Hybrid Common-mode EMI Filter Design for Electric Vehicle Traction Inverters

A feedforward current-sense current-compensation(CSCC)active EMI filter(AEF)for the direct current-side common-mode(CM)electromagnetic interference(EMI)suppression of high-power electric vehicle traction inverters is analyzed and designed.A detailed design of the components with formulas is provided based on an analysis of the CSCC AEF,including the CSCC AEF topology and its implementation.The feedforward active filter stage was implemented using a simple current transformer and a small circuit board.Only a small passive filter with a high resonant frequency is required for high-frequency noise attenuation.The filter’s effectiveness was validated using the simulation results and experimental measurements.

Dual-current-injection CSCC Active Common-mode EMI Filters with High Insertion Loss for DC-DC Converters

With the increase in the switching frequency and power density,DC-DC converters encounter more severe electromagnetic interference(EMI)problems.To suppress the common-mode EMI generated by converters,as well as maintain the high-power-density of converters,the active EMI filter(AEF)has attracted increasing interest owing to its small volume.The EMI suppression effect of the common single-stage single-sense single-injection AEF is confined because of the limited insertion loss,and the volume of the multi-stage AEF will be bulky.To solve this problem,this paper proposes a compact dual-current-injection current-sense current-compensation(DCJ-CSCC)AEF to increase the insertion loss in the entire conducted EMI frequency band,as well as considering the volume of the AEF.The structure and operating principle of the proposed AEF are introduced.Finally,taking a boost converter as an example,the effectiveness and advantages of the proposed DCJ-CSCC AEF were verified through a simulation and experiment,the results show that the proposed AEF has a better EMI suppression effect on the entire conducted EMI frequency band with a similar volume compared with existing single-injection feedforward current-sense current-compensation(FF-CSCC)and feedback current-sense current-compensation(FB-CSCC)AEFs.This paper provides a new selection for EMI suppression in DC-DC converters.

Research and Modeling on the Characteristic Changes of EMI Filter Passive Components under the Influence of Aging

At present,the power density of power electronic devices in data centers and electric vehicles is constantly increasing,and numerous electronic components are concentrated in a tight,high-temperature environment,which aggravates the performance degradation of electronic components.Consequently,X and Y capacitors,common-mode inductors,and differential-mode inductors used for electromagnetic interference(EMI)suppression suffer from aging effects,and their performance continues to decline.However,the electromagnetic compatibility test is often conducted immediately after the power electronic equipment leaves the factory.The electromagnetic compatibility of power electronic equipment is affected by aging,which is not assessed in current industrial testing.This study conducts aging experiments on passive electronic components in EMI filters and measures the impedance in the frequency range from 150 kHz to 30 MHz.Subsequently,a multi-element aging model based on electromagnetic field analysis is established.The proposed model is suitable for electromagnetic compatibility analysis considering aging.Finally,the aging performance of a commercial two-stage EMI filter is predicted to verify the model proposed in the study.The proposed model explains the degeneration of the EMI filter with aging in the frequency range of 150 kHz to 1 MHz,with a maximum amplitude error of 0.58 dB and phase error of 1.0°.

Filter Design of Wireless Base Station Power Supply

The design of electromagnetic interference(EMI)filters needs to fulfill the EMI standards.Designing a filter is a time-consuming process for new engineers as well as for those experienced engineers.This paper measures and compares the noise spectrum of the wireless base station power prototype with and without the original filter.The ideal insertion loss(IL)of the original filter is obtained by combining calculation and simulation.It is pointed out that the effect of the original filter is not good.Based on the improved insertion-loss method,the source impedance model of the prototype is established by combining measurement and theory.A procedure for designing EMI filters for switch power supply will be presented.The filter design procedure makes it possible to design filters quickly and easily.Finally,the proposed filter design method is proved to be effective by the EMI measurement of the wireless base station power supply prototype.

