Cogging Torque of Surface-mounted Permanent Magnet Synchronous Motor According to Segmented-Stator Core Effect

In this study, we address an electric power steering (EPS) motor using a T-shaped segmented stator-core. In the case of EPS motors, cogging torque should be minimized. When a segmented stator-core is applied, however, the manufacturing defects and error affect the peak cogging torque value and periodicity. We performed a 2D finite element analysis (FEA) in accordance with the ideal and non-ideal cases to compare and analyze their effect. In addition, magnetic equivalent circuit method was used to verify cogging torque variation. Finally, the manufactured 6-pole/9-slot EPS, surface-mounted permanent magnet synchronous motor, was evaluated and compared with the 2D FEA results in terms of cogging torque and back-electromotive force.