Analytic Calculation of Eddy Currents in the Slots of Electrical Machines: Application to Cage Rotor Induction Motors

Thierry Lubin (1) , Smail Mezani (1) , Abderrezak Rezzoug (1)

1 GREEN - Groupe de Recherche en Electrotechnique et Electronique de Nancy

This paper describes a two-dimensional analytic model for predicting the induced currents within conducting material placed in the slots of electrical machines. Slot-embedded conductors are subjected to a rotating magnetic field including space harmonics. The analytical method is based on the resolution of time-harmonic homogeneous Helmholtz's equation in polar coordinates by the separation of variables method. The global solution is obtained using boundary and continuity conditions between the different sub-domains (rotor slots and air-gap). The proposed model is applied for magnetic field and torque calculations in a rotor cage induction motor under steady state condition. The analytical results are verified with those obtained from finite element analyses.

Mots clés: Eddy currents; analytical solution; diffusion equation; rotor bars; induction motor

Domaines: Energie électrique; Electromagnétisme

Thierry Lubin, Smail Mezani, Abderrezak Rezzoug. Analytic Calculation of Eddy Currents in the Slots of Electrical Machines: Application to Cage Rotor Induction Motors. IEEE Transactions on Magnetics, 2011, 47 (11), pp.4650-4659. ⟨10.1109/TMAG.2011.2157167⟩. ⟨hal-00640594⟩