Discrimination of Stator Asymmetries and Magnetic Saturation in Self-Excited Induction Generators

Abstract

This work involves an efficient approach for the modeling and discrimination of the stator asymmetries and magnetic saturation in the self-excited induction generators. For this purpose, an improved model considering magnetic saturation has been developed for the self-excited induction generators operating under asymmetrical load conditions. Magnetic saturation must be considered for the modeling and analysis of the self-excited induction generators. This is because linear modeling with fixed parameters never makes it possible to analyze the performances of such machines. Due to fact that the magnetic saturation and stator asymmetries both cases generate similar harmonic components through the stator voltages and currents, we have to elaborate an improved model to evaluate the electromagnetic performances and to clearly discriminate the stator asymmetries and magnetic saturation. The contribution of this work is that a state model has been developed considering the increase of the common point voltage during asymmetrical conditions and the derivation of the machine inductances due to magnetic saturation. Various electromagnetic characteristics have been extracted such as stator voltages, currents and common point voltage. It will be deduced that the common point voltage can be considered as an interesting signal for the discrimination of the stator asymmetries and magnetic saturation. The concordance between simulation and experimental results shows the consistency of this approach for the modeling and discrimination of the stator asymmetries and magnetic saturation in the self-excited induction generators.