DESIGN OF LOW-VOLTAGE VARIABLE-FREQUENCY ELECTRICAL MOTORS - I - ANALYSIS OF THE MAGNETIC-THERMAL-ELECTRIC COUPLED PROBLEM

In this paper, the authors present a model for the multidisciplinary o peration analysis of a variable frequency electrical drive, in the cas e of low voltage supply. This model takes into account the coupling be tween the electromagnetic; thermal and electrical phenomena. It allows to evaluate the performances under permanent or transient thermal con ditions, as we can find in the working cycles of electrical vehicles w ith on board energy supply. This model is a part of an optimal design procedure, which will be described in an other article. For this reaso n, this paper is devoted to explain the dependences between the design variables and the performances. The proposed model is applied to a pe rmanent magnet brushless DC motor. The performances are evaluated for the S1 and S2 duty-cycling operations. The influence of the driving pa rameters of the converter is also examined.