Contribution à la modélisation des machines électriques par le calcul analytique.

Abstract

Electric drives are increasingly using asynchronous motors because of their robustness, mass power, and cost. Their maintenance and diagnosis become an economic issue. It is important to detect early defects that may appear in these machines and therefore develop methods of monitoring operation or preventive maintenance. Motor behavior under fault conditions, such as voltage, current, frequency, power, etc., can be determined by testing or analysis. The latter method is more flexible and less expensive because it allows a detailed analysis of the engines under various conditions. However, this analytical method requires a reliable and accurate model representing the engines under these conditions. Thus, a model of the machine, based on a technique of calculation of all the inductances of the machine was developed. All the inductances of the model used are calculated based on the theory of the winding function ""Winding Function Theory"". These inductances were used to study the spectral content of the stator current and the neutral voltage of the machine, which led us to find specific signatures for electrical failures, and to predict the evolution of these latter.This approach is based on the analysis of the signatures of the stator currents and their harmonic spectra. (MCSA). An experimental validation is necessary for the confirmation of the results found by simulation of the studied defects. So, test benches were used for that, and it allowed us to confirm what we found analytically. In the end, the results obtained were very indicative, especially for eccentricity defects and bearing defects, by comparing them with those existing in the literature.