永磁磁轴承数学模型的研究

对永磁磁轴承的5种建模方法及所建立的数学模型进行了比较,并以径向磁轴承为例进行了计算。发现在形状、尺寸和磁化强度相同的情况下,磁环轴向磁化与径向磁化所得的径向刚度及轴向力均存在差异;将环形磁体作为无限长条形磁体处理,忽略磁环曲率影响,建立的通用模型仅适用于磁环直径相比磁环截面而言非常大,且磁环截面尺寸比气隙小或相等的情况:采用等效磁荷法,按磁化方向不同建立的数值积分模型,能够较好地描述磁轴承径向力及轴向力随动、静磁环相对位置变化而变化的特性。

STUDY OF MATHEMATICAL MODEL OF PERMANENT MAGNET BEARINGS

Five mathematical models of the permanent magnet bearings are compared. And the methods for modeling are shown. The examples of the calculation of the parameters of radial magnetic bearings are presented. It is found that there is difference between the axial force and the radial stiffness of the axial magnetization radial magnetic bearing and these of the radial magnetization one, when the shape, the dimensions and the intensity of magnetization are same. The universal model is only suitable for the case of all the magnetic ring section dimensions are very small in comparison with the ring radius, and those are less than or equal to the gap between the two rings. The universal model ignores the effects of the curvature on the accuracy of the calculation, and deals with the magnetic rings as infinite long line magnets. The characteristics of the radial stiffness and the axial force varying according to the change of the relative position between the static ring and the rotor ring can be described well if the numerical integral model, which is based on the method of equivalent charges of magnetism and the direction of magnetization, is adopted.