EMI电源滤波器的设计探讨

电源EMI滤波器是一种抑制传导发射和辐射发射非常有效的方法.分析了电源线上的干扰类型,开关电源产生EMI的原理及其拓扑结构.讨论了电源EMI滤波器的设计和器件选取原则,并提出有关安装电源EMI滤波器时应注意的几个问题.     

T/R组件中的EMI问题及设计原则

针对电磁干扰(EMI)会导致收发(T/R)组件性能下降,功能不正常,严重时会导致电路损坏,功能失效,给雷达整机带来致命的影响的问题,文中主要介绍了T/R组件设计过程中常见的(EMI)问题及解决措施,同时梳理了针对EMI问题的T/R组件设计原则,以利于减少T/R组件设计中EMI问题的产生.     

数字有源EMI滤波系统延迟的建模与分析

随着数字处理技术的进步,数据采集速度与精度的大幅提高,使得数字有源电磁干扰滤波技术DAEF(Digital Active EMI Filter)成为EMI(Electro-Magnetic Interference)滤波技术发展的新方向.由于EMI信号频率较高,所以EMI滤波控制中的延迟对滤波性能的影响不可忽视,需要深入研究.本文详细分析了数字有源EMI滤波系统中产生延迟的原因,建立了具有延迟特性的数字有源EMI滤波系统模型,仿真分析了延迟时间对EMI滤波系统滤波性能的影响.搭建了基于FPGA(Field Programmable Gate Array)的数字有源EMI控制系统平台,验证了具有延迟特性的数字有源EMI滤波系统模型的正确性,揭示了数字有源EMI滤波系统延迟环节对滤波性能的影响规律,这有助于对数字有源EMI滤波器的进一步研究和推广应用.     

物联网电子产品设计中的低成本EMI/EMC预一致性测试

针对物联网设备在无线通信技术中的EMI/EMC问题,本文以基于USB接口的RSA306实时频谱分析仪进行EMI预一致性分析测试为例,就如何进行IoT的EMI/EMC测试进行分析.     

EMI快速诊断与对策

文章主要介绍了EMI快速诊断与对策实例，指出EMI改进的关键是EMI问题诊断，解决电磁兼容问题的根本办法是进行电磁兼容设计。     

接插元件、继电器、开关、熔断器

Y98-61402-439 9907202无电磁干扰的固态开关=EMI free solid state switching[会,英]/Mourougayane,K.& Latheef,G.A.//1997Proceedings of the International Conference on Electro-magnetic Interference and Compatibility.—439～442(HG)本文研究了 AC 电源开关应用中与固态开关有关的电磁干扰(EMI),测试了市售固态开关的电磁兼容性(EMC),并讨论了这种开关传导辐射超出国际 EMI标准极限的问题,针对传导辐射的各种 EMC 标准,设计并测试了一种无 EMI 的固态开关,文中讨论了这种开关的设计考虑、性能和 EMI 测试结果。参3     

D类放大器及EMI抑制

本文描述了D类放大器的特点及EMI抑制问题.     

变频器干扰抑制技术探讨

本文介绍并分析了变频器本身和外部EMI的来源,根据EMI产生的三要素原理,重点从硬件和软件两方面对比分析了变频器EMI的抑制措施。最后对各种方法,需要注意的问题以及未来变频器EMI抑制的发展方向进行了总结和展望。     

开关电源传导性电磁干扰共模噪声的研究

为了研究电磁干扰（EMI）噪声源的影响,实现对开关电源EMI参数的控制问题,文章基于PSPICE仿真软件,对各种常用结构的开关电路进行了分析,得出了一组开关电源电路引发传导性EMI的仿真实验数据及有关结论.仿真研究表明,当缓冲电路采用MUR190二极管、输入RC控制电路的参数设置为R=1kΩ,C=4nF时,所产生的共模噪声达到最小.     

