薄介质型集成模块传输线间耦合电容的提取

滤波器是抑制传导干扰的重要元件,平面滤波器以寄生参数小、抗电磁干扰强的优点在电力电子领域有较好的应用前景。提出一种以"桶壁型"感容结构为基础的EMI滤波器,它与平面型滤波器可以统称为薄介质型滤波器,其线匝间部分电容对该类滤波器性能有重要影响。以薄介质型滤波器为研究对象,建立轴对称静电场模型并计算任意线匝间的耦合电容。若分别将正对位置的两线匝看作微型平行板电容器和微型同轴圆柱电容器,则由解析表达式可以计算其耦合电容并与采用有限元法计算的电容值比较,并研究影响二者误差的相关因素。研究发现,在一般工程应用中,解析表达式的精度符合要求,可以不必采用数值计算方法计算匝间耦合电容,为该类滤波器的设计带来极大的方便。

Extraction of Coupling Capacitance among Transmission Lines of Thin Dielectric Material Integrated Module

Filter is an important component to restrain conducted interference.Planar EMI filter has a good application prospect in power electrics system for its advantages of small parasitic parameter and strong ability in anti-electromagnetic interference.An integrated structure formed by an "inductor-capacitor" in the shape of barrel wall was proposed firstly,which can be called thin dielectric filter with the planar EMI filter.As the thin dielectric filter's turn-to-turn partition capacitance,it has an important effect on the performance of this kind of filter.An axisymmetric electrostatic field model was established and turn-to-turn coupling capacitance can be calculated by researching the thin dielectric filter.The aspectant turns can be regard as the miniature plane-parallel capacitor or the coaxial cylindrical capacitor,thus the coupling capacitance can be calculated and the error compared to analytical expressions can be obtained.And then,the relevant factor of the error was researched.The result shows that in engineering applications the analytical expressions could meet actual requirement and there is no need to use the numerical computing method,which bring great convenience for designing the EMI filter.