Evaluation of Slotless Permanent Synchronous Motor with Toroidal Winding

This paper introduces a slotless synchronous motor that uses toroidal winding. Unlike the usual winding technique, in which the coil is wound around the stator teeth, a toroidal winding is wound along a ring-type stator yoke. First, this paper describes the structure of a slotless motor that uses toroidal winding. The structural advantages and disadvantages of the motor are also discussed. Next, the finite element analysis method is used to examine the motor's back electromotive force waveforms according to the rotating magnetic field and permanent magnet position to determine whether the motor is driven with respect to the toroidal coil structure. Finally, to validate the proposed motor, a prototype was built, and its back electromotive force and cogging torque were measured. In addition, dynamo load testing was used to examine the torque generation and performance of the motor.