电力电子电路PCB电场串扰及屏蔽研究

Research on Electric Field Crosstalk and Shielding of PCB Conductors in Power Electronic Circuits

由于开关电源中存在高du/dt干扰源,这对PCB上的电压采样等敏感导线将产生强烈的电场串扰。本文通过COMSOL软件研究了PCB上干扰源和敏感导线间的寄生电容及屏蔽方法和效果,仿真获取了不同干扰源导线宽度w1、敏感导线宽度w2,长度为L,以及两者间距d下的寄生电容Cp值,再采用拟合函数的方法,得到了寄生电容Cp与[w1,w2,d]的关联函数,并进行了特性分析。在两根导线之间插入宽度为w3、长度为L1、与干扰源和敏感导线距离分别为d1和d2的屏蔽地线,分析屏蔽系数η与[w3/d,d 1/d2,L 1/L]之间的关联。最后通过实验验证了PCB电场串扰特性和屏蔽特性与理论分析基本吻合。

Due to the existence of high du/dt interference sources in the switching power supply,this will cause strong electric field crosstalk to sensitive wires such as voltage sampling on the PCB.This article uses COMSOL software to study the parasitic capacitance and shielding methods and effects between interference sources and sensitive wires on the PCB.The parasitic capacitance Cp values of different interference source wire width w1,sensitive wire width w2,a nd the distance d between the two are obtained by COMSOL software simulation.Then,the relationship between the parasitic capacitance Cp and[w1,w2,d]are obtained by the fitting function method.Then,the shield ground is inserted between the two wires,and the correlation between the shielding coefficientηand[w3/d,d1/d2,L1/L]is also analyzed.Finally,it is verified by experiments that the crosstalk characteristics and shielding characteristics of PCB electric field are basically consistent with the theoretical analysis.