Design of dual rotor axial flux permanent magnet generators with ferrite and rare-earth magnets

Abstract

This article addresses dual rotor axial flux Ferrite permanent magnet (PM) generator, as an alternative to a surface mounted and spoke types Nd-Fe-B generator which have concentrated windings. The performance parameters of all generators, particularly the efficiency, are identical. The design objective function is the generators mass minimization using a population-based algorithm. To predict the performance of the generators a finite element (FE) technique is applied. Besides, the aims of the design include minimizing cogging torque, examining different rotor pole topologies and different pole arc to pole pitch ratios. Three-dimensional FE technique is employed. It is shown that the surface mounted Ferrite generator topology cannot develop the rated torque and also has high torque ripple. In addition, it is heavier than the spoke type generator. Furthermore, it is indicated that the spoke type Ferrite PM generator has favorable performance and could be an alternative to rare-earth PM generators, particularly in wind energy applications. Finally, the performance of the designed generators is experimentally verified.

Analysis of rotor asymmetry fault in three-phase line start permanent magnet synchronous motor

“…Unpredictable faults always create unexpected problems in electrical motors because of many stress mechanisms such as thermal, electrical, mechanical and environmental effects during the operation, that ultimately result in efficiency reduction, serious damage and breakdown. The consequent economic and security reasons justify the importance of fault detection techniques for preventive maintenance [7]. Faults in LSPMSMs can be classified in different types as indicated in Fig.…”