【作者】 魏乐；

【导师】 韩璞；

【作者基本信息】 华北电力大学（河北） ， 热能工程， 2009， 博士

【摘要】 机炉协调控制系统是单元制发电机组的控制中枢,是电站生产自动化系统中最为核心的组成单元。本文针对一典型锅炉-汽轮机单元非线性模型,应用非线性反推法的相关原理和方法研究了锅炉-汽轮机单元协调控制系统的设计和性能评价问题,致力于提高协调控制系统克服对象多变量耦合、非线性和参数不确定性的能力,提高单元制发电机组的运行水平。论文的研究内容及取得的主要成果体现在以下四个方面:①基于线性化模型的反推协调控制系统设计:线性化锅炉-汽轮机单元模型,进而分解出核心耦合部分,应用反推法进行控制律设计;为了便于工程实现,通过适当变换,将核心控制器转换成PID形式;利用核心耦合部分与线性化模型的对应关系得到反推协调控制器;在某500MW机组锅炉-汽轮机单元非线性模型上的仿真研究表明,该系统在额定负荷点附近具有良好的解耦能力和给定值跟随性能。②基于非线性模型的反推协调控制系统设计:直接针对非线性锅炉-汽轮机单元模型进行反推法的研究,通过模型的预处理,将原系统分解成两个子系统,通过合理选择虚拟控制变量,逐步构造出偏差信号的李亚普诺夫函数,进而设计出非线性机炉协调控制器,并将其转换成PID控制器形式;在某500MW机组非线性模型上的仿真试验表明,在大范围变工况条件下,该控制策略依然具有良好的负荷跟随性能,能够有效克服输出功率和主蒸汽压力通道的耦合作用。③考虑参数不确定性的非线性自适应反推协调控制系统设计:在非线性反推协调控制系统设计的基础上,将不确定参数对系统调节品质的影响考虑进去,重新构造偏差函数和相应的李亚普诺夫函数,通过逐步反推的方式,得到反推控制律和不确定参数的自适应更新率,并将最终的协调控制律转换成PID形式;在某500MW机组非线性模型上的仿真研究表明,自适应环节的添加有效地抵消了参数不确定性对系统的影响。④反推协调控制系统性能评价:通过时间序列分析方法,对设计出的锅炉-汽轮机单元反推协调控制系统的运行数据建立时间序列模型,从中提取出反馈不变项,用以估计系统的最小方差;然后基于实用型最小方差基准,对论文中依次设计的三个控制系统的性能进行分析和比较。更多还原

【Abstract】 A boiler-turbine coordinated control system is the control center of a power generation unit, and is the core of a modern power plant. This dissertation studies the design and implementation of the boiler-tubine unit coordinated control system for a classic nonlinear model of boiler-turbine units via nonlinear backstepping control theories and methods, with the motivation to apply advanced control strategies to engineering practice and to improve the adaptability of the coordinated control system to the process multi-variable coupling, nonlinearities and uncertainty of parameters.The main contributions of this dissertation are summarized as follows:①The nonlinear model of boiler-turbine units is linearized, and is decomposed to get the core of the control. The controller of the core is designed by using backstepping method, and is changed into PID form for engineering purpose. Then the backstepping coordinated controller is obtained by using the relationship between the core and the whole linearized model. Simulation studies of the backstepping coordinated control system based on the linearized model are done on a 500MW boliler-burbine unit, the results of which demonstrate that this control strategy has good ability to overcome the object coupling.②Retaining all the nonlinear information of the nonlinear model of boiler-turbine units and in accordance with the characteristics of the model and the using conditions of backstepping, the model is pretreated. After pretreatment, the system is divided into two subsystems. Then nonlinear backstepping controllers are designed for the subsystems separately, and the nonlinear backstepping coordinated control law is obtained and changed into PID form for engineering purpose. The designed nonlinear backstepping controller is applied to the 500MW nonlinear model. Simulation results show that this kind of control strategy can well overcome the coupling and nonlinear of the object.③Based on the design of nonlinear backstepping coordinated control system, and taking into account the impact of system ajust quality caused by uncertain parameters, the nonlinear adaptive backstepping coordinated controller is designed and changed into PID form. Simulations on the nonlinear model of the 500MW boiler-turbine unit show that the addition of adaptive link effectively offset the impact of uncertain parameters on the system.④Through time series analysis methods, time series models is fitted to the routine operation data of the designed boiler-turbine unit backstepping coordinated control systems. From these models the feedback-invariant forms of the control systems are extracted, which are used for estimating minimum variances. Then based on the benchmark of practical minimum variance, the control performances of the designed three coordinated control systems are evaluated and compared.更多还原