1、燕京理工學院機電工程學院外文文獻原稿和譯文燕京理工學院YANCHING INSTITUTE OF TECHNOLOGY 外文文獻原稿和譯文學院：機電工程學院專業：機械工程學號：130310208姓名： 張磊指導教師：王續明2017 年 3 月外文文獻原稿和譯文原 稿The water supply system is the national production and life indispensable important one annulus. The traditional method of water supply area, water pollution, infrastr

2、ucture investment, but the main drawback is that water can not be kept constant, causing part of the equipment can not work normally. Variable frequency speed control technology is a new mature AC motor stepless speed regulating technology, its unique excellent control performance is widely applied

3、to the speed control field, especially in water supply industry. Due to the safety in production and the water quality of special needs, for constant pressure water supply with the stringent requirements, so the frequency control technology has been more in-depth application. Constant pressure water

4、 supply ways to advanced technology, constant pressure, convenient operation, reliable operation, energy saving, high degree of automation, in pump station water supply can perform the following functions: (1) to maintain constant pressure; (2) the control system can be manual or automatic operation

5、;(3) a plurality of pump automatic switch operation; (4) system of sleep and wake, when people stop when water, the system is in a sleep state, until the water demand automatically wake;(5) adjusts the PID parameters on line; (6) pump unit and circuit protection detection alarm, signal display. The

6、actual pressure of the pipe network feedback and a given pressure were compared, when the pressure of a pipe network is low, increase the output of frequency converter, pump speed faster, water supply quantity increases, forcing the pipe network pressure rise. Vice pump speed slow down, reduce the w

7、ater supply pipe network pressure drop, to keep the constant pressure water supply. System hardware structure System uses a pressure sensor, PLC and inverter as a central control device, to achieve a desired function. Source: network transmission and distribution equipment installation in pipe line

8、pressure sensor, for detecting the water pressure of the pipe network, converting pressure is 4 20 mA current or voltage signal is 0 10V, supplied to the inverter.Converter pump motor control device, in accordance with the constant water pressure needs to be 0 50 Hz frequency signal supply pump moto

9、r, adjust its speed SAJ converter is powerful, i.e. pre-programmed set parameter set, will use the required in the process of setting the number of parameters is reduced to a minimum, default value according to the application parameter of the macro choice and different. The system adopts the PID co

10、ntrol application macro, closed loop control. Inverter based on a constant pressure corresponding to the voltage setting value and from the pressure sensor to obtain the feedback current signal, the use of PID control macro automatically adjust, change the frequency output value to adjust the contro

11、l the speed of the pump motor, to ensure that the pipe network pressure constant requirements.The application of inverter in the constant pressure water supply1.The characteristic and analysis of variable frequency speed regulation The water users in general is dynamic, so the water supply is insuff

12、icient or excess water supply situation has occurred. The water supply and the imbalance between the concentrated reflection in water supply pressure, namely water and watersupply is less, the low pressure; less water consumption and water supply, the pressure. Keep the water pressure constant, can

13、make the water supply and water balance between water supply and water for a long time, that is, less water when the water is less, so as to improve the quality of water supply.Constant pressure water supply system for the user is very important. In production and living water, if water supply due t

14、o insufficient pressure or short of water, may affect the quality of life, serious when can influence the survival safety, such as when a fire occurs, if the water pressure is insufficient or water supply, can quickly fire, may cause significant economic losses and casualties. Therefore, water area

15、by means of Arts is the constant pressure water supply system, can produce great economic benefit and social benefit.With the development of electric power technology, frequency conversion technology perfected, with variable frequency speed control as the core of the intelligent water control system

16、 replaced the previous high level water tank and a pressure tank and water supply equipment, stable starting, the starting current can be limited within specified current, thereby avoiding the starting time of the impact of power grid; because the average rotational speed of pump is reduced, which c

17、an extend the pumps and valves and other things of life; to eliminate the start and stop of the water hammer effect. The stable and safe performance, simple and convenient operation, and complete and thoughtful function, will make the water supply and water conservation, energy saving, labor saving,

