Influence of Magnetic Saturation on Induction Motor Model Selection

Effects of magnetic saturation on various equivalent circuit models of an induction motor are studied. The parameters of 2.2-kW and 37-kW motors with closed rotor slots are analyzed using finite element computations. Both skewed and unskewed rotor slots are studied. The magnetizing inductance not only depends on the main flux, but is also dependent on the rotor current, especially if the rotor slots are skewed or closed. The stator leakage inductance is essentially constant, while the rotor leakage inductance depends significantly on the rotor current. The performance of vector-controlled drives can be improved by using a T or Γ-equivalent circuit model whose inductances also depend on the rotor current.