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

This study presents the design of a magnetically levitated (maglev) axial magnetic flux brushless direct current motor (AF-BLDC) for an axial blood flow 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 flux 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 fluxes are parallel to blood flow 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.