Benoit Dupeux

A new modelling of DC machines taking into account commutation effects

In some specific manufactured electromechanical applications, power electronic converters must be avoided due to hostile environment. In such a context, stand-alone DC machines are good candidates because of their high reliability and low cost. However, the mechanical commutation is a big problem in this kind of machine especially in high current and low voltage applications. Losses due to arching contacts can be significant. The authors present an original technique to take into account every electrical aspect of brushes contacts (mechanical sliding contact and arching contact). The aim of this study is to determine currents and voltages of conductors during commutation in order to reduce significantly losses due to sliding contact. These evolutions are very important data for finite element analysis too.

Behavior analysis of a DC brush machine by space vector theory

The authors show that the space vector modelling, classically used for synchronous or asynchronous machines, can be applied with profit to DC machines. By leaning on the example of a permanent magnets machine and by comparing the results of the modelling with the experimental measurements, we notice that this process applies perfectly and allows taking into account the effects of the saturation or the possible effects of salience on the armature. This modelling constitutes an effective tool to analyze the role of every element of the machine and to lead an optimization approach.