Can IGBT module DM2G 100SH 12AE of inverter welding machine be replaced by SKM 100GB 12DN? I think the circuits of these two modules are the same. Please give me your advice.

Theoretically, it is irreplaceable, because the performance of different types of equipment is slightly different. But in practical application, it is actually replaceable and feasible. This is my experience from practice. I have repaired Tangshan Panasonic inverter welding machine and replaced it with different models of modules. As long as its basic circuit diagram is the same, its rated power and rated current are the same, its output current and voltage are no different from the welding effect.