INSTANTANEOUS MAGNETIC-FIELD DISTRIBUTION IN BRUSHLESS PERMANENT-MAGNET DC MOTORS, .2. ARMATURE-REACTION FIELD

In Part I an analytical technique for predicting the open-circuit magnetic field distribution in the airgap/magnet region of a brushless permanent magnet dc motor equipped with a surface mounted magnet rotor and a slotless stator was presented. In this paper the analysis is extended to the prediction of the armature reaction field produced by the 3-phase stator windings. As before the motor model is formulated in polar coordinates and accounts for the large effective airgap, but it is now developed further to cater for the effect of winding current harmonics on the airgap field distribution. Predicted instantaneous armature reaction field distributions are validated by comparing with corresponding finite element calculations.