A Bearingless Slice Motor with a Solid Iron Rotor for Disposable Centrifugal Blood Pump

In the field of extracorporeal circulation, the use of high cost NdFeB magnets (PMs) in the disposable pump head of centrifugal blood pumps (CBP) need be avoided. In this paper, a bearingless slice motor consisting of a solid iron rotor and a reusable part having ring PMs which can be applied to a CBP is introduced. It realizes a cost-effective disposable pump head and a compact reusable part. To eliminate PMs from the disposable rotor, two PM rings and two iron rings are axial-symmetrically arranged in respect of the stator. The bias magnetic flux generated by the PM flows past the iron rings, rotor tooth and stator tooth. The radial motion and rotational speed of the rotor are controlled using displacement and Hall sensor signals and electromagnetic actuators, and the axial and tilt motions are passively supported and stabilized by the magnetic coupling between the stator and the rotor. A prototype bearingless slice motor is fabricated and experimentally evaluated.