畢業(yè)設計-基于單片機的PWM信號輸出系統(tǒng)

包括電路圖，源程序


摘要
　　　隨著電力電子技術(shù)的飛速發(fā)展，PWM技術(shù)應用越來越廣泛。同時PWM技術(shù)本身也發(fā)展迅速，各種新理論層出不窮。PWM技術(shù)結(jié)合了電力電子技術(shù)、計算機技術(shù)、現(xiàn)代控制理論，具有抗干擾性強、效率高、可靠性好等顯著優(yōu)點，已經(jīng)在交流逆變、開關(guān)電源等領(lǐng)域得到廣泛應用。
  本文在研究PWM技術(shù)當前發(fā)展狀況基礎上，設計了一種基于單片機的PWM信號輸出系統(tǒng)。首先對系統(tǒng)結(jié)構(gòu)和PWM軟件算法進行了研究和分析，包括對各種PWM產(chǎn)生方法的對比分析和對稱規(guī)則采樣法的仔細研究以及系統(tǒng)的功能分區(qū)和總體結(jié)構(gòu)。在總體設計完成后又設計了硬件電路各個單元模塊。然后采用C語言編程實現(xiàn)了系統(tǒng)功能，完成設計目標。最后對設計的系統(tǒng)進行了計算機仿真。
　　　本設計是基于單片機控制的PWM信號輸出系統(tǒng)，系統(tǒng)以AT89C52單片機為核心，采用SPWM軟件生成法中對稱規(guī)則采樣法，用擴展按鍵中斷方式輸入有關(guān)控制信號及參數(shù)，可以實現(xiàn)頻率、占空比、輸出時間可調(diào)的直流斬波PWM信號和頻率、調(diào)幅比、輸出時間可調(diào)的SPWM信號，并在LCD1602上實時設置參數(shù)及輸出狀態(tài)監(jiān)視。
　　　
關(guān)鍵詞：單片機；PWM； SPWM；信號；規(guī)則采樣法
　　　ABSTARCT
　　　As the developing of power electronic technology, PWM technology has applying to more and more field. At the same time, PWM technology itself has taken a great progress, lots of new theory has emerged. PWM technology takes advantages of power electronic, computer technology, and modern control theory, has strong ability of anti-interference, and is more efficiency, reliable. It has applied to vast field ,such as AC converter, DC chopper.
　　　This paper firstly, analysis the situation of PWM technology’ development, then, designed a PWM signal output system based on SCM. At the beginning, we study the soft algorithm of PWM, including comparison and analysis of several PWM   algorithm and deep analysis of regular-sampling. We also designed the system structure. Following , hardware and software is designed. Every hardware module is designed with the computer, and the software is written in C language. At last, we take a simulation.
　　　The system is based on AT89C52. It use buttons to input parameters. It can output single polar PWM signals. The signal’s frequency, duty-cycle, output time can be changed. What’s more, all information is showed in a LCD1602, so that it is easier to communicated with the system.

Index terms: SCM; PWM; SPWM; signal; regular-sampling
目    錄

1 緒論 1
1.1 PWM的背景、應用及發(fā)展趨勢 1
1.2 PWM原理 1
1.3 本文的主要工作 2
2 系統(tǒng)方案設計 3
2.1系統(tǒng)PWM算法 3
2.1.1等面積法 3
2.1.2硬件調(diào)制法 3
2.1.3軟件生成法 3
2.2 系統(tǒng)結(jié)構(gòu) 5
2.3涉及元器件簡介 5
2.3.1 AT89C52介紹 5
2.3.2 LCD1602簡介 8
2.4  仿真工具介紹 9
2.4.1 Protues簡介 9
2.4.2 Keil uVision2簡介 11
3硬件電路設計 13
3.1電源 13
3.2單片機復位電路 14
3.3單片機時鐘電路 14
3.4按鍵中斷 15
3.5顯示電路 16
3.6輸出電路 17
3.7 SPWM測試電路 17
4 軟件設計 19
4.1軟件總流程 19
4.2 直流斬波PWM軟件計算法 19
4.3 SPWM軟件計算法 20
4.4輸出時間控制 22
4.5按鍵中斷 23
4.6 LCD1602編程 26
4.7顯示設計 27
5 系統(tǒng)調(diào)試 31
5.1系統(tǒng)的調(diào)試 31
5.2系統(tǒng)仿真過程 31
6 結(jié)論 36
參考文獻 37
附錄 38
翻譯部分 50
外文原文： 50