Propose efficient design of a controlled power source to supply gas metal arc welding machine

Abstract EN

The conventional electronically controlled power source for steady and pulsed direct current is converters and they contain thyristors or transistors.

For direct pulsed welding arc machine, a single-phase half wave rectifier is connected in parallel with a three-phase bridge converter to produce the desired pulsed direct current with different pulse repetition frequencies, but these power sources produce harmonics in the A.C mains, and, in the case of pulsed direct current welding, there is asymmetrical reaction in the A.C main source caused by the single half-wave rectifier.

In addition, the power source for pulsed direct current welding arc is complex in operation and maintain, large in size, less efficient and relatively expensive.

This study presents an efficient power source for steady and pulsed direct current arc welding machine using only a single fully controlled bridge converter with two suitable triggering circuits one for bridge fully controlled converter with power thyristors and other for TRIAC switching devices for two tuned resonant line passive filters F1 and F2.

A single fully controlled three-phase bridge converter was chosen in the power source as it contributes to reduce the reactive power loss with triggering angles less than or equal (60) electrical degree.

The distortions and harmonics for non-sinusoidal current produced by the A.C power system a result of the power supply and reactive power reduced with the help of two resonant line passive filters (F1 & F2).

The results and graphics are verified, plotted and presented using facilities of MATLAB version - 7-.