【作者】 周红军；

【导师】 方康玲；

【作者基本信息】 武汉科技大学 ， 计算机应用， 2002， 硕士

【摘要】 焦炉是一个分布参数，非线性、时变、多变量紧密耦合的被控对象，其中集气管压力和鼓风机吸力既是关键参数，又是具有紧密关系的强耦合变量，它们均是通过调节给煤量和一次送风量来实现控制的。在多座焦炉并联生产条件下，集气管压力控制对象存在复杂的耦合关系，且尚无精确的数学模型，这就给集气管压力控制系统的设计带来困难，难以实现精确的控制。 本文在比较了目前各种解耦方法的优缺点后，针对集气管压力控制的特点，基于相邻通道的波动引起的耦合现象，采用前馈补偿原则，同时考虑鼓风机吸力对集气管压力的影响，将常规PID控制技术、多变量经典控制技术和多变量模糊控制技术相结合，提出了一种基于模糊逻辑的模糊前馈解耦方法，用于集气管压力控制。该方法充分考虑了系统非线性、难以建模和具有强耦合性的特点，实际控制效果充分的表明，本文提出的模糊前馈解耦方法，简单且易于实现，能够有效的解决目前焦化行业中焦炉和煤气鼓风机控制系统中多变量间存在的严重相互耦合的问题。 介绍“水钢煤焦化公司鼓风机高压变频调速及系统PLC控制改造”的工程概况，对煤气鼓风机采用先进的变频调速技术和计算机控制技术进行改造，实现对两座焦炉集气管压力自动调节的闭环控制功能，既满足了煤气量的自动调节的要求，又避免了煤气鼓风机出口阀门的节流调节，节能效果相当可观。同时使初冷器前吸力保持稳定。 制定合理的控制策略，采用基于阀门开度的变频调节策略，即工况变化较小的情况下，电机带动鼓风机恒速运行，通过控制阀门开度自动调节集气管压力；当阀门开度到达极限值，还不能达到控制要求时，再通过变频器改变鼓风机转速，以自动调节集气管压力。此方法既可达到满意的控制效果又可避免对变频器的过度冲击，兼顾节能与可靠运行两方面的要求。 采用德国SIEMENS的S7-300型PLC开发了焦炉和鼓风机控制系统，完成PLC和上位机以及其他现场执行机构的可靠、有效的通讯。实际运行结果表明，该集气管压力解耦控制系统具有较好的动、静态品质，能减小被控对象之间的耦合作用，抗干扰能力强，完全能够满足炼焦工艺要求，而且该控制器算法简单，能由PLC加以实现。更多还原

【Abstract】 A coke oven represents a kind of controlled object with a full spectrum of closely coupled factors, such as distributed parameters, no-linearity, time-dependent change and multi-variable features. Among them, the discharge header pressure and fan suction are key parameters, and also constitute strongly coupled variables with very close inter-relation, which are fulfilled by the way of regulating coal-feeding and the rate of primary air supply in practice. When several coke ovens are connected in parallel, there are many external disturbance factors, as well as complex coupling relations, so the discharge header pressure system of coke oven is a complex multivariable control system and there is no mathematical model up to now. The above circumstances will create some difficulties for the design of a discharge header pressure of coke oven control system, whose difficulties make it hard to realize an accurate control.In this paper, after comparing the difference of some kinds of decoupling control method, aiming at the feature of the coke oven pressure system and based on the coupling phenomena caused by the fluctuate between border upon channels, using the theory of feedforward and thinking about the influence between the fan suction and the discharge header pressure, a kind method of fuzzy feedforward is presented and used to control the discharge header pressure. In this method, the system features, such as no-linearity, no-easy constructing model and serious coupling are fully considered. The control effect manifests the validity of the decoupling methods presented in this paper. It can solve many questions in the operation of coke oven.An engineer case is introduced, which is about "The Reconstruction of High Voltage Fan’s Speed-adjusting by Frequency Conversion and the Design of PLC(programmable logic controller) Control System in Shui Cheng Iron and Steel Company". In this project, an advanced controlling technology ,based on the method in this paper, is used to realize the closed loop control of discharge header pressure of two coke ovens. Based on the experience of regulating frequency according to different valve’s angle, a reasonable controlling tactic is proposed . When the situation changes to a small degree, electromotor makes fan running at a constant rate; when the situation changes to the limiting range, the discharge header pressure is automatically adjusted by the rate of fan.The style of PLC is SIEMENS’s S7-300, which is composed of the controlling system of coke oven and fan.The result of practical control shows that the pressure control system has better static and dynamic characteristics. This system can decrease the coupling influence of controlled objects, and has good anti-interference performance, so it can completely satisfy the need of coking craftwork. Additional, the algorithm is so simple that it can be realized by PLC and uses in practical production of coke oven process successfully.更多还原