I摘要本论文根据中国城市小区的供水要求，设计了一套基于PLC的变频调速恒压供水设备。变频恒压供水设备是一种新型的节能供水设备。变频恒压供水设备系运用当今最先进的微电脑控制技术，将变频调速器与电机水泵组合而成的机电一体化高科技节能供水装置。变频恒压供水设备以水泵出水端水压（或用户用水流量）为设定参数，通过微机自动控制变频器的输出频率从而调节水泵电机的转速，实现用户管网水压的闭环调节，使供水系统自动恒稳于设定的压力值：即用水量增加时，频率提高，水泵转速加快；用水量减少时，频率降低，水泵转速减慢。这样就保证了整个用户管网随时都有充足的水压（与用户设定的压力一致）和水量（随用户的用水情况变化而变化）。关键词：变频调速；恒压供水；PLCAbstractAccordingtotherequirementsoftheChineseurbancommunitywatersupply,thispaperdesignedasetoffrequencyconversionvelocitymodulationconstantpressurewatersupplyequipmentbasedonPLC.Variablefrequencyconstantpressurewatersupplyequipmentisanewtypeofenergy-savingwatersupplyequipment.Variablefrequencyconstantpressurewatersupplyequipmentisusingtoday'smostadvancedmicrocomputercontroltechnology,willbeacombinationoffrequencyconverterandmotorpumpmechanicalandelectricalintegrationofhigh-techenergy-savingwatersupplydevice.Variablefrequencyconstantpressurewatersupplyequipmenttopumpthewatersidepressure(oruser)waterflowtosetparameters,throughthemicrocomputerautomaticcontrolinverteroutputfrequencytoadjustthespeedofwaterpumpmotor,realizeuserpipenetworkpressureclosed-loopadjustment,automaticwatersupplysystem,steadytosetpressurevalue:thewaterconsumptionincreases,thefrequencyincrease,thewaterpumpspeedaccelerated;Watercut,thefrequencyisreduced,thepumpspeedslow.Soastoensuretheuser'snetworkatanytimesufficientwaterpressure(consistentwiththeusersettingpressure)andwater(changesovertheuser'swatersituation).Keywords:Frequencycontrolofmotorspeed;Constantpressurewatersupply;PLCII目录1绪论...............................................................11.1课题的提出....................................................11.1.1几种供水系统的比较......................................11.2变频器恒压供水产生的背景和意义................................21.3变频恒压供水系统的国内外研究现状..............................31.3.1变频恒压供水系统的国内外研究与现状......................31.3.2变频调速技术的国内外发展与现状..........................41.4本课题的主要研究内容..........................................42变频恒压供水系统的理论及控制........................................62.1变频恒压供水系统的理论分析....................................62.1.1电动机的调速原理........................................62.1.2变频恒压供水系统的节能原理..............................72.2变频恒压供水系统控制方案的确定................................92.2.1变频恒压供水系统控制方案的比较..........................92.2.2变频恒压供水方案的确定.................................103变频恒压供水系统的基本工作过程.....................................113.1变频恒压供水系统控制原理的组成和说明.........................113.2变频恒压供水系统的控制流程...................................133.3水泵切换条件分析.............................................134恒压供水系统单元电路的设计.........................................154.1系统硬件的结构................................................154.2变频器的选择.................................................164.2.1变频器的基本结构与分类.................................164.2.2变频器的控制方式.............
