Small axial flux motor with permanent magnet excitation and etched airgap winding

Disc-type motors with sintered Nd-Fe-B magnets benefit from the high remanence and near-ideal loop shape of the hardmagnetic material. Consequent advantages include a high torque for a given motor size and improved efficiency. Special airgap windings manufactured as multilayer etched windings contribute to flat package motors and to low torque harmonics. Different back iron designs were examined. For the operation of the brushless dc motor instead the classical hall sensors small magnetoresistive sensors can be used effectively for rotor position sensing.