基于磁通量计算的混合型轴向–径向磁悬浮轴承参数设计

Parameter Design of Hybrid Axial-radial Magnetic Bearing Based on Magnetic Flux Calculation

混合型轴向–径向磁悬浮轴承集轴向磁悬浮轴承与径向磁悬浮轴承于一体,应用于磁悬浮系统可降低系统功耗,减小体积与重量,但其结构及内部磁场分布复杂,参数设计的难度较大。该文提出一种基于磁通量计算的参数设计方法,计算出要达到设计承载力所需的偏置磁场与控制磁场的磁通量,建立起软磁材料内部磁场磁通密度与软磁材料结构参数之间的函数关系,从而计算出软磁材料的结构参数值,使其内部磁场磁通密度不超过其磁化曲线线性区间。利用有限元仿真验证了该设计方法的合理性与正确性。给出了转速为20000r/min时转轴的轴向与径向位移及磁悬浮轴承控制电流的波形。实验结果表明,基于所提方法设计出的混合型轴向–径向磁悬浮轴承具有良好的悬浮特性。

Hybrid axial-radial magnetic bearing （HARMB） is a combination of axial magnetic bearing and radial magnetic bearing. Power consumption, volume and weight of magnetic levitation system can be reduced when this kind of magnetic bearing is adopted. But its configuration and magnetic field distribution is complex that increases difficulties in parameter design. A parameter design method based on magnetic flux calculation was advanced. It should be figured out at first that how much bias and control magnetic flux was needed to get designed bearing force. Functional relationships between magnetic field flux density in soft magnets and structure parameters of the soft magnets were built up based on the calculated magnetic flux. Then the values of structure parameters of soft magnets could be figured out, which ensured the magnetic field flux density in soft magnets never exceed the linear range of the magnetization curve of soft magnets. The results of finite element （FE） simulation validate the rationality and validity of the design method. The axial and the radial displacements curves of the rotor and control currents curves of the magnetic bearing at 20 000 r/min are presented. The results of experimentation testify that the hybrid magnetic bearing designed by the method has good levitation performance.