A study on the influence of permanent magnet dimensions and stator core structures on the torque of the disc-type brushless DC motor

This paper presents a three-dimensional analysis of the magnetic field dist ribution for a disc-type, double-sided, permanent magnet, brushless de moto r with a toroidal stator core. Calculations are carried out using the OPERA . (3D) package with the TOSCA module. The electromagnetic torque is determi ned from the Maxwell stress tensor. For comparison, various permanent magne t dimensions and slotless vs. quasi-slotted stator cores are analysed, with an iron powder-resin composite effectively used to imitate the slotted cor e. The torque ripple is shown to be effectively reduced by appropriate perm anent magnet dimensions. The simulation results are in good agreement with experimental data obtained from the prototype motor, which confirms the use fullness of the computational approach presented.