EMI Mitigation for SiC MOSFET Power Modules Using Integrated Common-Mode Screen

Electromagnetic interference (EMI) remains a critical roadblock to fully benefitting from the various advantages provided by wide-bandgap devices. Of particular concern is the common-mode (CM) emissions generated during the device operation. This work aims to inform EMI mitigation strategies that can be implemented at the power module design stage and that can result in modules with lower noise emissions in the conducted EMI frequency range. Four 1.2 kV SiC MOSFET power modules are fabricated with different architectures found from literature to better understand their impact on EMI mitigation and to identify trade-offs. Module architectures with integrated CM screens connected to two different DC nodes are experimentally tested and an in-depth analysis on the EMI results is presented. Experimental results show that using a CM screen connected to the DC-link midpoint allows for up to 26 dB of CM current reduction at the baseplate of the module and the input of the converter. Furthermore, this integrated CM screen configuration enables a 0.5% increase in efficiency.