毕业设计论文三相异步电动机的闭环恒速控制系统专业名称：电气自动化论文提交日期：论文答辩日期：年月日【摘要】通过对光电编码器的结构及其工作原理的认识，掌握S7-200系列PLC高速计数器的运用，并且能够将两者结合起来，对电机进行转速的测量。了解闭环系统的构成，在学习PID算法的过程中，了解S7-200系列PLC的PID回路控制指令。结合之前所学的PLC、触摸屏和变频器等相关知识，设计一套闭环控制系统。要求一台三相异步电动机按需要设定的转速恒速运转。实现方法可由光电编码器检测电机的运行脉冲（每转300个脉冲），由PLC转换成实际转速，与触摸屏上设置的转速一起经PID运算后，再由PLC输出0~10V模拟信号控制变频器的运行，从而控制电机的正反转恒速运行。【关键字】高速计数器、PID回路控制、PLC、触摸屏、变频器Abstract：Throughtheopticalencoderstructureandworkingprincipleoftheunderstanding,grasptheS7-200seriesPLCusinghigh-speedcounter,andcancombinethetwo,themotorspeedmeasurement.Closed-loopsystemtounderstandthecompositionofPIDalgorithmintheprocessoflearningtounderstandtheS7-200seriesPLC,PIDloopcontrolinstructions.LearnedbeforewithPLC,touchscreenandinverter,andotherrelatedknowledge,todesignaclosed-loopcontrolsystem.Requiresathree-phaseasynchronousmotorspeedneedstobesetbyconstantoperation.Implementationofdetectionbytheopticalencodertorunthemotorpulse(300pulsesperrevolution),thePLCintotheactualspeed,andtouchscreentogetherwiththespeedsetbythePIDoperation,thenthePLCoutput0~10Vanalogsignaltocontrolthedriveoperation,therebycontrollingthemotorreversingconstantspeedoperation.Keywords:High-speedcounter,PIDloopcontrol,PLC,touchscreen,theinverter目录TOC\o"1-3"\h\z\uHYPERLINK\l"_Toc278784306"绪论PAGEREF_Toc278784306\h1HYPERLINK\l"_Toc278784307"第一章可编程控制器（PLC）简介PAGEREF_Toc278784307\h2HYPERLINK\l"_Toc278784308"1.1PLC的组成PAGEREF_Toc278784308\h2HYPERLINK\l"_Toc278784309"1.1.1CPU的构成PAGEREF_Toc278784309\h2HYPERLINK\l"_Toc278784310"1.1.2I/O模块PAGEREF_Toc278784310\h2HYPERLINK\l"_Toc278784311"1.1.3电源模块PAGEREF_Toc278784311\h2HYPERLINK\l"_Toc278784312"1.2PLC系统的其它设备PAGEREF_Toc278784312\h3HYPERLINK\l"_Toc278784313"1.2.1编程设备PAGEREF_Toc278784313\h3HYPERLINK\l"_Toc278784314"1.2.2人机界面PAGEREF_Toc278784314\h3HYPERLINK\l"_Toc278784315"1.2.3PLC的通信联网PAGEREF_Toc278784315\h3HYPERLINK\l"_Toc278784316"第二章触摸屏简介PAGEREF