【作者】 朱萍；

【导师】 陈克选；

【作者基本信息】 兰州理工大学 ， 材料加工工程， 2012， 硕士

【摘要】 MMA/TIG焊机是一种集手工电弧焊、直流TIG焊和脉冲TIG焊为一体的多功能焊机，该型号焊机已广泛地应用于汽车、机车车辆、化工、船舶等工业领域的焊接。本文是在综合国内外关于MMA/TIG弧焊电源的研究现状和发展趋势的基础上，针对实验室前期研制的基于80C196KB单片机控制MMA/TIG焊机出现的问题，从其主电路、控制电路、软件程序及抗干扰等方面进行可靠性研究，提出相应的解决办法并做出改进。实验表明改进后的MMA/TIG焊机具有控制电路简单、成本低廉、使用更可靠、控制精度更高等一系列优点。本文首先介绍了可靠性的概念，可靠性就是设备在产品在规定的条件下、在规定的时间内完成规定的功能的能力。MMA/TIG焊机要在批量化生产中应用，其各方面的性能必须达到一定的标准，涉及到工作效率、自动化、成本和可靠性等诸多因素，尤其是可靠性。根据该MMA/TIG焊机存在的一系列问题，通过其主电路结构及工作原理，从输入输出整流电路、中频变压器、开关功率元件IGBT三方面对主电路的可靠性进行了分析研究。然后从电源电路、脉宽调制电路、数据采集电路、数模转换电路以及IGBT驱动电路及保护电路方面对控制电路的可靠性进行了研究。为了IGBT能安全可靠的工作，分析了IGBT的结构及失效机制，针对工作过程中可能出现的过压、过流及过热等情况，提出了多种保护方法。结果表明主电路及控制电路其他各方面达到预期可靠性要求，数模转换电路改进为由MAX530数模转换芯片控制。其次进行了系统的软件程序结构及抗干扰措施方面的可靠性研究。根据MMA/TIG焊机在不同焊接方法下的时序要求，设计了控制系统软件，重点介绍了主程序和中断服务子程序，改进了参数预置与显示子程序，给出了程序流程图及部分程序。抗干扰方面，除了介绍了几种常用的硬件抗干扰措施外，还重点介绍了电流采样电路和高频引弧控制电路方面采取的抗干扰措施。软件程序设计中采取了如监视定时器、冗余指令、数字滤波等常用的抗干扰措施。最后，对焊机进行了脱机和联机调试以及试焊，并给出了相关的波形图。试验结果表明：改进后的MMA/TIG焊机能够更加可靠的满足脉冲TIG，直流TIG和手工电弧焊的要求。更多还原

【Abstract】 The MMA/TIG welding machine is a multi-purpose welding machine which includesthe manual arc welding, DC TIG welding and pulse TIG welding, It has been widely appliedin industrial field, automobile, rolling stock, chemical industry, ship welding and so on. Basedon the research and the development tendency of MMA/TIG welding power source,considering the problem of the MMA/TIG welding machine controlled by80C196KBMCU, we decided study its reliability on the main circuit, control circuit, software programs,anti-jamming. The experiment results showed that the improved MMA/TIG welding machinehas a series of merits such as small volume, simple control circuit, low cost, reliable use andhigher control precision.Firstly, we have introduced the concept of reliability in this thesis. The reliability ofequipment is the capacity to complete the required task under the specified function withinthe given time. For the mass production, all aspects performance of MMA/TIG weldingmachine must meet certain standards, including efficiency, automation, cost and reliability,especially reliability et al. Based on the main circuit structure and working principle, for theproblems in its application, we studied the reliability of main circuit from three aspects.Specifically, the three aspects was the enter and output rectifier, high-frequency transformerand the switching power IGBT respectively.Then the reliability of control circuit was researched on power circuit, parameters preset,display circuit, PWM circuit, data acquisition circuit, drive circuit and protect circuit. In orderto ensure IGBT work in safe, we analyzed the structure and failure mechanisms of IGBT onthe over-voltage, over-current and over temperature appearing in application, and weproposed several protection methods. The results showed that the main and control circuit canall meet the expected reliability. In addition, the data acquisition circuit was modified to becontrolled by MAX530.Secondly, we have analyzed the reliability of the software program structure andanti-jamming. According to the timing requirements of MMA/TIG welding machine, wedesigned the software for control system, highlighted the main program and the interruptservice program, improved parameters preset and display program, and showed the programflow chart and some of the key program. On anti-jamming, we have introduced not onlyseveral common hardware anti-jamming measures, but also the anti-jamming measures takenby the current sampling and the high frequency circuit. Besides, several softwareanti-interference measures, such as WDT, redundancy directive and digital filtering, were taken in designing the software program.Finally, we have done the offline and online debugging for this power source, andprovided the relevant oscillograph traces. The experiment results showed that the improvedMMA/TIG welding machine can be more reliable to meet the request of pulse TIG, directTIG and the manual welding. After the debugging, the specimens have been welded to testthis power source, which proved that this power source is suitable.更多还原