18、 ultimately achieve efficient operation.2.The application of variable frequency control constant pressure water supply modeUsually in the same way in the water supply system, setting multiple common pump, water supply when the quantity of multi pump full open, water supply on one or two hours. In th

19、e variable frequency speed control for constant pressure water supply, in two ways, one is all pumps with a frequency converter; and each water pump with a frequency converter. After a method based on pressure feedback signal, operated by PID automatically adjusts the output frequency of the inverte

20、r, change the speed of the motor, eventually reaching the purpose of network voltage, a closed loop, is relatively simple, but the cost is high. The previous method of low cost, less than kind of poor performance, but the control program is complex, is the future direction of development, such as th

21、e Shanghai arts and science and technology of constant pressure water supply control system can realize a inverter control any number of motor function. The principle mentioned below are multiple motor inverter drive system.3.The PID control principleAccording to the feedback principle: to maintain

22、a physical quantity unchanged or essentially unchanged, it should bring the physical quantity and the constant comparison, to form a closed loop system. We want to keep the pressure constant, so we must introduce the hydraulic feedback value with a given value, thereby forming a closed loop system.

23、But the control system is characterized by nonlinear, inertial system, now the control method combined with PID in the large pressure fluctuation, using fuzzy control, in order to accelerate the response speed in the pressure range; using PID to maintain static accuracy. This through the PLC and int

24、elligent instrument can show the algorithm, while the PLC programming to show when the pump frequency and inverter switching between. Practice has proved that, using this method is feasible, and the cost is not high.4.Frequency controlUsing frequency control to realize constant pressure water supply

25、, with adjustable valve to realize constant pressure water supply, energy-saving effect is very significant (according to the specific circumstances calculated ). The utility model has the advantages of: (1)Starting balance, the starting current can be limited within specified current, thereby avoid

26、ing the starting time of the impact of power grid;(2)Because the average rotational speed of pump is reduced, thereby prolonging the service life of pump and valve etc.(3)Can eliminate the start and stop of the water hammer effect;Generally speaking, when performed by a frequency converter to contro

27、l a motor, just make the inverter motor capacity and the actual capacity of the motor can be. When one inverter control two motors, principle of inverter motor capacity should be equal to the capacity of the two motors. But if the peak load of water more than two pumps at full supply a lot of differ

28、ence, Shanghai arts and science and technology engineers suggested, may be considered appropriate to reduce the capacity of the frequency converter, but attention should be paid to leave enough capacity.Although the pump at low speed, small working current of the motor. However, when the user with t

29、he water volume changes frequently, the motor will be in frequent ascending, descending and ascending, descending speed state, the current speed slightly over the motor rated current, cause the motor overheat. Therefore, the motor thermal protection is required. For this due to frequent ascending, d

30、escending speed and accumulated temperature rise, frequency converter in electronic thermal protection function is difficult to play a protective role, so should be used in thermal relay for motor thermal protection.The main function of preset, the highest frequency should be rated motor frequency c

31、onverter the highest working frequency. Ascending, descending speed time in using PID regulator case, ascending, descending velocity time should be set to be short, so as not to affect the PID adjuster determines the dynamic response process. Such as the frequency converter with PID regulation funct

32、ion, as long as the preset set PID function effectively, the setting of the acceleration and deceleration time will automatically lapse.譯 文供水系統是國民生產生活中不可缺少的重要一環。傳統供水方式占地面積 大，水質易污染，基建投資多，而最主要的缺點是水壓不能保持恒定，導致部分設備不能正常工作。變頻調速技術是一種新型成熟的交流電機無極調速技術，它以其獨特優良的控制性能被廣泛應用于速度控制領域，特別是供水行業中。由于安全生產和供水質量的特殊需要，對恒壓供水壓力有

33、著嚴格的要求，因而變頻調速技術得到了更加深入的應用。恒壓供水方式技術先進、水壓恒定、操作方便、運行可靠、節約電能、自動化程度高，在泵站供水中可完成以下功能： （1）維持水壓恒定；（2）控制系統可手動/自動運行；（3）多臺泵自動切換運行；（4）系統睡眠與喚醒，當外界停止用水時，系統處于睡眠狀態，直至有用水需求時自動喚醒；（5）在線調整PID參數；（6）泵組及線路保護檢測報警，信號顯示等。將管網的實際壓力經反饋后與給定壓力進行比較，當管網壓力不足時，變頻器增大輸出頻率，水泵轉速加快，供水量增加，迫使管網壓力上升。反之水泵轉速減慢，供水量減小，管網壓力下降，保持恒壓供水。工作原理 在供水系統中引進變

