Coil and magnet shape optimization of an ironless AFPM machine by means of 3D FEA

Coreless Permanent Magnet (PM) machines can be a viable solution for applications where light-weight and high-efficiency are requested, as the absence of an iron core in the stator reduces machine weight and losses at high-frequency losses. Due to the large airgap, main flux is not driven by a magnetic path into the stator, hence a 3D field analysis is necessary. In this paper, an AFPM ironless machine has been optimized in terms of maximum torque produced per joule losses. Several topologies of coils and magnets have been proposed and investigated with 3D FEA. © 2007 IEEE