智能电功率表的设计与制作

电子机电论文编号:JD862 论文字数:19083,页数:39

目   录

引言……………………………………………………………………………1
1  基本理论………………………………………………………………1
1.1 基本概念…………………………………………………………………2
1.2 全数字运算方案实现功率计算的实现理论…………………………………… 4
2  设计方案……………………………………………………………………6
2.1 方案选择………………………………………………………………………6
2.2 专用电能计量芯片ADE7755介绍………………………………………………8
2.3 设计原理及框图……………………………………………………………12
3  详细设计……………………………………………………………………13
3.1 功率计量模块………………………………………………………………13
3.2 控制模块……………………………………………………………………17
3.3 显示模块……………………………………………………………………19
3.4 串口模块……………………………………………………………………23
3.5 负载控制……………………………………………………………………24
3.6 直流电源……………………………………………………………………25
4  系统集成……………………………………………………………………26
4.1 制作PCB板……………………………………………………………………26
4.2 编译程序…………………………………………………………………29
4.3 调试…………………………………………………………………………29
5  校准…………………………………………………………………………29
结论…………………………………………………………………………29
谢辞…………………………………………………………………………31
参考文献……………………………………………………………………32
附录 ……………………………………………………………………………33

摘  要

随着大规模集成电路和计算机应用技术的发展,电子式测量仪表的种类越来越多,功能也越来越强大.本文介绍的智能电功率表便是其中一种.
 该智能电动率表采用了Analog公司生产的专用电能计量芯片ADE7755产生与负载有功功率成正比的脉冲信号,再利用AT89S51单片机对该脉冲进行计量和显示,并利用计量结果和按键等产生各种控制信号,从而实现对市电负载电功率的在线测量，同时实现对市电用户的使用状态进行在线监测，包括超负荷运转监测，用户窃电监测，远程强制关断，本地电量透支关断等功能.该智能电动率表还可以和计算机实现异步串行通信,便于组网,充分发挥PC机和网络的优势,提高该表的智能化程度.
专用电能计量芯片ADE7755是一种高准确度电能测量集成电路,其技术指标超过了IEC1036规定的精确度要求.ADE7755在ADC和基准源中使用模拟电源,其它信号处理部分使用数字电源,这是ADE7755在恶劣环境条件下仍能保持极高的准确度和长期稳定性的主要原因. ADE7755引脚F1和F2一较低频率形式输出有功功率平均值,能直接驱动机电式计度器.引脚CF以较高频率形式输出有功功率的瞬时值,用于校验.

关键词:专用电能计量芯片ADE7755;在线测量;在线监测;异步串行通信

Abstract

With the development of large scale integrated circuit and computer application technology, the kinds of the electronic instrument is becoming more and more large,and their functions are getting more and more stronger. The intelegent power instrument this thesis concerns is one of these electronic instruments.
The ADE7755 is a high accuracy electrical energy measurement IC. The part secifications surpass the accuracy requirements as quoted in the IEC1036 standard. See Analog Devices’ Application Note AN-559 for a description of an IEC1036 watt-hour meter reference design based on the AD7755.
The only analog circuitry used in the ADE7755 is in the ADCs and reference circuit. All other signal processing (e.g., multiplication and filtering) is carried out in the digital domain. This approach provides superior stability and accuracy over extremes in environmental conditions and over time.
The ADE7755 supplies average real power information on the low-frequency outputs F1 and F2. These logic outputs may be used to directly drive an electromechanical counter or interface to an MCU. The CF logic output gives instantaneous real power information. This output is intended to be used for calibration purposes or for interfacing to an MCU.
The intelegent power instrument makes the electrical energy measurement IC ADE7755 to give rise to a serial impulse proportional to the load’s instant active power.Then, It uses microcontroller unit AT89S51 to caculate the impulse and display the result, and give rise to all kinds of control singnal from the result and the keystroking.
Thus, The intelegent power instrument can realize on-line measurement to citizen users. It can implement on-line supervision to users’ using condition, which include overloaded runningsupervision, users’ stealing electricity supervision, tel-control, local electricity capacity’s overdraw control and so on. It also can realize asynchronous serial communications with the computer which connects with it to make up network to show the computer and network’s advantageous lightly and improve its intelegence. 

Key words: Intelegent power instrument; Electrical energy measurement IC ADE7755;
          Microcontroller unit AT89S51; on-line measurement; on-line supervision;
          asynchronous serial communications