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1、<p>  變頻器在供水控制系統(tǒng)的應(yīng)用 </p><p>  目前,在水位控制中有很大一部分水泵電機(jī)是不變速拖動(dòng)系統(tǒng),不變速電機(jī) 的電能大多消耗在適應(yīng)供水量的變化而頻繁的開(kāi)停水泵中。 這樣不但使電機(jī)工作 在低效區(qū)、減短電機(jī)的使用壽命,而且電機(jī)的頻繁開(kāi)停使設(shè)備故障率很高,導(dǎo)致 水資源嚴(yán)重浪費(fèi),系統(tǒng)的維護(hù)、維修工作量較大。 </p><p>  隨著高位生活用水和工業(yè)用水逐漸增多,傳

2、統(tǒng)的控制方法已經(jīng)落后。原先 用人工進(jìn)行水位控制,由于無(wú)法每時(shí)每刻對(duì)水位進(jìn)行準(zhǔn)確的定位監(jiān)測(cè),很難準(zhǔn)確 控制水泵的起停;使用浮標(biāo)或機(jī)械等水位控制裝置使供水狀況有了一些改變,但 由于機(jī)械裝置的故障多,可靠性差,給維修帶來(lái)很大的麻煩。 </p><p>  變頻技術(shù)以其在節(jié)能與恒壓方面的優(yōu)越性能可以解決水壓控制系統(tǒng)存在的 以上問(wèn)題??紤]選用單片機(jī)或 PLC 與變頻器結(jié)合為核心構(gòu)成的系統(tǒng)都能達(dá)到較 好的控制效果。但在軟件設(shè)

3、計(jì)上,PLC 比單片機(jī)的編程更簡(jiǎn)潔、直觀;從硬件接 口考慮,單片機(jī)電路稍微復(fù)雜一些;從經(jīng)濟(jì)方面考慮,由于 PLC 工藝的日漸成 熟,小型 PLC 的成本與單片機(jī)相差無(wú)幾,由于要根據(jù)現(xiàn)場(chǎng)情況調(diào)整系統(tǒng)參數(shù), PLC 的軟件中時(shí)間參數(shù)的調(diào)整更簡(jiǎn)單,這樣更有利于售后服務(wù)人員掌握?;谝?上原因,選用了 OMRON 的 CPM1 系列 PLC 與 ABB 的變頻器作為控制核心,再 加上 PSW7 調(diào)節(jié)器與 WSP300 壓力變送器,控制效果非常好

4、,軟件設(shè)計(jì)簡(jiǎn)單, 硬件接口簡(jiǎn)易可行、可靠性高,整個(gè)系統(tǒng)的性價(jià)比非常高。 </p><p>  在供水系統(tǒng)中引進(jìn)變頻器結(jié)合小型 PLC 技術(shù),不僅改變傳統(tǒng)用閥門(mén)控制水 量多少,而且在節(jié)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(diào)控技術(shù)在水泵控制中的應(yīng)用。 </p><p>  控制系統(tǒng)用一臺(tái)變頻器可以帶三臺(tái)水泵, 每臺(tái)水泵既可以工作在常規(guī)工頻泵 模式, 也可以工作在變

5、頻泵模式。 每臺(tái)泵只能處于變頻或工頻其中一種工作模式, 通過(guò)兩個(gè)繼電器互鎖保證它的安全與可靠。系統(tǒng)的結(jié)構(gòu)如圖一所示,利用安置在 的生活用水中的壓力變送器將水的壓力信號(hào)傳輸?shù)秸{(diào)節(jié)器, 根據(jù)與調(diào)節(jié)器的設(shè)定 值和報(bào)警上下限比較,送信號(hào)給 PLC 與變頻器,系統(tǒng)的起停泵分別由調(diào)節(jié)器的 壓力下限信號(hào)和變頻器的頻率下限信號(hào)決定,假如壓力低,調(diào)節(jié)器給 PLC 一個(gè) 壓力下限信號(hào),PLC 啟動(dòng)變頻器,并使一號(hào)泵處于變頻工作狀態(tài), 輸出的頻率 逐漸增大,

6、經(jīng)過(guò)一段時(shí)間的調(diào)節(jié),如壓力還低,這時(shí),PLC 讓一號(hào)泵處于工頻狀 態(tài)工作,使二號(hào)泵處于變頻工作狀態(tài)泵,如壓力還低,則讓二號(hào)泵處于工頻狀態(tài) 工作, 使三號(hào)泵處于變頻工作狀態(tài), 如此類推。 當(dāng)壓力達(dá)到調(diào)節(jié)器上限報(bào)警值時(shí), 調(diào)節(jié)器輸出降低,變頻器頻率降低,低到頻率下限設(shè)定值,這時(shí)變頻器給出一個(gè) 頻率下限信號(hào)給 PLC,PLC 根據(jù)先啟先停的原則控制泵的運(yùn)行順序,例如,PLC 收到頻率下限信號(hào)時(shí), 系統(tǒng)中泵的狀態(tài)是一號(hào)工頻,二號(hào)工頻,三號(hào)變頻,

