英文翻译外文文献翻译123供水系统的控制与节能的探索（中文资料）.doc

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1、【精品文档】如有侵权，请联系网站删除，仅供学习与交流英文翻译外文文献翻译123供水系统的控制与节能的探索（中文资料）.精品文档.恒压供水的控制与节能的探索摘要:在简要分析国内外给水系统现状的基础上,介绍了系统的组成,提出了以变频调速为核心所构成的全自动给水系统控制方式,并以实例详细分析了该系统的组成、工作原理以及在控制与节能方面所表现出的优越性.文中根据作者的实际使用经验,简要阐述了该系统在应用中应注意的一些问题。关键词: 变频调速;恒压供水。PID调节器中图法 一、引言目前,我国居民小区与高层建筑的生活供水,普遍采用工频方式.它存在着能耗大,噪音高,水源存在二次污染等诸多问题.而用变频调速控

2、制的给水装置是一种较为理想的模式.进入90年代中后期,随着变频调速技术的不断发展与完善,基于该项技术的全自动恒压给水方式已在发达国家得到广泛的应用,且日趋成熟.近几年来,作者在变频调速给水控制系统的设计与施工方面做了些实际工作,积累了一些经验,并形成了对于一些问题的看法.水泵节能原理变频调速系统之所以得到推广,一个很重要的原因就是它有较好的节能效果.一台水泵的实际扬程与电源频率的平方成正比.因而通过变频器改变水泵电机的供电频率,就可控制水泵的供水压力.恒压供水自动控制变频恒压供水原理框图如图1所示. 为给定的压力值, 为压力传感器从管道上所测得的实际压力值,PID调节器通过对两者的误差运算,并

3、经过控制变频器的频率输出,从而使管道的压力始终保持在设定值上。该系统能自动检测用户的瞬时水压,据此调节给水量的多少及电机的运行状况.还可根据所需的给水压力设定控制压力值,让设备始终处于恒压状态,从负载电机的特性可知,所配电机的轴功率与其转速的三次方成正比,即 .例如,当变频器输出频率为35Hz(最高设定为50Hz),也就是实际转速为额定转速的70%时,调速器的用电量为0.343,约占额定的35%.也就是说,水泵总处于恒压变流量匹配方式的工作状态,从而消除了超压和回流的无功损耗.恒速与变频调速轴功率变化曲线如图2所示,比较可知,变频调速方式节能效果最为明显。二、实例分析：恒压供水是通过变频调速来

4、调节水的流量从而达到恒压的目的,它最终控制的目标是水压.控制对象具有非线性、滞后特性.PID调节器性能的好坏,在很大程度上决定了恒压供水的质量.当系统在启动与停止阶段,或压力设定值大幅度变化时,由于在短时间内存在很大的偏差,因而无论PID调节器的控制算法采用增量式还是位置式,其积分项将取蓄水池、水泵组(1M,2M)及相关辅配件构成.本系统的核心是变频调速控制柜,它通过压力传感器对管网压力进行实时监测,并转换为电信号提供给变频器进行运算,通过变频器、可编程控制器PLC与继电器阵列的共同控制,构成了完善的全自动变频调速给水系统。变频器的品种繁多,如三菱、富士、三肯及ABB等型号.一般常选用泵类、风

5、机专用系列.以三菱FR-A140E为例,它除了一般品牌所具有的功能外,还有如下特点:内部采用IPM智能功率模块,使电机的噪音减至最低;变频器与工频电源之间可进行切换,用户只需通过PLC输入启动、停止及自动切换指令,就可方便地通过接触器的互锁动作来切换不同的水泵,而不需要像以往那样自行设计繁琐的控制程序,这是该变频器所特有的功能之一;内置的瞬时停电再启动与再试启动功能,在无人看管的情况下,即使变频器停机后也可自行启动,完全实现了以自动化方式的运行.本系统中的PID调节器可用变频器内置式值很大,这就会存在偏差调节.在消除偏差调节的过程中,必然导致系统出现较大的超调和长时间的振荡,同时还会产生严重的

