中文摘要：

提出一种新型永磁“蝶形”转子偏转式三自由度电机，建立永磁转子偏心后气隙变化的三维解析模型，通过有限元分析软件，对该新型电机的气隙磁通密度和径向电磁力特性进行分析，并基于球谐函数理论对磁场以及径向力谐波含量进行了定量分析。对样机进行了测试后并将实验结果与二者进行了对比验证。结果表明：转子偏心造成转子两侧气隙不等，磁通分布不均匀，磁拉力不平衡和谐波含量加重，有限元和解析法的分析结果与实验结果相吻合。

英文摘要：

This paper proposed a novel 3-DOF deflection type PM motor with a new ＂butterfly type＂ rotor structure, built the three-dimensional analytical model of the air gap between rotor and stators under rotor eccentricity. The air-gap flux density and radial electromagnetic force were presented here based on finite element method （ FEM ） and Matlab simulation. The harmonic model for radial electromagnetic force distribution was analyzed quantitatively by magnetic scalar potential equation using spherical harmonic series. Finally, the rotor MF model has been validated by experiments of prototype system compared with analytical method and FEA. The results indicate that the motor eccentricity can cause serious effects, such as unequal air gap on both sides of the rotor, uneven flux distribution, unbalanced magnetic force and aggravated harmonic content.