High-Torque Density Magnet-Assisted Wound Field Motor using a Field-Unit-Type Rotor

This study presents a novel rotor structure for a magnet-assisted wound field motor. In the proposed motor, the field coil, bobbin, and pole piece are integrated to form field units, which are inserted into the rotor core from the axial direction. This structure allows reluctance torque, which is unavailable in conventional motors, to be utilized and exhibits improved torque density compared to that of conventional motors. Numerical verifications are conducted using the finite element method to validate the effectiveness of the proposed structure. Moreover, manufacturing tests are performed to verify the feasibility of the field-unit-type rotor. From the numerical results, it can be confirmed that the proposed structure achieves a magnet-assisted wound field motor with higher torque density than that of conventional motors.