Research in Engineering and Aviation

Subdomain analytical magnetic field prediction of slotted brushless machines with surface mounted magnets

April 2012

Author(s): Rahideh, A., Korakianitis, T.

Journal: International Review of Electrical Engineering, 7(2), pp. 3891-3909.


An analytical magnetic field calculation is presented for slotted brushless machines with surface mounted magnets. The magnetic field distributions due to both permanent magnets (PMs) and armature currents are predicted using the sub domain technique considering the effects of tooth-tips. The open-circuit magnetic field calculation can be used for any radius-independent magnetization pattern and in this study six different magnetization patterns have been studied: radial sinusoidal amplitude; ideal Halbach; radial; parallel; 9-segment Halbach; and 2-segment Halbach magnetization. The armature reaction field prediction is presented for both overlapping and non-overlapping winding structures and two non-overlapping winding cases with all teeth wound and alternate teeth wound are investigated. The calculations are applicable to any rotary motion radial-flux internal rotor slotted stator brushless machine equipped with surface mounted magnets with any pole and slot combination. The analytical results of the magnetic flux density for a 6-slot/4-pole brushless DC motor have been presented and compared to those obtained from the finite element method to evaluate the analytical expressions.

Request Publication from Author