Development Of Variable Polarity Tig Welding Power Source

The variable polarity power source for TIG welding developed in this thesis is introduced, with its main circuit ,the controlling principle and configuration of soft~vare and hardware. This power source developed incorporates constant source and inverter. Here the constant current power is half-bridge inverter with IGBTS. And a controlling system is developed using 80C552 single-chip computer as its core unit with circuit of sampling ,drive ,PWM and display. The pulsed constant is outputted by the double lg(IlgI and 1g2) in the constant source. the programmed timer-8253 is used to control turn-on and turn-off of the second inverters. The result of experiments show that this variable polarity power source is rational. and reliable ,and polarity time and current amplitude of DCEN and DCEP can be adjusted separately ,which satisFy the needs for aluminum welding.