摘要
通过对变极性TIG焊电弧负载特性试验研究,发现EN(钨极接负)时电弧的等效电阻小于EP(钨极接正)时电弧的等效电阻,而且随着电流的增大电弧等效电阻都减小,当从EP切换到EN时刻电弧等效电阻急剧减小。对电弧等效电阻的形成机理进行了分析,指出电弧等效电阻与阴极区、弧柱区、阳极区在不同电流条件下的工作机理有关,着重分析了阴极区电子发射和阳离子发射的机理。针对从EP切换到EN时刻电弧等效电阻急剧减小引起的电流冲击问题,提出一种变参数PI控制结合超前控制降低切换极性时的电弧冲击电流的控制策略。结果表明,控制策略既保证了焊接电弧的稳定,又显著降低了切换极性过程中电流冲击的峰值。
Welding arc load characteristics of variable polarity TIG welding was studied through experiment.The experimental results indicate that equivalent resistance of welding arc in EN is less than it in EP,both of them decrease as increasing of welding current,the equivalent resistance will drop rapidly at the time when EP commutate to EN.The mechanism of equivalent resistance analyzed is concerned with the working mechanism of negative,arc column and anodic at different load current.A control strategy incorporate variable parameter PI into advance control is presented to solve the problem of vary equivalent resistance at the time EP commutate to EN.Experimental results prove this control strategy is available.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2008年第9期31-34,共4页
Transactions of The China Welding Institution
基金
河海大学常州校区创新科技基金资助项目(CC2007-01)
关键词
变极性
等效电阻
电子发射
超前控制
variable polarity
equivalent resistance
thermionic emission
advance control
