多年来一直专注于工业自动化领域的高品质工业模组全球贸易。我们专注于PLC组件数控和伺服驱动机器故障？购置更换零件？停产设备麻烦？DCS系统PLC系统机器人系统备件解决方案不要犹豫与我们联系！我们可以提供快速和合格的工业备件援助。************************************************************************ABBIEFAN90ABBIEFAN90ABBIEFAN90*****************************************************************************************************引言电能表作为电能计量的专用仪表，在电能管理仪器仪表中占有很大比例，其性能直接影响着电能管理的效率和科技水平。从产品的功能、性能及经济效益等多方面来看，全电子电能表与传统的感应式电能表相比，存在着明显的优势。而且电能表作为计量管理和用电管理的终端，它所提供的各种功能是实现电力系统自动化管理必不可少的。传统的测量都是采用A／D转换电路，但这种方法使部分电参量测量精度欠佳，性价比不理想，且软件编程相对复杂，微控制器必须对采样电路进行数据处理(如电压、电流的平均值、有效值，有功、无功计算等)。而随着现代电子产业的高速发展，测量电路的集成化、模块化成为未来发展的趋势，各大器件公司也纷纷推出自己的电能计量芯片。这种集成芯片不仅精确度高，而且硬件、软件设计简单，价格便宜，性价比高，极具市场潜力。本文给出了基于Microchip公司的MCP3906单相电能计量芯片，并以AVR公司的ATMega16为MCU设计开发的一款新型单相电能表实现方案。与以往电能表相比，该方案具有设计接口简单、结构紧凑、可靠性高等特点。1MCP3906单相电能计量芯片MCP3906是Microchip公司推出的单相电能计量芯片，它支持国际电能计量标准技术规范IEC62053，可提供与平均有功功率成比例的频率输出，以及与瞬时功率成比例的高频输出用于电表校准。MCP3906内部包含两个16位△-∑ADC，可用于各种IB和IMAX电流和小分流器(<200μΩ)的电表设计。该芯片还包含一个超低温漂(<15ppm／℃)参考电压，通过特殊设计的带隙温度曲线，可在整个工业级温度范围内使温度梯度达到最小。固定功能的片上DSP模块可用于计算有功功率，此外，片上还有驱动机械计数器的高输出驱动器，可以减少现场故障和机械计数器咬合。芯片的空载门限模块可防止任何电流潜变(Creep)测量，而上电复位(PoweronReset，POR)模块则可在低电压时限制电表测量。因此，MCP3906是具备高现场可靠性的精密电能计量IC，并采用业界标准的引脚配置。1.1MCP3906的内部结构及工作原理MCP3906是混合模拟／数字信号的CMOS集成电路，其内部结构框图如图1所示。MCP3906可提供与有功功率成比例的频率输出和与瞬时功率成比例的高频输出来用于校准。它的两个通道均使用16位二阶△-∑ADC，能以MCLK／4的频率对输入进行采样，同时允许对动态范围很宽的输入信号进行采样。可编程增益放大器(ProgrammableGainAmplifier，PGA)扩大了电流输入通道(通道0)的可用范围。其有功功率的计算以及与计算有关的滤波均可在数字域中完成，从而提高了其稳定性和温漂性能。MCP3906的两个数字高通滤波器(HPF1和HPF2)可以滤除两个通道的系统偏移量，因此，有功功率的计算不含任何电路或系统偏移量。经过高通滤波后，电压和电流信号相乘，即可得出瞬时功率信号。此信号不含直流偏移分量，因此可有效利用求平均法(AveragingTechnique)计算出所需的有功功率输出。瞬时功率信号包含的有功功率信息就是瞬时功率的直流分量。求平均法可用于计算正弦和非正弦波形，以及所有功率因数。瞬时功率经过低通滤波器(LPF)就可以产生瞬时有功功率信号。通过MCP3906的DTF转换器可对瞬时有功功率信息进行累加，以产生输出脉冲，此脉冲的频率与平均有功功率成比例。FOUT0和FOUT1输出的低频脉冲可用于设计驱动机电式计数器和双相步进电机，以便显示实际消耗的有功功率。每个脉冲对应于一个固定的有功电量值，其功能可由F2、F1和F0的逻辑进行选择。HFOUT输出具有较高的频率设定和较低的积分周期，可用于表征瞬时有功功率信号。由于累加时间较短，该输出可使用户在稳定的负载条件下进行快速的校准。1.2MCP3906的引脚功能MCP3906采用24引脚SSOP封装，其引脚排列如图2所示。各引脚的功能说明如表1所列P0922KSP0922KTP0922KUP0922KVP0922KWP0922LAP0922LBP0922LCP0922LDP0922LEP0922LFP0922LGP0922LHP0922LJP0922LLP0922LMP0922LNP0922LPP0922MFP0922MGP0922MPP0922MXP0922MZP0922NFP0922NGP0922QAP0922QLP0922QNP0922QSP0922RKP0922RNP0922RVP0922RWP0922RXP0922RYP0922SAP0922SDP0922SGP0922SKP0922SNP0922SRP0922SUP0922SWP0922SZP0922TCP0922TEP0922THP0922TLP0922TVP0922UAP0922UDP0922UGP0922UJP0922UKP0922ULP0922UMP0922UNP0922UPP0922UQP0922URP0922USP0922UTP0922UUP0922UVP0922UWP0922UXP0922VCP0922VSP0922VTP0922VUP0922VVP0922VWP0922WEP0922WFP0922WKP0922WNP0922WPP0922