2014届毕业生毕业论文（设计）题目：基于单片机的三相交流异步电机保护器的设计院(系)别专业班级学号姓名指导教师二○一四年六月摘要电动机因具有结构简单、价格低廉、使用维护方便等优点，在国民经济各方面被广泛采用。然而，由于供电状态和机械负荷的多变性，使得电动机的故障率较高，不仅会损坏电动机本身，而且会影响整个生产，造成较大的经济损失。因此，电动机的安全运行对保证企业的正常生产是非常重要的。本文以8位单片机AT89C51做微处理器,首先分析了三相交流异步电动机的常见故障，以对称分量法为依据，采用检测过流幅值、负序电流、零序电流的方法，得出了电动机故障的准确判据，确定了各种故障的保护措施，对电动机实现了短路、堵转、过热、负序电流、零序电流、低电压、过电压、启动时间过长、频繁启动、漏电闭锁等保护功能。AT89C51单片机内置128字的RAM和4K字的ROM，可以进行外部扩展数据存储器和程序存储器，具有性能较好的I/O端口及运算等功能，有合适的指令系统，能够实现电机智能保护，电路简单，功能齐全。关键词：电动机，智能保护，单片机AT89C51AbstractMotorhasmanyadvantages，suchassimplestructure,beingcheap，maintainingandusingconvenientlyandsoon,soitisadoptedextensivelyinthedifferentfieldsofnationaleconomy.However,becauseofsupplypowerstateandmechanicalloadgettingchangeable,itmakesthemalfunctionrateofthemotorveryhigh.Themalfunctionwilldamagethemotor,butalsoinfluencethewholeproduction,causetheenormouseconomiclosses.So,inordertoguaranteethenormalproductionoftheindustrialenterprise,thesafeoperationofthemotorisveryimportant.Thistexthasselected8-bitcomputerAT89C51asmicro-controller,hasanalyzedthecommonmalfunctionofthethree-phaseasynchronousmotoratfirst.Andthenit,whichisbasedonsymmetricalweighttheory,hasdrawnaccuratecriterionofthetroubleofthemotor,confirmedtheprotectivemeasuresofdifferenttroubles.Finally,ithasrealizedkindsofprotectionfunctions,suchasshort-circuitprotection,rotate-stopprotection,over-headprotection,negativecurrentprotection,zerocurrentprotection,low-voltageprotection,over-voltageprotection,overlongstart-uptimeprotection,frequentstart-upprotection,lockprotectionofelectricleakageandsoon..Thesingle-chipcomputerhasbuilt-inRAMandROM,andcanneedtoexpandtheRAMandROM.Havingstrongfunctionandhigh-efficientinsructionsystem,ithasrealizedintelligenceprotectionofthemotor.Itscircuitissimpleanditsfunctioniscomprehensive.Keywords:Motor,IntelligenceProtection,single-chipcomputerofAT89C51TOC\o"1-3"\h\z\uHYPERLINK\l"_Toc389224447"前言PAGEREF_Toc389224447\h1HYPERLINK\l"_Toc389224448"