摘要
传统的混合磁悬浮轴承悬浮力建模主要是基于气隙定长的方法。假设气隙长度固定,目前的磁轴承建模方法主要集中为磁场分割法。然而,在实际运行条件下,气隙的长度并不是一成不变的,而且会受到转速变化的影响。实际上,气隙变形会使悬浮力曲线偏离传统模型(零转速定长气隙模型)的曲线。而且,转速越高、气隙长度越长,误差越大。针对传统模型的不足,文章提出了一种基于不固定气隙长度的建模方法。通过分析传统模型中由气隙变形引起的某些参数的变化规律,将与运行速度有关的气隙长度可变的参数替换为传统模型中的固定参数。因此,所提出的模型更符合转子的实际运行情况。以向心力型磁轴承为例,研究气隙变形对悬浮力精度的影响。此外,它还揭示了气隙变形对力-电流刚度和力-位移刚度的影响规律。通过有限元方法验证了所提出模型的可行性和准确性。
The traditional modeling method of levitation force of hybrid magnetic bearing is mainly based on the method of fixed air gap.Suppose that the length of the air gap is fixed,the current modeling methods of magnetic bearings mainly focus on the magnetic field segmentation method.However,under the actual operating conditions,the length of the air gap is not constant and will be affected by the change of rotational speed.In fact,the air gap deformation will make the levitation force curve deviate from the curve of the traditional model(zero speed fixed length air gap model).Moreover,the higher the rotational speed and the longer the air gap length,the greater the error.Aiming at the shortcomings of the traditional model,a modeling method based on unfixed air gap length is proposed in this paper.By analyzing the change law of some parameters caused by air gap deformation in the traditional model,the parameters with variable air gap length related to running speed are replaced by the fixed parameters in the traditional model.Therefore,the proposed model is more in line with the actual operation of the rotor.With the centripetal force magnetic bearing as an example,the influence of air gap deformation on the accuracy of levitation force is studied.In addition,this paper also reveals the influence of air gap deformation on force-flow stiffness and force-displacement stiffness.The feasibility and accuracy of the proposed model are verified by finite element method.
出处
《科技创新与应用》
2021年第30期28-31,共4页
Technology Innovation and Application
关键词
混合磁轴承
建模
气隙
有限元
hybrid magnetic bearing
modeling
air gap
finite element method
