Research on pole optimization of semi-inserted dual-rotor axial flux permanent magnet motor for high power density

Purpose The purpose of this study is to propose an optimized magnetic pole design for AFPM motors to address the issues of low permanent magnet utilization, non-sinusoidal air gap flux density and inefficient use of axial space, thereby enhancing power density under the constraint of a constant permanent magnet volume. Design/methodology/approach In this paper, a semiinserted three-segment double-layer magnetic pole structure is proposed for the dual-rotor single-stator AFPM motor. First, the effects of rotor core reduction and permanent magnet insertion on the performance of the motor are compared. Considering the output torque, magnetic field distribution, manufacturing process and other factors, the optimal permanent magnet insertion thickness is selected and the utilization rate of the axial space of the motor is optimized. Second, the semiinserted permanent magnet is divided into three sections with equal ring width along the radial direction, and then each section is divided into an insertion layer and a surface-mounted layer. The spatial distribution of the permanent magnet and the shape of the rotor surface core are optimized by changing the pole arc coefficient of each section and each layer of the permanent magnet. Finally, the advanced Latin hypercube sample method is used to analyze the sensitivity of the magnetic pole parameters that need to be optimized, and the adaptive metamodel of optimal prognosis method is used to optimize the magnetic pole parameters. Findings Compared with the original motor, the volume is reduced by 6.2%, the average output torque is increased by 7.4%, the torque ripple is decreased by 73.9% and the power density is increased by 14.5%. Originality/value The proposed pole structure can reduce the axial length of the motor, improve the utilization rate of the permanent magnet and suppress the torque ripple. It has important engineering value in reducing the cost and volume of the motor.