34、頻器結合小型PLC技術，不僅改變傳統用閥門控制水量多少，而且在節能、恒壓控制等方面均有非常好的效果，本文介紹了變頻器-PLC調控技術在水泵控制中的應用。 控制系統用一臺變頻器可以帶三臺水泵，每臺水泵既可以工作在常規工頻泵模式，也可以工作在變頻泵模式。每臺泵只能處于變頻或工頻其中一種工作模式，通過兩個繼電器互鎖保證它的安全與可靠。生活用水中的壓力變送器將水的壓力信號傳輸到調節器，根據與調節器的設定值和報警上下限比較，送信號給PLC與變頻器，系統的起停泵分別由調節器的壓力下限信號和變頻器的頻率下限信號決定，假如壓力低，調節器給PLC一個壓力下限信號，PLC啟動變頻器，并使一號泵處于變頻工作狀態，

35、輸出的頻率逐漸增大，經過一段時間的調節，如壓力還低，這時，PLC讓一號泵處于工頻狀態工作，使二號泵處于變頻工作狀態泵，如壓力還低，則讓二號泵處于工頻狀態工作，使三號泵處于變頻工作狀態，如此類推。當壓力達到調節器上限報警值時，調節器輸出降低，變頻器頻率降低，低到頻率下限設定值，這時變頻器給出一個頻率下限信號給PLC，PLC根據先啟先停的原則控制泵的運行順序，例如，PLC收到頻率下限信號時， 系統中泵的狀態是一號工頻，二號工頻，三號變頻，這時一號泵最先啟動，所以先停，接著如壓力還高，則停二號泵。系統采用了每次都進行低速啟動，高速運行以提高運行效率。系統硬件構成系統采用壓力傳感器、PLC和變頻器作為

36、中心控制裝置，實現所需功能。 來源:輸配電設備網安裝在管網干線上的壓力傳感器，用于檢測管網的水壓，將壓力轉化為420 mA的電流或者是010V的電壓信號，提供給變頻器。 變頻器是水泵電機的控制設備，能按照水壓恒定需要將050 Hz的頻率信號供給水泵電機，調整其轉速SAJ變頻器功能強大，即預先編置好的參數集，將使用過程中所需設定的參數數量減小到最小，參數的缺省值依應用宏的選擇而不同。系統采用PID控制的應用宏，進行閉環控制。變頻器根據恒壓時對應的電壓設定值與從壓力傳感器獲得的反饋電流信號，利用PID控制宏自動調節，改變頻率輸出值來調節所控制的水泵電機轉速，以保證管網壓力恒定要求。變頻器在恒壓供水

37、中的應用 一、 變頻調速的特點及分析用戶用水量一般是動態的，因此供水不足或供水過剩的情況時有發生。而用水和供水之間的不平衡集中反映在供水的壓力上，即用水多而供水少，則壓力低；用水少而供水多，則壓力大。保持供水壓力的恒定，可使供水和用水之間保持平衡，即用水多時供水也多，用水少時供水也少，從而提高了供水的質量。 恒壓供水系統對于用戶是非常重要的。在生產生活供水時，若自來水供水因故壓力不足或短時斷水，可能影響生活質量，嚴重時會影響生存安全，如發生火災時，若供水壓力不足或或無水供應，不能迅速滅火，可能引起重大經濟損失和人員傷亡。所以，用水區域采用正藝恒壓供水系統，能產生較大的經濟效益和社會效益。 隨著電力技術的發展，變頻調速技術的日臻完善，以變頻調速為核心的智能供水控制系統取代了以往高位水箱和壓力罐等供水設備，起動平穩，起動電流可限制在額定電流以內，從而避免了起動時對電網的沖擊；由于泵