在混合磁轴承(hybrid magnetic bearing,HMB)建模过程中,通常忽略涡流效应、边缘效应和漏磁等因素,使得悬浮力数学模型精度降低。为了提高模型精度,提出了计及磁极端部边缘效应的混合磁轴承改进模型。该文以交流径向混合磁轴承为例分析其工作原理和磁通分布特性,采用磁场分割法分别求解不同边缘磁通区域的磁导,通过叠加原则获得单个磁极下的总磁导,根据等效磁路法建立径向悬浮力的精确数学模型。实验结果表明:改进前模型计算所得悬浮力与实验所得悬浮力误差接近10%,改进后的数学模型所得悬浮力与实验所得悬浮力误差小于5%。比较结果证明了计及边缘效应能有效提高悬浮力数学模型的精度。
In modeling proceeding of hybrid magnetic bearings(HMBs), factors such as the eddy current effect, the edge effect and the flux leakage are commonly ignored, which decreases the precision of the mathematical model of suspension forces. In order to improve the precision, an improved mathematical model of hybrid magnetic bearings considering the edge effect was established. An AC hybrid magnetic bearing was taken as an example, its working principle and features of flux distribution were analyzed. Then, the magnetic field division method was employed to calculate the permeances of different regions located around the end portion of the pole. The permeances were added by the superposition principle, and the total permeance of the single pole was obtained. The accurate model was obtained by using the equivalent magnetic circuit method. The experimental results show that the error between original model values and experimental values is about 10%, the error between improved model values and experimental values is less than 5%. The results of the comparison have verified that the consideration of the edge effect can effectively improve the precision of the mathematical model of suspension forces.