磁悬浮陀螺飞轮用隐式洛伦兹力磁轴承

针对磁悬浮陀螺飞轮用显式洛伦兹力磁轴承气隙磁密均匀性差的问题,提出了一种磁钢内置的隐式洛伦兹力磁轴承,并采用三维有限元法对两种方案的气隙磁密进行比较分析。隐式方案的气隙磁密在周向和纵向的变化率分别为0.8%和8.4%,远优于显式方案的15.0%和23.7%。利用磁场分割法对隐式方案的磁阻进行了区域分割,采用积分法精确计算各区域磁阻,建立了磁轴承磁路数学模型,得到了影响偏转电流刚度的关键结构参数,并基于有限元法对隐式方案形状及结构参数进行详细优化。结果表明,在不恶化气隙磁密变化率的前提下,优化前后绕组区域的最大磁密和最小磁密分别从0.404T和0.368T增加至0.464T和0.427T,增幅为14.6%和16.0%。根据优化结果研制了一台隐式洛伦兹力磁轴承,并进行了气隙磁密和偏转电流刚度实验测试,测试结果与设计结果相符,对洛伦兹力磁轴承的设计具有重要意义。

Novel internal Lorentz magnetic bearing for magnetic bearing gyrowheel

To remedy the limitations of external Lorentz magnetic bearing with poor gas flux density uniformity, an internal Lorentz magnetic bearing for magnetic bearing gyrowheel was presented. The three dimensional finite element method was used for analysis of the gas flux densities of two schemes. The gas flux density rates of internal scheme in circumferential and longitudinal directions were 0.8% and 8.4%, less than that of extern scheme of 15.0% and 23.7%, respectively. The integration method was applied to accurate calculation of internal scheme magnetic resistances segmented by magnetic field division. The magnetic mathematical model of magnetic bearing was established, and the key structure parameters of reverse current stiffness were obtained. Then, by taking shape and structure parameters of internal scheme, the optimal design was achieved through finite element method. The results show that in the case of improvement of gas flux density uniformity the maximum and minimum flux densities in winding region are 0.464 T and 0.427 T, which are increased by 14.6% and 16.0% compared with initial values of 0.404 T and 0.368 T, respectively. According to optimization results, an internal Lorentz magnetic bearing is manufactured and its gas flux density and current stiffness are measured. Tests have a good agreement with design results, which has great significance in the design of Lorentz magnetic bearing.