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1、南京航空航天大学硕士学位论文基于专用芯片的三相多费率电能表研制姓名：马文耀申请学位级别：硕士专业：交通信息工程及控制指导教师：干敏梁20070101南京航空航天大学硕士学位论文 I摘 要 摘 要 多费率电价政策是我国近年来正在大力推广的电力计量制度， 能够有效的缓解高峰期用电紧张的局面，调整用电负荷曲线。民航企业是用电大户，积极实施多费率电价政策，对于国家削峰填谷目标的落实，以及提高其自身的效益也具有显著的作用。三相式多费率电能表是专门为民航企业设计的电能计量仪表， 也是近年来电力计量领域研究的热点之一。本课题所取得的成果也可以推广到其他工业领域。 本论文阐述了该三相多费率电能表的解决方案，系
2、统主控制器采用片内资源丰富、抗干扰能力较强的 PIC18F452 单片机。仪表按照相关国家标准要求设计，具有对三相电能分时段计量的功能，并且还集成了时段管理、自动月结、RS-485 抄表接口等智能化的电能管理手段。 文章首先介绍了三相电的理论及经典的电能测量方法， 然后给出了系统的设计目标和总体方案，并对系统所采用的专用芯片如 DS1302、ATT7026、MAX485 等进行了简要的介绍。在第五章用较大的篇幅从模块的角度对系统进行了功能划分，并分别从硬件和软件的角度描述了各个模块的实现细节，论述中涉及到了信号变换和隔离、电能累加和时段控制算法以及各种通信方式的软硬件实现。 文中对三相多费率电
3、能表的时钟准确性及抗干扰设计、校表方法等也有很详细的介绍。 文章的最后给出了系统的运行结果， 并且对仪表测量的准确度和运行可靠性进行了分析。 关键词：关键词：三相多费率，电能计量，PIC18F452 单片机，ATT7026，时钟芯片 基于专用芯片的三相多费率电能表研制 IIABSTRACT The multi-rate electric charge policy is broadly used in our country during these years. It can effectively ease the situation of power emergency, and reg
4、ulate the electric power load curve. Civil aviation enterprises and factories consume a great part of the annual electricity supply, by positively adopting the multi-rate policy, will not only be helpful to the target of peak shaving and valley filling, but also improve its operation benefits. The t
5、ri-phase multi-rate watt hour meter, which is a hotspot of electric power instruments research area in recent years, is specially designed for those civil aviation enterprises. The achievement of this research project can also be promoted to other industry areas. This dissertation discussed the desi
6、gn alternative of this tri-phase multi-rate watt hour meter. The system uses PIC18F452, which has abundant on-chip resources and strong EMC ability, as its master controller. The design strictly referenced the national standard of energy metering, has various functions such as time-sharing energy ca
7、lculating, time interval management, automatic balancing and RS-485 communication. Firstly, this paper introduces the theory of tri-phase energy and its classical methods of measurement, after that, it put out the design objection and whole frame of this metering system. Several important ICs, such
8、as ATT7026, DS1302 and MAX485 are also introduced. In the 5th chapter, the system is divided into modules. Modules are discussed both in their detailed solutions of hardware and software, which include signal transform and isolation circuits, energy metering and time interval control algorithm, and
9、various communication realizations. The accuracy of RTC, EMC design and meter adjust method have also been discussed. Finally this dissertation gives the running result of this system, and analyzed the accuracy of the meter and its stabilization. Keywords： tri-phase multi-rate， energy metering， PIC1
10、8F452 MCU， ATT7026， real-time clock 南京航空航天大学硕士学位论文 V图、表清单 图 2.1 三相电压波形及相位差图示4 图 2.2 三相电源的星形连接和三角形连接5 图 2.3 三相负载接法图示5 图 2.4 电能表的两种接线方法6 图 2.5 二表法测三相能量接线原理图7 图 3.1 三相多费率电能表硬件框图11 图 3.2 主程序软件流程13 图 4.1 PIC18F452 单片机引脚排列及名称16 图 4.2 PIC18F452 单片机内部结构16 图 4.3 ATT7026 内部框图19 图 4.4 ATT7026 每相能量的测量框图19 图 4.5 ATT7026 输入通道信号变换电路20 图 4.6 ATT7026 与 MCU 之间的接口21 图 4.7 DS1302 引脚图22 图 4.8 DS1302 内部框图22 图 4.9 秒寄存器定义23 图 4.10 MAX485 芯片引脚排列24 图 4.11 RS-485 光电隔离电路24 图 5.1 单相电压变换模块27 图 5.2 单相电流变换模块27 图 5.3 单相信号滤波和输入电路27 图 5.4 电能计算流程图29 图 5.5 ATT7
