Design and Control of a Wide-Gap Magnetic Bearing for a Centrifugal Blood Pump

Abstract

This paper presents a radial magnetic bearing with a wide air-gap for improving durability and reducing contamination of a centrifugal blood pump with a disposable pump head. The rotor is magnetically suspended by the radial magnetic bearing and driven by an external motor through a permanent magnetic coupling. The pump housing where an impeller-rotor is encapsulated should be as thick as possible in terms of mechanical strength. Hence, an air-gap between surfaces of the rotor and the stator is designed to be wide. The wide air-gap, however, may cause a reduction in suspension force and torque. This paper considers design and control of a radial magnetic bearing that has wide air-gap of 7 mm for a disposable blood pump application.