基于周期平均值外特性的脉冲MIG焊弧长稳定性研究

通过对脉冲熔化极惰性气体保护(Metal inert gas,MIG)焊脉冲平均电流电压变化率的计算,提出脉冲周期平均值外特性曲线,并对弧焊电源脉冲周期平均值外特性曲线和电弧静态性曲线的动态稳定工作点进行详细分析,得出利用脉冲平均值外特性控制脉冲MIG焊的控制策略。同时运用双闭环控制实现了基于弧压反馈的I/I模式控制数字化弧焊电源,此电源能在送丝速度稳定情况下自适应弧长扰动变化,实现脉冲弧焊过程一脉一滴熔滴过渡。通过弧长阶跃试验表明,脉冲弧焊过程中焊丝熔化速度快速跟踪弧长变化,具有良好的弧长动态调节性能,保持弧长动态稳定,即焊接过程稳定,焊缝成形良好,同时验证了分析过程正确性和设计过程的可行性。

Study on Arc Length Stability of Pulsed MIG Welding Based on Average Output Characteristics of Pulse Cycle

Average output characteristics curve is proposed by calculate rate of changes of average arc current and average arc voltage for pulsed metal inert gas(MIG) welding in a period of pulse.In addition,arc operating points of dynamic stability are analyzed for intersection of average output characteristics curve of a pulse cycle for arc welding power and arc static characteristics curve.A control strategy is obtained for pulsed MIG welding using average output characteristics in a pulse cycle.At the same time,digital arc welding power source of I/I mode control based on arc voltage feedback is realized by using double-loop control.Arc welding power adapts to change of arc length perturbation in the case of wire-feed speed stability.Droplet transfer of one-drop per pulse has achieved in pulsed arc welding process.Finally,through arc length step test shows that wire melting rate tracked arc length change immediately,there is a good dynamic performance adjustment and maintain dynamic stability for arc length.This is concluded that pulsed welding process is stable,weld appearance is beautiful.It is verified that the analysis process is correct and the design process is feasibly by experiment.