High-Speed MW-Class Generator With Multi-Lane Slotless Winding for Hybrid-Electric Aircraft

Abstract

This paper presents a comprehensive design and analysis of a high-speed, multi-lane, 2.5 MW , 15000 rpm , 3 kV slotless generator system tailored for hybrid-electric aircraft. The armature of this generator incorporates FiberPrinting™ technology, featuring four galvanically isolated concentric winding rings. An assessment of the generator's performance metrics was conducted through finite element analysis (FEA). The 2.5 MW slotless 8-pole generator achieved a power density of 24.4 kW/kg (for active mass) and an efficiency above 99 \% at the current density of 15 A/mm2. To further enhance the system's efficiency, we investigated the possibility of incorporating a filter between the generator and frequency converter. However, this investigation revealed that the weight and losses associated with the filter outweigh any potential gains in generator efficiency. Additionally, the study explored the impact of elevating the current density to levels comparable to the state-of-the-art (SotA) machines ( 20 - 27.5 A/mm2 ). The results indicate that such an enhancement would significantly raise the power density to 35 - 40 kW/kg. Furthermore, increasing the number of poles from 8 to 12, in combination with the elevated current density, can surpass the threshold of 40 kW/kg. Comparing our findings against the SotA, we demonstrate that the proposed topology exhibits the potential to outperform conventional technologies, provided adequate cooling measures are implemented.