自动并且控制作用相当有效。

 关键词：锅炉系统 常规三冲量控制 虚假液位 模糊控制 仿真

MATLAB emulation of the fuzzy water level system studies
Abstract
Range that the industrial automation involves is extremely wide, It is the most important branch among them that the course is controlled. Therefore, The course is controlled and occupies the extremely important position in national economy. Requests controlled for the course in industrial production are in many aspects, Can sum up for three requests finally, Namely the security, economy and stability, Among them, the security is the most important and most basic request.
The boiler is numerous essential important power equipment of industrial department. So, the boiler has often become an indispensable part of many factories. Therefore, it is essential for automatic control system in the boiler equipment to analyse and research. The water level control system of the boiler is that the boiler produces the most important link in the control system. If unreasonable to the production operation of the boiler, manage improperly, it is improper to deal with, will often cause the accident. The majority in these accidents is improper in control because of the water level of the boiler were caused, can see the importance in the equipment control system of the boiler of control of water level of steam dome of the boiler.
The modern industry boilers all develop in the direction of the large capacity high parameter, the general boiler is the larger in capacity, person who holds water of steam dome relative and light, water demand fluctuated to allow less . Have expected much the water level of the steam dome like this. Among routine three impulse control system, because reason of " false liquid location" make steam load rise and drop dynamic characteristic when curve asymmetric, degeneration, can't ask out the accurate mathematics model when and there are the systematic parameters, can't design the accurate feedforward controller either, can only realize the static feedforward , can realize that there is not error in the stable state , but does not control dynamic performance well. In this way, the request for meeting the modern craft that it can't be very good.
Consider that the design of the fuzzy controller does not need to know that mathematics model and its other characteristics of this course are suitable for this kind of steam feedforward to control , So we determine replace three impulse steam feedforward of the control system control routine controller of with fuzzy controller in here. And this course of change of water level of steam dome caused to perturbation of water flow can pass experiment test and receive the accurate mathematics model with data processing , can design the routine controller to control like this, and can reach very good result.