Review of application of the electrical structure in resistance spot welding

Resistance spot welding (RSW) is frequently employed in current industrial occasions. This paper reviewed recent advances of the electrical structure of the RSW system. Two types of electrical structures are used in RSW machines. Single-phase ac power source has a simple structure but low control frequency and power factor, and the measurement and control for the machine have some special operations. While three-phase medium frequency dc power source has a complex structure and high control frequency but high cost, and frequently switching the direction of the output welding current may induce many negative phenomena in the welding transformer. The characteristics of the two structures are presented in detail in this paper. Corresponding measures have been taken to deal with the phenomena during the process, respectively, for the two types of electrical structures, according to the previous works. Though many significant achievements have been gained in previous works, it is expected to be more improvements required in the future. This paper can provide references and enlightens for academic researches or actual production in RSW operations.