An Analytical-Numerical Approach to Model and Analyse Squirrel Cage Induction Motors

Nowadays, finite element analysis represents themost accurate tool to analyse electrical machines. However, thetime domain resolution of electromagnetic problem, in somecases, requires long simulation time due to the induced natureof the currents. The computational burden increases when themachine features a skewed layout on the stator or rotor struc-tures, since this requires 2D multi-slices approximated analysisor even a full 3D model.In this paper, a general analytical method to model electro-magnetic devices is applied to a squirrel cage induction motorfeaturing a skewed rotor structure. The modelling approachis wisely implemented and adapted to pursue a fair balancebetween accuracy of the analysis and computational burden,taking advantage of all the symmetries existing in the rotor cageof the machine, aiming to minimize the model complexity. Acomparative analysis in term of the inductances between analyt-ical and finite element is proposed. The results provided by themodel developed are compared with respect to the correspondingvalues provided by both finite element and experimental testperformed on the reference machine. Such comparisons showthat the proposed model is actually able to achieve a pretty goodbalance between accuracy and computational efficiency