1、 PDF外文：http:/ 中文2175字 学 号 24081900389 南湖学院 毕业设计（论文）英文翻译 英文题目 ： Research on Fuzzy Control for Steam Generator Water Level 中文题目： 蒸汽发生器水位 模糊控制 研究 文献出处 ： Computer, Mechatronics, Control and Electronic Engineering
2、; (CMCE), 2010 International Conference on Date of Conference: 24-26 Aug. 2010 作者姓名： Pengwei 译者姓名： 杨 胜 专 业： 机械设计制造及其自动化 完成时间： 2012.5.25 &n
3、bsp; Research on Fuzzy Control for Steam Generator Water Level I. INTRODUCTION The steam generator is one of the main devices in PWR nuclear power plant, in order to ensure the safety of nuclear power plant during operation； the steam generators water level must be controll
4、ed in a certain range. When the nuclear power plant is running, as the steam flow or the water flow changing, the amount of boiling bubbles in the steam generator will change due to local pressure or temperature change, the instantaneous water level showed “false water level” phenomenon . The existe
5、nce of “false water level” made it difficult to control the water level. The introduction of feed-forward control to the traditional single-loop PID control can, in a certain extent, overcome the "false water level" phenomenon. But the conventional PID control method in the process of stea
6、m generator water level control has some shortcomings. To the steam generator that has highly complex, large time-delay and nonlinear time-varying characteristics, the PID parameters tuning is a tedious job and the control effect is very poor. Furthermore, to achieve good control performance still a
7、s conditions changing, it often needs to change the PID controller parameters. But the analog PID controller parameters are difficult to regulate online. Fuzzy control is a kind of nonlinear control strategy based on fuzzy reasoning, which express operating experience of skilled manipulation men and
8、 common sense rules of inference through vague language. Fuzzy control do not need to know precise mathematical model of controlled object, is not sensitive to the change of process parameters, is highly robust and can overcome non-linear factors, so, fuzzy control has faster response and smaller ul
9、tra- tone, can get better control effect. Based on understanding above, this paper design a steam generator water level fuzzy controller, the simulation shows that the controller has good control performance and practical value. II. DYNAMIC CHARACTERISTICS OF STEAM GENERATOR The transfer function of
10、 PWR steam generators mathematical model of the general form shows below: y(s)=GW(s)QW(s)+GS(s)QS(s) （ 1） where y is the steam generator water level； QW for the water flow； QS for the steam flow； GW (s) for the impact of the water flow to the steam generator water lev
11、el； GS (s) for the effect of the steam flow (load) to the steam generator water level. The balance of the steam generator water level is maintained through the match between the water flow and steam flow. The process that water level changes with the steam flow or water flow changing can be regarded
12、 as a simple integration process, but impact of the water flow and steam flow s change on water level is different. A. Dynamics Characteristics under Water Flow Disturbance Suppose steam flow GS remains unchanged, and water flow GW step increases, on the one hand because the temperature of fee
13、d water is much lower than the temperature of saturated water in the steam generator, so that , when feed water entering, it will absorb a lot of extra heat, the vapor phase bubble contents will reduce, resulting in water level decreasing； on the other hand, the increase in water flow GW made it gre
14、ater than steam load, and cause water level increases linearly. Comprehensive two factors, after the step increase of the water flow, the water level rise has a time delay process, showing a down then up. B. Dynamic Characteristics under Steam Load Disturbance Suppose feed water flow GW remains unch
15、anged, and steam load GS step increases, on the one hand the water level will flow down because the steam flow rate is greater than the water flow rate. On the other hand, as the steam load increased, vapor pressure is reduced； the bubble volume on the liquid surface increases, causing the water lev
16、el increased. Comprehensive two factors, after the step increase of the steam flow rate, the water level down has a time delay process, showing a up then down. The impact on the water level of water flow or steam flow stepping decreased has similar principle as above. As analysis can be seen a
17、s above, when the water flow or steam load change, the water level did not follow the change immediately, but there is an opposite process at first. This phenomenon is called "false water level" phenomenon. III. DESIGN OF WATER LEVEL FUZZY CONTROLLER The conventional PID controller has a p
18、oor control performance to the steam generator that exist “false water level” characteristics, showing a greater overshoot in the tracking time. But a well-designed fuzzy controller is able to overcome the "false water level" phenomenon, and has good control performance. A. Sstructure of Fuzzy Controller The structure showed in Figure 1.
