HEV Motor Comparison of IPMSM With Nd Sintered Magnet and Heavy Rare-Earth Free Injection Magnet in the Same Size

In the near future, usage of heavy rare-earth element needs to be reduced, due to resource risk and rising price with vehicle electrification. This paper compared two hybrid electric vehicle traction motors of the same size using Nd sintered magnet and heavy rare-earth free magnet. We designed two interior permanent magnet synchronous motors varying only the rotor design and material. A new motor was developed using heavy rare-earth free magnet with performance and size equal to Nd sintered motor. The rotor shape was designed as the one of a synchronous reluctance motor to overcome the lack of heavy rare-earth free motor torque. The motor performance was verified with a series of experiments.