摘要
铁氧体电感器在较高频率时可等效为"电阻、电感"的串联支路与一寄生电容的并联,该电容的存在对电感器的高频性能有重要影响。建立铁氧体环形电感器2D平行平面场和3D静电场有限元模型,分别计算任意两线匝之间的杂散电容,由此得到其等效电容网络。若在电感器输入和输出线匝间加一单位电流,基于节点电压方程,则可求解得到电感器的容性集中参数——寄生电容。在假定该寄生电容与频率无关时,利用测试电感器的谐振频率,可得到该寄生电容。计算与实验对比显示,电感器的边缘效应在静电场的模型建立中占据非常重要的地位,即包括线匝杂散电容计算在内的静电场分析必须以3D模型进行。若仅考虑相邻3匝间的杂散电容,则电感器等效寄生电容值可达考虑所有线匝间杂散电容时寄生电容的95%以上,寄生电容与铁氧体磁心和导线绝缘材料的介电常数呈线性关系,且绝缘材料的介电常数对寄生电容的影响更大。
In the higher frequency range, the ferrite core inductor can be considered as an equivalent circuit model, which is formed of a series branch of a resistance and an inductance paralleling a parasitic capacitance, and the capacitance can play an important role in the high performance of the inductor. The models of 2D parallel plane field and 3D electrostatic finite element （FE） for the toroidal ferrite core inductor are presented, and the stray capacitances between every two turns are calculated. Then, the equivalent network of capacitances can be obtained. If a unitary current is applied between the input and output turns of the inductor, the capacitive lumped parameter, i.e., the parasitic capacitance can be calculated using the node-voltage equation method. The stray capacitance can be measured using resonant frequency method on the assumption that the capacitance is independent of frequency. Contrasting calculated results with the measured one, it is shown that the fringe effect of inductor is very crucial to build electrostatic model, i.e., the problems of the electrostatic field must be analyzed using 3D model as well as calculating the stray capacitance of turn to turn for inductor. If only considering the stray capacitance between the adjacent three turns, the value of equivalent parasitic capacitance can reach to above 95% of the total value of which all turns of the coil are considered. The parasitic capacitance has a linear relationship with permittivity of the ferrite magnetic core and the insulating coats of conductor, in which it is more obviously influenced by the insulating coats.
出处
《电工技术学报》
EI
CSCD
北大核心
2009年第4期22-29,共8页
Transactions of China Electrotechnical Society
基金
台达电力电子科教发展基金
南京航空航天大学创新基金资助项目
关键词
电感器
有限元法
寄生电容
谐振频率
Inductor, finite element method （FEM）, parasitic capacitance, resonant frequency
