基于单片机的电能计量系统设计[1].doc

I摘要电能是现代社会中国民经济和人民生活的重要保障，随着社会的快速发展往往导致电能的供应与使用之间产生矛盾。为了解决这一矛盾，电能计量的分时计费方式可以通过调节人们的用电行为，对提高电能利用的合理性和缓解电力供需矛盾具有重要价值。但是传统的机电式电能表无法执行分时计量和分时计费的功能，因此基于单片机技术设计的新型数字电表是实现新型电能管理方式的前提。本文提出了一种以AT89C51为核心的电量计量系统，单片机通过AD7751对电网的电压和电流取样，经过内部处理后以频率的形式输出，送给单片机测量频率，计算出有功功率，对时间进行积分后便可得到电能；时钟芯片DS1302提供当前的时间信息，单片机将电量、电费和时间数据送LCD显示，用户可通过独立键盘对系统的工作状态进行操作，包括时间的设定、时间与电量及电费的显示、过去时刻的电量和电费查询等。本设计中电压电流采集电路具有特色和成本优势；探索了利用AT89C51的有限硬件资源与软件的有机结合实现实时钟和串行通信等接口的设计方法；以电能表为对象，重点探讨了基于低功耗单片机的低功耗仪表的基本原理和设计技术，对其它低功耗仪表的设计具有参考价值。关键词：电能表，AT89C51单片机，低功率设计，硬软件合成，AD7751单片机IIAbstractTheelectricenergyisaguaranteetonationaleconomyanddailylifeinmodernsociety.Withthefastdevelopmentofthesociety,contradictionbetweenthedemandandproductionofelectricalenergyoccurs.Time-scheduledtariffsystem,thatchangesuser'sbehaviorinenergyconsumingandrationalizestheelectricalenergyutilization,isaneffectiveandvaluablemeasuretosolvethisproblem.Fortheenergymeasurementthetraditionalmechanicalelectricitymeternolongercanmeettherequirementsofthisnewtariffsystem,andmicrocontroller-baseddigitalE-meterbecomestheprerequisiteandbackboneofthistariffsystem.ThispaperpresentsaAT89C51powermeteringsystemasthecore,microcontrollerthroughtheAD7751onthegridvoltageandcurrentsampling,afterinternalprocessingafteroutputintheformoffrequency,giventhefrequencymeasurementmicrocontrollertocalculatetheactivepower,integrationoftimeavailableafterpower,clockchipDS1302providesthecurrenttimeinformation,theprocessorwillpower,electricityandtimeofdatasenttoLCDdisplay,separatekeyboard,theusercanworkonthestateofthesystemoperation,includingsettingtime,timeandpowerandthetariff,inthepasthourofelectricityandelectricityinquiries.Thedesignofvoltageandcurrentacquisitioncircuitswithfeaturesandcostadvantages;DesignmethodsthatintegratestheAT89C51slimitedhardwareandsoftwareresourcestoimplementreal-timeclock,ICandserialcommunicationinterfaces;WithE-meterasaplatform,astudyonthefundamentalsandtechniquesoflow-powerdesignthemightbeofreferencevaluetootherlow-powerprocessmeasuringdevices.Keywords：Electricenergymeter,AT89C51seriesmicrocontroller,low-powerdesign,Integrationofhardwareandsoftware,AD7751seriesmicrocontrollerIII目录摘要....................................................................................................................IABSTRACT..........................................................................................................II1电能计量系统方案论证1.1方案一机械电子式...........................................................................................................11.2方案二模数转换式...........................................................................................................11.3方案三功率累加式...........................................................................................................11.4方案选择.............................................................................................................................22绪论2.1课题背景.............................................................................................................................32.2数字仪表的发展历程.........................................................................................................32.2.1智能仪表的概念..............................................................................................................32.2.2智能仪表的特点..............................................................................................................42.2.3智能仪表的发展..............................................................................................................42.2.4虚拟仪表是智能仪表发展的新阶段..............................................................................62.3国内外电能表技术发展的现状.........................................................................................72.4选题概述.............................................................................................................................83总体方案及各模块简介3.1AT89C51简介....................................................................................................................103.2AD7751原理及应用.........................................................................................................123.2.1AD7751性能特点..........................................................................................................123.2.2AD7751工作原理..........................................................................................................133.3EEPROM............................................................................................................................143.4DS1302...............................................................................................................................163.5.LCD1602...........................................................................................................................183.6通信系统...........................................................................................................................194系统硬件设计4.1功率检测电路设计......................................................................................................