预整定自适应PID控制在350MW超临界机组给水控制系统中的应用

发布时间：2018-05-04 07:12

本文选题：超临界 + 给水系统　；参考：《华北电力大学》2017年硕士论文

【摘要】：为了满足不断增长的电力需求,伴随着能源和环保压力的不断增大,我国的火电机组建设向大容量、高参数的大型机组的发展转变。20世纪80年代以来,我国开始引进亚临界火电机组技术,虽在机组技术的消化、吸收、运用、改进方面取得一定的成绩,并广泛推广300MW、600MW的亚临界火电机组,使其成为我国火力发电厂的主力发电设备,但该机组仍然存在能耗高和污染环境这两大突出缺点。这两大缺点十分突出,成为制约我国电力工业发展的突出矛盾。因此,学习掌握国内、国外在本专业领域的先进技术,研究并制造超临界、超超临界火电机组,成为提高火电机组的热效率,实现节能降耗和改善环保状况的必由之路。作为调节锅炉给水流量功能的锅炉给水控制系统,是火力发电厂单元机组控制系统中较为重要的环节之一,该控制系统性能水平的高低直接影响机组能否安全、稳定、经济运行。近年来,随着机组容量的不断增大,来自锅炉受热面产生的热负荷也随之不断提高,因而给水的系统对锅炉负荷的影响不断增加,系统动态特性变化幅度也随之增加。然而锅炉作为一种动态特性存有较大时变且内部存在较多非线性变量的特点,决定了当对其进行建模时,难以建立精确的模型,因而在控制方法的选择上存在着诸多的困难,特别是利用传统控制方法。首先,在对控制器进行参数整定时就要耗费大量的人力、时间成本;其次,因被控对象存在较大的时变性,有时系统表现为非线性,更有甚者控制设备会发生变化,为了适应上述特性,在给水控制过程中必须高频地对控制器比较带进行切换操作,但即使如此操作,采用常规控制方法的给水控制系统也难以实现理想的控制效果。因此,一种算法简单、鲁棒性强,同时能够进对控制器的参数自整定的控制方法亟需被提出。本文在超临界锅炉给水控制对象中引入自适应PID控制器,作者在机组调试过程中,设计了自适应PID模型,并进行仿真实验,应用到超临界机组的调试中,进行了参数整定,投入自动。若使用传统方法对经典PID控制器参数整定,其方法为首先获取控制对象的数学模型,然后依照具体整定原则来确定PID参数。然而在实际工控领域中,被控过程原理复杂,不同于理论模型,实际存在高度非线性、时变不确定性和纯滞后等等特点。因此在实际控制中,一种不仅不用依赖数学建模就能进行PID参数整定,并且能够实时在线调整PID参数的方法成为可以满足实时控制的新需求。自适应PID控制是解决这一问题的有效途径。自适应PID控制顾名思义,同时整合了自适应控制和常规PID控制的优点。首先,从自适应控制的角度来看,其优点在于可以自动识别被控过程参数、自动整定控制器参数、自动适应被控过程参数的变化等;其次,从常规PID控制的角度来讲,其优点在于结构简单、鲁棒性好、可靠性强,且为工程调试人员所熟知。上述描叙的优点,使得自适应PID控制成为工控领域令学者和工程师满意的控制装置,是该领域研究的热点和发展方向。
[Abstract]:In order to meet the increasing demand for electricity, with the increasing pressure of energy and environmental protection, the construction of thermal power units in China has changed to large capacity and high parameters of large units. Since the 80s of.20 century, the technology of subcritical thermal power unit has been introduced in China. Although the technology has been digested, absorbed, applied and improved in the machine group technology, we have obtained one. As a result, the 300MW and 600MW subcritical thermal power units are widely popularized to make it the main power generation equipment of China's thermal power plants, but the unit still has two prominent shortcomings such as high energy consumption and pollution of the environment. These two shortcomings are very prominent and become the prominent contradiction that restricts the development of power industry in China. Therefore, learning to master the country, China It is the only way to improve the thermal efficiency of the thermal power unit, to save energy and reduce the consumption and to improve the environmental conditions. The boiler feed water control system, which is the function of regulating boiler feed water, is more important in the control system of the unit unit of the thermal power plant. The performance level of the control system directly affects the safety, stability and economic operation of the unit. In recent years, with the increase of the capacity of the unit, the heat load from the heating surface of the boiler is also increasing, so the influence of the system on the boiler load is increasing and the dynamic characteristics of the system are changed. However, as a dynamic characteristic of the boiler, there is a large time variation and a lot of nonlinear variables in the interior, which determines that it is difficult to establish a precise model when modeling it. So there are many difficulties in the selection of the control methods, especially the traditional control method. First, the controller is carried out. It takes a lot of manpower and time cost for the parameter timing. Secondly, because of the large time variability of the controlled object, sometimes the system is nonlinear and the control equipment will change. In order to adapt to the above characteristics, the switching operation must be carried out at high frequency to the controller comparison belt in the water supply control process, but even if such operation is done. The water supply control system with conventional control method is also difficult to achieve the ideal control effect. Therefore, an algorithm is simple and robust. At the same time, the control method that can enter the controller's parameter self-tuning is urgently needed. In this paper, an adaptive PID controller is introduced in the feed water control object of the supercritical boiler. The author is in the unit debugging process. The adaptive PID model is designed, and the simulation experiment is carried out. The parameter tuning is applied to the commissioning of the supercritical unit. If the traditional method is used to set the parameters of the classical PID controller, the method is first to obtain the mathematical model of the control object, and then to determine the PID parameters according to the specific setting principle. However, it is practical. In the field of industrial control, the principle of the controlled process is complex and different from the theoretical model. It has the characteristics of high nonlinearity, time-varying uncertainty and pure lag. Therefore, in actual control, a method not only does not rely on mathematical modeling to adjust the PID parameters, and the method of real-time on-line adjustment of PID parameters can satisfy the real-time control. The adaptive PID control is an effective way to solve this problem. Adaptive PID control has the advantages of self-adaptive control and conventional PID control. First, from the angle of adaptive control, the advantages of adaptive control are that the parameters of the controlled process can be automatically identified, the parameters of the controller are automatically adjusted, and the control is automatically adapted to the control. Secondly, from the point of view of conventional PID control, its advantages are simple structure, good robustness, strong reliability and well known to engineering debugger. The advantages of this description make adaptive PID control a satisfactory control device for scholars and engineers in the field of industrial control. It is a hot spot and development of the research in this field. Direction.

【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621;TP273

【参考文献】