Consideration of space harmonics in complex finite element analysis of induction motors with an air-gap interface coupling

A method for coupling the stator and rotor fields of induction motors in time harmonic finite element (FE) analysis with consideration of space harmonics is presented. The coupling scheme is derived from Fourier series of the magnetic vector potential at air-gap interface conditions. A transformation technique is used to introduce the coupling scheme in the saturated time harmonic FEs model coupled to the electrical circuits. The obtained results are compared to experiments in critical situations