7、這 時(shí)一號(hào)泵最先啟動(dòng),所以先</p><p>  采用變頻器-PLC 恒壓供水裝置有以下幾個(gè)優(yōu)點(diǎn):</p><p>  A:節(jié)電效益高。傳統(tǒng)水泵電機(jī)均采用大容量電機(jī),用閥門(mén)控制水量恒定,造 成電能浪費(fèi)。 變頻系統(tǒng),無(wú)論工作參數(shù)如何,電機(jī)的效率不會(huì)降低,電機(jī)的功率因數(shù)會(huì)得 到提高。</p><p>  B:運(yùn)行可靠、穩(wěn)定。系統(tǒng)中的核心部件—變頻調(diào)速器本身的可靠性很高,

8、一般 情況下可連續(xù)使用 10 萬(wàn)/h 以上。系統(tǒng)還采用軟啟動(dòng)方式,不存在電氣沖擊,不 污染電網(wǎng),而且變頻器自帶欠壓、過(guò)壓、過(guò)流、過(guò)載、過(guò)熱以及失速等各種保護(hù) 功能。系統(tǒng)對(duì)管網(wǎng)壓力波動(dòng)采取阻尼濾波處理,供水恒壓精度較高,通常能控制 在 0.002Mpa 范圍內(nèi)。 </p><p>  C:結(jié)構(gòu)簡(jiǎn)單,操作簡(jiǎn)便。裝置的控制系統(tǒng)采用集成度高,配套方案靈活多樣, 由可編程控制器得到水泵運(yùn)行的各種組合。調(diào)速范圍廣,對(duì)水量變化

9、的適應(yīng)能力 強(qiáng)。 </p><p>  D:使用壽命長(zhǎng),自動(dòng)化程度高,無(wú)需人看管,維護(hù)量少。 以上系統(tǒng)在實(shí)際的應(yīng)用中效果顯著, 如將 PLC 與變頻器中自帶編程器的功能 集成,可開(kāi)發(fā)成一些專用的變頻器,這樣系統(tǒng)的可靠性與健壯性大大增強(qiáng),應(yīng)用 更加簡(jiǎn)單,系統(tǒng)的總成本也會(huì)下降。 </p><p>  可以預(yù)見(jiàn):未來(lái)的變頻技術(shù)會(huì)向以下方向發(fā)展: </p><p>  高性

10、能化 包括內(nèi)部的整流電路、逆變電路都采用高頻 PWM 電路從而使輸入、輸出都 是正弦波;對(duì)于大容量變頻器采用多重化和多機(jī)并聯(lián);降低變頻器自身?yè)p耗,實(shí) 現(xiàn)高效率化;實(shí)現(xiàn)自動(dòng)調(diào)諧或自優(yōu)化、遙控和遠(yuǎn)控;更加面向用戶,進(jìn)一步提高 可使用性和維修性:向著小型、輕量發(fā)展,以及降低成本等。</p><p>  智能化 包括兩個(gè)方面:盡量減少硬件,實(shí)現(xiàn)硬件軟件化;采用智能電力電子器件 和其他智能化部件。集成化是智能化的基礎(chǔ)。&l

11、t;/p><p>  全數(shù)字化 近年來(lái),各種現(xiàn)代控制理論、專家系統(tǒng)、模糊控制及神經(jīng)元控制等都是發(fā)展 的熱點(diǎn),將使電力電子控制技術(shù)發(fā)展到一個(gè)嶄新的階段。預(yù)計(jì) 21 世紀(jì)全數(shù)字控 制的應(yīng)用將更加廣泛深入,甚至取代模擬控制。 </p><p>  系統(tǒng)化 變頻技術(shù)的發(fā)展與其相關(guān)技術(shù)的發(fā)展是分不開(kāi)的, 21 世紀(jì)變頻技術(shù)的發(fā) 在 展是將電網(wǎng)、整流器、逆變器、電動(dòng)機(jī)、生產(chǎn)機(jī)械和控制系統(tǒng)等作為一個(gè)整體、

12、從系統(tǒng)上進(jìn)行考慮的。 </p><p>  Transducer in the water control system applications Currently, the water level control in a large part of the electrical pumps are not towing gear shift system, no gear shift most of the

13、 electrical energy consumed in the water supply to the frequent changes in the pumps stopped. This not only makes the electrical work in inefficient zones, cut short the useful life of electrical and electrical equipment

14、 for the frequent failure to stop the high rate, leading to serious waste of water resources, </p><p>  With high living water and industrial water gradually increased, the traditional control methods that a

