Enhancing the Torque Density of Conventional PM-SynRel Machine with Hybrid Flux Barrier

Electrical machines with high torque density are required for traction application. Availability of bonded magnets with complex shapes and magnetization pattern can significantly extend the design space of electrical machines. This paper introduces a hybrid flux barriers design to improve the torque density of permanent magnet assisted synchronous reluctance (PM -SynRel) machine using ferrite magnets. The torque density with hybrid flux barriers is found to improve along the entire range of speed compared to the conventional flux barriers. The hybrid barrier design achieves similar performance to that of curved barrier with relatively flat shaped magnets in the last flux barrier. Thus, the hybrid barrier is able to enhance the torque density at a potentially reduced cost of manufacturing. The hybrid flux barrier design is validated for both electromagnetic and mechanical performance using commercial finite element analysis (FEA) packages.