智能電功率表的設計與制作

電子機電論文編號:JD862 論文字數:19083,頁數:39

目   錄

引言……………………………………………………………………………1
1  基本理論………………………………………………………………1
1.1 基本概念…………………………………………………………………2
1.2 全數字運算方案實現功率計算的實現理論…………………………………… 4
2  設計方案……………………………………………………………………6
2.1 方案選擇………………………………………………………………………6
2.2 專用電能計量芯片ADE7755介紹………………………………………………8
2.3 設計原理及框圖……………………………………………………………12
3  詳細設計……………………………………………………………………13
3.1 功率計量模塊………………………………………………………………13
3.2 控制模塊……………………………………………………………………17
3.3 顯示模塊……………………………………………………………………19
3.4 串口模塊……………………………………………………………………23
3.5 負載控制……………………………………………………………………24
3.6 直流電源……………………………………………………………………25
4  系統集成……………………………………………………………………26
4.1 制作PCB板……………………………………………………………………26
4.2 編譯程序…………………………………………………………………29
4.3 調試…………………………………………………………………………29
5  校準…………………………………………………………………………29
結論…………………………………………………………………………29
謝辭…………………………………………………………………………31
參考文獻……………………………………………………………………32
附錄 ……………………………………………………………………………33

摘  要

隨著大規模集成電路和計算機應用技術的發展,電子式測量儀表的種類越來越多,功能也越來越強大.本文介紹的智能電功率表便是其中一種.
 該智能電動率表采用了Analog公司生產的專用電能計量芯片ADE7755產生與負載有功功率成正比的脈沖信號,再利用AT89S51單片機對該脈沖進行計量和顯示,并利用計量結果和按鍵等產生各種控制信號,從而實現對市電負載電功率的在線測量，同時實現對市電用戶的使用狀態進行在線監測，包括超負荷運轉監測，用戶竊電監測，遠程強制關斷，本地電量透支關斷等功能.該智能電動率表還可以和計算機實現異步串行通信,便于組網,充分發揮PC機和網絡的優勢,提高該表的智能化程度.
專用電能計量芯片ADE7755是一種高準確度電能測量集成電路,其技術指標超過了IEC1036規定的精確度要求.ADE7755在ADC和基準源中使用模擬電源,其它信號處理部分使用數字電源,這是ADE7755在惡劣環境條件下仍能保持極高的準確度和長期穩定性的主要原因. ADE7755引腳F1和F2一較低頻率形式輸出有功功率平均值,能直接驅動機電式計度器.引腳CF以較高頻率形式輸出有功功率的瞬時值,用于校驗.

關鍵詞:專用電能計量芯片ADE7755;在線測量;在線監測;異步串行通信

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