6、积分饱和现象,从而影响了设备的正常运行.要把这种影响降至最低,就应在控制算法中采用积分分离的PID控制方式,以达到预期效果.经这样处理后,可大大缩短系统达到稳定的过渡过程时间.系统中配备两台11kW水泵(1M为主泵,2M为备用泵)供600余户居民用水.两台泵同时工作时提供最大高峰流量,单台则满足小流量和夜间供水.另外,所有水泵均能以变频方式运行,即可以循环方式软启动,这样能减小对电网和管网的冲击.值得注意的是,两泵在变频与工频之间切换时,仅有程序互锁是不够的,输出必须采用机械联锁接触器,这样可避免两个接触器瞬间同时闭合的情况,以免造成电源的瞬间短路。变频调速系统的主回路原理图,压力传感器P实时

7、监测水压信号的大小,信号经PID处理,输入至变频器.小流量时,水泵电机1M运转(1KM1吸合),并通过反馈通道不断调整其转速,以保持压力的恒定;在大流量的情况下,经压力比较电路通过PLC发出“变频/工频切换”与“运行联锁”指令,机械联锁接触器(2KM(2KM1+2KM2)中的2KM2、接触器3KM得电.这时,电机2M以变频方式启动,1M则切换至工频全速运行.这样,本系统能始终将用水量维持在一个恒定的压力上.前述小区建成初期,供水采用工频方式,因能耗大,可靠性差,住户反映强烈.改用变频供水后,装机总容量较原设备减小25%,实际综合节电指标接近30%,效果显著。三、应用中的几个问题在大多数情况下,

8、现场的使用环境较为恶劣.变频器虽然本身具有很强的保护功能,如欠压、过压、过流、电流限幅选择整定、过载、过热、缺相、短路及断水保护功能等,但仍应做到防患于未然.经使用发现,三菱、富士两种品牌,由于在设计和制造中充分考虑了各种恶劣的运行环境.在同样条件下的可靠性和使用寿命较某些品牌高.湖北鄂西山区某小城市,平均海拔1200m,常年大部分时间湿度偏高(80%左右),二氧化硫污染严重,某厂生产的一套变频供水设备,因未考虑上述因素,以至于不到一年的时间,设备的有关部件严重腐蚀.而我们在同一地区设计、安装的同类产品,因充分考虑了各种不同的情况,在设备与元件的选型上,采用了船用标准.经两年多的使用,运行良好

9、,经受了各种严峻的考验.在实际使用中发现,变频器本身就是一个强大的干扰发生源,往往会影响设备的正常运行.特别是水泵低转速运转时,变频器上显示的频率与实际运行频率不符.干扰的传播途径一般有两种:线路串扰和空间辐射干扰.根据现场的实际情况可采取相应的措施予以解决.例如,对可编程控制器的电源端增加滤波与吸收回路,PID调节器单元的输入输出一定要有可靠屏蔽,将变频器、电机上的接地端子牢固地与接地桩子相连,控制线与动力线要留有一定的距离,以增强抗电磁干扰的能力.只有这样,才能使系统在高温、潮湿、霉菌、强干扰等严酷的条件下保持长期稳定的工作状态。四、结束语以变频调速为核心的供水方式,节水、节电效果明显,可

10、广泛适用于2010000户居民生活区、高层建筑、宾馆、饭店、消防或小区加压供水,也是中小型自来水厂给水的理想设施.其供水质量高,经济效益明显,社会效益巨大,随着国民经济的发展和人民生活水平的不断提高,它一定会在我国逐步得到应用与推广。五、参考文献张万忠,王民权.一种新型变频恒压供水泵站的设计方案.电气时代,1999(10):22232刘迎春.传感器原理设计与应用.北京:国防科技大学出版社,1989.59623吕光大.建筑电气安装工程手册.北京:水利电力出版社,1995.2222244给排水自动化工程编写组.给排水自动化工程.北京:水利电力出版社,1997.301312毕业设计(论文)翻译资料

11、信息与电子工程 系 工业电气自动化 专业 04 级 1 班课题名称：S7-200 PLC控制的变频调速恒压供水系统设计毕业设计(论文)起止时间：2007年3 月1 日6 月10 日(共17周)学生姓名： 赵晋 学号： 3040221123指导教师： 黄云龙、朱秋琴、廖东进 报告日期： 2007-3- The control and Energy-saving of automatic Water Supply SystemAbstract: Based one simple analysis of the methods for water supply used domestically a

12、nd abroad, this paper discusses the principe and systems structure of automatic water supply system by using frequency conversion speed regulation in detail. Then the systems advantages are discussed and some key problems that should be pay attention to designing are presented.Keyword: Frequency con

