An Experimental and Simulation Study of Ultrasonic-Assisted MIG Welding Power Supply

This paper presents the design and control of a digitally regulated MIG welding power supply capable of superimposing ultrasonic-frequency current (20-100 kHz) onto a low-frequency pulsed current (0-500 A, 10 ms period). The proposed topology employs a full-bridge inverter at the primary stage and three Buck converters at the secondary stage, with IGBT modules as switching devices. To ensure stable high-frequency operation, an active snubber and energy feedback circuit are integrated. The control system, implemented on an STM32 microcontroller with PI-based closed-loop regulation, enables flexible waveform modulation and precise current control. System parameters were optimized in MATLAB/Simulink and validated experimentally. Results demonstrate accurate generation of complex current waveforms and improved stability of droplet transfer compared with conventional power supplies. The developed system provides a viable solution for next-generation MIG welding applications requiring high efficiency, reduced spatter, and controllable heat input.