Rotor flux-barrier design for torque ripple reduction in synchronous reluctance motors

The torque produced by a synchronous reluctance machine (including the PM assisted configuration) is studied analytically, to the aim of characterizing the effect of the position of the flux-barriers on the torque ripple. It is verified that the position of the flux-barrier ends highly influences the torque waveform. To the aim of reducing the torque harmonic contents, a new strategy is proposed based on the choice of couples of flux-barriers of different shapes. The couples of the flux-barriers are chosen so as to obtain compensation between the torque harmonics produced by each couple of them. Experimental results on two prototypes confirm the analytical prediction