Influence of stator slot geometry and rotor eccentricity on field distribution in cylindrical magnetic actuators
Influence of stator slot geometry and rotor eccentricity on field distribution in cylindrical magnetic actuators
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DOI：
10.1109/20.996023
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发表时间：
2002-08
影响因子：
2.1
通讯作者：
L. S. Stephens;M. Casemore
中科院分区：
文献类型：
--
作者：
L. S. Stephens;M. Casemore
本文提出了一种计算带槽定子和转子偏心的圆柱磁致动器瞬时气隙磁通分布的解析方法。该方法不依赖于渗透函数；因此，由此得到的磁链分布可用于计算执行器的特性，如负刚度、齿槽扭矩和反电动势。该方法采用傅里叶级数展开法对气隙边界上的电流分布和作为磁动势源的永磁体进行建模，然后求解永磁体和气隙区域内磁动势偏心环空中的Dirichlet边值问题。它通过在解中加入一个边界摄动步骤来解释狭缝效应，该步骤包括狭缝渗透率的降低。该方法应用于一个样本问题，考察了槽长和槽宽对负刚度系数的影响。该方法以有限元解为基准；在一定的临界槽长范围内，两种模型吻合良好。这个临界槽长度对应于传统的无限槽长度（超过该槽长度，通量分布不会发生明显变化）。虽然该方法适用于内转子结构的永磁电机，但它通常适用于许多作动器拓扑结构。
The paper presents an analytical method for computing the instantaneous air-gap flux distribution in cylindrical magnetic actuators with slotted stators and rotor eccentricity. The method does not rely on permeance functions; therefore, the resulting flux distribution can be used to compute actuator properties such as negative stiffness, cogging torque, and back-emf. The method uses Fourier series expansions to model current distributions and permanent magnets as sources of magnetomotive force (MMF) on the air-gap boundary and then solves the Dirichlet boundary value problem in the eccentric annulus for the MMF within the permanent magnet and air gap regions. It accounts for the slotting effect by adding a boundary perturbation step to the solution that includes the decreased permeance of the slots. The method is applied to a sample problem that examines both the effects of slot length and slot width on negative stiffness coefficients. The method is benchmarked against finite-element solutions; the two models agree well up to a certain critical slot length. This critical slot length corresponds to the traditional infinite slot length (that slot length beyond which no appreciable change in flux distribution occurs). While the method is applied to a permanent magnet motor of internal rotor construction, it is generally applicable to many actuator topologies.