GMAW power supply based on parallel full-bridge LLC resonant converter

In order to reduce energy loss and improve the electrical energy conversion efficiency during the welding process and decrease electromagnetic interference (EMI) of the welding power supply, this paper introduces a gas metal arc welding (GMAW) power supply with an LLC resonant converter. The parallel full-bridge LLC resonant converter was selected according to the characteristics of GMAW, including high open-circuit voltage, low arc voltage, high welding current, and changeable arc load. Load simulation tests and welding tests were carried out using the proposed power supply. Results of load simulation tests show that the switching frequency has a significant effect on the power supply. When the load changes from a light load to the rated load, the shape of the primary-side resonant current gradually approaches the shape of a standard sine wave. Welding test results reveal that the proposed power supply achieves complete arc ignition. The stable working point of the welding process is within the efficient operating range of the LLC resonant converter. The weld bead produced in the welding test was well formed.