Influence of Flux Barrier Shape and Mechanical Constraints on Field-Weakening Performance in Double-Layer Interior Permanent Magnet Machines

Journal article, 2024

This paper investigates the influence of flux barrier shape on the field-weakening performance of interior permanent magnet rotors with two layers of magnets. The field-weakening performance of four topologies, with different flux barrier shape, has been maximized using combined electromagnetic and mechanical optimization of the rotor geometry. The impact of the mechanical stress constraint on the optimization result is quantified. The rotor topologies differ in both their optimal balance between saliency and normalized magnet flux linkage, and in how severely they are affected by mechanical constraints. Including stress constraints strongly increased the differences between the rotor topologies and it was shown that careful handling of the mechanical constraints was of similar importance for the field-weakening performance as the shape of the flux barrier. Among the included topologies, the double V-shape design was found to have the highest power capability across the speed range and lowest sensitivity to mechanical constraints.