電氣工程自動化論文


恒壓變頻供水系統(tǒng)的研究

摘要
隨著電子技術(shù)、交流調(diào)速技術(shù)的不斷完善和計算機技術(shù)的迅速發(fā)展，變頻調(diào)速方法在恒壓供水控制系統(tǒng)得以應(yīng)用，這不僅大大提高了系統(tǒng)的自動化程度，而且也有效地減少了能源浪費。
本文首先根據(jù)管網(wǎng)和水泵的運行特性曲線，闡明了供水系統(tǒng)的變頻調(diào)速節(jié)能原理。接著分析了變頻恒壓供水的原理及系統(tǒng)的組成結(jié)構(gòu)。本文采用變頻器和PLC實現(xiàn)恒壓供水，采用AT89C51單片機系統(tǒng)模擬供水網(wǎng)絡(luò)。采用PID控制算法對系統(tǒng)中的恒壓控制器進行設(shè)計。最后對系統(tǒng)的軟硬件設(shè)計進行了詳細的介紹。
關(guān)鍵詞
變頻調(diào)速；恒壓供水；PLC；PID控制

Abstract
With the development of electrical and AC motor control technology as well as computer technology，the frequency control technology has been applied in water supply system of constant pressure，which can not only boost the degree of automation but also reduce energy waste．
This paper explains water supply system’s energy-saving principle of pump variable frequency speed regulating according to characterisitic curve of running pipelines and water pump，analyzes the structure of variable frequency regulating constant pressure water supply．In this paper，the executing agency is the programmable logic controller（PLC） and the frequency converter． AT89C51 has been applied in order to simulate the water supply network．Proportion integration derivative （PID） has been applied in order to design the controller for constant pressure．By the end of this paper introduces the hardware and software of the system．

 Key words
Variable frequency speed control；Constant pressure water supply；Programmable logic controller（PLC）；Proportion integration derivative（PID）
目  錄
1．引言 1
2．恒壓變頻供水系統(tǒng)簡介 1
2.1．供水系統(tǒng)的基本特性 1
2.2．變頻調(diào)速原理 2
2.3．水泵調(diào)速運行的節(jié)能原理 3
3．恒壓供水系統(tǒng)的理論分析及方案設(shè)計 5
3.1．供水壓力和變頻器輸出頻率的關(guān)系 5
3.2．恒壓控制的理論分析 7
3.3．恒壓變頻供水系統(tǒng)的方案設(shè)計 9
3.3.1．恒壓變頻供水控制系統(tǒng)控制方案的設(shè)計 9
3.3.2．恒壓變頻供水系統(tǒng)的構(gòu)成 9
3.3.3．恒壓變頻供水系統(tǒng)中加減泵的條件分析 10
4．恒壓變頻供水的PID控制 12
4.1．PID控制算法的一般形式 12
4.2．離散PID控制算法 14
4.3．OMROM PLC的PID控制指令 15
5．變頻恒壓供水系統(tǒng)的軟硬件設(shè)計 17
5.1．系統(tǒng)的硬件組成 17
5.1.1．PLC的輸入輸出 17
5.1.2．變頻器參數(shù)設(shè)置 17
5.2．被控對象的硬件設(shè)計 18
5.2.1．主控芯片 18
5.2.2．A/D轉(zhuǎn)換電路 19
5.2.3．D/A轉(zhuǎn)換電路 20
5.2.4．數(shù)碼管顯示電路 20
5.3．系統(tǒng)的軟件設(shè)計 21
5.3.1．被控對象的軟件設(shè)計 21
5.3.2．恒壓變頻供水系統(tǒng)的控制流程 22
6．系統(tǒng)仿真研究及調(diào)試 23
6.1．系統(tǒng)的仿真研究 23
6.2．系統(tǒng)調(diào)試 24
7．總結(jié)與展望 26
參考文獻 27
致謝 28
附錄一：被控對象原理圖 29
附錄二：系統(tǒng)接線圖 30
附錄三：被控對象程序 31
附錄四：PLC程序 36