Design and Application of a Dual Processor Digital Control System for Ultra-High Frequency Pulsed Gas Tungsten Arc Welding

Abstract

Ultra-high-frequency pulse modulation is an innovative and effective means of arc regulation. However, the application of this technique in gas tungsten arc welding (GTAW) faces several problems. To solve these problems, this paper selects a main circuit topology for the welding power sources, and designs a dual processor digital control system, in which the pulse width modulation (PWM) signals are generated collaboratively by a digital signal processor (DSP) and a complex programmable logic device (CPLD). Through simulations and experiments, it is learned that our control system could output ultra-high pulsed GTAW current of over 100A, and realize a fast current conversion rate. Besides, multiple welding modes could be realized easily without changing the system design or electrical connection. The proposed control system effectively automates ultrahigh-frequency pulsed gas tungsten arc welding (UHFP-GTAW), and promotes the engineering application of ultra-high-frequency pulse modulation.