15、re outdated. Originally used for artificial water level control, water level due to the lack of accurate positioning hour monitoring, it is difficult to accurately control the pumps have stopped; Using buoys or mechanica

16、l control devices such as water supply situation has made some changes, but because of mechanical failure more devices, poor reliability to maintenance will face great trouble.</p><p>  Frequency conversion

17、technology, with its superiority in the area of energy efficiency and Constant Pressure control system can be solved by the existence of the above problems. Consider selecting Single Chip Micro controller or PLC and tran

18、sducer combination at the core of the system can achieve a better control results. But in software design, PLC programming of more than Single Chip Micro controller concise, and visual; From the hardware interface consid

19、erations, Single Chip Micro controller </p><p>  Transducer in the water system in conjunction with the introduction of small PLC technology not only change the traditional use of water control valves, and i

20、n energy conservation, Constant Pressure control, are very good results, the paper introduced a transducer --PLC control technology in the pump control applications. </p><p>  Control system using one Taiwan

21、 transducer can bring three pumps, pumps can work at the frequency pump in the conventional model can work in the frequency conversion pump model. At the pump only in frequency conversion or one of the working frequency

22、mode through two relays efficient ensure its security and reliability. System structure as figure 1 shows, the use of placement in the life of water pressure Biansongqi water pressure signal transmission to the regulator

23、, in accordance with the regu</p><p>  Introduces the frequency changer union small PLC technology in the water supply system, not only change tradition with valve control water volume how many, moreover in

24、aspects and so on energy conservation, constant pressure control had the extremely good effect, this article introduced the frequency changer--PLC regulation technology in water pump control application. </p><

25、p>  The control system may bring three water pumps with a frequency changer, each water pump already may work in the conventional power frequency pump pattern, also may work in the frequency conversion pump pattern. E

26、ach pump only can be in the frequency conversion or the power frequency one kind of working pattern, guarantees its safety and the unreliability mutually through two relay locks. System structure as shown in Figure one,

27、the use places in the domestic water pressure transmitting instrume</p><p>  Uses the frequency changer - PLC constant pressure water supply installment to have following several merits: </p><p>

28、;  A:The electricity saving benefit is high. The traditional water pump electrical machinery uses the large capacity electrical machinery, is constant with the valve control water volume, creates the electrical energy wa

29、ste. </p><p>  Frequency conversion system, regardless of the operational parameter how, the electrical machinery efficiency can't reduce, the electrical machinery power factor can obtain the enhancement

30、.</p><p>  B:Moves is reliable, is stable. In the system core part - frequency conversion velometer itself reliability is very high, in the ordinary circumstances may the long-term usage 100,000/Above h. The

31、 system also selects the soft start method, does not have the electrical impact, does not pollute the electrical network, moreover frequency changer bringing owes presses, the pressure, the overflow, the overload, superh

32、eat as well as loses speed and so on each kind of protection function. The system ad</p><p>  C:The structure is simple, the operation is simple. The installment control system uses the integration rate to b

33、e high, necessary plan nimble diverse, obtains water pump movement each kind of combination by the programmable controller. The velocity modulation scope is broad, to water volume change adaptiveness. </p><p&g

34、t;  D:The service life is long, the automaticity is high, does not need the human to safeguard, maintains the quantity to be few. </p><p>  Above system the effect is remarkable in the actual application, if

35、 brings in PLC and the frequency changer the programmer the function integration, potential becomes some special-purpose frequency changers, such system reliability and the toughness big enhancement, the application is s

36、impler, the system total cost also can drop.</p><p>  May foresee: The future frequency conversion technology will be able to develop to the below direction: </p><p>  high performance </p>

37、;<p>  Thus including internal leveling circuit, the contravariant electric circuit all use the high frequency PWM electric circuit to cause the input, the output all are sine waves; Uses the multi-densification r

38、egarding the large capacity frequency changer and many machine is parallel; Reduces frequency changer own loss, the realization high efficiency; Realizes autotune or from the optimization, the remote control and controls

39、 far; Even more faces the user, further enhances the workability and Maint</p><p>  Intellectualization</p><p>  Including two aspects: Reduces the hardware as far as possible, realizes the hard

40、ware software; Uses the intelligent electric power electronic device and other intellectualized part. The integration is the intellectualized foundation.</p><p>  (3) entire digitization</p><p>

41、  In recent years, each kind of modern control theory, the expert system, the fuzzy control and the neuron control and so on all were the development hot spots, will cause the electric power electronic control technologi

42、cal development to a brand-new stage. Estimated the 21st century entire numerical control the application will be more widespread thoroughly, even will substitute for the simulation control. </p><p>  system

43、atization </p><p>  Frequency conversion technology development is inseparable from the development of related technologies, frequency conversion technology development in the 21st century is to grid, regula

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