The amplitude of phase voltage and current waveforms are limited by electronic supply. The aim of this study is to achieve a maximum power near of the base speed one on an extended speed range. A parametric analysis of motor electromagnetic characteristics is made to show the influence of armature reaction and magnetic saliency on speed range. We show that exists an ideal condition to obtain a constant power speed range theoretically unlimited.
Magnetic saliency permits to enhance the power factor especially when .
As main hypotheses, we consider no saturation, e.m.f. and current sine waveforms and a sinusoidal airgap flux density. Finally, we recapitulate the permanent magnet rotor structures able to obtain a flux-weakening operation.