Analysis of the Magnetic Skin Effekt in Motors and Inductors

The common skin results from the interaction of electrical conductivity and magnetic permeability. However, it is not so common that the skin effect may appear even in materials which are isolators. In general, dissipation is the general reason of the skin effect, independent of the question whether it is electric or magnetic dissipation. In this way, a reasonable skin effect may emerge in the ferrite core of inductors if they are operated in the MHz range. This may result in a significant inhomogeneous field distribution which has to be considered in future inductor designs for power electronics. The magnetic skin effect may prevent also high-frequency magnetic fields to penetrate deep into the rotor. This could be an important issue for injecting-based speed sensorless controls.