基于频变参数辨识的共模扼流圈集中参数模型

Lumped Parameters Modeling of Common Mode Chokes Based on Frequency-varying Parameters Identification

为避免传统阻抗测量法受寄生参数与导线非理想特性的影响,造成误差较大,以及无法表征模型参数随频率变化特性的问题,提出基于频变参数辨识的共模扼流圈高频建模方法。建立共模扼流圈高频集中参数模型,模型包括共模扼流圈的绕组电感、绕组漏感、绕组间寄生电容、绕组内寄生电容、磁心等效电阻和绕组铜损等效阻抗。采用在传统最小二乘法的基础上引入遗忘因子和矩形窗的算法,对模型中的频变参数进行辨识提取,证明了该方法的均方收敛性。通过对比一个实际共模扼流圈在150kHz～30MHz的扫频结果和仿真结果,验证了建模方法的合理性。研究发现,共模扼流圈在谐振频率处对电磁干扰的抑制效果最好,通过共模扼流圈对一开关电路产生的电磁干扰的抑制情况验证了这一结论。

In order to overcome the disadvantages in the impedance measurement which is influenced by parasitic parameters and nonideal characters of conductor lines as well as no way to perform the frequency-varying parameters,this paper presents high frequency modeling method of common mode chokes based on frequency-varying parameters.A high frequency lumped parameter model was built,which included winding inductances,leakage inductances,parasitic capacitances between and in the windings,equivalent resistances of magnetic cores and copper losses.On the basis of traditional least square method,the forgetting factor and rectangular window were introduced to estimate the frequency-varying parameters.The convergence in square mean of this method was also proved.The proposed modeling method is proved rationally by comparing the experimental result with simulation result between 150 kHz～ 30 MHz.The restraining effects are best at the resonance frequency of the common mode choke.And an experiment is conducted to verify the conclusion by restraining the electromagnetic interference produced by a switching circuit.