基于PFM调节的脉冲MIG焊电弧调节机理分析

Analysis of arc adjustment mechanism to pulsed MIG welding based on PFM adjustment

针对脉冲MIG焊电源弧长控制方面存在的问题,展开对脉冲MIG焊电弧自我调节机理以及在脉频调制(PFM)控制下的电弧调节机理的研究.建立了电弧弧长数学模型,分析了PFM双闭环电弧调节系统的工作原理,给出了PFM电流调节数学模型,并分析了非阻性焊丝和阻性焊丝PFM电弧控制机理及在电弧控制中存在的问题.从理论上推导出对于非阻性焊丝PFM电流调节可以获得更稳定的焊接效果,而对阻性焊丝CTWD固定时可获得稳定的焊接效果,在CTWD变化时无法获得满意的焊接效果.最后分别对阻性焊丝和非阻性焊丝进行PFM电弧调节阶跃试验,通过对试验结果分析,验证了上述理论推导.

Aimed at the problems of arc length control in pulsed MIG welding power supply,the research of arc self-regulating mechanism and arc adjusting mechanism under the control of the pulse frequency modulation(PFM) was developed.The mathematical model of arc length was established.The principle of PFM arc adjustment system was introduced and the PFM current regulation model was given.The PFM arc control mechanism and the problems existing in the arc control were analyzed for non-resistance wire and resistance wire.A more stable welding effect can be obtained for PFM current regulation of non-resistance wire from theoretical derivation.For the resistance wire,the stable welding effect can be obtained when CTWD is fixed and satisfactory welding results cannot be obtained while CTWD changing.Finally the step tests of PFM arc adjustment were carried out by using non-resistance wire and resistance wire,respectively.The theory above is verified by test results.