Integrated Magnetics, Insulation and Cooling Architecture for Slotless Electric Machines

This paper proposes an integrated magnetics, insulation, and cooling architecture to improve the thermal performance of a high frequency permanent magnet (PM) motor. The proposed architecture can be used for any motor topology to improve its thermal and insulation performance. The proposed stator yoke design interleaves copper sheets between yoke core lamination to achieve better thermal conduction from winding to heat sink. A ceramic winding holder is integrated into the armature to introduce a parallel thermal conduction path from windings to the iron yoke and to provide additional insulation. The architecture is applied to a 300 kW slotless PM synchronous motor consisting of an outer rotor Halbach PM array, slotless stator, and heatsink. 3D electromagnetic finite element methods (FEM), 2D heat transfer FEM, and an analytical thermal circuit are used to analyze the architectures impact on torque production, eddy currents, and thermal performance when compared to the baseline motor. Finally, a pole-pair prototype was built as a proof-of-concept and to verify the performance benefits of the proposed architecture.