Modeling Skew by Single- and Multi-Slice 2-D Machine Models

Skew is taken into account in single- and multi-slice 2-D finite-element machine models by skew interface conditions applied at a cylinder hull in the center of the air gap. A set of biorthogonal basis functions is constructed to discretize the tangential magnetic field strength at the interface and to weakly enforce the tangential continuity of the magnetic vector potential. The harmonic filtering as a result of skew is already observed in a single-slice model. Multi-slice models with different numbers of stator and rotor slices increase the modeling accuracy.