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1、摘要随着我国社会经济的发展，城市建设发展十分迅速，同时也对基础设施建设提出了更高的要求。城市供水系统的建设是其中的一个重要方面，供水的可靠性、稳定性、经济性直接影响到用户的正常工作和生活。随着人们对供水质量和供水系统可靠性要求的不断提高，利用先进的自动化技术、控制技术以及通讯技术，设计出高性能、高节能、能适应供水厂复杂环境的恒压供水系统成为必然趋势。本系统包含三台水泵电机，它们组成变频循环运行方式。采用变频器实现对三相水泵电机的软启动和变频调速，运行切换采用“先启先停”的原则。压力传感器检测当前水压信号，送入PLC与设定值比较后进行
2、PID运算，从而控制变频器的输出电压和频率，进而改变水泵电机的转速来改变供水量，最终保持管网压力稳定在设定值附近。通过工控机与PLC的连接，采用组态软件完成系统监控，实现了运行状态动态显示及数据、报警的查询。关键词：变频调速，恒压供水，PLC，组态软件-55-ABSTRACTAsChina'ssocialandeconomicdevelopment,urbanconstructionanddevelopmentveryquickly,butalsotheconstructionofinfrastructurefacilitiesha
3、sputforwardhigherrequirements.Citywatersupplysystemconstructionisoneoftheimportantaspectsofthewatersupplyreliabilityandstability,theeconomyofadirectimpactontheuser'snormalworkandlife.Aspeopleonthewaterqualityandwatersupplysystemsinthecontinuousimprovementofreliabilityr
4、equirements,theuseofadvancedautomationtechnology,controltechnologyandcommunicationtechnology,designahigh-performance,high-energy,watersupplyplantstoadapttothecomplexenvironmentofconstantpressurewatersupplySystemsbecomeaninevitabletrendThissystemisformedbythreepumpgener
5、ators,andtheyformthecirculatingrunmodeoffrequencyconversion.Withgeneralfrequencyconverterrealizeforthreephasepumpgeneratorsoftstartwithfrequencycontrol,operationswitchadoptstheprincipleof”startfirststopfirst”.Thedetectionsignalofpressuresensorofhydraulicpressure,viaPLC
6、withsetvaluebycarryoutPIDcomparisonoperation,so,controlfrequencyandtheexportvoltageoffrequencyconverter,andthentherotationalspeedthatchangespumpgeneratorcometochangewatersupplyquantity,eventually,itisnearbytomaintainpipenetpressuretostabilizewhensetvalue.Throughworkcon
7、trolmachinetheconnectionwithPLC,withgroupformsoftwareconsummatelysystematicmonitoring,haverealizedoperationstatedevelopmenttoshowanddata,reporttothepoliceinquiry.Keywords:variablefrequencyspeed-regulating,constant-pressurewatersupply,PLC,supervisioncontrolanddataacquis
8、ition.-55-目录1绪论11.1课题的提出51.2变频恒压供水系统的国内外研究现状.................................................61.2.1变频调速技术的国内外发展与现状...
