Comparative study of slotted and slotless BLDC motors for blood pump applications

In order to match physiological characteristics, the application of pulsating rotational speed in blood pumps has become popular. This places greater demands on the motor of the blood pump, necessitating low power, rapid response and compact dimensions, among other considerations. In consideration of the characteristics inherent to the slotless BLDC motor, this paper proposes the implementation of a slotless stator as a replacement for the slotted stator in a magnetic-hydrodynamic double levitated axial blood pump. Initially, the slotless stator was conceived in accordance with the theory of slotless motors, incorporating helical windings and meeting the drive capacity requirements of the blood pump. The torque exerted on the rotor of the slotted stator motor and slotless stator motor was then compared through the application of the finite element method. An experimental system was constructed for the purpose of measuring the difference in performance between the two motor types. The attributes, the speed characteristics, the power and the temperature of the stators of the two motors were detected. The findings indicate that the slotless motor exhibits a reduced size, diminished speed fluctuations, expedited speed response, yet concomitantly exhibits almost double the power consumption and a more substantial temperature increase in comparison with the slotted motor.