电表通信抄表集中器硬件设计

I电力载波通信抄表集中器硬件设计摘要随着我国电力事业的迅速发展，传统的用电抄收管理方式己经不能满足市场需求。本文在大量收集查阅国内外有关远程抄表系统资料、深入用户及用电管理部门广泛调研的基础上，提出了一种采用低压电力线载波通信技术的远程自动抄表系统。该系统具有三层网络结构，即上位机管理系统、集中器和载波电表。重点分析研究了集中器及其与各组成部分的通信。由于我国低压电力线上存在的高削减、高噪声、高变形，必须采用特殊的通信技术。本文首先分析了高频信号在电力线中的传输特性；重点讨论了扩频通信技术在电力线载波通信中的应用；深入研究了以扩频调制解调技术通信技术为基础的、高性能的电力线载波专用MODEM芯片SSCP300的内部工作原理。在此基础上，采用SSCP300实现了远程抄表系统中集中器与终端载波电表之间可靠的数据传输。集中器是连接上位机与终端载波电表之间的枢纽，起着上传下达的作用。根据中华人民共和国电力行业标准规定的集中器的主要功能及性能指标要求，本文重点研究设计了集中器的硬件系统。其中硬件系统主要包括主控制器、外部扩展数据存储器、时钟模块、看门狗模块、上位机通信接口电路以及电力线载波通信电路及其外围电路等。关键词：电力线载波，扩频通信技术，集中器，抄表系统IIHardwareDesignofPowerLineCommunicationMeterReadingConcentratorABSTRACTWiththerapiddevelopmentofpowerundertakingofourcountry,thetraditionalwaysofmeterreadingcannotsatisfythedemandofmarketanymore.Basedonthevastcollectingandconsultingoftheconcernedinformationoftheremotemeterreadingsystemofthehomeandabroadandgoingdeepintotheconsumersandpowerconsumptionadministrativedepartmentstoinvestigateandresearchwidely,aremotemeterreadingsystemadoptingcarriercommunicationtechnologyofthelow-voltagepowerlinecommunication(PLC)hadbeenproposedinthispaper.Ithadnetworkstructureofthreelayers，i.e.thecomputeradministrativesystem，concentratorandcarriermeter.Andthefunctionsandcharacteristicsofthewholesystemtogetherwithitseverycomponenthadbeenanalyzed.Becausehighattenuation，highnoiseandhighdistortionexistinthelow-voltagepowerlinesofourcountry,specialcommunicationtechnologymustbeadopted.Firstofall,thetransmissioncharacteristicwhenhigh-frequencysignalwastransmittedthroughpowerlineswasanalyzed.Secondly,theapplicationofspreadspectrumcommunicationtechnologytocarriercommunicationofthepowerlinewasemphaticallydiscussed.Thirdly，theinteriorprincipleofthespecialMODEMICSSCP300adoptingSpread-spectrummodemcommunicationtechnologywasdeeplystudied.Basedonthis，SSCP300wasselectedtothereliabledatatransmissionbetweentheconcentratorofthelong-distancemeterreadingsystemandtheterminalsignalcarrierammeter.Beingtheheartoftheautomaticmeterreadingsystem，theconcentratorconnectedthecomputerwiththeterminalcarriermeter.ThehardwaresystemoftheconcentratorwasemphaticallydesignedaccordingtothemainfunctionsandthedemandsforperformancetargetsoftheconcentratorstatedinthepowertradestandardofPRC.ItwasmainlycomposedofMCUexternalexpandedRAM，clockmodule，watchdogmodule，thecomputercommunicationinterfacecircuitandthePLCcommunicationcircuittogetherwithitsperipheralcircuits·KEYWORDS：carrierpowerline,spreadspectrumcommunicationtechnology,concentrator,meterreadingsystemIII目录摘要....................................................................IABSTRACT................................................................II1绪论...................................................................11.1电力线载波通信的意义及发展状况......................................11.2低压电力线通信的特点................................................11.3国内外研究现状和动态................................................21.4设计电力载波抄表集中器的目的和意义..................................21.5课题的可行性分析....................................................31.6本文的主要任务......................................................32电力线载波通信技术.....................................................42.1电力线载波通信中信号传输特性分析[8]...................................42.2常用的低压电力线载波通信技术[13]......................................52.3扩频通信技术........................................................62.3.1扩频通信的工作原理..............................................62.3.2扩频通信的特点[4].................................................62.4电力线载波通信的实现................................................72.4.1国外的电力线载波专用Modem芯片..................................73电力载波抄表系统总体设计...............................................93.1自动抄表系统的组成..................................................94电力载波抄表集中器的硬件设计..........................................114.1电力线载波远程抄表系统集中器的硬件设计.............................114.1.1集中器的功能及技术指标[8]........................................114.1.2集中器的结构框图...............................................114.2集中器主控器的设计.................................................124.2.1主控器的作用[11].................................................124.2.2主控器的选型[11].................................................124.2.3单片机W77E58的简单介绍........................................134.3数据存储器的扩展...................................................154.3.1数据存储器RAM的选择...........................................154.3.2硬件电路设计...................................................164.3.3存储器的掉电保护...............................................174.4时钟模块...........................................................184.4.1设计思想.......................................................18IV4.4.2时钟模块的选择[15]...............................................184.4.3时钟模块与单片机的连接[14].......................................194.5电力线载波通信电路设计.............................................194.5.1载波通信芯片SSCP300的发送与接收原理...........................204.5.2单片机与SSCP300通信的控制工作过程.............................234.6主控器与MODEM通信接口.............................................244.6.1MODEM简介.....................................................254.6.2主控器与MODEM通信接口电路..............