Design and analysis of a magnetically levitated axial ux BLDC motor for a ventricular assist device (VAD)

Abstract

This study presents the design of a magnetically levitated (maglev) axial magnetic ux brushless direct current motor (AF-BLDC) for an axial blood ow ventricular assist device (VAD). It has three phases, twelve salient stator poles, and eight rotor magnet poles. It is designed in miniature size. Twin AF-BLDC motors are placed in the VAD symmetrically and rotors are coupled to the pump from two sides. The stator and rotor of the proposed motor are designed with a hole since magnetic ux does not pass through the central part. Pump impellers may be placed in this hole for larger pump chamber volume and lower speed. The motor has a passive magnetic bearing and does not involve contact and friction to minimize blood damage. Bearing magnets ensure magnetic suspension. Axial magnetic uxes are parallel to blood ow direction, thus minimizing penetration of magnetic field into blood. Magnetic parameters, axial pull force, and torque of the proposed motor have been analyzed by the 3-dimensional finite elements method (3D-FEM) to confirm the motor design. Solutions are compared with maglev and non-maglev designs.