具有软启动功能的EMI直流滤波器设计

宽禁带半导体器件的应用使电动汽车的电机驱动系统更加小型化和轻量化,但也引发了更为严重的电磁干扰,使得驱动系统的可靠性面临严峻挑战。为此,以24 V/2 A的EMI直流滤波器为例,通过噪声源、滤波器原理及阻抗影响的分析,依据插入损耗指标进行滤波器参数设计。同时,考虑到整车启动时刻的启动冲击,加入软启动电路,进一步提高电动汽车驱动系统可靠性。实验测试验证了滤波器的电磁干扰抑制效果和软启动性能,证明了滤波器设计的可行性和有效性。

基于电磁干扰对消EMI有源滤波模块设计

针对火控设备因开关电源电磁干扰所引起的辐射超标问题,基于差模与共模结合的混合抑制原理,运用电磁干扰对消技术,制作一款小型化的有源滤波模块。该模块尺寸为25.4 mm×25.4 mm×6.0 mm,满足低剖面及便于电路板集成的需求。经实测,其能够抑制10 kHz~10 MHz频段内电源干扰,满足GJB 151B相关电磁兼容要求。通过实测比较发现,与无源滤波相比,其具有体积小、成本低、滤波性能稳定等优点。

基于人工神经网络的差模EMI滤波器插入损耗预测

在电力电子设备中,高速开关经常会导致严重的电磁干扰EMI(electromagnetic interfere),严重影响电力电子系统的可靠性。为解决EMI问题,EMI滤波器是1种常用的解决方案。插入损耗作为噪声衰减能力的评价指标,其模型的准确性直接影响EMI滤波器的参数设计精度。为了提高EMI滤波器插入损耗模型的预测精度,首先准确描述系统行为并预测EMI滤波器滤波性能,提高EMI滤波器设计效率,然后利用反向传播神经网络对单级差模EMI滤波器的插入损耗进行建模。相较于理想模型和高频电路的行为模型,所提神经网络模型预测精度具有更好的实际应用价值,可以快速评估EMI滤波器的实际插入损耗,提高EMI滤波器设计效率,并为EMI滤波器的设计和优化提供指导。

SUPPRESSING CONDUCTED EMI FROM A DC/DC HIGH POWER CONVERTER BASED ON MIXED-MODE FILTER

Conducted electromagnetic interference (EMI) from a 7.5kVA DC/DC high power converter is investigated to agree with EN class A. Here in some passive methods of suppressing conducted EM Noise, such as mixed-mode (MM) EMI filters, snubbing circuits and other means, are used. Based on measurement, the sources of noise are detected with the characteristics analyzed in detail. The MM EMI filters is valuable means with which low-frequency part and some of the high frequency part of conducted EM Noise can be efficiently reduced. How to lay out the MM filters on both sides of the converter is outlined in detail. In addition, multiple grounding and RDC snubbing circuits are employed to improve the performance in high frequency. The experimental results confirm the methods adopted.

基于SiC MOSFET同步BuckDC-DC变换器的宽频混合EMI滤波器设计

由于SiC MOSFET在高速开关电源中的广泛应用,导致严重的电磁干扰(EMI)问题,因此EMI滤波器的设计成为研究热点。为了满足电磁兼容(EMC)标准,无源EMI滤波器可以有效地降低DC-DC变换器产生的电磁干扰,但是无源磁性器件的体积较大,不利于提高DC-DC变换器的功率密度。该文分析DC-DC变换器的电磁干扰源和噪声源阻抗特性,建立无源和有源EMI滤波器的理论模型,提出宽频混合EMI滤波器的设计方法。最后,通过实验验证宽频混合EMI滤波器对DC-DC变换器EMI的抑制效果。