13、version speed regulation; water supply with stable pressure: PID regulator.1、 ForewordAt present , supply water in residential area and life of the skyscraper of our country generally adopt the way common frequently . It has heavy energy consumption, high noise ,and there has a great deal of questio

14、ns in the source of water, such as secondary pollution etc. And it is a kind of comparatively ideal mode to adjust the watersupply device controlled rapidly with frequency conversion .Entering the middle and later periods of the 1990s, as the speed technology of frequency conversion achieves more de

15、velopment becomes perfect, the way of the full-automatic constant pressure that based on this technology supplied water has already been widely used in the developed country , and is becoming riper.In recent years, author has made some real work on rapidly to the transformation in frequency conversi

16、on supply water design and construction of control system , have accumulated some experience, and has formed the view on some questions. The reason why the energy-conserving principle frequency conversion of the water pump system of speed adjustmentbecomes popularized , is mainly because that it has

17、 a better energy- conserving result. To pump system of frequency conversion, the water pump after adjusting the speed has functional relation of the following:Q1/Q2 =n1/n2(1) H1/H2 = (n1/n2)2(2)of the type. Q1, Q2 represents the flow before and after the speed for the water pump respectively; N1, n2

18、 represents the rotational speed before and after the speed for the water pump respectively; H1, H2 represents the lift before and after the speed for the water pump respectively . According the above:H1/H2=(f1/f2)2Namely real lift of a water pump is power the square offrequency in direct radio. The

19、refore changing the power supply frequency of the electrical machinery of water pump through the frequency converter , can control supporting water pressure strength of the water pump . 2 constant pressure as Fig. 1 shows supply water of the automatically controlled frequency conversion water -suppl

20、y system principle block diagram. P1is the give pressure value, p2 for the actual pressure value had examined from the pipeline of the pressure sensor, PID regulator passes the error operation of the two value, and through controlling the frequency output of the frequency converter, thus make the pr

21、essure of the pipeline remain throughout on establishing value p1.This system can measure users instantaneous water pressure adjust automatically, regulate the amount of quantity of supplying water and operation conditions of the electrical machinery in view of the above. Can according to give water

22、 pressure strength to set for and control pressure value which needed , make the equipment in the constant pressure state all the time, can know from load characteristic of electrical machinery axle power and its the third power of in direct radio rotational speed of electrical machinery mixed, that

23、 is p1/p2=(n1/n2)3. For example, as the frequency converter output frequency for 35Hz (establish as 50Hz at most), that is to say that the actual rotational speed is 70% oclock of specified rotational speed, the power consumption of the governor is 0.73 =0.343, account for specified 35%. That is to

24、say , the water pump is always in constant pressure and turn the working state of matching the way into the flow , is it is it keep to exceed to dispel and backset current have work loss. Constant speed transfer with frequency conversion speed axle power change curve as Fig. 2 shows , relatively can

25、 know, it is the most obvious that frequency conversion adjusts the energy-conserving result of speed way.2、 Caseanalyse Constant pressure is it regulate flow of water to the purpose to up to constant pressure through suiting well rapidly in frequency conversion to supply water, the goal that it con

26、trols finally is the water pressure. Controlling the target has non-linear , lagging characteristics. The quality of PID regulator performance , has determined the quality of the water -supply system to a great extent When the system is during the course of starting and stopping, or the pressure est

27、ablishing value changes by a large margin , because there is a very great deviation within short time, no matter the controll algorithm of PID regulator adopts the increment type or the position type, its total mark one will fetch the cistern , water pump group (1M , 2M ) and complement the fittings

28、 to form relevantly. The core of this system is that frequency conversion adjusts the speed switch board, it monitors the pressure of the pipe network in real time through the pressure sensor , and change into the electric signal and offer the frequency converter to to make operation, through the co

29、ntrolling commonly of frequency converter , programmable controller PLC and relay array, adjust the system of supplying water rapidly after forming perfect full-automatic frequency conversion.Frequency converter is various in kind, for instance the types , such as Mitsubishi , Fuji , three Kenya and

30、 ABB ,etc. Generally often select the pumps , special-purpose series of air blower for use. Whether take Mitsubishi FR-A140E as an example, it except general function had of brand , there are the following characteristics : The inside adopts the intellectual power module of IPM, it is lowest to make

