Design and Implementation of a Magnetically Levitated Single-Axis Controlled Axial Blood Pump

This paper presents the design and implementation of a magnetically levitated axial blood pump. The rotor has a hollow structure for fluid flow, and the impeller is mounted on the rotor inner surface. The magnetic suspension system is realized using two passive magnetic bearings for radial direction balancing and an electromagnetic actuator for axial direction balancing. A sensor assembly for the rotor´s axial position control is also presented. This sensor can measure axial displacement with good accuracy. A prototype pump was built and investigated. The experimental results demonstrate successful magnetic levitation and water-pumping operations. Because radial movements were not actively controlled, noticeable oscillations existed in these directions. These oscillations were caused mainly by the radial force produced by the actuator.