Increasing concerns over costs and supply of rare earth magnets have introduced more attention to Permanent Magnet Synchronous Machine (PMSM) designs that can work with ferrite magnets. Ferrite magnets have a major disadvantage in that they don't produce as much flux density as rare earth magnets do, which leads to lower torque density and thus less power in PMSMs. Several approaches have been taken in design of PMSMs in order to tackle this problem. Two of these designs are presented and compared in this work. The first design is the spoke-type (or Flux squeeze) PMSM which places the magnets radially in the rotor to increase the magnetic flux density in the airgap. The second design is the Permanent Magnet Assisted Synchronous Reluctance Machine (PMASynRM) which produces the majority of its torque from saliency and uses permanent magnets to produce an additional magnet torque component. The main metrics used to evaluate the performance of each design are: maximum torque, operating range, torque ripple, magnet material required, and efficiency. Finite Element Analysis (FEA) is used to simulate and analyze both designs. Experimental characterization results are shown for the spoke-type PMSM and are compared to the same results obtained with FEA in order to have a guideline as to how accurate the FEA results are. A prototype of the PMASynRM design was constructed in the laboratory and some experimental results are presented.
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