基于PFM平均电流调节的脉冲MAG焊熔滴过渡控制

一脉一滴熔滴过渡形式是脉冲MAG焊熔滴过渡的最理想过渡形式。根据脉冲MAG焊一脉一滴熔滴过渡的要求，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，通过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。

PFM Based Effective Current Modulation for Droplet Transfer Control in Pulsed MAG Welding

One droplet per pulse transfer in pulsed MAG welding is the most favorable transfer mode because of its high welding quality. In order to meet the request of one droplet per pulse transfer mode in pulsed MAG welding, the constant current external characteristic of peak phase and base phase is adopted, the melt of wire is decided by the effective current, the effective current modulation is realized by pulse frequency modulation (PFM) to overcome the disadvantages of arc length control of constant current external characteristic in constant speed feeding statement. The results of the experiment demonstrate that PFM based effective current modulation for droplet transfer control in pulsed MAG welding has the ability to accomplish the excellent one droplet per pulse transfer mode, the stabilities of pulsed MAG welding process is obtained and the welding line formation is pretty good.