高速电机磁力轴承—转子系统临界转速的计算

Critical Speed Calculation of Magnetic Bearing-rotor System for a High Speed Machine

在建立高速电机磁力轴承-转子系统的动力学方程基础上,利用有限元法计算了高速电机转子的临界转速。首先分析了磁力轴承支承刚度及其与系统结构参数以及气隙静态偏置磁通密度的关系,然后基于磁场分析证明磁力轴承对转子的支承是各向同性的,计算了电磁轴承的线性支撑刚度。在此基础上,建立了磁力轴承-转子系统的动力学方程,用有限元法计算了高速电机转子的临界转速。利用该计算方法,设计研制的1台采用磁力轴承的高速电机已成功实现60000r/min的运行。

In this paper, based on the dynamical equation of magnetic bearing-rotor system, the critical speeds of the rotor for a high speed machine by means of finite element method （FEM） are calculated. First, the supporting stiffness of the magnetic bearings and its relationship with the structural parameters and flux density of the static bias magnetic field are analyzed. Then, the isotropy of the magnetic bearing supporting to the rotor is proved by the static magnetic field analysis and the linear stiffness is calculated. At last, the dynamical equation of the magnetic bearing-rotor system is built up and used to calculate the critical speeds of the rotor of the high speed machine by means of finite element method. The proposed method was used to design and build a high speed machine with magnetic bearings which has been operating successfully at 60 000 r/min.