永磁球形电机定子绕组的永磁体模型及磁场分析

采用等效磁网络法分析了永磁球形电机定子磁场．在永磁体的体电流模型基础上，推导了电流密度与永磁体磁化强度的关系，得到了定子绕组的永磁体模型．在此基础上，在柱坐标下对分析模型进行剖分，并将不同磁场边界条件表达为磁阻单元对应节点或支路的不同状态，建立了永磁球形电机定子绕组磁场的二维等效磁网络模型．推导了各单元磁阻及磁动势的表达式，并利用平均磁能法求得了磁通密度在空间的分布．结果表明，定子绕组近场和远场具有不同的分布特征，远场时磁通密度小且变化相对平缓．通过与有限元法的析结果比较可知，相对误差均在6％左右，证明了所提方法具有较好的计算精度．

Permanent Magnetic Model and Magnetic Field Analysis for Stator Coil of Permanent Magnetic Spherical Motor

A new method to analyze stator magnetic field of permanent magnetic （PM） spherical motor was presented. First, based on the body current model of PM, the relationship between current density and PM magnetization was derived, and then the equivalent PM model of stator coil was obtained. Furthermore, the PM model and the air re gion were meshed in cylindrical coordinates. Taking the symmetry and analogy with electric circuit into account, the magnetic field boundary conditions were represented by the corresponding states of nodes and branches of the reluc- tance elements. Finally, a simplified 2-D magnetic equivalent circuit （MEC） method was obtained. The expressions of the reluctances and magnetomotive force sources of the element were deduced, and the spatial distribution of flux density was analyzed by means of the average magnetic energy. The analysis results show that the near-field distribu tion of the stator coil is different from the far-field distribution, and the flux density has a smaller magnitude and changes relatively smoothly at the far field. Comparison with the results of the FEA shows that the relative errors are about 6%, which verifies that the proposed method has a reasonable accuracy.