EMI滤波器设计

EMI滤波器是电磁兼容设计及抑制电磁干扰的重要技术.电子电路设计人员应掌握EMI滤波器基本原理和各种类型滤波器的基本特性和使用方法,根据实际工作中的具体情况合理选择滤波元件,设计有效的EMI滤波器,从而实现EMC设计或抑制EMI的目的.在本文中主要阐述了EMI滤波器的相关理论,包括公模噪声、差模噪声、阻抗失配原则、滤波...     

变压器耦合式直流固体继电器传导发射分析与抑制

在采用变压器耦合作为隔离电路的固体继电器中,变压器工作在自激振荡状态,通过磁芯将高频信号传递到变压器次级。这使得变压器成为对外传导发射的主要干扰源,严重时会影响到其他电子设备的正常工作。文中以某型号变压器耦合式直流固体继电器为研究对象,首先根据GJB1515A 中CE102(10kHz-10MHz 电源线传导发射要求)的规定,试验测量得到输入端电源线对外传导发射。首先,将传导发射分为差模干扰和共模干扰两种形式,并分析了传导发射的干扰源和主要传播通道。其次,在建立考虑铁心损耗和绕组铜损的变压器高频模型的基础上,利用ANSOFT Q3D 和Orcad Pspice 仿真软件得到该固体继电器用于传导发射分析的等效电路模型。仿真结果与试验结果相吻合,均表明该继电器输入端电源线对外传导发射超出国军标的要求。为抑制传导发射,文中提出在固体继电器输入端串入EMI 滤波器的优化方案。试验结果显示,优化后输入端电源线对外传导发射低于国军标的规定,提高了变压器耦合式固体继电器的电磁兼容性能。     

Electromagnetic interference (EMI) of system-on-package (SOP)

Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI of substrate, which work as coupling paths or unwanted antennas, is described. Maintaining the return current path is an important aspect of substrate design for suppressing EMI and for maintaining signal integrity (SI). In addition, isolating and suppressing the resonance of the DC power bus in a substrate is another important design aspect for EMI and for power integrity (PI). Various electromagnetic simulation methodologies are introduced as indispensable design tools for achieving high-performance SOPs without EMI problems. Measurement techniques for near electric and magnetic fields are explained, as they are necessary to confirm the appropriateness of designs and to investigate the causes of EMI problems. This paper is expected to be useful in the design and development of SOPs that take EMI into consideration.     

A low-noise multiresolution high-dynamic ultra-broad-band time-domain EMI measurement system

A time-domain electromagnetic interference (EMI) measurement system allows to reduce measurement time by several orders of magnitude in comparison with conventional systems. This will considerably reduce the costs of compliance tests. In this paper, a novel multiresolution time-domain EMI measurement system is presented. The multiresolution time-domain EMI measurement system exhibits several channels with limiters, amplifiers, and analog-to-digital converters. The amplitude range of the signal is subdivided into several intervals. In each interval the analog-to-digital conversion is performed with an amplitude discretization proportional to the width of the amplitude interval. The signal-to-noise ratio of the multiresolution time-domain EMI measurement system compared with a conventional time-domain measurement system for transient signals is enhanced by at least 50 dB. It is shown that the multiresolution time-domain EMI measurement system has a higher overload factor than conventional systems working frequency domain. The noise floor is 5 dB lower than the noise floor of a conventional EMI receiver. The multiresolution time-domain EMI measurement system shows a higher 1-dB compression point than conventional EMI receivers. Measurements were performed in the frequency range from 30 MHz to 1 GHz and compared with results obtained by an EMI receiver.     

开关电源EMI的抑制策略

分析了开关电源EMI的产生机理,并结合一款60W Topswitch开关电源,提出了一系列的EMI抑制策略。整机EMI测试结果表明,采用所提出的抑制策略能有效地减小开关电源的电磁干扰。     

