Estimación de las pérdidas adicionales inducidas por la utilización de convertidores en máquinas de imanes permanentes

Abstract

Within the scope of the industrial rotating machines, the progressive inclusion of PWM (Pulse Width Modulated) voltage converter based systems has become the norm in the present days. Rather than a sinusoidal waveform, these voltage converters present the peculiarity of generating rectangular voltage pulses with low rising time and variable pulse width. Feeding an electric machine with such a characteristic waveform is the cause of supplementary or additional losses in the stator of the aimed machine, being the main consequences: a) a decrease in the performance and b) an increased heating on the stator windings. It is thereby necessary to have available an analytic calculus method for the estimation of the additional losses in the Permanent Magnet machines (those losses related to the high frequency harmonics coming from the converter and being therefore dependent on the modulation strategy). The quantification of that losses, due to the complex physics phenomena involved in them, becomes difficult, and there is no commonly accepted methods in the industry on such purpose. That is the reason why from GAMESA and University of Oviedo it has been detected the need of developing a mathematical model that is capable of characterizing such additional losses, which constitutes the origin of this project.