WQP0922WRP0922WSP0922WTP0922WUP0922WWP0922WZP0922XQP0922XRP0922XSP0922XTP0922XUP0922XVP0922XWP0922XXP0922XYP0922YAP0922YCP0922YHP0922YJP0922YKP0922YUP0922ZAP0922ZBP0922ZCP0922ZGP0922ZHP0922ZJP0922ZLP0922ZMP0922ZNP0922ZPP0922ZTP0922ZUP0922ZVP0922ZWP0922ZZP0923ACP0923AFP0923AGP0923AHP0923AKP0923ALP0923ANP0923APP0923ATP0923AXP0923BQP0923BRP0923BSP0923BTP0923BUP0923BVP0923BWP0923BXP0923BYP0923CAP0923CBP0923CCP0923CDP0923DAP0923DBP0923DCP0923DDP0923DGP0923DHP0923DKP0923DNP0923DPP0923DRP0923DSP0923DUP0923DVP0923DWP0923DYP0923DZP0923FBP0923FQP0923FSP0923FTP0923GFP0923GGP0923GLP0923GMP0923GNP0923GPP0923GQP0923GRP0923GTP0923GWP0923GXP0923GZP0923HMP0923HNP0923HPP0923HQP0923HRP0923HTP0923HUP0923HVP0923HXP0923JAP0923JDP0923JGP0923JKP0923JNP0923JVP0923JWP0923JXP0923JYP0923JZP0923KAP0923KDP0923KLP0923KPP0923KSP0923KVP0923LHP0923LLP0923LNP0923LRP0923LUP0923LVP0923LWP0923LXP0923LYP0923MAP0923MBP0923MCP0923MDP0923MEP0923MFP0923MGP0923MHP0923MMP0923MNP0923MPP0923MRP0923MXP0923MYP0923MZP0923NEP0923NFP0923NGP0923NLP0923NNP0923NPP0923NSP0923NTP0923NUP0923PFP0923PGP0923PHP0923PJP0923PKP0923PLP0923PMP0923PNP0923PPP0923PQP0923PRP0923PSP0923PTP0923QFP0923QGP0923QLP0923QMP0923QSP0923QTP0923QUP0923QVP0923QWP0923QXP0923QYP0923VAP0923VDP0923VEP0923VFP0923VJP0923VRP0923VSP0923VTP0923VVP0923ZBP0923ZCP0923ZDP0923ZEP0923ZFP0923ZGP0923ZHP0924DTP0924EAP0924EBP0924ECP0924EDP0924JHP0926AHP0926BEP0926CAP0926CBP0926CCP0926CDP0926CEP0926CFP0926CMP0926CNP0926CPP0926DFP0926DJP0926DPP0926DSP0926DVP0926DZP0926EAP0926EKP0926ELP0926EQP0926GGP0926GHP0926GJP0926GQP0926GRP0926GSP0926GUP0926GVP0926GWP0926GXP0926HCP0926HFP0926HJP0926HMP0926HQP0926HTP0926HWP0926HZP0926JCP0926JFP0926JJP0926JMP0926KEP0926KHP0926KKP0926KLP0926KMP0926KNP0926KPP0926KQP0926KRP0926KSP0926KTP0926KWP0926KZP0926LCP0926MXP0926MYP0926MZP0926NKP0926NLP0926NMP0926NNP0926NPP0926NQP0926NSP0926PAP0926PSP0926PTP0926QLP0926QMP0926QNP0926QPP0926QSP0926QTP0926QVP0926QWP0926QXP0926RVP0926SPP0926SQP0926SZP0926TDP0926THP0926TJP0926TKP0926TLP0926TMP0926TNP0926TPP0926TQP0926TRP0926VYP0926WGP0926WHP0926WJP0926WKP0926WLP0926WMP0926WNP0926WPP0926WQP0926XAP0926XBP0926XEP0926XMP0926ZNP0926ZPP0926ZYP0926ZZP0927AHP0927AJP0927BAP0927BBP0927BCP0927BDP0927BGP0927BHP0930ASP0930AUP0930CAP0930CBP0930CCP0930CDP0930CEP0930CFP0930CGP0930CHP0930DAP0930DBP0930DCP0930DDP0930DEP0930DFP0930DGP0930DHP0930DMP0930DNP0930DPP0930DRP0930DSP0930DTP0930DUP0930DVP0930DWP0930DXP0930DYP0930DZP0930EEP0930EFP0930EGP0930EKP0930EUP0930EVP0930EYP0930FCP0930FDP0930FEP0930FFP0930FG)