电驱系统高压无源EMI滤波器建模研究

实际工程中,通常使用无源EMI滤波器来抑制电磁干扰(electromagnetic interference,EMI),准确的滤波器模型对滤波器的性能仿真及优化设计具有重要意义。为此,对磁环的频变特性进行等效,采用全电路方法建立精准的EMI滤波器模型。首先,建立磁环的共模和差模高频等效电路模型,模型参数通过遗传算法获得;基于阻抗计算公式建立了X、Y电容的高频电路模型;然后,利用有限元提取了母排、接地以及PCB走线的寄生参数;根据共、差模等效原则建立0.009~60 MHz频段的全电路模型,该模型与滤波器实际的结构相对应,同时包含共模特性和差模特性;最后,通过插入损耗和端口阻抗验证了模型的有效性。

EMI滤波器和DC/DC电源模块失效案例分析

混合集成EMI滤波器和DC/DC电源模块广泛地应用于军工领域。由于电源需要连续运行,同时经受恶劣环境条件考验,EMI滤波器和电源模块失效情况时有发生。针对某装备中滤波模块和电源模块的失效案例开展分析,详细地介绍了该类混合电路失效分析方法,提出了混合电路失效分析的思路,找到了滤波模块和电源模块的失效原因和机理,并给出了相应的改进措施,为电源模块的失效分析开展提供了参考。经失效分析,发现滤波模块和电源模块的失效原因为电源模块内部电阻受损,使用过程中微裂纹扩展,电阻开路,导致与之相连的MOSFET过功率烧毁,电源模块输入和输入地短路失效。电源模块短路失效,导致滤波模块的输出与输出地短路,从而形成大电流,导致基板过温,部分元器件焊点脱落,最终导致滤波模块无输出。

开关电源传导EMI仿真与滤波电路设计

本文基于开关电源的高频模型,建立了DC/DC变换器的传导EMI仿真模型,提出了一种基于传导EMI仿真模型进行变换器电磁兼容设计方法,利用仿真结果设计巴特沃斯滤波电路参数,确定衰减目标、输入阻抗和截止频率,最后通过对比仿真验证所设计滤波电路的有效性。

大功率开关磁阻电机EMI噪声综合分析与处理

针对开关磁阻电机传导电磁干扰问题,分析了3 kW大功率开关磁阻电机电磁干扰(electromagnetic interfere,EMI)噪声生成机理,提出噪声特征提取及基于散射参数的EMI滤波器性能优化方法,并据此研制出传导噪声综合分析与处理装置。实验表明,上述装置可准确提取EMI噪声特征并有效抑制噪声,最大可达30 dBμV,验证了文中所提方法的有效性。

EMI滤波器阻抗失配与EMI信号的有效抑制

为了使EM I滤波器的传导EM I信号在其内部得到最大衰减,依据EM I滤波器应具有双向抑制性的基础上,分析了阻抗失配对插入损耗和反射损耗的影响,给出了理想EM I滤波器的确定原则,以及为减小阻抗失配给插入损耗带来的影响,提出了实际设计和选用EM I滤波器时应遵循的最大失配原则。试验结果表明,这一原则对减小阻抗失配给插入损耗带来的影响非常有效。

一种基于转移函数的电机驱动系统共模EMI滤波器设计方法

为抑制电机驱动系统传导干扰发射,提出一种基于转移函数的共模EMI滤波器设计方法。采用该方法针对一个电机驱动系统设计了逆变器直流侧和交流侧共模电磁干扰滤波器。实验结果表明,该方法能够在保证交流侧共模干扰强度不增加的同时,有效抑制直流侧共模干扰。

