Design and Experimental Evaluation of One-DOF Axial Magnetic Bearing for Hemolysis Assessment Platform Development

A Hemocompatibility Assessment Platform (HAP) was proposed to previously quantify blood trauma caused by individual Left Ventricular Assist Device (LVAD) components. Magnetic-Levitation (Maglev) bearings and BLDC motors were used to support and rotate the rotor without any contact to eliminate mechanical wear and hemolysis. Passive magnetic bearings (PMBs) that utilize the repulsive force of permanent magnets (PMs) provide radial direction control of the rotor-impeller. The resultant axial instability forces generated by the PMB are supported actively by an Active Magnetic Bearing (AMB) that combines PMs and electromagnets. The AMB’s suspension force stiffness must exceed the radial PMB’s negative spring stiffness in meeting the target controllable range. Therefore, a detailed design of the axial AMB was created through magnetic FEM to design an axial AMB that can generate the required support force under the structural size constraints. Based on the design results, an experimental apparatus was fabricated. Then, a Maglev motor system for the proposed HAP was developed.