Optimal Design of Magnetic Geared PM Synchronous Motor Pole Shape to Improve Magnetic Field Distribution and reduce Cogging Torque

In this paper, the combined axial flux structure of a permanent magnet synchronous motor with a magnetic gearbox is investigated to increase the torque density. The motor has two rotors with tangential magnetized spoke type PMs and coreless structure. Modulators play the role of magnetic field modulation for the stator and rotor over the air gaps. The shape of permanent magnets allows higher efficiency and at the same time lower axial length. Soft magnetic poles of the rotor located between the magnets play a decisive role in the magnetic field distribution as well as the torque and magnetic field profile of the machine. In this paper, the shape of the soft magnetic pole is optimized to obtain a higher sine field distribution and higher output torque as well as lower cogging torque using the variable airgap.