基于PFM平均电流调节的脉冲MAG焊熔滴过渡控制

Droplet Transfer Control in Pulsed MAG Welding Using PFM-Based Average Current Modulation

为实现一脉一滴熔滴过渡这种最理想的脉冲熔化极活性气体保护(MAG)焊熔滴过渡形式,采用峰值阶段恒流和基值阶段恒流实现电源外特性,针对两阶段恒流外特性等速送丝条件下弧长的控制问题,基于高频逆变技术和DSP数字化控制技术,通过脉冲频率调制(PFM)调节方式实现平均电流的调节,从而调节焊丝熔化速度,解决一脉一滴熔滴过渡过程中弧长的控制问题.试验结果表明,所设计的PFM平均电流调节系统能实现良好的脉冲MAG焊一脉一滴熔滴过渡,焊接过程稳定,焊缝成型美观.

One droplet per pulse is the most ideal mode of droplet transfer for pulsed metal active gas （MAG） welding. In order to meet the requirements of this transfer mode, this paper adopts constant peak and base phases to implement the current external characteristics, and uses the pulse frequency modulation （PFM） combined with the high-frequency inverter and the DSP digital control to adjust the average current and to further control the melting velocity of the welding wire. Thus, the difficulty in the arc length control is overcome. Experimental results indicate that the PFM-based average current modulation implements the droplet transfer control of pulsed MAG welding with high stability and good welding quality.