超声能—电阻热复合焊电源控制系统研究

发布时间：2019-01-19 19:00

【摘要】：随着有色金属在现代工业生产中的需求越来越大,有色金属微型零件焊接困难的问题越来越受到重视。超声能-电阻热复合焊是结合超声波金属焊和电阻点焊特点,针对有色金属微型零件提出的一种焊接方法,通过超声能和电阻热两种能量的复合作用,来提高焊接接头的性能。由于此方法尚处于研究初期,缺乏复合焊专用电源,因此设计超声能-电阻热复合焊电源控制系统,实现超声激励信号和电阻焊电流的协调输出,提高复合能量输出的可控性,以满足不同的工艺实验及研究需求。本文首先确定电源的整体方案,搭建超声及电阻焊功率主电路,并确定控制策略;根据复合焊电源控制需要,设计以DSP为核心的控制系统,主要包括信号反馈电路、DDS电路、移相脉冲调制电路、CPLD电路、开关量控制电路等,并根据要求设计制作了控制电路PCB板;完成控制软件的设计与调试,包括超声频率跟踪程序、A/D采样程序、输入捕捉程序、PI控制程序等。组装复合焊电源并搭建复合焊接试验平台,对复合焊电源进行调试,通过超声电压反馈及频率跟踪实现了超声振幅恒定输出且连续可调,通过电流反馈控制实现了电阻焊恒流输出;可灵活设置三段超声电压及电阻焊电流,实现多种复合能量波形输出,可满足不同的工艺需求。利用复合焊电源对铜铝焊件进行工艺试验,结果表明在超声能及电阻热共同作用下,复合焊界面出现扩散层,进一步的拉伸试验结果表明,复合焊接头的拉伸性能及延展性比单一超声作用下的有所提高。
[Abstract]:With the increasing demand of nonferrous metals in modern industrial production, more and more attention has been paid to the difficulty of welding non-ferrous metals micro parts. Combined with the characteristics of ultrasonic metal welding and resistance spot welding, ultrasonic energy-resistance thermal composite welding is a welding method for non-ferrous metal micro-parts. The performance of welded joints can be improved by the combination of ultrasonic energy and resistance heat. Because this method is still in the early stage of research and lacks of special power supply for composite welding, the control system of ultrasonic energy-resistance heat welding power source is designed to realize the coordinated output of ultrasonic excitation signal and resistance welding current, so as to improve the controllability of composite energy output. To meet the needs of different process experiments and research. In this paper, the overall scheme of the power supply is first determined, the main circuit of ultrasonic and resistance welding power is built, and the control strategy is determined. According to the control needs of composite welding power supply, a control system based on DSP is designed, which includes signal feedback circuit, DDS circuit, phase-shift pulse modulation circuit, CPLD circuit, switch control circuit, etc. The PCB board of the control circuit is designed and manufactured according to the requirement. Complete the design and debugging of control software, including ultrasonic frequency tracking program, A / D sampling program, input capture program, PI control program and so on. The composite welding power source was assembled and the test platform was set up to debug the composite welding power source. The ultrasonic amplitude was constant output and continuously adjustable by ultrasonic voltage feedback and frequency tracking. The constant current output of resistance welding is realized by current feedback control. The three-stage ultrasonic voltage and resistance welding current can be flexibly set to realize the output of multiple composite energy waveforms, which can meet different process requirements. The process test of the brazed parts is carried out by using the composite welding power source. The results show that the diffusion layer appears at the interface of the composite welding under the combined action of ultrasonic energy and resistance heat, and the further tensile test results show that, The tensile properties and ductility of the composite welded joints are higher than that of the single ultrasonic joint.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG409

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