基于广义预测控制的锅炉再热汽温系统设计与应用

发布时间：2018-05-01 13:05

本文选题：再热汽温 + 广义预测控制　；参考：《华北电力大学》2017年硕士论文

【摘要】：随着电力行业的发展,大容量、高参数的火电机组所占比例越来越大,对其控制品质提出了更高的要求。为了提高超临界机组的循环热效率,超临界机组广泛采用中间再热系统,将汽轮机高压缸的排汽再一次加热至高温,然后再送到中、低压缸膨胀做功。将电站锅炉再热蒸汽温度控制在允许的范围内,是提高发电机组的经济效益、保证机组安全运行的不可缺少的环节。然而由于火力发电生产过程的特殊性和蒸汽管道构造的复杂性,对再热蒸汽温度对象的控制比较困难。尤其当主蒸汽流量大幅度变化时,再热汽温更难以控制。而现有的锅炉再热汽温控制策略仍存在一定的局限性和缺陷,难以达到理想效果。本文在总结前人工作的基础上,主要将广义预测控制算法引入到再热汽温的控制中做进一步的研究。本文研究的主要内容包括如下两个方面:(1)控制算法方面:在常规串级PID算法的基础上引入比例积分型GPC算法,形成比例积分型GPC-PID算法。广义预测控制具有多步预测、滚动优化和反馈校正三个基本特征,能有效地克服被控对象的迟延、不确定性和时变性等因素的动态影响,从而能更好的实现控制目标并使系统有较强的稳定性和鲁棒性。(2)逻辑切换方面:设计一种再热汽温的烟气侧和蒸汽侧联合广义预测控制,实现了两种调节手段的平滑、无扰切换且在任意时刻只需要一种调节方式。最后,将该方法应用到锅炉燃烧器摆角—再热汽温的对象模型中。仿真结果表明:本文设计的基于广义预测控制的锅炉再热汽温具有很好的控制效果,提高了机组的热经济性,避免了常规设计的控制方法所带来的一系列不良问题。
[Abstract]:With the development of power industry, the proportion of large capacity and high parameter thermal power units is increasing. In order to improve the circulating heat efficiency of the supercritical unit, the intermediate reheat system is widely used in the supercritical unit. The exhaust steam of the high-pressure cylinder of the steam turbine is heated to high temperature again, and then sent to the middle and low pressure cylinder to do the work. It is necessary to control the reheat steam temperature of utility boiler within the allowable range to improve the economic benefit of the generating set and to ensure the safe operation of the unit. However, because of the particularity of thermal power production process and the complexity of steam pipeline construction, it is difficult to control the reheat steam temperature object. Especially when the main steam flow rate changes greatly, the reheat steam temperature is more difficult to control. However, the existing boiler reheat steam temperature control strategy still has some limitations and defects, so it is difficult to achieve ideal results. On the basis of summarizing the previous work, this paper mainly introduces the generalized predictive control algorithm into the control of reheat steam temperature for further study. The main contents of this paper include the following two aspects: on the basis of the conventional cascade PID algorithm, the proportional integral GPC algorithm is introduced to form the proportional integral GPC-PID algorithm. Generalized predictive control (GPC) has three basic features: multistep prediction, rolling optimization and feedback correction, which can effectively overcome the dynamic effects of delay, uncertainty and time-varying of the controlled object. Thus it can better realize the control goal and make the system have strong stability and robustness. In the aspect of logic switching, a combined generalized predictive control of flue gas side and steam side of reheat steam temperature is designed, which realizes the smoothing of two regulation methods. No disturbance switching and only one adjustment mode is required at any time. Finally, the method is applied to the object model of boiler burner wobble angle and reheat steam temperature. The simulation results show that the boiler reheat steam temperature designed in this paper based on generalized predictive control has a good control effect, improves the thermal economy of the unit, and avoids a series of bad problems caused by the conventional control method.
【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】：TM621.2;TP273

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