电磁屏蔽膜设备的开发及应用

介绍了国内外对电磁屏蔽膜(EMI)研究的现状,比较了制备EMI膜的各种方法,指出采用磁控溅射法制备的EMI膜质量较好,并给出制备EMI膜的工艺流程。     

EMI滤波器的PSpice辅助设计

提出了一种使用PSpice仿真软件设计EMI滤波器的方法。首先给出了EMI滤波器设计的一般步骤;然后结合具体实例设计出一款二阶EMI滤波器,并将加入滤波器前后的输入电流波形进行对比。结果表明：采用PSpice设计的滤波器使输入电流的纹波系数降低,符合设计要求;同时还具有抑制浪涌电流和防止系统振荡的能力。     

Multilayer power printed structures suitable for controlling EMI noises generated in power converters

Electromagnetic interference (EMI) noises generated in power converters are diffused on the surface of conductors. This means influences occur from radiated EMI noises emitted from power transmission lines as well as conducted EMI noises transmitted from them. EMI noises diffusing on the surface of conductors are generally difficult to control using conventional concentrated constant theory. Thus, a new approach based on distributed constant circuit theory is needed in order to control EMI noises. A power converter structure to control EMI noises using multilayer power printed circuit technology is studied in this paper. A structure which can control EMI noises should simultaneously satisfy two conditions, i.e., one to shut down and one to attenuate EMI noises. The structure satisfying these conditions is studied through simulations using the Transmission-Line Modeling Method. The simulations show that the diffusion of EMI noises is controlled by dividing the flow of currents produced by EMI noises into the horizontal and perpendicular directions. That is, the horizontal current flow is controlled inside using the differences in the resistance produced from differences between inner and outer diameter of power transmission lines and the perpendicular current flow can be controlled by properly designing the thickness of the dielectric layer sandwiched between P-and N-power transmission lines with the symmetrical structure. Moreover, it is confirmed by simulations and experiments that the attenuation of EMI noises is affected by the width of the power transmission lines. It is expected that the results obtained in this paper can provide important rules when designing power converters with EMI noise control functions which use the multilayer power printed circuit technology.     

FDTD and experimental investigation of EMI from stacked-card PCBconfigurations

Stacked-card and modules-on-backplane printed circuit-board geometries are advantageous for conserving real-estate in many designs. Unfortunately, at high frequencies, electromagnetic magnetic interference (EMI) resulting from the nonnegligible impedance of the signal return at the connector may occur. This effective EMI coupling path results in the daughtercard being driven against the motherboard and attached cables, resulting in common-mode radiation. The connector geometry can be modified to minimize the EMI coupling path when high frequencies are routed between the motherboard and daughtercard. Current speeds and printed circuit board (PCB) sizes result in geometries that are of significant dimensions in terms of a wavelength at the upper frequency end of the signal spectrum. The PCB geometries are then of sufficient electrical extent to be effective EMI antennas. The resonant lengths of the EMI antennas may, however, be quite removed from the typical half-wavelength dipole resonances. The finite difference time-domain method can be used to numerically analyze the printed circuit board geometries, determine antenna resonances, and investigate EMI coupling paths. EMI resulting from the stacked-card configuration has been investigated experimentally and numerically to ascertain the EMI coupling path at the bus connector, and EMI antennas     

可控硅整流系统直流侧传导干扰的研究

本文针对三相可控硅整流系统建立了EMC模型,提出了用π型RLC等效网络的级联来表示直流电缆寄主参数的EMC模型,构建了实验系统,对系统的直流侧传导干扰进行了测量,并采用Simulink工具对系统进行了时域传导干扰分析,分析结果与实验吻合,揭示出主要传导干扰出现在低频段,在0-15khz频段中,随频率增加,传导干扰减小,其中共模传导干扰占主要成分,电缆寄生参数对其影响主要是在高频段,它使100KHZ以上频段的传导干扰大约减小20dBμV,本文的工作为今后进一步研究更高频段的传导干扰打下基础。     

家用微波炉整机的EMI测试与设计

微波炉存在EMI问题，国际上对家用微波炉规定了严格的EMI标准，微波炉中电磁干扰的主要源头之一是磁控管，如果微波炉和磁控管的设计协调，微波炉整机的EMI会得到很的抑制，文章就微波炉和磁控管的相关设计与EMI测试关系进行了讨论，在成本和测试效果之间找到了平衡点。