弧焊发电机下降及平外特性控制

Dropping and constant voltage external characteristics control of arc welding generator

用于野外焊接施工的弧焊发电机,有时需要有下降特性和平特性的双重输出外特性。通过采样焊接电流和焊接电压的瞬时波形,直接通过运算电路得到控制IGBT导通的脉冲信号,用于调节同步发电机的励磁电流,对弧焊发电机的外特性进行快速的控制,可实现在电弧负载变化范围内对焊接电流的快速响应。通过改变焊接电压反馈和焊接电流反馈的深度,可使弧焊发电机获得下降特性和平特性两种输出。下降外特性输出具有下降带可调外拖的特点,在野外大口径管道焊接中可用于焊条电弧焊进行根焊;平特性输出用于等速送丝气体保护自动焊进行填充及盖面。

Arc welding generator used for field welding,sometimes is required to have both dropping and constant voltage external characteristics.By sampling welding current and welding voltage instantaneous waveform taken as feedback signal,an operational amplifier circuit produces pulse width signal to control IGBT which regulates excitation current of arc welding generator.This control method can improve responding speed of welding variables of arc welding generator to change of arc length.By regulating the feedback depth of welding voltage and welding current ,arc welding generator can obtain dropping and constant voltage external characteristics.In the field large diameter pipeline welding, dropping external characteristic can be used for root welding by shielded metal arc welding,and constant voltage external characteristic can be used for fill and cap welding by gas metal arc welding with constant wire-feed speed.