A Compact Magnetic Bearing System for Axial Flow Blood Pump

In this paper, a compact magnetic bearing system has been developed for axial flow blood pumps. The system is composed of two radial hybrid magnetic bearings (HMBs) and a brushless permanent magnet DC motor. The impeller of the pump is enclosed in the rotor that is suspended by the two HMBs with five-degree of freedom (DOF) control, among which four radial directions are actively controlled, and one axial direction is passively controlled. PID controllers are used to control the HMBs. A Lorentz-typed DC motor drives the rotor in sensorless mode using STMicroelectronics ST7FMC microcontroller. The magnetic bearing system is compact: the outside diameter of the stator is 40mm and the length of the rotor is 48.72mm