Experimental Validation and Comparison of an Electrically Excited Synchronous Motor and a Hybrid Excited Permanent Magnet Motor

This work presents the design, prototyping, and experimental comparison of two air-cooled salient pole electric motors: the electrically excited synchronous motor and the hybrid excited permanent magnet motor. Both types are suitable for use as traction motors in electric vehicles due to their high torque and power density, as well as their enhanced capability at high speeds. The hybrid excited permanent magnet motor features small NdFeB permanent magnets embedded in each pole shoe, which provide additional magnetic flux and generate a second component of synchronous torque. The motors are designed through finite element simulations, followed by the construction of two prototypes and experimental testing. For the electrically excited synchronous motor, a technique is employed to optimize the air-gap flux density waveform through air-gap shaping. Furthermore, thermal and mechanical analyses are carried out to ensure the motor can handle a continuous operating mode.