Abstract

Abstract. Simulation techniques are useful tools for study and research of new welding technologies, and for the rapid development of new control algorithms and control units such as power source circuits, and welding current or voltage controllers. The objective in this research is to combine the simulation of Gas Metal Arc Welding (GMAW) process models with the simulation models of inverter based power machines. The GMAW process is considered as an electrical circuit and the mathematical model is based on physical descriptions of several parts of GMAW process, as are the electric circuit of power supply, the arc dynamics, and the electrode melting process. To establish the validity of the proposed GMAW model, a simple welding application was simulated and welding parameters were derived from experimental conditions. Next, the simulation model of fullbridge DC-DC converter is presented and the discrete PI controller for welding current feedback control is proposed. Both models, the GMAW model and the inverter power supply model, are combined and simulated together. Finaly, the simulation study of firing the thyristors, which enables steady and pulsed direct current welding with a single fully controlled bridge converter is shown.