E ffect of voltage ringing in SiC Power Modules on conducted EMI of traction inverters

Abstract:
This analysis deals with fast switching automotive SiC half bridge power modules. In this context the effect of oscillations in the switching waveforms on conducted electromagnetic emissions and on parasitic noise currents is analysed. Therefore an analytic simulation method is implemented, which considers the ringing of the MOSFET voltage in a common mode model of a buck converter. Applying the model, the major influencing parameters are identified. Furthermore, the simulated noise levels are compared to the relevant electromagnetic compatibility limits. So an acceptable maximum of the ringing effects of the switching transients is proposed. Finally, the model is verified by measurements.