用于经颅磁刺激铁芯线圈的仿真研究

Simulation research on iron-core coils for transcranial magnetic stimulation

目的研究铁芯线圈感应电场的仿真方法,分析铁芯截面大小对线圈性能的影响。方法针对铁芯线圈结构复杂及存在非线性介质的特点,采用有限元分析软件Ansoft对铁芯线圈模型进行瞬态磁场仿真,求解不同铁芯大小的线圈模型在空间域的感应电流分布,利用静态仿真求解电感值。结果计算出不同线圈在深度5 mm沿坐标轴的电场分布曲线,并统计曲线中旁峰值与最大值之比。对比仿真结果发现随着铁芯截面增大,线圈的刺激强度与电感值增加,聚焦性能先增强后减弱。当铁芯截面约为空心区域面积1/16时,铁芯线圈聚焦性最好。结论本研究对带铁芯磁刺激线圈的设计具有参考作用。

Objective To investigate a simulation method for induced electric field of iron-core coils and analyze the influence of iron core with different cross-section size on the coil performance. Methods Due to iron-core coils with complex structure and nonlinear material,transient magnetic field simulation of iron-core coils was conducted by the finite element software Ansoft. The induced current distributions of the coils with different core size were simulated and inductance value was conducted by using static simulation solution. Results The electric field distribution curves of coils in the depth of 5mm along the coordinate axis were calculated,and the ratio of the second peak value and the maximum value in the curve was counted. As the cross-section of the iron core increased,both stimulus intensity and inductance of iron-core coils increased,focusing performance first increased and then decreased. Besides,the coils with iron core whose cross-section is about 1/16 of the hollow area had the best focusing performance. Conclusions This research provided a point of reference for the design of iron-corn coils for transcranial magnetic stimulation.