Rotor Flux-Barrier Design for Improving Field-Weakening Capability of an Interior Permanent Magnet Synchronous Machine

This paper proposes a novel rotor flux-barrier design for interior permanent magnet synchronous machine with single-layer, tangential magnets. A motor for vehicle traction application is employed as baseline design equipped with double-layer, 18-teeth/10-poles concentrated winding. The new design improves field-weakening capability significantly and yet has no decline in the peak torque, only through two modifications: (i) adding ten pieces flux barriers of half circle form in the q-axis position to the rotor inner surface; (ii) and slightly increasing tooth width. The design rule is presented, and the effect of two modifications is explained. Furthermore, a study of comparing the baseline to the new design is carried out in the aspects of no-load performance, field-weakening capability, machine parameters in dq-axes, current density, and torque ripple.