Semi-Stranded and Shaped-Profile Hollow Additively Manufactured Coils with Integrated Heat Pipes for All-Electric Aircraft Motors

Additively Manufactured (AM) solid/hollow conductors might suffer from increased AC windings losses due to the solid nature of the coil design. In addition, unbalanced turn loss compared to the adjacent turn in the same layer is another design issue which could occur in some designs equipped with fractional slots concentrated windings. Therefore, semi-stranded and shaped-profile AM coil that has cooling passages along the axial length of the coil to accommodate the Heat Pipes (HPs) is proposed in this paper. The key achievement with the newly designed coil is to have balanced turn losses for the first layer turns that share the same slot with significant reduction in winding losses that reach up to 65% in the first layer turns losses closest to the motor airgap. The motor performance is optimized at multiple speed points using genetic algorithms and compared against previously optimized designs in terms of power-to-weight ratio, efficiency, winding losses, and performance at different operating points all of which show significant improvement.