超音频复合脉冲GMAW电源设计

Design of hybrid ultrasonic frequency pulsed GMAW power source

提出了一种全新的脉冲熔化极气体保护焊(GMAW)方法,并研制出新型超音频复合脉冲GMAW电源,即在传统脉冲GMAW电流基础上复合叠加频率为20~80 k Hz、电流幅值为0~100 A、占空比为0%~100%的连续可调的超音频脉冲电流。设计了并联结构的主电路拓扑及MCU+DSP双处理器数字化控制系统,通过软件编程实现了电流给定信号与PWM信号的同步输出及不同逻辑组合,可实现不同工作模式的焊接电流波形输出。对电源输出电流波形的测试结果表明:本文所设计的超音频复合脉冲GMAW电源输出电流波形满足不同工作模式的设计目标,超音频脉冲电流频率在80 k Hz时,仍保持较快的电流上升沿与下降沿变化速率。初步进行了铝合金平板堆焊试验,焊缝成形良好。

A new type of gas metal arc welding （GMAW） method was proposed and a novel hybrid ultra- sonic frequency pulsed GMAW power source was developed. In this method, an ultrasonic frequency pulse current was superposed upon the conventional pulsed GMAW current with frequency from 20 to 80 kHz, cur- rent amplitude from 0 to 100 A, and duty cycle from 0% to 100%. Main circuit topology in parallel structure and dual-processor digital control system consisting of MCU and DSP were designed. Synchronized output and different logical combinations of current given signal and PWM signal were realized through software program- ming, resulting in several output current waveforms for different work modes. Testing results of the output current indicate that output current waveforms of the designed hybrid ultrasonic frequency pulsed GMAW pow- er source satisfy the requirement of different work modes with a fast current rising and falling rate even at ultra- sonic frequency pulse current frequency of 80 kHz. Aluminium alloy bead-on-plate experiment was conducted with this power source and a good weld bead appearance was obtained.