Unshielded Cable modeling for Conducted Emissions Issues in Electrical Power Drive Systems

In power electronics applications, high frequency models for cables are necessary to understand EMI issues in pulsewidth modulation drives. This paper shows the approach developed at the French Institute of Technology (IRT) Saint-Exupery, in order to take account of the frequency dependency of unshielded power cables per-unit-length parameters for EMC simulations. Fast, predictive models are compared to different shapes numerical models. The method was applied to unshielded two and three wires cables. Finally, common mode (CM) emissions modeling is proposed to predict the CM noise currents, which are the most disturbing in any variable-speed drive systems. The modeling principle is to consider the complete CM circuit as a chain of quadripolar matrices.