【作者】 郑亚利；

【导师】 汪泉弟；

【作者基本信息】 重庆大学 ， 电气工程， 2011， 博士

【摘要】 在汽车向电子化、智能化方向发展的趋势要求下,车载电子设备不断的增加,而线束作为各种电子设备的连接纽带,在汽车的电器网络中扮演着十分重要的角色,可以说没有线束网络就没有汽车电气系统,汽车的电子化、智能化也就不可能实现。另一方面,车内电子设备增加的同时也恶化了汽车内部的电磁环境,线束的增多则使车内的电磁兼容问题更加严重。因此,为保证汽车的安全性和可靠性,建立适用于汽车电磁兼容仿真的线束模型成为具有重要理论意义和工程价值的研究课题。本论文在国家自然科学基金项目“汽车电磁兼容预测与电磁干扰抑制关键技术研究”(No.50877081)及重庆市自然科学基金重点项目“汽车电气系统电磁兼容性研究”(No.CSTC,2006BA6015)的资助下,重点研究了汽车线束在电磁兼容研究中的建模仿真方法,并对建模方法进行了实验验证。在研究过程中,综合运用了电磁场、电路及电磁兼容技术和测试方法的基本理论,实现了用“路”的方法对线束的等效、用“场”的方法对线束等效模型电磁辐射敏感度及电磁辐射发射的仿真分析。其主要工作如下:①从Maxwell基本方程组出发,详细系统的推导出了多导体传输线方程,解释了电容矩阵元素的物理意义;讨论了多导体传输线的单位长度电感、电容矩阵的解析解和数值解,为汽车线束多导体传输线方程的电感矩阵和电容矩阵的计算奠定了基础。②提出了描述多导体传输线电磁特性的等效波阻抗的定义,推导出了计算公式;根据导线终端负载与等效波阻抗的相对大小关系对导线进行了分组,使得线束最多等效为4根等效导线,简化了线束建模的复杂度。研究了导线终端的差模负载、共模负载、激励源的等效处理方法,完成了线束等效模型的理论基础研究,建立了线束等效模型。实现了用“路”的方法建立线束的等效模型,为线束电磁兼容性的高效计算创造了条件。③推导了外界入射波在导线上产生感应电流的计算公式,分析得到了导线上产生感应电流的外界入射波的耦合方式;仿真验证了有限元方法计算导线感应电流的有效性;讨论了导线终端负载、终端结构及周围绝缘介质对感应电流的影响;以9根导线组成的线束为例,详细叙述了建立线束电磁辐射敏感度等效模型的全过程。该算例的仿真结果说明线束等效模型在保证等效前后计算精度不变的前提下明显节约了计算资源。实现了“场”的方法对线束等效模型的仿真分析。设计并搭建了由7根导线组成的线束电磁辐射敏感度的实验平台,在半电波暗室中实现了测试,与仿真结果对比说明了等效模型的正确性。④由天线辐射原理建立了导线辐射发射的简单模型,验证了有限元法计算导线周围电场强度、磁场强度和辐射总功率的有效性;讨论了导线终端负载、终端结构及周围绝缘介质对电磁辐射发射的影响;以12根导线组成的线束为例,阐述了建立线束电磁辐射发射等效模型的过程,验证了在导线终端负载与线束等效波阻抗相同的情况下,该导线分组的灵活性。该算例的仿真结果说明,在保证计算精度不变的前提下,等效模型提高了计算速度并降低了对计算资源的要求;由7根导线组成的线束电磁辐射发射实验说明了等效模型的正确性。⑤在深入分析汽车点火系统传导电磁干扰的基础上,得出了点火系统的辐射电磁干扰主要来源于点火线圈初级侧电流,并通过初级侧线缆的天线效应对外产生辐射的结论,由此建立了点火系统电磁辐射发射的等效模型;介绍了利用汽车CAD数据在HFSS软件中建立电磁兼容预测的有限元整车车体模型的方法,并通过了实验验证;仿真分析了汽车点火系统的电磁辐射发射在车内线束上产生感应电流,说明了线束等效模型可用于分析研究汽车电磁兼容性问题。⑥根据汽车底盘的大小设计了复杂的线束网络,建立了线束网络的等效模型;仿真结果表明线束等效模型可以用于结构复杂的线束网络中,并且在保持计算精度不变的情况下,大大降低了计算时间、计算机内存。更多还原

