【作者】 王军；

【导师】 刘咸定； 任庆昌；

【作者基本信息】 西安建筑科技大学 ， 供热、供燃气、通风及空调工程， 2003， 博士

【摘要】 变风量空调系统具有多变量、彼此耦合强烈、非线性等特点，其自动控制系统的多个控制回路同时工作时，各个控制回路之间具有强烈的耦合作用，相互影响，相互干扰。这种耦合作用直接影响到变风量空调系统的控制品质和稳定性，本文通过建立被控对象的数学模型和设计解耦控制系统的方法以减小多个控制回路之间的耦合，提高变风量空调系统的控制性能和稳定性。 本文首次建立了变风量空调系统的机理模型，并通过采用机理分析和实验数据分析相结合的方法，建立了所研究的五输入、五输出的变风量空调系统的传递函数矩阵，并对这五个控制回路的被控对象的非线性数学模型，采用两种方法加以处理：第一种方法是在系统的工作点附近进行泰勒级数展开，使输出的变化量与输入的变化量之间呈现近似的线性关系；第二种方法是将非线性的数学模型进行分段线性化，即用分段线性化来逼近非线性化的模型。本文研究表明，这两种线性化方法用来处理变风量空调系统的非线性问题都是有效的。 解耦控制是一个难度比较大的研究领域，很重要的原因是解耦补偿器的设计很困难，一般情况下，三输入、三输出系统解耦的难度就已经很大。本文采用前馈补偿法设计了变风量空调系统的解耦补偿器，并得出了五输入、五输出变风量空调系统前馈补偿解耦器的传递函数矩阵，该解耦补偿器可以使本文所研究的变风量空调控制系统的开环传递函数矩阵和闭环传递函数矩阵都变换为对角矩阵，从而解除五个控制回路之间的耦合，使变风量空调系统实现解耦。此前未见到国内外文献有这方面的报道。 本文采用逆推法与遗传算法相结合的PID控制器的设计方法可以有效地控制变风量空调系统。本文直接找出PID参数与闭环控制系统的特征方程的根之间的关系，只要使特征方程的根在z平面的单位圆内任意取值，然后再求出相应的PID参数，则闭环控制系统必然是稳定的。本文所采用的这种确定PID参数的方法，虽然可以使特征方程的根在z平面的单位圆内任意取值，但各种取值情况对变风量空调系统的控制品质的影响却不同，因此，要对各种特征方程的根的取值情况进行寻优，本文采用遗传算法对特征方程的根进行寻优，从而使控制器的参数得以优化。 西安建筑科技大学博士学位论文一 本文在变风量空调系统解耦控制的研究过程中，将网络控制技术中的Lonworks技术与变风量空调技术有机地结合起来，建立了基于Lonworks技术的变风量空调解耦控制实验系统，目前国内尚未见到有关这方面的报道，该实验系统在国内具有先进水平。 本文提出了实现Lonworks和METASYS网络进行数据交换的新见解。在本文所研究的变风量空调解耦控制系统的实验装置中，存在着Lonworks和METASYS两套系统，而这两套系统的通信协议遵守不同的标准，使得这两套系统之间的数据交换出现困难。本文在处理这一问题时采用了一个巧妙的方法。由于 LON网络、METASYS网络及Visual Basic都支持动态数据交换 （DDE）协议，因此，可以将 LON网络的数据通过该系统中的 LNS DDE Server送到 VisualBasic上；同时将METASYS网络的数据通过 Metalink DDE送到同一个Visual Basic上，经过Visual Basic进行处理后，分别送给LON网络和WITASYS网络，从而实现这两个网络的数据交换。该方法简单实用，不仅节省了硬件投资，还节省了开发网关所需的时间。更多还原

【Abstract】 VAV system has the feature of multi-variable, intense conpling and nonlinear. When the several control loops in the control system are working together.there is intense coupling among them. The loops influence as well as interfere each other.The coupling may directly affect the property and the stability of VAV system.This thesis focuses on reducing and eliminating the coupling among the control loops by means of setting up the mathematical model of VAV system and designing the decoupling control system. Thus the controlling property and the stability of VAV system may be well improved.Here the theoretical model of VAV system is set up for the first time.Besides,the transfer function matrix of the 5 inputs and the 5 outputs is established by combining the theoretical analysis with the data analysis of experiment. Then the non-linear mathematical model of the five loops is delt with in two method: In the first method, Taylor progression is applied near the working point of the system in order to make the volume of change between the output and the input become similar to a linear relationship. In the second mothed, the non-linear mathematical model realize linear by means of being devided into sections.The study shows that both the motheds are effective in dealing with the non-linear issue in VAV system.In this thesis, the decoupling unit of VAV system is designed in the way of feedforward conpensation. Then the transfer function matrix of the feedforward conpensation decoupling unit of the 5 inputs & 5 outputs VAV system is worked out. The decoupling conpensation unit can change the transfer function matrix of the open loop and closed loop control system into diagonal matrix,so that the coupling among the five control loops is eliminated,and VAV system is decoupled. Before this thesis, similar report is unseen in both domestic and foreign reference.This thesis presents an effective way to design PID controller through a combination of adverse deduce and genetic algorithm. The relationship between PID parameter and the root of the characteristic equation of the closed loop control system has been found out directly. As long as the root of the characteristic equation is within the unit circle of z-plane and the corresponding PID parameter is got, the closed loop control system is sure to be stable. Although the root of the characteristic equation can vary within the unit circle of z-plane,different value may affect the control property differently. Therefore,it is better to optimize the root, here the optimizing method is carried out by genetic algorithm.In this thesis, the VAV decoupling control experiment system based on LonWorks technology is set up by means of combination of Lon Works technology of networks control technology and VAV technology. So far, there is no such report in domestic reference. So the experiment system can be regarded as advanced.This thesis offers a new way to exchange data between LonWorks and Metasys networks. Acturelly, there are two systems in the experiment unit of the VAV decoupling control system. They are LonWorks system and Metasys system. As the communication protocols follow their respective standard, the data exchanging between the two systems becomes difficult. Here an ingenious method is adopted. Since LON net, Metasys net and Visual Basic all support dynamic data exchange (DDE)protocol, the data of LON net can be conveyed to Visual Basic through LNS DDE Server of LON system. Meanwhile, the data of Metasys net can be conveyed to the same Visual Basic through Metalink DDE . Then the Visual Basic is expected to deal with the data, after that, the data are conveyed back to LON net and Metasys net. Thus the data exchange is realized. Simple and practical, this method helps to save the cost of the hardware as well as the time spent in exploiting the gateway.更多还原