Aerospace electric generator design considerations

This article explores four preselected permanent magnet synchronous machine (PMSM) topologies suitable for direct mounting on low pressure spool in a turbo fan engine. The challenge of contributing to More Electric Engine (MEE) development is that the electrical machine needs to operate over wide speed range, take advantage of available space that forces to use a high number of poles and last but not least a high-power density is anticipated. The initialization of these PMSM topologies fulfills the space requirements, evaluates and compares different core materials, FeCo and FeSi, and addresses mechanical load and cooling integration aspects. The design goal is to find affordable and rational set of materials and manufacturing methods in combination with machine characteristics that suits the best for the mission. It is found that PMSM with FeCo core with distributed winding and Halbach magnet arrangement would meet best the low ripple, high efficiency and power requirement while concentrated winding machine would provide appealing option of individually controlled direct cooled hollow conductor coils for better thermal management.