基于單片機(jī)的智能電子負(fù)載系統(tǒng)設(shè)計(jì)

電子機(jī)電論文編號(hào):JD131  字?jǐn)?shù):14905,頁(yè)數(shù):49

目錄
1  電子負(fù)載的原理及概述 .....................................................1
1.1  電子負(fù)載的定義 .........................................................1
1.2  電子負(fù)載的工作方式..................................................... 1
1.2.1恒定電流方式 ...........................................................2
1.2.2恒定電阻方式........................................................... 2
1.2.3恒定電壓方式 ...........................................................3
1.3  電子負(fù)載設(shè)計(jì)模塊方框圖..................................................3
2  電流、電壓的測(cè)量技術(shù) .....................................................4
2.1  電流的測(cè)量..................................................... ........4
2.1.1電流的檢測(cè)方法......................................................... 4
2.1.2幾種常用電流傳感器的性能比較........................................... 5
2.1.3 ACS750型集成電流傳感器的原理與應(yīng)用.....................................5
2.2  電壓的測(cè)量............................................................. 6
3  模數(shù)、數(shù)模與單片機(jī)接口技術(shù)............................................... 8
3.1  D/A轉(zhuǎn)換器接口..................................................... .....8
3.1.1典型D/A轉(zhuǎn)換芯片DAC0832................................................. 8
3.1.2運(yùn)算放大器的考慮 ......................................................10
3.2  A/D轉(zhuǎn)換器接口 .........................................................10
4  系統(tǒng)硬件設(shè)計(jì)............................................................ 13
4.1  系統(tǒng)顯示模塊.......................................................... 13
4.2  MOSFET場(chǎng)效管的應(yīng)用.....................................................14
4.2.1 MOS型場(chǎng)效應(yīng)管的特點(diǎn)...................................................14
4.2.2 MOS型場(chǎng)效應(yīng)管的輸出特性曲線 ..........................................14
4.2.3 MOS型場(chǎng)效應(yīng)管的選型...................................................15
4.3  基準(zhǔn)電源的產(chǎn)生..................................................... ...15
4.3.1 TL431介紹..................................................... .......15
4.3.2 TL431的應(yīng)用..................................................... .....16
4.4  集成運(yùn)放的應(yīng)用 ........................................................18
4.4.1 集成運(yùn)放基本反相放大電路應(yīng)用..........................................18
4.4.2 集成運(yùn)放基本同相放大電路應(yīng)用 .........................................19
4.4.3 集成運(yùn)放基本差動(dòng)放大電路應(yīng)用..........................................19
4.5  AT89S51單片機(jī)的應(yīng)用....................................................20
4.5.1 AT89S51單片機(jī)性能特點(diǎn) ................................................20
4.5.2 AT89S51各引腳圖及各管腳功能...........................................21
4.6  系統(tǒng)保護(hù)電路的設(shè)計(jì).................................................... 23
4.6.1過(guò)流保護(hù).............................................................. 23
4.6.2 過(guò)壓、短路保護(hù) .......................................................24
5  系統(tǒng)軟件設(shè)計(jì) ............................................................25
5.1  匯編程序設(shè)計(jì)概述...................................................... 25
5.2  模塊式子程序設(shè)計(jì)...................................................... 26
5.2.1  ADC0809模數(shù)轉(zhuǎn)換子程序設(shè)計(jì) ...........................................26
5.2.2  DAC0832數(shù)模轉(zhuǎn)換子程序設(shè)計(jì)............................................27
5.3  電子負(fù)載程序設(shè)計(jì)流程圖 ................................................27
6.1 硬件系統(tǒng)的可靠性設(shè)計(jì) ...................................................30
6.1.1硬件系統(tǒng)的可靠性設(shè)計(jì)...................................................30
6.1.2 硬件系統(tǒng)可靠性設(shè)計(jì)所注意事項(xiàng) .........................................30
6.2 軟件系統(tǒng)的可靠性設(shè)計(jì) ...................................................31
6.2.1指令冗余.............................................................. 32
6.2.2攔截技術(shù).............................................................. 32
6.2.3軟件“看門狗”技術(shù).....................................................33
7  結(jié)論.....................................................................35
致謝 .......................................................................36
參考文獻(xiàn)................................................................... 37
附錄：電子負(fù)載設(shè)計(jì)程序..................................................... 38

摘要
本設(shè)計(jì)介紹了基于51系列單片機(jī)為控制單元，以模數(shù)轉(zhuǎn)換器ADC0809測(cè)量電壓電流參數(shù)，以數(shù)模轉(zhuǎn)換器DAC0832輸出控制電壓，通過(guò)運(yùn)算放大器對(duì)電流電壓信號(hào)的比較放大，直接控制大功率場(chǎng)效管的通過(guò)電流值，吸收電源提供的大電流,從而模擬復(fù)雜的負(fù)載形式、測(cè)試電能輸出裝置或轉(zhuǎn)換裝置的輸出性能。在對(duì)比傳統(tǒng)測(cè)試所用的靜態(tài)負(fù)載的基礎(chǔ)上, 提出新型電子負(fù)載的概念, 并作了原理和電路分析及電路調(diào)試, 同時(shí)進(jìn)行了功能完善及性能改善的探討。實(shí)驗(yàn)證明, 該裝置解決了傳統(tǒng)測(cè)試中用電阻、電阻箱、滑線變阻器等模擬不了復(fù)雜負(fù)載的問(wèn)題，能對(duì)測(cè)試電源進(jìn)行恒電阻負(fù)載測(cè)試，恒電壓負(fù)載測(cè)試和恒電流負(fù)載測(cè)試。
在對(duì)大功率直流電源的帶負(fù)載能力測(cè)試試驗(yàn)中，本設(shè)計(jì)更顯其自身的優(yōu)越性。若對(duì)場(chǎng)效管進(jìn)行擴(kuò)展，此設(shè)計(jì)測(cè)試的最大電流可達(dá)±75A，測(cè)試最大負(fù)載功率可達(dá)500瓦。完全滿足日常生活中大部分電源的帶負(fù)載能力測(cè)試工作。
關(guān)鍵詞：電子負(fù)載；單片機(jī)（MCU）；數(shù)模（D/A）；模數(shù)（A/D）。

Abstract
In this design, we introduce an equipment ,which is controlled by 51 series singlechip.By this equipment, voltage value and current value are measured using the chip of Analog to Digital Convertor ADC0809. The controlled-voltage value is formed by using the chip of Digital to Analog Convertor DAC0832. We call this equipment E-LOAD.By using this equipment, we can test the output
Level of some power supply systems. It can replace some kinds of rheostats in some areas.Different from the usual rheostats,this E-LOAD equipment can simulate most  kinds of the load.
 This article introduces a method to measure the voltage and currtnt of power system with a microprocessor.The equipment,using software, processes the data in real-time and all along the line.
It can also calculate and compensate the error of every algorithm,
And increase the precision in measurement.
 In our test,if this E-LOAD can be effectively  extended,
It can measure the current level highly at ±75A. It also can measure the power level highly at 500 Watts.

Key Words: E-LOAD, SingleChip(MCU), Analog to Digital Convertor,
           Digital to Analog Convertor.