Magnetic Levitation Performance of Miniaturized Magnetically Levitated Motor with 5-DOF Active Control

Mechanical circulatory support (MCS) therapy plays a significant role in an alternative therapy of heart transplants for pediatric heart disease patients. However, technical difficulties, such as high durability, better blood compatibility and miniature device size, prevent the pediatric MCS device development. In this study, a double stator axial gap maglev motor for pediatric MCS device has been developed. The maglev motor has two identical motor stators, and a levitated rotor impeller which is aligned between the stators. The levitated rotor impeller is fully suspended with 5-degrees of freedom (5-DOF) active control. A miniaturized maglev motor is designed and developed based on FEM magnetic field analysis for use in implantable ventricular assist devices (VADs). The developed maglev motor has an outer diameter of 22 mm and a length of 33 mm. This paper is an initial report on the magnetic levitation and rotation performance of the miniaturized maglev motor. The levitated rotor impeller is magnetically levitated and rotated with the 5-DOF active control. The oscillation amplitudes (x, y and z) and inclination angles (θx and θy) of the levitated rotor impeller are then evaluated in both air and water. The developed maglev motor achieves non-contact rotation up to 1600 rpm in air and 4500 rom in water, respectively. The oscillation amplitudes and inclination angles are sufficiently suppressed in water due to fluid damping. The developed maglev motor indicates potential to achieve the practical use of maglev rotatory pediatric VAD.