Field Prediction and Validation of a Slotless Segmented-Halbach Permanent Magnet Synchronous Machine for More Electric Aircraft

High-performance propulsion motors for more electric aircraft (MEA) are highly appreciated in transportation electrification. For the widely adopted permanent magnet synchronous machines (PMSMs) for MEA propulsion, the segmented Halbach magnetization has distinct merit that it contributes to sinusoidal air-gap magnetic fields for smooth operation. However, it is hard to fast predict the field distribution and machine performance due to the model complexity. Based on the subdomain method, this article first proposes an exact analytical model for slotless PMSM with the segmented Halbach PMs. Then, the model is applied in the fast computation of the magnetic field and performance prediction. Subsequently, the analytical results are compared with the finite element method (FEM), including the flux density, flux linkage, induced voltage, and steady-state torque at different loads. Also, the computation burden and prediction error are included to validate the model's rapidity and accuracy. Finally, by prototype fabrication and unique field measurement methods, the flux density distribution is originally validated.