High-voltage 3-phase inverters operating above 400 V represent the high-end of industrial and infrastructure power conversion. Often driving permanent magnet synchronous motors (PMSM) and AC induction motors (ACIM) in demanding applications such as industrial pumps and compressors, traction drives, wind turbine pitch control and grid-tied energy storage systems. At these voltage levels, semiconductor stress, insulation coordination and system-level safety become paramount concerns, while the choice between GaN FETs, SiC MOSFETs and IGBT modules defines the efficiency, switching frequency and thermal envelope of the entire drive system. The increasing adoption of variable speed drives (VSD) at high voltage is further intensifying demands for wider operating voltage ranges, longer service lifetimes and compliance with stringent industrial and grid standards.