Effect of Varying Number of Poles on Performance of a PM-Assisted Synchronous Reluctance Machine Enabled with Iron Nitride Magnet Combinations

Permanent Magnet Assisted Synchronous Reluctance Machine (PMASynRM) possesses the advantage of both reluctance and electromagnetic torque, which makes it a cheaper alternative compared to surface PM machines. Further improvement in cost and performance is achieved by adjusting the contribution of each torque component either by optimizing the rotor structure or utilizing a combination of different magnet grades. This paper employs both alternatives through the design optimization of a U-shaped PMASynRM topology featuring 2-layers of rotor magnets incorporating a blend of various magnet types. Four arrangements of Iron Nitride magnets combined with different types of rare-earth (RE) and rare-earth-free (RE-free) magnets are suggested for 8-pole and 6-pole PMASynRM topologies. The optimal designs for each magnet combination in both the 8-pole and 6-pole configurations are utilized to investigate how altering the number of poles influences various performance characteristics of the machine. The comparative analysis of various results is utilized to derive insights into the most suitable topology for the given application.