Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

A Heteropolar Bearingless Slice Motor with PM-free Rotor for Disposable Centrifugal Blood Pump

Zeqiang He1, Naohiro Sugita2 and Tadahiko Shinshi2

1Department of Mechanical Engineering, Tokyo Institute of Technology, R2-38, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan

2Institute of Innovative Research, Tokyo Institute of Technology, R2-38, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan


To achieve sufficient rotational torque and simple control of the levitated blood pump impeller, we develop a novel heteropolar 12/8 slot/pole bearingless slice motor with permanent magnets (PMs) free rotor. The bearingless motor adopts separated winding configurations, including three-phase motor windings (U, V, W) and two-phase suspension windings (a,b) in the heteropolar design. Due to the unique locations of the suspension windings on the yokes and the four-pole stationary biased flux, the radial force is produced regardless of the rotor angle, leading to a simple control diagram and the minimum number of amplifiers. Therefore, while being rotated, the rotor can be actively positioned in the radial directions with two independent controllers. We fabricate a prototype to prove the validity of the design. The bearingless slice motor reaches a rotational speed of 3,500 rpm without contact.

Keywords: Bearingless slice motor, Compact motor, Centrifugal blood pump

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