Design of a Hybrid-Type Short-Span Self-Bearing Motor

In this paper, a self-bearing motor is newly proposed for the application to an artificial heart pump. The motor consists of two functions using a stator in common; one part is a general permanent magnet (PM) motor and the other is the so-called hybrid active magnetic bearing (AMB). An outer rotor is actively controlled only in two radial directions while the other motions are passively stable owing to the short-span structure. Main advantages of this hybrid-type self-bearing motor are low power consumption, simple control mechanism and smart structure. A mathematical model for the hybrid AMB part is built with consideration of the radial movement of the rotor. The model helps us not only to design a levitation controller but also to expect the system performance. Some experimental results show the feasibility of the proposed self-bearing motor for use in the artificial heart.