Experimental identification of an induction motor considering the effects of main flux saturation by using a constrained minimization

This paper presents the experimental application of a new identification methodology, based on a constrained minimization technique, for the estimation of both the magnetisation curve of an induction machine and the variation of its electrical parameters caused by the main flux saturation. The parameter estimation algorithm is based on the dynamic mathematical model of the induction motor in the stationary reference frame and exploits a constrained least-squares algorithm. The experimental results obtained on a test set-up confirm the capability of the parameter estimation algorithm to estimate the electrical parameters of the machine correctly under different magnetic excitations. Moreover the method requires no complicated voltage waveform for supplying the motor, unlike other methods, as well as no a priori knowledge of the name-plate data of the machine and can be easily applied even with only one auto-transformer.