Design and analysis of a novel bearingless motor for a miniature axial flow blood pump

Abstract

In this paper, a novel design for the axial flow blood pump is proposed, based on the bearingless permanent magnet (PM) motor concept. The design of the impeller, the rotor, and the stator is explained. The axial length of the impeller is optimized based on the finite-element analysis (FEA), and because of reduced axial length of the rotor, only one radial active magnetic bearing is used, whose functionality is embedded in the same stator, which is used for generating-motor torque. A novel design of the rotor and the stator is proposed formeasuring the radial position of the rotor using four linear Hall effect sensors. This sensor assembly can measure the radial position of the rotor with good accuracy. The angular position of the rotor is measured with two Hall effect sensors. The 3-D FEA of the complete system is performed, and suspension forces, stiffness, and torques are evaluated under various control conditions. The control strategy for the bearingless PM motor based on the Hall effect position sensors is explained. The experimental setup is built in order to guide the process of design. The experimental results of the system are evaluated under different operating conditions and compared with FEA results.