The inverter welding machine is mainly generated by the inverter arc welding power source, also known as arc welding inverter. The working frequency (50Hz) alternating current is first rectified and filtered into direct current through a rectifier, and then inverted into medium frequency alternating current of several kHz to several tens of kHz through high power switching electronic components (thyristor SCR, transistor GTR, field effect tube MOSFET or IGBT), while lowered to several tens of V suitable for welding through a transformer, rectified again and filtered by reactance to output a fairly smooth. The output of the DC welding current is quite smooth.
The conversion sequence can be simply expressed as follows: industrial frequency AC (filtered by rectification) → DC (through the inverter) → medium frequency AC (step-down, rectification, filtering) → DC. That is: AC → DC → AC → DC.
Inverter step-down AC, due to its high frequency, then the inductive resistance is large, the active power in the welding circuit will be greatly reduced. Therefore, it needs to be rectified again. This is the mechanism of the inverter welder commonly used today.
Characteristics of inverter power supply: The basic feature of the arc welding inverter is the high operating frequency, which brings many advantages.
Because the potential E of the transformer, whether the primary or secondary winding, has the following relationship with the frequency f of the current, the flux density B, the cross-sectional area S of the core and the number of turns W of the winding: E=4.44fBSW
The terminal voltage U of the winding is approximately equal to E, i.e.: U≈E=4.44fBSW
When U and B are determined, if f is increased, S decreases and W decreases, therefore, the weight and volume of the transformer can be greatly reduced.
The weight and volume of the whole machine can be reduced significantly.
There are also many advantages brought about by the increase in frequency and other factors, compared with the traditional arc welding power source, its main features are:
1. Small size, light weight, material saving, easy to carry and move.
2. High efficiency and energy saving, the efficiency can reach 80%~90%, more than 1/3 power saving than traditional welding machine.
3. Good dynamic characteristics, easy arc initiation, stable arc, beautiful weld seam formation and small spatter.
4. Suitable for combining with robot to form automatic welding production system.
5. One machine can be used for multiple purposes and complete multiple welding and cutting processes.
