Flux-Barrier Based Rotor Design of Permanent Magnet Assisted Synchronous Reluctance Motor with Power Density and Torque ripple Improvement for e-Mobility

SynRM and PMaSynRM are emerging as promising alternatives to the use of PMSMs for e-mobility but have compromised performance characteristics and lower power density. Use of rare-earth free motors for electric vehicles (EVs) with low torque ripple being of paramount importance. This paper proposes a new design approach for ferrite magnets based PMaSynRM by adopting the fluid flux barrier based outer rotor configuration and introduces the phase advanced angle. Using finite element analysis (FEA), magneto-static parametric analysis is performed first to determine the optimum phase advanced angle leading to maximum torque. Subsequently, for reduction of torque ripple, transient simulations are carried out and torque profiles are generated from FEA iteratively by varying the carrier and barrier widths using PSO algorithm. FEA is carried out in Ansys Maxwell to validate the proposed design and is coupled with MATLAB to perform optimization studies. Finally, the rotor design that yields the least torque ripple is chosen as the best design. Later, use of skewed rotor is also proposed to further reduce the torque ripple. The results obtained for the PMaSynRM with the design approach proposed in this paper shows a 100% improvement in the power density in addition to 61% reduction in the torque ripple when compared to one of the recently reported works.