Salient-rotor PM synchronous motors for an extended flux-weakening operation range

Abstract—This paper proposes some novel designs of perma- nent-magnet synchronous motors for extending their flux-weak- ening capabilities. According to such a proposal, the motors are greater than one, whereas characterized by a saliency ratio classical designs exhibit a saliency ratio lower than one. The in- novative and classical design solutions are deeply compared in the paper. In order to understand better the basic differences in the motor design, the same base and flux-weakening performance are fixed. The influence of the saliency ratio on inverter voltampere ratings, maximum feasible speed, and current control characteris- tics is highlighted and discussed.