【Abstract】 With the development of the electronic and intelligent technology, auto electronic equipments are increasing rapidly. For the electronic devices in the automotive electrical network varying, the wiring harness plays an important role. Without it, there are no electronic and intelligent autos. Meanwhile, the increase of electronic equipments worsens the auto electromagnetic environment. Especially with the wiring harness growing in number, the automotive electromagnetic compatibility (EMC) becomes more serious. Therefore, in order to ensure vehicle safety and reliability, setting up automotive wiring harness model for EMC simulation become significant whether in theoretical field or in engineering research field.This thesis, supported by the National Natural Science Foundation of China,“Automotive EMC forecast and key technologies for electromagnetic interference suppression”(No.50877081) and Chongqing Natural Science Foundation of China,“Electromagnetic Compatibility for Automotive Electrical System”(No.CSTC, 2006BA6015), focuses on the emulation methods of automotive wiring harness and experimental verification.In the course of this research, the thesis uses the electromagnetic theory, circuit theory, and EMC technology theory and testing method. The aspects concerned are as follows:①Deduce Multi-conductor transmission line equation from Maxwell fundamental equations in details and explains the physical meaning of capacitance matrix elements, and discuss the analytical and numerical methods of multi-conductor transmission line unit length inductance and capacitance matrix. These are the foundations for calculating the automotive wiring harness multi-conductor transmission line inductance matrix and capacitance matrix.②Propose the principle of equivalent impedance defined the electromagnetic characteristics of the multi-conductor transmission line. Then, the equivalent impedance formula is deduced. According to the size of the terminal impedance and the equivalent impedance, the wiring harness can be classified in different groups. This approach greatly simplifies the wiring harness modeling by making the multi-conductor transmission lines reduce to four groups mostly. The equivalent methods of calculating differential-mode load, the common-mode load and the source are obtained. Establish the equivalent model by the circuit for the wiring harness efficient simulation.③The induced current by the plane incident wave is calculated from the electromagnetic wave theory. Analyze the coupling modes which can produce the induced current. Verify the effectiveness of the finite element method (FEM) in calculating the induced current. Discuss the terminal load, terminal structures and the dielectric effect in the induce current. Taking the wiring harness consisting of nine conductors for example, the whole process of establishing the equivalent model for electromagnetic radiation (EMR) sensitivity is described in details. The emulation results show that the wiring harness equivalent model can save computing resources under accuracy condition. The experiment which is carried out in the semi-anechoic chamber validates the correctness of the equivalent model for EMR sensitivity emulation.④Establish the simple wire radiation emission model based on the antenna theory. Verify the effectiveness of the FEM to calculate the electric field strength, the magnetic field strength, and the total power of radiation around the wire. Discuss the terminal load, terminal structures and the dielectric effect in the EMR emission. Taking the wiring harness consisting of 12 conductors for example, the whole process of establishing the equivalent model for EMR emission is described in details. The example proves that the conductor can be classified flexibly if its terminal load is equal to the equivalent impedance, and it also illustrates that the wiring harness equivalent model can save computing resources under accuracy condition. The experiment validates the correctness of the equivalent model for EMR emission emulation.⑤Based on the analysis of the ignition system conducted electromagnetic interference (EMI), it is drawn conclusion that the radiated EMI of the ignition system is come from the current flowing through ignition coil primary side which acts as an antenna in this situation. Thereby, the EMR emission model of the ignition system is established. The process of building the vehicle body FEM model in HFSS software for EMC forecast is introduced. The experiment certificates the model. The induced current in the vehicle wiring harness generated by ignition system EMR emission is simulated using the equivalent model, and it shows that the equivalent model can be used in automotive wiring harness for EMC analysis.⑥Establish a harness network according to the size of the chassis. The harness network equivalent model is built by the wiring harness equivalent model. The emulation results show that the equivalent model can be used to the complex structure harness network. Under the accuracy condition, it can reduce the computation time, computer memory greatly.更多还原