Medium-frequency transformer is one of the key components of isolated power electronic converters. The parasitic capacitances of the transformer provide paths for the common-mode current inside the converter. The electromagnetic interferences due to fast switching are among the main concerns for the design of SiC MOSFET based power converters. The conducted emissions of the converter are directly linked to its physical layout. In this work, the main loops of the common-mode current in the presence of a 3-phase medium-frequency transformer are discussed. The experimental studies show the effects of the transformer construction and vector group (star/delta) on the common-mode currents through the gate drivers of SiC MOSFETs in a 100kW 1.2kV three-phase dual active bridge converter.

Hadiseh GERAMIRAD, Florent MOREL, Piotr DWORAKOWSKI, Bruno LEFEBVRE,
Thomas LAGIER1 Philippe CAMAIL, Christian VOLLAIRE, Arnaud BREARD

Presented at PCIM Europe 2020 Digital Days