Tig welding machine

BY ROSARIO CASANUEVA, FRANCISCO J. AZCONDO, F R A N C I S C O J . D´A Z , & I ˜ CHRISTIAN BRANAS

PHOTO COURTESY OF U.S. NAVY

A

MULTIPLE TWO-PHASE resonant converter module connected in parallel is the chosen architecture for a

tungsten inert gas (TIG) welding power supply. Connection to the utility is performed through a frontend power factor correction stage. Fine tuning is performed by overlapping the control signals of the resonant converter phases. Output ripple is reduced by interleaving each module, and the arc strike is achieved with no extra circuitry and at low voltage. DC and multiple pulsating operations from 20 Hz to 5 kHz with different pulse widths have been tested. The resulting arc stability, welding parameters, and efficiency are analyzed in this article. The experimental results show the welding performance and near unity power factor.
IEEE INDUSTRY APPLICATIONS MAGAZINE  SEPT j OCT 2011  WWW.IEEE.ORG/IAS

A design for multiple two-phase resonant converter modules
Digital Object Identifier 10.1109/MIAS.2010.939654 Date of publication: 5 July 2011

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1077-2618/11/$26.00©2011 IEEE

IEEE INDUSTRY APPLICATIONS MAGAZINE  SEPT j OCT 2011  WWW.IEEE.ORG/IAS

TIG or GTAW Welding TIG or gas-tungsten-arc welding (GTAW) is a widely used high-quality, high-precision welding process. In TIG welding (Figure 1), an arc is established between a nonconsumable tungsten electrode and the metal that is heated and melted. Filler wire may be added for the weld. The inert gas: 1) shields the welding area from the air, preventing oxidation, 2) transfers heat from the electrode to metal, and 3) helps to start and maintain a stable arc (due to the low ionization potential). This process can be used for many types of materials in all welding positions, and it provides a concentrated, stable arc and a high-quality and neat weld deposit. Before the arc is initiated, the electrode is too cold to emit electrons to establish the arc. Any of the