電焊技術的開始，擴張了人類對金屬的需求，同時也加快了工業發展的速度。終端用戶涉及各金屬加工業、船廠、油田、工廠、建築營造、航太科技、傳統電鍍等金屬溶接加工相關行業。目前電焊機功能上，除了對於焊接精度、高輸出功率、高可靠度需求日益增加外，針對不同應用場合之特殊輸出功能需求也大幅上揚，因此如何因應多元的客製化、輕量化與高可調精確度等顧客需求，是現今產品開發上需要考量之處。
　　國內市面上的電焊機，大部分採用類比電路進行電力控制，使得儀器體積及重量相當龐大，且在電力輸出亦具有精確度較低的劣勢，反觀歐美大廠已開始進行全數位化的研發，實現於部分產品。全數位化之優勢除了體積與重量的優化，在運算能力、功能擴充性及輸出精確度都有大幅的提升；為達成此數位化之目標，需將類比控制電路完整移植至數位系統，輸出正確的訊號準位並克服延遲的問題。
　　本研究透過FPGA開發板整合電焊機的三大主要功能，inverter控制、二氧化碳送氣及送線機馬達控制，根據焊接條件的不同（焊材、線徑、外觀需求）來調整電壓電流輸出、送線速率及送氣模式，並套用不同的控制理論，以應付更嚴苛的焊接條件。在實驗結果中，控制訊號能夠正確且安全地驅動inverter電路。

Welding technology boost the develop speed of industry. Customers involve various metal processing industry, shipyards, oil fields, factories, building construction, aerospace technology, traditional electroplating and metal welding related industries. Currently on the welding machine functions, in addition to the requirement of welding precision, high output power and high reliability increasing, the output function for the special needs of different applications also rose sharply. How to deal with multiple customized, lightweight, highly adjustable accuracy and other customer needs, is now the focus of product development.
With respect to the analog, the biggest advantage of digital systems is high precision. In analog system, through operational amplifier circuit because of the slight error cause by environment, using the digital system will be able to solve this issue.
In this thesis, the FPGA develop board can control the main functions of welding machine: inverter, gas and wire feeding safely.

Abstract in Chinese ...............I
Abstract in English ...............II
Contents ..........................III
List of Figures ...................V
1 Introduction ....................1
1.1 Background ....................1
1.2 Literature Review .............6
1.3 Problem Statement .............7
2 Traditional welding machine .....8
2.1 Functions .....................8
2.2 Analog control circuit ........9
3 Digital welding machine .........11
3.1 H-bridge control ..............12
3.2 Solution for active Functions .14
3.2.1 Inert gas ...................14
3.2.2 Wire feeding ................14
4 Experiment result ...............16
4.1 Experiment Equipment...........16
4.2 Program map ...................19
4.3 Signal adaptation .............20
4.4 Experiment result .............22
5 Conclusion ......................24
References ........................25
List of Figures
1.1 shielded metal arc welding ..........2
1.2 Gas metal arc welding ...............3
1.3 Flux-cored arc welding ..............4
1.4 Submerged arc welding ...............5
2.1 H-bridge circuit ....................9
2.2 BEM-350 full circuit ................10
3.1 Digital system on welding machine ...11
3.2 H-bridge positive through ...........12
3.3 H-bridge Negative through ...........12
3.4 SPWM principle ......................13
3.5 SPWM principle ......................14
4.1 DE1-SoC FPGA board ..................16
4.2 IGBT driver board ...................17
4.3 Power supply ........................17
4.4 Hero Power BEM-350 welding machine ..18
4.5 Hero Power BEM-350 welding machine ..18
4.6 Program structure ...................19
4.7 RTL on FPGA .........................20
4.8 PWM signal before driver ............21
4.9 PWM signal after driver .............21
4.10 (a)PWM signal from driver (b)PWM signal on IGBT at error = 3 V ......22
4.11 (a)PWM signal from driver (b)PWM signal on IGBT at error = 7 V ......23
4.12 (a)PWM signal from driver (b)PWM signal on IGBT at error = 14 V .....23

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