數(shù)控恒流源的設(shè)計(jì)畢業(yè)設(shè)計(jì)說明書(已修改)
2024-10-24 13:45 本頁面
【正文】 畢業(yè)設(shè)計(jì)（論文）任務(wù)書 題 目 ： 數(shù)控恒流源的設(shè)計(jì) 任務(wù)與要求 ： （ 1） 通過鍵盤來設(shè)置直流電源的輸出電流，設(shè)置步進(jìn)等級(jí)可達(dá)1mA，并可由數(shù)碼管顯示實(shí)際輸出的電流值和電流設(shè)定值。 （ 2） 系統(tǒng)輸出電流穩(wěn)定，并具有很高的精度，輸出電流誤 差范圍177。 5mA，輸出電流可在 20mA2020mA 范圍內(nèi)任意設(shè)定。 時(shí) 間 ： 所屬系部 ： 電子工程系 學(xué)生姓名 ： 學(xué) 號(hào) ： 專 業(yè) ： 電子信息工程技術(shù) 指導(dǎo)單位或教研室 ： 指導(dǎo)教師 ： 職 稱 ： 摘要 本文主要闡述了：以直流電流源為核心， AT89S52 單片機(jī)為主控制器，通過鍵盤來設(shè)置直流電源的輸出電流，設(shè)置步進(jìn)等級(jí)可達(dá) 1mA，并可由數(shù)碼管顯示實(shí)際輸出電流值和電流設(shè)定值。本系統(tǒng)由單片機(jī)程控輸出數(shù)字信號(hào)，經(jīng)過 D/A 轉(zhuǎn)換器（ AD7543）輸出模擬量，再經(jīng)過運(yùn)算放大器隔離放大，控制輸出功率管的基極，隨著功率管基極電壓的變化而輸出不同的電流。單片機(jī)系統(tǒng)還兼顧對(duì)恒流源進(jìn)行實(shí)時(shí)監(jiān)控，輸出電流經(jīng)過電流 /電壓轉(zhuǎn)變后，通過 A/D 轉(zhuǎn)換芯片，實(shí)時(shí)把模擬量轉(zhuǎn)化為數(shù)據(jù)量，再經(jīng)單片機(jī)分析處理， 通過數(shù)據(jù)形式的反饋環(huán) 節(jié)，使電流更加穩(wěn)定，這樣構(gòu)成穩(wěn)定的壓控電流源。實(shí)際測(cè)試結(jié)果表明，本系統(tǒng)輸出電流穩(wěn)定，不隨負(fù)載和環(huán)境溫度變化，并具有很高的精度，輸出電流誤差范圍177。 5mA，輸出電流可在 20mA~2020mA 范圍內(nèi)任意設(shè)定，因而可實(shí)際應(yīng)用于需要高穩(wěn)定度小功率恒流源的領(lǐng)域。 關(guān)鍵詞 ：壓控恒流源；智能化電源；閉環(huán)控制 The Digital Controlled Direct Current Source Abstract: For the system that DC source is center and 89S52 version single chip microputer (SCM) is main controller, output current of DC power can be set by a keyboard which step level of 1mA can be available, while the real output current and set value can be displayed by LED. In the system, the digital programmable signal from SCM is converted to analog value by DAC (AD7543), then the analog value that is isolated and amplified by operational amplifiers, is sent to the base electrode of power transistor, so an adjustable output current can be available with the base electrode voltage of power transistor. On the other hand, The constant current source can be monitored by the SCM system realtimely, its work process is that output current is converted voltage, then its analog value is converted to digital value by ADC, finally the digital value as a feedback loop is processed by SCM so that output current is more stable, so a stable voltagecontrolled constant current power is designed. The test results have showed that the system can output a stable current, which has no influence with load and environment temperature, and can output a precise current of 177。 5mA error with a width, which can be set liberally in 20mA~2020mA, so it can be applied in need areas of constant current source with high stability and low power. Key Words: voltagecontrolled constant current source 。 intelligent power 。 closed loop control數(shù)控恒流源的設(shè)計(jì) 目錄 1 總體方案論證 .........................................................................2 恒流源簡(jiǎn)介 .....................................................................2 系統(tǒng)框架 .......................................................................2 2 系統(tǒng)原理及理論分析 ...................................................................3 單片機(jī)最小系統(tǒng)組成 .............................................................3 系統(tǒng)性能 ..........
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