Inverter arc welding power source, also known as arc welding inverter, is a new type of welding power supply. This power supply generally first rectifies and filters the threephase power frequency (50Hz) AC grid voltage into DC, then through the switching action of highpower switching electronic devices, inverts it into a mediumfrequency AC voltage of several kHz to several tens of kHz. At the same time, it is stepped down by a transformer to several tens of volts suitable for welding, then rectified again and filtered by a reactor to output a fairly smooth DC welding current.