【正文】 宜春學院物理科學與工程技術學院畢業(yè)設計 I 基于數控直流電流源系統(tǒng)的設計 宜春學院 物理科學與工程技術學院 電子信息科學與技術專業(yè) 李偉 指導老師：胡振平 摘要： 隨著電子技術的發(fā)展、數字電路應用領域的擴展，人們對數控恒定電流器件的需求越來越高。應社會發(fā)展的需求， 對基于單片機控制的“數控 直流電流源的設計 ”進行研究論證，并運用 Proteus軟件進行仿真。 以直流穩(wěn)壓電源和穩(wěn)流電源為核心，結合單片機最小系統(tǒng)實現對輸出電流的控制。首先采用了單片集成穩(wěn)壓芯片實現直流穩(wěn)壓，然后采用了分立元件實現穩(wěn)流。為實現對輸出電流的精確控制：一方面，通過Ｄ／ Ａ輸出實現電流的預置，再通過運算放大器控制晶體管的輸出電流；另一方面，運用Ａ／Ｄ轉換器件將輸出電流的采樣值送入單片機，與預置值進行比較，將誤差值通過Ｄ／Ａ轉換芯片添加到調整電路，從而進一步降低了輸出電流的紋波 。 Abstract： The requiements of numerical controlling constant current devices is increasing as development of electronic technology and expanding of digital circuit applicational field. As to satisfy society development, do a study based on Numerical control dc current source design of SCM controlling and apply Proteus to simulating （ digital current ） Voltage regulator and DC current regulator is the key part of the design， its output current is controlled by single chip microprocessor,Firstly,single chip IC（ integrated circuit） Voltage regulator LM338K is used to generate stable voltage, and then desperate devices is used to generate stabilize current . Tocontrol the output current ， on one hand ,system sets output current by D/A（ digital／ analogue converter and controls current of transistor by operational amplifier ； on the other hand ， with the help of A/D（ analogue／ digital） converter， system samples the output current and convert it into digital data ， pares it with preset value ， converts the error value into analogy and puts it on adjusting circuit ， and decreases the ripple of the system output current ． 宜春學院物理科學與工程技術學院畢業(yè)設計 II 目錄 1 引言 ..........................................................................................................................................1 數控直流電流源的發(fā)展現狀 ............................................................................................1 數控直流電流源的研究意義 ............................................................................................1 該研究解決的主要內容 ...................................................................................................1 2 設計任務及要求 .......................................................................................................................1 任務 ..................................................................................................................................1 設計思路 ..........................................................................................................................2 方案論證 ..........................................................................................................................2 總體方案設計 ...................................................................................................................2 3 硬件系統(tǒng)的設計 .......................................................................................................................3 硬件系統(tǒng)的模塊 .............................................................................................................3 單片機最小系統(tǒng) ....................................................................................................3 自制電源模塊 .......................................................................................................5 顯示模塊 ..............................................................................................................5 鍵盤模塊 ..............................................................................................................7 電流源模塊 ...........................................................................................................8 負載模塊 ..............................................................................................................8 D/A、 A/D 轉換模塊 ..............................................................................................8 系統(tǒng)的原理圖 .................................................................................................................9 4 軟件系統(tǒng)的設計 ..................................................................................................................... 10 單片機資源使用情況 .................................................................................................... 10 軟件系統(tǒng)的模塊 ........................................................................................................... 10 程序 流程圖 .................................................................................................................. 11 程序清單 ...................................................................................................................... 15 5 仿真測試及結果 ..................................................................................................................... 15 設計結論及使用方法 .................................................................................................... 15 仿真結果 ...................................................................................................................... 15 輸出電流范圍仿真 .............................................................................................. 15 步進調整仿真 ..................................................................................................... 17 輸出電流仿真 ..................................................................................................... 17 誤差分析 ...................................................................................................................... 18 6 總結 ........................................................................................................................................ 20 參考文獻 ..................................................................................................................................... 21 謝辭 ............................................................................................................................................ 22 附 錄 ..........................