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摘要本项目充分地利用了DSP强大的信号处理能力和现代数值分析方法。设计了电能表前端采样及计量模块的硬件，以及一套符合国标GB/T17883-1999的0.2S级精度要求的算法，同时扩展了谐波分析功能。系统概述为：三相电压、电流AD采样，采样数据通过串口送至处理器(DSP)，由DSP对采样数据作电参数计量和谐波分析，处理结果通过定制LCD显示，并通过脉冲口发出有功、无功校表脉冲。DSP采用ADI公司的BLACKFIN531-16位定点芯片，昀高处理能力可达800MIPS，采样芯片为16bit的AD73360，支持六通道同步转换，无同步误差。数字化、高精度、创新性和可扩展性是本项目的特点，准同步采样算法和谐波分析是本项目的新颖之处。本文包括以下方面内容：（1）系统方案，（2）功能与指标，（3）实现原理，（4）系统误差分析，（5）系统软件设计，（6）系统测试，结果分析及功能实现，（7）总结。关键词：ADSP-BF531，电能表，准同步采样，汉宁窗，快速傅立叶变换ABSTRACTTheprojectmakesfullofDSP’shighperformanceandthemodernCalculationMethod,designsasuitofHigh-PrecisionThree-PhasePowerMeter,anddevelopsthearithmeticofpowermeasurement.Alsodesignsamethodtoanalysetheharmoniclevelofthepowersystem.TheprincipleisthatSignalssampledbyADCistransmittedtoDSP,processedbyDSPandworkingoutRMSvalue,Power,frequency,harmonicandsoon.Afterthat,theresultscanbedisplayedonLCD.Digitaldesign,high-precision,creativityandextendablearethefeaturesoftheproject.Thisreportincludesfollowingissues:(1)Systemsolution.(2)Functionsofthesystem.(3)Principleofimplementation.(4)AnalysisofMeasurementerror.(5)Softwaredesignofthesystem.(6)Systemtest.(7)SummarizationKEYWORDS:ADSP-BF531.PowerMeter,Quasi-Synchronoussampling,Hanningwindow，FFT.22目录摘要...................................................................................................................11系统方案...........................................................................................................31.1系统概述.................................................................................................31.2功能模块设计.........................................................................................41.2.1信号调理和AD采样.................................................................41.2.2处理器模块...............................................................................51.2.3系统时钟设计...........................................................................71.2.4人机交互...................................................................................71.2.5电源管理模块............................................................................82功能与指标.......................................................................................................93实现原理.........................................................................................................103.1测量方法..............................................................................................113.2准同步算法..........................................................................................143.2.1准同步算法原理.....................................................................143.2.2准同步算法误差分析.............................................................163.3数字滤波设计......................................................................................173.4谐波分析..............................................................................................183.4.1离散傅立叶变换的泄漏与栅栏效应......................................193.4.2加窗处理...............................................................................203.4.3加窗的插值算法.....................................................................223.4.4谐波分析的软件仿真..............................................................263.5误差补偿..............................................................................................283.6电能脉冲输出......................................................................................304系统误差分析.................................................................................................305系统软件设计.................................................................................................316系统测试.........................................................................................................337总结.................................................................................................................42附录1：关键算法模块的源代码......................................................................431电表主程序......................................................................................................432采样中断程序.................................................................................................443相位补偿函数.................................................................................................464功率平滑滤波器.............................................................................................475加窗插值的FFT算法.....................................................................................48附录2：原理图与PCB......................................................................................53附录3：电能误差检定......................................................................................57附录4：参考文献..............................................................................................59331系统方案1.1系统概述首先对电网的三相电压、电流信号进行调理，电压经过分压电阻，电流经过高精度电流互感器，把大信号转换为小信号，然后通过一个抗混叠滤波器，调理后的信号进行A/D采样，通过串行通信口，DSP接收到采样数据。DSP实时处理采样数据，计算出电压、电流有效值，有功、无功功率，累积电量，电网频率及功率因数等电网参数。采用高精度算法对电压、电流信号进行谐波成分，得到各次谐波分量有效值、频率和相位信息，利用这些信息，还可以计算各次谐波功率。计算结果通过LCD面板显示，同时也能与外部进行通讯，系统提供电能脉冲输出，方便校表。系统框图如图1.1所示。DSP系统信号调理及采样显示、校表