New Trends in Electrical Machines Technology-Part II

The machine reference application is the wind energy production for which variable load operations are very common and they could make fault identification difficult. To consider speed changes and other transient operations, the authors have selected the extraction of the instantaneous frequency of the fault stator and rotor current components. It has been shown that trends of the fault component instantaneous frequency as function of the slip are linear. For the moment, results of the proposed analytical model have been compared with a finite-element numerical analysis showing similar accuracy for the analytical model accounting for all slots together. Effects of main design parameters on the open-circuit ac winding losses have been investigated. These parameters are the conductor layout, the slot width, the slot opening width, the tooth-tip height, the magnet pole-arc-to-pole-pitch ratio, and the gap between tooth tips and conductors.