Modeling of Connections Taking Into Account Return Plane: Application to EMI Modeling for Railway

The modeling of electrical characteristics of connections is an important stage of the design phase of a structure. Indeed, they have an impact on the current density distributions inside conductors as well as on the current distributions when several components are connected in parallel. In the case of a return plane in the studied structure as for power electronics converters or railway applications, the model of connections has to be improved in order to represent the physics better. For the first application field, the cooling system itself can be a ground plane, and for the second one, the earth has to be modeled. This paper presents different ways to take into account a return plane while modeling the electrical equivalent circuit of connections above it. It starts with the simplest one, the image method, and continues with the use of a complex skin depth result of solving the Carson integral.