Common-Mode Impedance of an Electric Motor and the Impact of Material and Geometry Uncertainties

We compute the common-mode impedance of an electric motor with hairpin conductors. We use a 2D model of the cross-section of the electric motor, where the per-unit-length parameters are computed by the finite element method (FEM). These results are then used in a transmission line model aligned with the motor axis, which gives an approximate 3D model with favorable computational cost. Given this model, we study the impact on the common-mode impedance given uncertainties in the material and geometry description of the motor’s cross-section. The results are useful for the understanding of uncertainties associated with manufacturing, temperature, aging, et cetera and how such uncertainties influence the EMC behavior in electric propulsion systems that are ubiquitous in the electrification of the transportation system.