The Repulsive Passive Magnetic Bearing for the Magnetically Levitated Artificial Heart

Abstract

We have developed a magnetically levitated total artificial heart. The stator of the device has a magnetic bearing and a motor stator set at center of the device. The left and right impellers are connected by a shaft through the center hall of the stator core. The axial position and tilting of the levitated impeller are controlled by the magnetic bearing. The radial displacement of the impeller is supported with a passive stability. We propose the application of a repulsive passive permanent magnetic bearing, PMB, for improvement of the radial stiffness of the device. A magnetic field analysis with finite element method was performed to investigate a suitable PMB. As a result, the PMB which has two radially magnetized outer permanent magnets and an axial magnetized inner permanent magnet has better performance and the radial stiffness increased up to 2.5 times of passive stability's one.