Design of Magnetic Bearing and BLDC Motor for a Novel Third-Generation LVAD

In the last decade, considerable development is achieved in the usage of blood pumps for the treatment of heart failure instead of heart transplants. Blood pumps demand small size, lightweight, low power operation, and minimum blood damage with increased lifetime and reliability. The third-generation Left Ventricular Assist Device (LVAD) is a non-contact pump with a magnetic bearing and/or hydrodynamic bearing. The main attraction of the levitated rotor over conventional mechanical bearings is the increased life of the device. This paper focuses on the design of magnetic bearing and drive motor for a novel third-generation LVAD. In the proposed novel LVAD configuration, a centrifugal pump is levitated by an active magnetic bearing in the radial plane and by a passive magnetic bearing in the axial direction. The impeller of the pump is rotated using a BLDC motor configured in the same plane of magnetic bearing. Eddy current based gap sensors are used for sensing the rotor position.