Electromagnetic performance analysis of novel vernier permanent-magnet motor with improved torque capability

Vernier permanent-magnet (PM) motors which exploit magnetic gear effects to modulate the magnetic fields are capable of producing high torque at a relatively low speed. Due to its structural compactness, high torque density, high efficiency, these motors are very suitable for direct-drive applications such as electric vehicles. A new kind of vernier PM motor has been presented in [4], which employs two sets of PMs and drum windings. However, its two airgap is too complicated, thus suffering from difficulty of manufacture. Therefore, a new class of vernier motor was introduced. Due to its one layer airgap, this motor offers simpler structure than the aforementioned one, but it suffers from relatively low torque density.