Varible polarity process of inverter AC arc welding power source
Liao Pin · Electric Welding Machine · 2003
The varible polarity output process of the inverter AC arc welding power source we designed is a very quickly alternating dynamic one.The signals of current and voltage are obtained respectively by transfering them with ammeter shunt and non-inductor resistance.Three experiments are designed in which the waveforms of current and voltage in the alternate polarity output process are measured.Based on the experiments,the conclusion is drawn that it is reasonable to set a2μs dead time between driving signals of inverter AC arc welding during positive and negative polarity period.According to the above scheme ,the time of the polarity alternation is almost zero and the value of voltage after it is the largest,which is very helpful to the reignition of AC PMIG arc after polarity alternation.