31、 the noise of the electrical machinery to reduce; Frequency converter, and work-frequency power can is it switch over to go on frequently, user is it is it start , stop through PLC and switch over the order automatically to input to need only, can conveniently through to lock movement switch over di

32、fferent water pump each other contactor, and does not need to design the tedious control procedure by oneself like the thing that in the past , this is one of this peculiar functions of frequency converter; Built-in instantaneous power cut starts and retries and starts the function , in a situation

33、that nobody guarded, even if can be started by oneself after the frequency converter shuts down, totally realize with the operation of the automatic way. PID regulator available frequency converter of system this built-in value very heavy, this will store deviation in regulate. During the process of

34、 dispelling the deviation to regulate , must lead to the fact the system and present greater ultra mediation long-time vibration , can produce the serious integration saturation phenomenon also at the same time , thus influence the normal running of the equipment. Is it drop the influence to most lo

35、w to want , should adopt PID control method that integration separate among controlling algorithm, in order to reach the anticipated result. After dealing with like this , can shorten the system and reach steady transition course time greatly System allocate two 11kW water pump support 600 over resi

36、dent water. Two pump offer large peak flow most when working at the same time, single platform meet the small flow and supply water at night. In addition all water pump can run by way of frequency conversion , can circulate way soft to start, in this way , can reduce the impact to the electric wire

37、netting and pipe network . What merits attention is two pump when frequency conversion and worker are switched over frequently , have procedure it locks to be enough each other only, outputting must adopt machinery to interlock the contactor , can avoid the situation that two contactors close at the

38、 same time in the twinkling of an eye in this way, so as not to short out in twinkling of an eye causing power .pressure sensor P monitors the size of the water pressure signal in real time, the signal is dealt with by PID, input it to the frequency converter. At the small flow, water pump electrica

39、l machinery 1M turn round (whether 1KM1 is it shut to suck), and through feedback password change his rotational speed constantly, it is invariable in order to keep the pressure; In case of large flow , compare frequency conversion by pressure circuit send out through PLC constant/changed switch ove

40、r frequently operate and interlock the order, machinery interlocks the contactor ( 2KM2 in 2KM (2KM1 +2KM2 ), contactor 3KM have the electricity. At this moment, electrical machinery 2M is started by way of frequency conversion, 1M is switched over and run at full speed frequently to run . In this w

41、ay, this system can maintain water consumption on a invariable pressure all the time . Built up in the aforesaid district initial stage , supply water and adopt the way frequently of workers, because of energy consumption being heavy dependability is bad, the household reflects strongly. Use instead

42、 after frequency conversion supply water, installation total capacity reduce 25% than original equipment , economize on electricity the index is close 30% synthetically actually, the result is remarkable.3、 Several questions while apply are in case of great majorityThe environment for use of the sce

43、ne is comparatively abominable . Though frequency converter has very strong protection functions itself, such as owe keep , excessive pressure , is it flow to pass, electric current amplitude limiting is it make exactly to choose, overload, overheated lacking looking , shorting out and disconnected

44、ink protect the function But must prevent trouble before it happens . Through using finding , two kinds of brands of Mitsubishi , Fuji, because has fully considered various kinds of abominable running environment in design and manufacture. The dependability and service life under the same condition

45、are higher than some brands. One small city of mountain area of west place in Hubei in Hubei, average 1200m above sea level, the humidity on the high side of long-term most of the time (about 80%), the sulfur dioxide is seriously polluted, a set of frequency conversion that one factory produces supp

46、lies water of the equipment, because has not considered above-mentioned factors , less than one year, the relevant parts of the equipment are corroded seriously. And the like product which we designed , installed in the same area, because has fully considered the situations of different difference,

47、on the selecting types of the equipment and component , have adopted the ship standard. Through the use of more than two years , ran well , stood the tests of different sternness. Find in using actually , the frequency converter itself is that a strong interference takes place in the source , will o

48、ften influence the normal running of the equipment. Especially when the low rotational speed of the water pump operates, the frequency shown on the frequency converter does not correspond to actual operation frequency. Generally there are two kinds of spread ways to interfere: The circuit bunch is d

49、isturbed and space radiation is interfered. Can take the corresponding measure to solve according to the actual conditions of the scene. For example is it strain wave and absorb the return circuit to increase to programmable power end of controller, PID regulator introduction of unit output sure to have reliable shielding , link frequency converter , ground terminal of electrical machinery w