轴向磁悬浮轴承支承特性理论分析和实验

The Theoretical Analysis and Experimental Research on the Supporting Characteristics in Axial Magnetic Bearing

磁悬浮轴承广泛用于高速旋转机械,磁悬浮轴承的支承特性对研究该系统的动力学问题具有重要影响。提出了准确地测量轴向磁悬浮轴承支承参数的通用方法,为磁悬浮轴承转子系统动力学仿真分析、优化设计提供了可靠的建模依据。以一轴向磁悬浮轴承为例,首先在理论上计算了力-电流系数和力-位移系数,然后采用载荷法进行实验测定,实验结果略小于理论计算结果,因为实际系统存在漏磁,所以这是合理的。实验测定磁悬浮轴承刚度阻尼的方法主要是利用外部激振力对系统的激振和测试得到的系统响应之间的关系来识别,采用力锤脉冲激振法,从轴向磁悬浮轴承稳定悬浮下的频响函数中,测出系统的刚度约为4.55×106N/m,阻尼约为748N.s/m。

Magnetic bearings are now applied in the area of high speed rotating machine widely. The supporting characteristics of magnetic bearing are the key problems of the system dynamic. In order to build reliable system model for the optimal design and system dynamic analysis,the accurate measurement methods of the supporting characteristics of axial magnetic bearing are developed in this paper. Firstly,force-current coefficient and force-displacement coefficient is calculated theoretically. Then applying load method is used to measure these two coefficients. The values of measurement are a little less than the theoretical value. Because there is the magnetic leakage in the real system,the above result is reasonable. Using the outside excited force experimental measurement of stiffness and damping of magnetic bearing is abtained,and the stiffness and damping of magnetic bearing can be identified by the relationship between the input and output. The main method used in this paper is hammer impulse excitation through which ,the stiffness of the system is about 4.55 10^6N/m,and the damping is about 748 N s/m.