复杂电子系统电磁干扰噪声机理建模与抑制方法研究

【作者】 颜伟；

【导师】 王恩荣； 赵阳；

【作者基本信息】 南京师范大学 ， 物理电子学， 2014， 博士

【摘要】 随着汽车电子、无线通讯和物联网等行业不断发展,大量电子设备通过线缆传输和空间耦合方式产生大量的电磁干扰(EMI)噪声,引起严重的电磁环境污染,并影响同一电磁环境内其它电子设备的正常运行。针对上述问题,本文：(1)评估了人工电源网络拓扑结构高频寄生参数对传导EMI噪声标准检测不确定度的影响；建立了基于平衡和非平衡噪声电流的共模和差模传导EMI噪声模型；提出了基于射频变压器和共模扼流圈的新型噪声分离网络,以及基于双阻抗校准和麦夸尔特法的噪声源内阻抗提取方法。(2)建立了基于电偶极子和磁偶极子的共模和差模辐射EMI噪声模型及其等效电路；提出了基于近场波阻抗的辐射EMI噪声机理诊断方法及其近场辐射机理诊断实验台；还提出了基于电压驱动模型的辐射EMI噪声预估方法。(3)提出了因串扰、接地不良和阻抗失配引起的传导EMI噪声抑制方法,以及因接地不良、信号大环路、串扰、传输线缆和阻抗失配引起的辐射EMI噪声抑制方法。(4)建立了磁流变阻尼器(MRD)励磁线圈传输阻抗等效电路；建立了MRD及其半主动控制策略通过线缆传输和空间耦合引起的传导和辐射EMI噪声模型；提出了基于外壳结构和励磁电路优化设计的MRD的EMI噪声抑制方法；还提出了一种不带延时的半主动控制信号平滑滤波算法,以有效降低MRD半主动控制策略引起的EMI噪声。理论仿真与实验结果表明,文中新网络的特性参数优于Mardiguian网络,其中差模插入损耗降低了2dB,差模抑制比提高了8dB；噪声源内阻抗提取方法能够获取被测阻抗的幅频、相频特性及其等效电路参数,测试精度较高且.不存在约束条件；辐射噪声诊断方法能够得到被测设备表面的电场和磁场分布情况及其近场波阻抗随测试距离的变化关系,以有效提取共模和差模辐射EMI噪声；辐射噪声预估方法能够根据线缆中的噪声电流、测试距离和线缆辐射阻抗估计最大辐射电场强度,尤其是250MHz以前；噪声抑制方法能够有效降低车载导航、医疗设备和电力设备等8款电子产品的传导和辐射EMI噪声,并通过GB9254标准；MRD传输阻抗提取方法能够有效提取静态和不同驱动电流条件下的MRD励磁线圈传输阻抗的幅频和相频特性；MRD结构和励磁电路优化设计及其控制信号平滑滤波算法能够有效降低EMI噪声,为今后MRD及其半主动控制策略等复杂电子系统EMI噪声抑制方案的设计提供理论依据与实践指导。更多还原

【Abstract】 With the rapid development of automotive electronics, wireless communications and the internet of things, electromagnetic interference(EMI)noises are produced by the electronics devices via cable transmission and space coupling, which give rise to severe electromagnetic environment pollution and affect the operational functions of the other electrical equipments. According to the above problems, in the paper:(1) The uncertainty of conducted EMI noise standard measurement was evaluated based on high frequency parasitic parameters in circuit topology of artificial mains network. Common mode (CM) and differential mode(DM) conducted EMI noise models were established based on balance and non-balance noise circuits.A novel noise separation network was proposed with radio-frequency transformer and CM choke. And noise source impedance was extracted by employing dual resistances calibration and Levenberg-Marquardt’s algorithm.(2) CM and DM radiated EMI noise models and equivalent circuits were established based on electric dipole and magnetic dipole.Radiated EMI mechanism and its experimental setup were proposed through the relationship between near field wave impedance and measurement distance. And radiated EMI noise was estimated by employing voltage driven model.(3) Conducted EMI noise suppression methods were presented based on crosstalk, no well grounding and impedance mismatch, and radiated EMI noise suppression approaches were proposed according to no well grounding, large loop signal,crosstalk, transmission line and impedance mismatch.(4) The equivalent circuit of the excitation coil’s transfer impedance was introduced for magneto-rheological damper(MRD).Conducted and radiated EMI noise models were established through cable transmission and space coupling based on MRD and its semi-active control strategy. EMI noise suppression methods of MRD were proposed by employing the optimization design of shell structure and excitation circuit. Smoothing filter algorithm without delay of the semi-active control signal was designed for radiated noise reduction.The theoretical simulation and experimental results show that the characteristic parameters of the present novel network, whose DMIL decreases2dB and DMRR increases8dB,are superior to Mardiguian’s network. The amplitude frequency and phase frequency characteristics and their equivalent circuits can be obtained by using the proposed method with high precision and no constraint. The electric field and magnetic field distribution and the relationship between near field wave impedance and measurement distance can be analyzed based on radiated noise diagnosis method, which can separate CM and DM noises.The maximum radiated electric field intensity can be calculated through noise circuit in the cable, measurement distance and radiated impedance of the cable according to the present radiated noise estimation approach, especially250MHz before. The conducted and radiated EMI noises can be reduced effectively and pass GB9254for8electronics products, such as vehicle navigation, medical equipment and electric power equipment. The amplitude frequency and phase frequency characteristics of the excitation coil’s transfer impedance of MRD can be extracted based on the introduced method under the condition of static and different drive current.The EMI noises of MRD and the semi-active control strategy are suppressed efficiently by employing the optimization structure and excitation circuit of MRD and smoothing filter algorithm without delay, which can provide theoretical basis and practical guidance to scheme design of the EMI noise reduction for the complex electronics devices, such as MRD and its semi-active control strategy.更多还原