Study on High-Speed Permanent Magnet Synchronous Motor with Large Airgap for Electrically Assisted Turbocharger

In order to solve the problem of poor aerodynamic performance of the electrically assisted turbocharger with a front-mounted motor and difficulty in dissipating heat from the rotor, three new structures of highspeed permanent magnet synchronous motor (PMSM) with large airgap are proposed in this paper, which reduce the friction loss of the air passing through the motor and improve the heat dissipation conditions of the motor. The electromagnetic performance of the motor and the air friction loss of the system are considered overall to select the optimal structure. In the electromagnetic design, the influence of the airgap length and the slot opening width on the performance of motor is studied, which is instructive to the optimal design of the large-airgap motor. The schemes of motors with different structures under different airgap lengths and ventilation areas are designed. For motors of the same structure, the effects of the airgap length and ventilation area on the electromagnetic loss and air friction loss are analyzed. In addition, the electromagnetic loss and air friction loss of motors with different structures are compared when the airgap length and ventilation area are the same.