交流脉冲MIG弧焊电源及弧长控制

AC PMIG的控制模式是一周一脉一滴，脉冲电流设计在电弧EP极性时间里，其余时间均为基值电流。弧焊电源一次逆变控制电流快速动态过程，二次逆变控制电弧极性。控制系统采用双闭环结构，内环模拟控制电弧电流，外环80C196KC单片机控制电弧电压及电弧极性。根据电弧电压偏差信号及电弧状态，设计了四个控制规则及其控制参数的计算方法。正常焊接状态时变频控制交流脉冲频率。采用这种控制方案，获得了稳定性高、熔滴过渡均匀的焊接过程。

AC PMIG arc welding power source and arc length control

The control mode of AC PMIG welding is a pulse with a droplet in a cycle.Pulse current is designed in arc EP time,while the other time is basic current in a cycle.Dynamic process of current is controlled quickly by the first inverter,and arc polarity is controlled by the second inverter of arc welding power source.Double closed loop is used in control system.Arc current is controlled by inner loop,and arc voltage and arc polarity is controlled by outer loop through 80C196KC single chip microcomputer.According to the signals of arc voltage errors and arc state,four control regulations and counting measure of control parameters are designed.Varying frequency is used to control AC pulse frequency in normal welding state.It has been proved that the welding process has high stability and even droplet transfer with the proposed control scheme.