混合动力汽车直流电源变换系统传导电磁干扰分析与抑制研究

发布时间：2018-03-01 22:12

本文关键词： 混合动力汽车电源变换系统电磁兼容电磁干扰传播路径建模寄生参数抑制方法滤波器　出处：《重庆大学》2014年博士论文　论文类型：学位论文

【摘要】：混合动力汽车相比传统汽车电磁兼容(Electromagnetic Compatibility, EMC)问题更加突出，其车载大功率电力电子设备产生的强烈电磁干扰(ElectromagneticInterference, EMI)会对自身系统和车内其它系统造成干扰影响。为了解决混合动力汽车大功率电力电子系统的EMC问题，本文重点研究车载大功率直流电源变换器系统EMC问题，掌握该系统的EMI测量方法、产生机理、传播路径、预测模型和优化方案，本文的研究思路和方法可以推广到解决车载其它EMC问题较突出的系统研究中，能够为混合动力汽车EMC问题研究提供理论和实践指导。论文主要研究内容及取得的成果有： 1）采用消耗型铁氧体磁环对直流电源变换系统线束EMI进行排查，对多个线束上的EMI信号进行独立测量，获得直流电源变换系统单独产生的EMI水平。采用小波变换分解EMI信号并提取对应的小波系数，基于各分解尺度下的小波系数计算出了干扰信号频域内的三种特征参数：累积能量参数、突变参数和不平衡参数，该特征参数能够表征时域EMI信号的频域特征。 2）通过对直流电源变换器系统EMI产生机理分析，建立了产生干扰振荡波形的等效电路模型，并推导出振荡波形的数学表达式，该数学模型能够表征干扰波形的主要特征。在EMI传播路径研究过程中，依据变压器主电路中变压器的结构和初次级线圈之间寄生电容的分布，建立了EMI通过变压器的耦合路径模型。推导出了EMI从初级绕组耦合到次级绕组的机理，并定性分析出降低EMI耦合作用的三种方法。 3）建立了直流电源变换器系统传导EMI预测模型，包含的子模块主要为：基于传输线理论的电缆模型、基于多软件联合仿真计算的变压器和带铁芯电感的“实体-场-路”模型、干扰源的集中等效模型、基于静电场有限元方法的寄生电容计算模型。将各个模块的模型集合成系统仿真模型，，仿真计算得到系统的传导EMI水平，并通过实验对比验证了该系统EMI预测模型的准确性。 4）基于直流电源变换器系统差模和共模EMI传播路径，分别建立其等效电路模型，分析得出功率器件对机壳的寄生电容是影响系统共模EMI水平的重要因素，提出通过改变寄生电容大小的方法来改善系统EMI。通过仿真分析增大功率器件导热片与散热器之间导热硅脂的填充厚度，减小导热片与散热器之间导热硅脂的介电常数，以及减小功率模块导热片的面积这三种优化方法，能够有效地降低系统共模EMI水平，并根据实验条件验证了前两种优化方法在低频段抑制传导EMI的正确性和有效性。 5）设计研究了电源变换器系统EMI滤波器。通过测量直流电源变换器系统干扰源内阻抗和电源线EMI水平，建立滤波器的高频等效电路模型并提取参数，通过对滤波器插入损耗的仿真验证了滤波器的有效性，并将设计制作的滤波器加入直流电源变换器系统进行滤波效果验证，实验结果表明本文所设计的EMI滤波器能够有效地抑制变换器系统电源线上的传导EMI水平，并且弥补了导热硅脂只能抑制低频EMI的缺陷。
[Abstract]:Hybrid cars compared to the traditional automotive electromagnetic compatibility (Electromagnetic Compatibility EMC) problem is more prominent, strong electromagnetic interference of the automotive power generated by power electronic equipment (ElectromagneticInterference, EMI) will cause interference on the system itself and other systems. In order to solve the problem of the car EMC hybrid car power electronic system, this paper focuses on the study on on-board high-power DC power converter system EMC, master EMI measurement method, the system mechanism, propagation path, prediction model and optimization scheme, research ideas and methods of this paper can be generalized to solve other EMC system of vehicle is a prominent problem in providing theoretical and practical research on dynamic EMC problem hybrid car guidance. The main research contents and results are:
1) the consumption of ferrite magnetic investigation on DC power conversion system of wire harness EMI, independent measurement of EMI signal of a plurality of wire harness, DC power converter system independently generated EMI level. The wavelet coefficients using wavelet transform to decompose EMI signals and extract the corresponding wavelet coefficients, the scale is calculated three parameters in the frequency domain interference signal based on cumulative energy parameters, mutation parameters and unbalanced parameters, the parameters can characterize the frequency domain EMI signal.
2) through the analysis of the mechanism of DC power converter system EMI, established equivalent circuit model of interference waveform, and deduced the mathematical expression of oscillation waveform, this mathematical model can be used to characterize the main interference wave. In the transmission path of the EMI in the course of the study, based on the structure and distribution between the primary and secondary coils of transformer circuit the transformer parasitic capacitance, EMI is established by coupling path model of transformer is deduced. The mechanism of EMI from the primary winding is coupled to the secondary winding, and the qualitative analysis of three kinds of methods to reduce the coupling effect of EMI.
3) establish conduction EMI DC power converter system model, sub module mainly contains: cable model based on transmission line theory, based on multi software co simulation calculation of transformer and inductor iron "entity field circuit model, centralized equivalent model of interference source, calculation model of parasitic capacitance Co. finite element method based on the electrostatic field. The set of modules into a system simulation model, simulation system EMI transmission level, and verified by experiment of the system EMI the prediction accuracy of the model.
4) DC power converter system of differential mode and common mode EMI propagation path based on established the equivalent circuit model, analysis of parasitic capacitance of power device of the housing is an important factor that affects the system of common mode EMI level, proposed by changing the size of the parasitic capacitance to improve the EMI. system through simulation analysis of filling thickness increases between the power devices conducting sheet and radiator thermal grease, the decrease in dielectric constant between the conducting sheet and radiator thermal grease, and reduce the power module thermal film area of these three optimization methods can effectively reduce the EMI level low common mode system, and verify the correctness and effectiveness of the optimization method two EMI suppression at low frequency according to the experimental conditions.
5) design of EMI filter for power converter system. Through the power line impedance and EMI level measurement of DC power converter system interference source, a filter high frequency equivalent circuit model and parameter extraction, through the simulation of the filter insertion loss to verify the effectiveness of the filter, and the filter design with DC power converter system for filtering effect verification, the experimental results show that EMI filter designed in this paper can effectively restrain the power line transmission converter system EMI level, and make up for the defects of thermal grease can only inhibit the low frequency of EMI.

【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM46

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