Scalability, Design and Optimization of High Specific Power 500 kW SPM Machine with Additively Manufactured Coils and Integrated Heat Pipes

This paper focuses on the scalability effects on key specifications (including specific power and efficiency) of surface permanent magnet machines. Therefore, a 500 kW and 10,000 rpm (geared), 36/30 slot/pole combination SPM machine with hollow conductor coils and integrated heat pipes for hybrid/electric propulsion for aerospace applications is proposed in this work. The proposed machine in this paper achieves 40.7 kW/kg active specific power with a 2kV DC link voltage. In order to determine the benefits of the final optimized design, and assess scalability, a comparison is conducted between the proposed machine and two other machines different in speed and slot/pole combination. The comparison with a 250 kW and 5,000 rpm (direct-drive) and 36/30 slot/pole combination machine shows 65.4% increase in specific power while the efficiency reduced by 3%. The comparison with 250 kW and 10,000 rpm (geared) and 24/20 slot/pole combination machine shows that the proposed design offers significantly higher specific power at the same rotational speed.