A fast semi-analytical model for the slotted structure of induction motors

•We have developed an harmonic modeling technique for the analysis of slotted induction motor structures.•We have examined two different methods to represent the slots and slot opening in the model.•The results of the model have been compared to 2D FEA simulations for a set of four test motors.•The obtained magnetic field solution is in relatively good agreement with the magnetic field predicted by linear 2D FEA simulations.•The electromagnetic torque calculated from the harmonic model is in very good agreement with linear 2D FEA simulation results.

A fast, semi-analytical model for induction motors (IMs) is presented. In comparison to traditional analytical models for IMs, such as lumped parameter, magnetic equivalent circuit and anisotropic layer models, the presented model calculates a continuous distribution of the magnetic flux density in the air gap and both the stator and rotor slots of the IM. Due to its semi-analytical nature, the computation time of the model is short in comparison to finite element analysis (FEA) simulations. However, the curved shapes of typical IM slots require a suitable representation of each slot in polar coordinates. Two different polar slot representations are investigated and it is shown that a double region representation is favorable to a single region representation. Finally, the model is implemented for four different benchmark motors. The calculation results are shown to be in good agreement with linear 2D FEA simulation results. This makes the model a suitable candidate for fast design tools.