數控高精度直流電源

測控論文編號:CK095   論文字數:24333,頁數:52

目 錄
摘要………………………………………………………………………………………….. II
Abstract……………………………………………………………………………………..Ⅲ
目錄……………………………………………………………………………………….. ……Ⅳ
1緒論…………………………………………………………………………………1
1.1恒流源的應用…………………………………………………………………………1
 1.2恒流源的發展…………………………………………………………………………3
     1.3國內外現狀……………………………………………………………………………4
1.4論文的研究內容………………………………………………………………………4
   2數控恒流源的設計理論和總體方案…………………………………………6
2.1  系統總體方案…………………………………………………………………….…6
2.2  系統性能指標…………………………………………………………………….…6
2.3  恒流源基本設計原理與實現方法…………………………………………….……7
     3統硬件設計……………………………………………………………….……9
 3.1  單片機功能介紹……………………………………………………………………9
 3.2  電源模塊設計………………………………………………………………..……15
 3.3  A/D模塊設計………………………………………………………………..……15
  3.4  D/A模塊設計…………………………………………………………..…………20
      3.5  鍵盤接口電路設計………………………………………………….……….……22
      3.6  顯示接口電路設計…………………………………………………….….………24
      3.7  計算機接口電路設計………………………………………………….…….……27
 3.8  原理圖………………………………………………………………….….………28
 3.9  印制板的制作………………………………………………………….…….……29
 3.10 電路板………………………………………………………………..……………32
4系統的軟件設計…………………………………………………………...……33
 4.1  控制算法………………………………………………………………..…………33
 4.2  軟件流程………………………………………………………………..…………35
             4.3  上位機程序……………………………………………………………38
5統功能調試、測試與分析………………………………...……………….39
 5.1  測試儀器  39
 5.2  測試數據及結果分析  39
6總結……………………………………………………………………….……...42
參考文獻……………………………………………………………………..…………….43
致謝………………………………………………………………………….……………...45
附錄1 PCB圖…………………………………………………….……………………….46
附錄2 總電路圖…………………………………………………………………………47

摘  要
 目前電源技術已逐步發展成為一門多學科互相滲透的綜合性技術學科，它對現代通訊、電子儀器、計算機、工業自動化、電力工程、國防及某些高新技術提供高質量、高效率、高可靠性的電源起著關鍵作用。
 本文設計了一種基于單片機控制的高精度數控直流恒流源。該恒流源以AT89C52 為控制核心，采用了高共模抑制比低溫漂的運算放大器OP07 和達林頓管TIP137 構成恒流源的主體，配以高精度采樣電阻及12 位D/A 芯片AD5320、16 位A/D 芯片AD7715，完成了單片機對輸出電流的實時檢測和實時控制。人機接口采用4×4 鍵盤及LED 數碼管顯示器，控制界面直觀、簡潔，具有良好的人機交互性能。還具有串口通訊能力，實現了遠程控制功能。
 本文在軟件設計上采用增量式PID 控制算法，即數字控制器的輸出只是控制量的增量。增量式控制雖然只是算法上作了一點改進，卻帶來了如下的優點：一是算式中不需要累加，控制增量的確定僅與最近三次的采樣值有關，容易通過加權處理獲得比較好的控制效果；其次是計算機每次只輸出控制增量，即對應執行機構位置的變化量，故機器發生故障時影響范圍小、不會嚴重影響生產過程。
 文章最后對該恒流源的主要性能參數進行了測定，測試結果表明：該系統已基本達到預期的設計目標，具有精度高、性能可靠、體積小、電路簡單的特點，可以應用于需要高穩定度的小功率恒流源領域。

關鍵詞：單片機；數控；恒流源；ID算法

Abstract
 At present, the technique of power supply is becoming a comprehensive technique imbued with multiplex techniques and playing a crucial role in providing the power supply with highq- uality and high efficiency to the following fields:telecommunication, technical instruments, co - mputer, industrial automatic control, electric power engineering, national defence as well as some high-technology industry.
 In the paper we designed a DC constant-current power controlled based on SCM. The system adopt AT89C52 as hard core and the main circuit of constant-current source consist of darlington device TIP137 and operational amplifier OP07 which has high CMRR(Common Mode Rejection Ratio) and low temperature shift. Moreover, we adopt 12 bit D/A chip AD5320 and 16 bit A/D chip AD7715 to realize a real-time test and control to the current output controlled based on SCM. The display interface with 4× 4 keyboard technique and LED enables operator to read the screen more intuitively.Next,the equipment can be long-distance controled by the RS232.
 This paper adopt incremental PID control algorithm in software design，namely the output
of digital controller is just the increment of controlled variable. Incremental control is a little im- provement at algorithm. However, it has some advantage as follows: first, accumulating is not
needed in equation, the decision of increment is just involved in last three sampling values and it
can obtain good controlled effect with weighted processing. Next, the computer output only co- ntrolled increment every time, namely the variable value of position corresponding operator. So the range of influence is small and it will not affect the production process when the machine get out of order.
 In the end, the paper measured the primary parameter of the constant-current source. And it
confirmed that the system has reached the anticipated objective. This system armed comprehend- sive functionalities in the following aspects: power suit, high credibility, simple circuit design. It can be used flexibly in the domain which in a demand of high-stable constant-current source with small power.
 
Keywords：MCU；igital-control；onstant-current source,；ID control arithmetic