A New Gate Drive Power Supply Configuration for Common Mode Conducted EMI Reduction in Phase-Shifted Full-Bridge Converter

This article presents a cascaded gate drive power supply configuration to reduce the common mode (CM) current in phase-shifted full-bridge (PSFB) converters. In such converters, there are at least two $dV/dt$ sources generated at different floating points associated to the parasitic capacitances of the isolated barriers of the gate drivers (power supplies, and control signal isolation units), which can increase the conducted electromagnetic interference perturbations. This article is focused on the analysis of a new gate drive power supply configuration, which reduces the CM currents that circulate in the control part of the switching cells. This improvement is achieved by modifying the impedance network of CM current pathways. Experimental results are provided to prove the effectiveness of the new gate drive power supply configuration on a PSFB converter based on SiC-MOSFET devices.