Magnetic Suspension Performance Enhancement of Ultra-compact 5-DOF Controlled Self-bearing Motor for Rotary Pediatric Ventricular Assist Device

Research interests of the compact magnetically levitated motor have been strongly increased in development of durable and biocompatible mechanical circulatory support (MCS) devices for pediatric heart disease patients. In this study, a tiny axial gap type 5-degrees of freedom (DOF) controlled selfbearing motor for use in pediatric MCS devices has been developed. The motor consists of two identical motor stators and a centrifugal levitated rotor. This paper investigated design improvement of the magnetic circuit for the developing selfbearing motor to enhance the magnetic suspension and rotation performance. The motor geometries were refined by using numerical calculation and three-dimensional magnetic field analysis. The modified motor can achieve the higher suspension force and torque characteristics than the previously developed motor, and indicates stable magnetic suspension performance up to the rotating speed of 8000 rpm.