基于散射参数法的EMI滤波器电磁噪声抑制效果预测

EMI滤波器是抑制传导噪声的重要手段之一,尤其是高性能的EMI滤波器的应用,对电力电子设备的干扰具有很好的抑制作用。基于传输线理论得到并联传输线的共模及差模参数,通过推导和测试得到噪声源阻抗、负载阻抗及其等效结构,求解得到基于阻抗法的插入损耗(IL)。但是,在高频条件下,EMI滤波器及传输线不仅存在自寄生参数,还存在互寄生参数,这些互寄生参数很难通过阻抗法来等效。本文在传输线等效共模与差模参数频率特性的基础上,根据传输线理论得到噪声源阻抗及负载阻抗;以共模滤波器为例,基于阻抗法预测滤波器对噪声的衰减能力,并与实际测试值进行比较。然而,由于阻抗法不能很好地预测高频条件下的噪声衰减,本文以波的"入射与反射"为核心,进一步提出一种利用S参数来预测阻抗不匹配条件下噪声衰减的方法,研究表明,散射参数法由于考虑了元件间的互寄生参数,具有更好的高频性能。

二端口网络散射参数理论及其在平面EMI滤波器测试中的应用

EMI滤波器以其抑制开关电源中传导电磁干扰的有效性而得到越来越多的重视。相比于分立元件构成的滤波器,平面EMI滤波器拥有整体体积小、高频性能好等优点。但是现有的方法尚不能精确的预测其在实际电源系统中工作特性。本文提出采用散射参数法测量平面滤波器特性:分析推导了EMI滤波器散射参数与EMI滤波器插入增益的函数关系,提出预测不同的外部阻抗条件下EMI滤波器插入增益的方法;建立平面滤波器近场耦合模型,利用散射参数与阻抗参数关系,提出近场耦合模型中互感提取方法;完成一台平面EMI滤波器样机,对其不同阻抗条件下的插入增益特性进行了理论计算与实际测量,同时推导其差模结构的近场耦合模型并计算模型在标准阻抗条件下的插入增益,与实际测量进行比较,验证了理论的可行性。

厚膜EMI滤波器用X7R介质瓷料的研究

利用先驱体NiNb2O6与MnNb2O6掺杂法改性BaTiO3系统。由于2种先驱体可以有效地起到展宽与移峰效应,使系统居里峰在室温附近取得最大值,在1290℃烧结时介电常数达到5000以上,容量变化率ΔC/C≤±15%;在系统中加入适量助熔剂可以实现中温烧结(1150℃),介电常数大于3600,容量变化率ΔC/C≤±12%,满足X7R特性要求,可用于厚膜EMI滤波介质瓷料的制备。

一种新型的平面无源集成EMI滤波器结构

为了减小电磁干扰(EMI)滤波器的体积,提高开关电源的功率密度,提出一种堆积式交错并联平面无源集成EMI滤波器结构,将滤波器的共模电感、差模电感、共模电容和差模电容集成为一个单元模块,解决了现有结构难于集成大电容的问题,减小了集成电容的等效串联电阻(ESR)和等效串联电感(ESL);在考虑共模电感的等效并联电容(EPC)和共模电容的ESL以及它们的ESR情况下,建立了平面无源集成EMI滤波器的高频共模等效电路模型;利用二端口网络的A参数矩阵推导了插入损耗的计算公式。仿真和实验表明了该结构的有效性,以及高频模型和插损公式的正确性。

基于噪声仿真的EMI滤波器研究

提出一种依据仿真得到的开关电源噪声进行电磁干扰(EMI)滤波器设计的方法。针对Boost功率因数校正变换器,应用SABER软件仿真不同寄生参数下的噪声幅值,得到了影响共模噪声和差模噪声的主要因素:差模噪声主要是由功率器件的高频模型引起的,而共模噪声则与无源器件的高频模型以及MOSFET对地漏电容相关,且随着漏电容的增加而增加。在考虑功率器件的高频模型、MOSFET的对地漏电容以及无源器件的高频寄生参数等影响的情况下,采用噪声仿真的方法分离出变换器的共模噪声和差模噪声。在此基础上,应用插入电压增益的方法,计算出共模滤波器和差模滤波器的截止频率,设计了EMI滤波器。实验验证了仿真的准确性以及滤波器设计方法的正确性。