【正文】 make the speed of electromotor and performance curve of pump change. At last, it makes the status of a pump alter. Through analyzing the figure of energy wasting of pump, the quality i n pipes is direct proportion of the speed of pump if the speed of pump is reduced. The power of electromotor fells the cube of the speed of pump. So the energy wasting of constant pressure water supply based on variable frequency speed regulating technology is evidently less than the traditional mode is used throttle to supply water. Through using S7200 program software of SIMENS Company in German in the control system. The controller can pare the measure value and the value in advance of pressure. Through realtime controlling the output voltage and frequency of transducer, the output quality of pump is changed along with the changing of pump39。 在變頻調(diào)速恒壓供水系統(tǒng)中，單臺(tái)水泵工況的調(diào)節(jié)是通過(guò)變頻器來(lái)改變電源的頻率f 來(lái)改變電機(jī)的轉(zhuǎn)速 n ，從而改變水泵性能曲線得以實(shí)現(xiàn)的。再加上目前能源緊缺，利用先進(jìn)的自動(dòng)化技術(shù)、控制技術(shù)以及通訊技術(shù)，設(shè)計(jì)高性能、高節(jié)能、能適應(yīng)不同領(lǐng)域的恒壓供水系統(tǒng)成為必然趨勢(shì)。本論文結(jié)合我國(guó)中小城市多層住宅小區(qū)的用水現(xiàn)狀，設(shè)計(jì)了一套基于 PLC 的變頻調(diào)速恒壓自動(dòng)控制供水系統(tǒng)。分析水泵工況的能耗比較圖，可以看出利用變頻調(diào)速實(shí)現(xiàn)恒壓供水，當(dāng)轉(zhuǎn)速降低時(shí)，流量與轉(zhuǎn)速成正比，功率以轉(zhuǎn)速的三次方下降，與傳統(tǒng)供水方式中用閥門節(jié)流方式相比，在一定程度上可以減少能量損耗，能夠明顯節(jié)能。s speed. It makes the pressure of pipe selfregulating and steady in the scheduled value. Key Words: PLC, variable frequency speedregulating, constant pressure watersupply, 畢業(yè)設(shè)計(jì)（論文） 3 目錄 第 1 章 緒論 ......................................................................................................................................1 課題來(lái)源及研究意義 .................................................................................................1 水泵調(diào)控技術(shù) ................................................................................................................1 調(diào)速節(jié)能分析 ......................................................................................................1 常用的調(diào)速方式 .................................................................................................2 主要研究?jī)?nèi)容 ............................................................................................................... 4 多泵恒壓供水的關(guān)鍵問(wèn)題 .............................................................................4 本文的主要研究?jī)?nèi)容 .......................................................................................4 本章小結(jié) ..........................................................................................................................5 第 2 章 變頻調(diào)速恒壓供水系 統(tǒng)能耗機(jī)理分析 ................................................................6 水泵理論及水泵工況點(diǎn)確定的研究 ...................................................................6 水泵的工作參數(shù) .................................................................................................6 水泵基本性能曲線 ............................................................................................8 水泵理論工況點(diǎn)的確定 ..................................................................................9 水泵工況的調(diào)節(jié) ......................................................................................................... 10 變頻調(diào)速恒壓供水系統(tǒng)能耗機(jī)理分析 ........................................................... 12 水泵工況的調(diào)節(jié)過(guò)程 ..................................................................................... 12 水泵工況調(diào)節(jié)與傳統(tǒng)節(jié)流調(diào)節(jié)能耗之比較 ........................................ 12 調(diào)速范圍的確定 ............................................................................................... 13 本章小 結(jié) ........................................................................................................................ 14 第 3 章 內(nèi)置 PID 變頻頻器 ...................................................................................................... 15 PID 控制及其調(diào)節(jié)規(guī)律 ........................................................................................... 15 經(jīng)典 PID 控制及調(diào)節(jié) ..................................................................................... 15 數(shù)字 PID 控制 .................................................................................................... 16 數(shù)字 PID 控制器的設(shè)計(jì) .......................................................................................... 17 本系統(tǒng)內(nèi)置 PID 變頻器選擇 ................................................................................ 17 變頻器輸入輸出接口 ..................................................................................... 17 變頻器的外圍設(shè)備選擇 ................................................................................ 17 變頻調(diào)速恒壓系統(tǒng)的基本特點(diǎn) ........................................................................... 20 本章小結(jié) ........................................................................................................................ 21 第 4 章 可編程控制器 PLC ....................................................................................................... 22 PLC 的定義 .................................................................................................................... 22 PLC 的發(fā)展階段及發(fā)展方向 ................................................................................. 22 PLC 的特點(diǎn)與應(yīng)用領(lǐng)域 ........................................................................................... 23 可編程序控制器的特點(diǎn) ................................................................................ 23 可編程序控制器與繼電器控制系統(tǒng)的比較 ........................................ 24 可編程序控制器的應(yīng)用領(lǐng)域 ...................................................................... 24 PLC 在現(xiàn)代自動(dòng)控制系統(tǒng)應(yīng)用中所面臨的問(wèn)題 ............................... 25 我國(guó)常用 PLC 的性能比較研究 ........................................................................... 25 PLC 的一般結(jié)構(gòu) ................................................................................................ 25 畢業(yè)設(shè)計(jì)（論文） 4 PLC 基本工作原理 ........................................................................................... 26