Novel Rotor Design with Reduced Rare-Earth Material for PM Machines

This paper presents a new rotor topology for permanent magnet machines aiming to reduce the amount of rare-earth material by improving the utilization of permanent magnets on air-gap flux density production. The new rotor configuration consists of two different rotor topologies which are combined in one rotor core, where each of them includes magnetic flux barriers to reduce their rotor MMF sub-harmonics and simultaneously to amplify the 3
^rd
one which has been used as an operation wave. This ability has been used to reduce the required magnets amount for producing the same air-gap flux density compared with the common PM rotor topologies. The investigations carried out on a traction motor with the proposed rotor concept indicate a significant magnet amount reduction in comparison with the considered reference BMW-i3 motor.