超磁致伸缩体内涡流效应有限元分析

为补偿涡流效应产生的温度与反相磁场对超磁致伸缩微位移驱动体位移输出造成的非线性,从电磁场基本原理出发,推导了超磁致伸缩驱动器内的涡流分布和大小的数学模型。利用伽辽金加权余量法和牛顿-拉夫逊迭代法得到涡流效应数学模型的解析公式。通过解析公式分析超磁致伸缩驱动器内驱动体横截面上的电磁场分布,进而得到驱动体上各部分涡流大小及分布与输入电流频率增加的对应关系。当输入频率大于1 kHz时,涡流有限元模型计算得到的涡流导致磁场损耗量与实测磁场强度相差约4.6 mT,表明此模型可以对超磁致伸缩驱动体内的涡流损耗进行有效的补偿。

Analysis on eddy current effect in giant magnetostriction with finite element method

To compensate the nonlinear displacement of the giant magnetostrictive micro-displacement actuator caused by temperature and eddy current induced reverse magnetic field, a mathematic model used to describe the distributing and magnitude of eddy current in the giant magnetostrictive micro-displacement actuator was derived based on electromagnetic theory. Galerkin method and Newton-Laphson iteration were used to analyze the mathematic model of eddy current. The electromagnetic field distributing of cross-section in the giant magnetostriction micro-displacement was calculated by this mathematic model to gain the corresponding relation of eddy current and frequency of input current in actuator. When the frequency of input current is greater than 1 kHz, the difference of the dissipation of eddy current induced magnetic field calculated by eddy current model of finite element with magnetic field intensity measured actually is 4.6 mT,which shows that the model can effectively compensate the dissipation of the giant magnetostriction micro-displacement actuator caused by eddy current.