A study on the effect of wire feeding speed controller in inverter arc welding machine

In the conventional wire feeder drives of the welding machine, most controllers have a simple speed control loop. The circuit topology of a wire feeder drive is composed of the diode rectifier and one switching device like a MOSFET or thyristor. Because they have no torque control loop, their speed is not regular in the welding processing. For complete speed control of wire feeding speed, the control loop must consist of a torque control loop and a speed control loop. Therefore the conventional wire feeder drive has bad response for sudden disturbance like arc pressure. It can affect some welding performance such as spatter generation and irregular bead forming. Welding performance using a full-bridge PWM speed control scheme was compared with conventional driving scheme and made an experiment in this paper. The result confirms the possibility of welding performance improvement by proposed constant speed control scheme in the experiment.