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发布时间：2018-04-18 09:16

本文选题：线束 + 串扰　；参考：《南京航空航天大学》2017年硕士论文

【摘要】：线缆是复杂电气、电子系统中重要的连接部件,其长线的固有特点导致线缆容易受到电磁干扰,导致系统的可靠性降级甚至失效。在设计的早期阶段预测线缆耦合电磁干扰可以让设计人员及时解决潜在的电磁干扰问题,从而降低了后期整改的成本投入,因而受到了广泛关注。目前对线缆间耦合电磁干扰的预测已经有较多研究,研究内容主要集中在线缆的耦合机理,对于线束这一典型对象所产生的耦合电磁干扰的预测仍需深入。为此,以多导体线束为研究对象,本文将开展一系列研究,主要包括以下几部分:1.阐述了平行线缆间耦合电磁干扰噪声预测模型的建立。利用模量转换法,结合终端边界条件求解多导体传输线方程;利用有限元软件ANSYS获取电磁参数;还简单介绍了矩量法,利用电磁仿真软件FEKO验证本文建立的模型。2.深入研究了线束内串扰噪声的概率分布特性。线束内导线存在扭绞、换位的特性,束内导线间的串扰也具有不确定性。假定线束横截面固定,导线的换位仅是改变导线位置,则每段导线都存在相同的互有参数分布。利用卷积获得整个线束的互有参数概率分布,进而利用蒙特卡洛方法求得线束内串扰的概率分布特性。实验结果表明,线束的扭绞程度和线束内串扰的概率分布规律密切相关。3.讨论了在均匀外施激励场条件下,线缆的场耦合模型。利用模量转换法求解方程,并给出方程特解和待定系数的求解思路。在垂射式(垂直极化)和侧射式(水平极化)两种入射条件下,以均匀平面波为激励源,对噪声电压进行预测和仿真。对比结果表明,场耦合的噪声大小与入射场的大小和方向、线束的几何结构有关。4.探究存在非均匀激励场时,噪声预测的处理方法。对于非均匀复杂电磁场,其特解的求解不再是均匀平面波激励的简单情形。通过FEKO进行电场采样的方法,得到多导体传输线沿线等效电压、电流源,利用三次样条插值方法求得方程特解,进而利用边界条件获得噪声的仿真电压。利用一个电偶极子产生的非均匀场的实例进行仿真和对比验证。此外,搭建实验平台在一电波暗室中依靠周期对数天线产生激励,在100~220MHz进行测量,测量实验与仿真结果的趋势基本吻合。
[Abstract]:Cable is an important connecting part in complex electrical and electronic system. The inherent characteristics of long wire lead to electromagnetic interference and downgrade or even invalidation of system reliability.In the early stage of the design, the cable coupling electromagnetic interference can be predicted for designers to solve the potential electromagnetic interference problem in time, thus reducing the cost of the later rectification investment, so it has attracted wide attention.At present, much research has been done on the prediction of coupling electromagnetic interference between cables and cables. The research mainly focuses on the coupling mechanism of cable, and the prediction of coupling electromagnetic interference caused by wire harness, a typical object, still needs to be further studied.Therefore, a series of studies will be carried out in this paper, including the following parts: 1: 1.The noise prediction model of coupled electromagnetic interference between parallel cables is presented.The method of modulus conversion and terminal boundary condition are used to solve the multi-conductor transmission line equation, the finite element software ANSYS is used to obtain the electromagnetic parameters, and the method of moments is briefly introduced, and the electromagnetic simulation software FEKO is used to verify the model. 2.The probability distribution of crosstalk noise in wire harness is studied.There are twisting and transposition of wires in the wire harness, and the crosstalk between the wires in the bundle is uncertain.Assuming that the cross section of the wire harness is fixed and the transposition of the conductor is only to change the position of the conductor, each section of the wire has the same distribution of mutual parameters.The probability distribution of mutual parameters is obtained by convolution, and the probability distribution of crosstalk in the harness is obtained by Monte Carlo method.The experimental results show that the twisting degree of the wire harness is closely related to the probability distribution of crosstalk in the wire harness.The field coupling model of cable is discussed under the condition of uniform external excitation field.The modulus conversion method is used to solve the equation, and the special solution of the equation and the solution of the undetermined coefficient are given.Under two kinds of incident conditions: vertical (vertical polarization) and lateral (horizontal polarization), the noise voltage is predicted and simulated with uniform plane wave as excitation source.The results show that the noise of the coupling is related to the size and direction of the incident field and the geometric structure of the wire harness.The processing method of noise prediction in the presence of nonuniform excitation field is explored.For the nonuniform complex electromagnetic field, the solution of the special solution is no longer a simple case of uniform plane wave excitation.The equivalent voltage and current source along the multi-conductor transmission line are obtained by the method of electric field sampling by FEKO. The special solution of the equation is obtained by using cubic spline interpolation method, and the simulation voltage of noise is obtained by using boundary conditions.An example of inhomogeneous field generated by an electric dipole is used for simulation and comparison.In addition, the experiment platform is built in an anechoic chamber to generate excitation based on the periodic logarithmic antenna, and the measurement is carried out in 100~220MHz. The experimental results are in good agreement with the simulation results.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN811

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