Identification of the induction motor dynamic and static inductance with regard to saturation

The performance of indirect vector control depends upon accurate prediction of the motor slip angular frequency for the demand torque. The required slip gain depends upon the rotor time constant of the motor. This value varies significantly over the operating temperature range and saturation level of a typical motor. This variation, if not compensated for, results in a significant degradation in torque production from a vector control system. The saturation effect can be compensated by an adaptive flux model if precise knowledge of the induction motor magnetizing curve is available. This paper presents the application of an advanced system identification methodology enabling the offline estimation of the magnetizing curve (dynamic and static inductance) of induction motors.