Suspension Force Stiffness by Stator Shape in Double-side Stator Magnetic Levitation Motor

We have developed an innovative axial bearingless motor with tilt control function for total artificial heart (TAH) applications. While different patient sizes pose different motor size/capacity requirements for the optimal fitting in the chests, the performance of the maglev bearing, particularly the force stiffness, should not be compromised. In order to understand the effect of the stator shape, which is the most often altered design parameter for maglev motors, two motors with different stator pole lengths and winding coils were modelled and fabricated. An experimental setup to measure the force and thus to calculate the stiffness were custom-made. FEM simulations and experimental testing were performed and the suspension force results of the two motors were recorded. The control performance of the bearingless motor was also investigated. Especially, we improved the suspension force characteristics of the magnetic levitation motor. In this paper, the operating principle of the bearingless motor, outline of the maglev TAH pump and the effect of two stator shapes on the force stiffness are explained.