Cogging torque reduction based on segmented skewing magnetic poles with different combinations of pole‐arc coefficients in surface‐mounted permanent magnet synchronous motors

Abstract

The calculation and reduction of cogging torque are fundamental to the evaluation and optimisation of motor performance. Considering that the accuracy of the cogging torque calculated by analytical method (AM) is low, an accurate calculation model of the effective air‐gap length considering the actual stator slot structure and suitable for any motor is proposed, the cogging torque of 6p36s surface‐mounted permanent magnet synchronous motor (SPMSM) are calculated accurately and verified by finite element method (FEM). Furthermore, the segmented skewing magnetic poles with different combinations of pole‐arc coefficients are designed to weaken cogging torque, and the optimal combination of pole‐arc coefficients and tilting angle of the adjacent magnetic poles are summarised by AM and particle swarm optimisation (PSO) algorithm. Finally, the cogging torques of six SPMSMs with different slot‐pole combinations including 6p36s, 4p36s, 6p9s, 8p9s, 8p12s and 10p12s are analysed, and the results indicate that the cogging torque can be greatly weakened based on segmented skewing magnetic poles with different combinations of pole‐arc coefficients, and other performances of the motors are basically not affected.

Design and comparison of dual‐stator axial‐field flux‐switching permanent magnet motors for electric vehicle application

“…Magnetic attraction results from a force component in the x direction and a force component in the y direction. The magnetic attraction force approaches zero, as inferred from Equation ( 16) and (17), where the forces F x and F y result in an asymmetrical shape.…”

“…Dual side PM motors are troublesome due to their high cogging torque, even though they have higher flux density and torque than traditional single side PM motors. For AFFSPM machines, a number of techniques, including slots/poles skewing, magnet segmentation, and harmonic field current injection, have been proposed to reduce two unfavourable factors, including the cogging torque and torque ripple [16][17][18][19].…”

Reduction of cogging torque and electromagnetic vibration based on different combination of pole arc coefficient for interior permanent magnet synchronous machine

“…To ensure the comparison fairness, except for the difference in pole arc coefficient configuration and rotor assembly form, other machine configurations including amount of PMs are kept the same. It is worth noting that previous research work has shown that the 4-segment structure is a more reasonable choice for the machine with rotor segmented skew poles [23]. Therefore, 4-segment structure is adopted in the machine with rotor segmented skew poles in this study.…”

Design of high power density double‐stator permanent magnet synchronous motor

“…In ref. [13], the rotor pole skewing is used to reduce the torque ripple, and influence of different skewing segment numbers on the torque ripple is researched. In ref.…”