The nature of the torque ripple in fractional-slot synchronous PMAREL machines

摘要

This paper deals with the analysis of average torque and torque ripple in synchronous reluctance machines assisted by Ferrite permanent magnets, for applications requiring high torque at low speed. The machines distinguish themselves by an anisotropic rotor and a high number of poles. As a peculiar feature, the analysed machines are characterized by fractional-slot non-overlapped coil windings. When anisotropic rotors are employed in stators with fractional-slot winding, there is a worsening of the torque quality: the average torque decreases and the torque ripple increases with respect to the distributed winding machines. This paper aim is to analyse the nature of the torque generation in such machines, that is, to investigate the magnetic phenomenon causing the average torque decrease and the torque ripple increase.