基于等效电流密度模型的多层有限长螺线管轴线磁场分析

Analysis on the Axial Magnetic Field of Multi-layer Finite Solenoid Based on the Equivalent Current Density Model

为了解决短杆轴向霍尔磁场探头现场校准的难题,提出了采用便携式有限长螺线管作为标准磁场发生器的方法。建立圆柱坐标系下螺线管线圈模型,并提出等效电流密度(ECD)法,结合Biot-Savrt定理及磁场叠加原理,计算其轴线磁场强度,获得多层有限长螺线管轴线磁场的分布规律。同时,建立了多层有限长螺线管静磁场有限元模型,仿真计算获得给定激励电流条件下的空间磁场分布情况。根据理论分析结果,设计了中心磁场100 mT的螺线管试验样机,对ECD模型理论计算结果、仿真分析结果和样机测试数据进行对比。结果显示,在螺线管中心处,理论计算与仿真结果偏差在0.1%以内,试验测试结果与理论计算偏差在0.8%以内。分析结果验证了ECD法分析螺线管轴线磁场的有效性。该方法对于提高螺线管结构设计效率、优化设计参数等具有重要意义。

In order to resolve the calibrating problem of axial Hall magnetic probe with short rob,a portable finite solenoid was proposed as the reference magnetic field generator.The axial magnetic filed was calculated to obtain its distribution based on the Biot-Savart law and superposition principle of magnetic field,by establishing the solenoid model in a cylindrical coordinate system.In addition,a finite element model(FEM)was established for the multi-layer finite solenoid to analyze its spatial magnetic filed with given exciting current.A solenoid prototype with 100 mT central magnetic intensity was designed according to above theoretical analysis.The data from the ECD model,FEM and prototype testing were compared,and the results show that at the solenoid center the deviation between theoretical calculation and FEM is less than 0.1%,and it's less than 0.8%between theoretical calculation and prototype testing.It's demonstrated that the ECD model is effective to analyze solenoid axial magnetic field.This method is suggested to be applied in designing and optimizing parameters of a finite solenoid more efficiently and accurately.