Electromagnetic Characteristics Analysis of a Novel Bearingless Permanent Magnet Slice Motor with Halbach Arrays for Artificial Heart Pump

The death rate of heart failure is extremely high, and the number of patients continues to rise. Artificial heart pump is the most effective way, even the last hope, for the heart failure patients to prolong their survival. Most of the third-generation magnetic levitation magnetic levitation artificial heart pumps are driven by bearingless permanent magnet slice motor, whose performance directly affects the curative effect of an artificial heart pump. In order to improve the rotor levitation performance of artificial heart pump, a novel configuration of bearingless permanent magnet slice motor is proposed in this paper. Firstly, the working principle of BPMSM, the current common rotor structure and its defects was described. Then a novel Halbach arrays permanent magnet rotor that can levitates steadily in the pump chamber was designed to optimize the structure of the artificial heart pumps bearingless permanent magnet slice motor. Secondly, the finite element analysis and comparison were carried out for the surface-mounted permanent magnet rotor, the conventional Halbach array permanent magnet rotor and the novel Halbach array permanent magnet rotor. Finally, the magnetic field distribution, the induced electromotive force, the cogging torque and the radial levitation force of the mentioned-aboverotors were obtained, which can reflect the electromagnetic characteristics of the motor. The analysis results demonstrated that the novel Halbach array designed in this paper can significantly improve the dynamic torque performance the levitation performance of the bearingless permanent magnet slice motor. By using the new design, permanent magnets with the same material and thickness can generate greater air-gap flux density and thus greater levitation force and electromagnetic torque, which are the crucial criterion for evaluating the performance of an artificial heart pump. Therefore, the novel Halbach array BPMSM has a good application prospect in the field of artificial heart pumps.