植入式人工心脏泵要求体积小、质量轻、功耗低,为了满足这些要求,需要研究磁悬浮人工心脏泵的轴承特性。为此,对径向永磁轴承自身的耦合特性进行了理论分析与仿真,据此提出了心脏泵转子的磁悬浮支承方案,该方案采用两个径向永磁轴承和一个轴向电磁轴承来实现转子的五自由度稳定悬浮。根据径向永磁轴承的磁场分布特性,提出了采用两个关于转子轴线对称布置的霍尔传感器,从转子径向方向检测转子轴向位移的方法,理论分析揭示了转子径向位移和轴向位移在检测结果中的耦合关系,并给出了解耦方法,得出了轴向位移。基于研究成果设计了轴流式磁悬浮人工心脏泵原型机,并成功实现了转子的五自由度稳定悬浮。
The implanted artificial blood pump requires small volume,light weight,low power dissipation and so on. To meet these requirements,the force coupling and stiffness coupling of the radial permanent magnetic bearing are studied by theory analysis and simulation. Basing the force coupling characteristics, a scheme of hybrid magnetic levitation system for the axial-flow maglev blood pump was presented. This scheme employed two radial permanent magnetic bearings and only one axial active magnetic bearing to levitate the blood pump rotor in five degrees of freedom. Then,the rotor axial displacement detection method was studied. This method used two Hall sensors,which were arranged symmetrically about the pump rotor axis and in the rotor radial direction,to detect the magnet field variation caused by the movement of rotor ring of the radial magnetic bearing. But the rotor radial displacements and axial displacement were all included in the outputs of the two Hall sensors. Therefore it analyzed the coupling relationship between the radial displacement and the axial displacement in the outputs of sensors. Then the decoupling method was studied and presented. According to the theory study results,a prototype of the axial-flow maglev blood pump was designed and manufactured. The rotor of the prototype is stably and successfully levitated in five degrees of freedom.