Design of Torque Density Improved Spoke-Type IPMSM for Electric Brake Booster Take Into Account Axial Leakage Flux

In order to analyze spoke-type interior permanent magnet synchronous motors (IPMSMs) accurately, it is necessary to apply 3-D finite element analysis (3-D FEA) that takes into account axial leakage flux. However, 3-D FEA is disadvantageous due to the significant inputs of time and effort required. Therefore, it is necessary to use 2-D finite element analysis (2-D FEA) to produce reliable analysis. Precise analysis of IPMSMs using 2-D FEA should consider the leakage magnetic flux generated at the axial end of the rotor core. The magnetic loss caused by leakage flux along the axial direction can be considered in 2-D-FEA by estimating the axial leakage flux path of the rotor due to the potential difference between poles and poles and correcting the permeability of the permanent magnets (PMs). The proposed 2-D FEA was applied to analyze a spoke-type IPMSM with overhanging and cross-laminated rotor structures. Finally, the reliability of the proposed analysis method was verified by comparing the results of the proposed model with 3-D FEA results and experimental results.