Abstract

This paper proposes an improved subdomain model of squirrel-cage induction machines (SCIMs) with imposed stator currents. This new model enables to accurately compute electromagnetic quantities such as air-gap flux density, instantaneous torque and forces, and electromotive force including all harmonic contents. The first improvement is to explicitly account for rotor motion with time-stepping technique. The second improvement consists in modeling the skin effect in rotor bars by considering each space harmonic of the stator magnetomotive force separately. Eddy currents in rotor bars are therefore “skin limited” and not “resistance limited”.’ The results are then validated with linear transient finite-element analysis for both no-load and load cases, taking a topology of squirrel-cage machine already used in the previous references. The time and spatial harmonic content of all electromagnetic quantities is also validated by comparison with analytical expressions. The computation time is a hundred times lower than finite element as it does not require achieving a numerical transient first, and the resolution for a time step is shorter. Thanks to its computational efficiency and intrinsic mesh insensitivity, this method is particularly suited to magnetic forces computation and vibroacoustic analysis of SCIMs.

Preprint and full paper

The full paper can be found on IEEE Xplore here. The preprint can be found here:

Notes

This method has been efficiently implemented in MANATEE software.