Slotless Brushless DC Motors For Disc Drives - Winding Technique Performances And Comparison

摘要

Slotless brushless DC motors, spindle or inner rotor type for disc drives, are a solution with different advantages such as detent torque suppression, noise reduction, simplified structure. Different winding techniques may be used: centre dot basket winding, such as Faulhaber's or rhombic shape; centre dot rectangular concentric coils in the gap; centre dot Gramme's winding around the stator yoke. Each of these solutions has first to be analyzed and optimized for itself, according to the winding technique, to the gap flux density distribution and to the sizes. Then a comparison of the differnet solutions is presented, according to the sizes and particularly to the ratio length/diameter and to the polarity.