Calculation of slot harmonic effects in induction motors by finite element method

This paper proposes the use of the two-dimensional finite element method (2-D FEM) for simulating squirrel cage induction motors taking into account slot harmonic effects. A series of linear field solutions provide the stator-rotor inductance matrix which takes into consideration the anisotropy of the magnetic structure, including stator and rotor slots, besides winding distributions. Successively, the procedure consists in decomposing each self and mutual inductance by Fourier analysis. Finally, the inductance harmonic matrix is inserted in the circuit equation and stator and rotor currents and electromechanical torque can be calculated. The model was tested on two motors having different combinations of slot numbers and simulation results are compared with those obtained by analytical and experimental procedure