Design Guidelines for Synchronous Machine Topologies with High Torque and Wide Field Weakening Demands

In this paper, the characteristics of multiphase synchronous machines (PM Rare-earth, PM Ferrite, PM-free)are evaluated for a highly demanding application with limited installation space. Critical design criteria, both electrical and thermal, are recognized to assess various topologies and on that basis, four different rotor geometries are considered in detail. The first machine is an IPMSM with flat buried magnets. The second and third machines are IPMSM with an emphasis on reluctance structure with two flux barriers and rare-earth magnets. The fourth machine is an IPMSM with ferrite magnets and three flux barriers. The machines are compared based on their performance with respect to maximum phase current requirement, efficiencies at operating points, constant power range, and cost. The machines are also classified in the Synchronous-Machine (SM)design plane, which provides a guideline for designing machines with high torque and wide field weakening demands.