Halbach Array for an in- Wheel Traction Motor

This paper compares a Halbach array to a more conventional surface mounted permanent magnet arrangement for an in wheel traction motor. Demagnetisation, physical air-gap and torque capability at continuous and overload operation is considered. Without increasing the machine operating space, using one transition per pole was found to increase rated torque by 5% and overload torque by 3 %. A second comparison was done using 3 transitions per pole and this topology was found to give an increase in the overload torque of 4%. Finally, a novel trapezoidal Halbach array arrangement has been proposed to reduce the demagnetisation of the transition magnets and increase their permeance coefficient.