Torque improvement of a dual-airgap flux-modulated permanent magnet motor in perspective of harmonic-oriented design

In order to further improve motor output torque, a harmonic-oriented design and analysis method is proposed for a dual-airgap flux modulated permanent magnet (FMPM) motor. In this paper, based on flux modulation theory, airgap flux harmonics are investigated, and the torque generation mechanism under different operation modes is analyzed in detail. Also, the leading airgap flux harmonics have a significant influence on the motor output torque. Then, numerical optimization methods are employed to specifically optimize key design parameters such as the tooth widths of inner and outer rotors, aiming to increase leading airgap flux harmonics under different operation modes. The results indicate that the motor performance following optimization demonstrates a significant enhancement in the effect of specific working harmonics, thereby improving the torque characteristics of the motor. The prototype was fabricated and tested, verifying the feasibility of the proposed DSFMPM motor and the effectiveness of the harmonic-oriented optimization design. This research not only elucidates the relationship between the mechanism of torque generation, airgap harmonics, and motor design parameters but also provides a new perspective and methodology for the design of efficient and high-performance dual-stator motors.