传导EMI噪声源内阻抗测量研究

基于传导电磁干扰产生机理,对传导 EMI 噪声源阻抗分析仪内阻抗测量的基本原理进行分析,并对比三种噪声源测量方法。利用插入损耗法对某一开关电源进行实际测试,给出了测试结果。     

基于新能源发电的微网系统电磁兼容分析

该文针对新能源发电微网系统的传导电磁干扰噪声进行了综合分析,包括微网逆变系统直流侧以及交流侧的理论分析,且对功率因数校正器（PFC）进行了理论分析。最后以某一风能逆变系统为实验对象,分析了该系统传导干扰噪声特性,通过设计传导EMI滤波器使得噪声得以有效抑制,实验结果验证了该文分析方法的有效性。     

传导噪声分析技术在滤波器中的应用

传导发射是电磁兼容设计中的重要问题之一。为了满足标准中对传导发射限制的要求,通常使用EMI滤波器来抑制电子产品产生的传导噪声。快速选择或者设计一个满足需要的滤波器是解决问题的关键。传导噪声分析技术包括共模噪声、差模噪声分析,共模阻抗、差模阻抗分析,这是滤波器设计的基础。     

电动汽车充电桩电磁辐射测试研究

本文通过研究电动汽车充电原理,分析噪声生成机理及其传输路径,并利用无线电监测设施设备对充电桩辐射EMI噪声开展实地测试.理论分析与实验结果表明:电动汽车充电过程中,电能变换器的开关管通断状态高速切换会产生大量传导EMI噪声,并通过电源线传输至电网中;充电产生的高频噪声还会通过电路板向周围空间发射电磁波,形成辐射EMI噪...     

直流微网母线电压纹波集中补偿自寻优策略

为抑制直流微网母线电压二次纹波,文中提出了一种直流有源滤波器集中补偿自寻优策略。在双向DC/DC变换器电压/电流双闭环控制的基础上,加入直流母线电压纹波控制,通过引入带通滤波器消除了传统控制方法中采用低通滤波器提取纹波时所产生的相位滞后问题。采用迭代自寻优方法获取重要控制参数阻抗系数K,实现直流有源滤波器对直流母线电压纹波变化的实时跟踪和集中补偿。在MATLAB/Simulink中搭建了含互联接口变流器、分布式电源、直流负荷、由DC/AC变流器接入的交流负荷以及直流有源滤波器的直流微网模型,建立了相应的实验平台。仿真和实验结果均验证了所提控制策略的有效性。     

DC/DC辐照损伤与VDMOS器件1/f噪声相关性研究

通过对DC/DC转换器低频噪声测试技术以及在γ辐照前后电性能与1/f噪声特性变化的对比分析,发现使用低频噪声表征DC/DC转换器的可靠性是对传统电参数表征方法的一种有效补充.对DC/DC转换器辐照损伤与其内部VDMOS器件1/f噪声相关性进行了研究,讨论了引起DC/DC转换器辐照失效的原因.     

40GPIN/TIA光电探测器接收组件的噪声分析

从理论上分析了40GPIN/TIA的各种噪声源,并通过各个噪声源产生噪声的机理,推导出了各种噪声的计算公式,从而可量化探讨探测器组件的噪声.根据仪器性能,采用测试噪声功率测试方法,对光电探测器接收组件的噪声进行了测试,测试结果与理论能很地好吻合.     

大功率InGaAsP/GaAs量子阱半导体激光器的直流和1/f噪声性质

对大功率InGaAsP/GaAs量子阱(QW)半导体激光器(LD)的直流(DC)特性和小注入下的低频噪声(LFN)特性进行了实验研究.DC检测发现,V-J和I dV/dI-I可以对LD的电流泄漏作出判断.LFN检测发现,小注入下的1/f低频电压噪声幅值Bv(I)∝I<'βv>.理论分析和老化实验均表明,电流指数βv与载流子输运和电流泄漏机制之间有很好的相关性,存在电流泄漏和无辐射复合的器件其|βv|较小,可靠性较差.     

射频电子设备的辐射电磁干扰诊断与抑制技术研究

射频电子设备产生的电磁干扰(EMI)噪声包括传导干扰噪声和辐射干扰噪声。其中,辐射EMI噪声是以空间电磁场形式影响其它电子设备的。针对射频电子设备产生的辐射EMI噪声,该文分别建立因传输线缆与芯片时钟信号引起的辐射EMI噪声理论模型与等效电路。同时,还针对上述辐射EMI噪声理论模型提出了相应的噪声抑制方法。实验结果表明,采用该文中方法,某型家用液晶显示器的EMI噪声得到了很好的抑制,从而验证了方法的有效性。     

DC/DC电源用光电耦合器低频噪声测试方法研究

光电耦合器是DC/DC电源的关键器件,光电耦合器低频噪声的随机增大是该类电源主要失效模式之一。目前,国内尚未形成光电耦合器低频噪声的有效测试方法,更未建立相关标准。文章详细分析了光电耦合器低频噪声特性及产生机理,提出了其低频噪声测试的偏置电路、测试设备和测试方法。针对用于DC/DC电源的典型光电耦合器(4N47)的实测结果表明,该方法能够准确测试光电耦合器的低频噪声,为DC/DC电源用光电耦合器的系统适用性和典型故障提供了一种有效的评估方法。     

AC/DC characterization of NMOS and PMOS hot-carrier-induceddegradation under AC/DC stress

The AC/DC measurements of NMOS and PMOS I_dsat shifts are compared following DC stress. The results of the I _dsat shifts are found to be the same. The AC I_dsat measurements were performed under a variety of different conditions (varying frequency, amplitude, and base level) and showed that hot-carrier-induced interfaced states are shallow and fast (<20 ns). AC versus DC stressing was also examined. In PMOS devices, pulsed drain stress was found to be generally quasi-static, while pulsed gate stress produced enhanced device degradation under certain bias conditions. In NMOS transistors AC drain stress was found to be quasi-static in strong device saturation, while AC gate stress resulted in significantly enhanced degradation. In weak device saturation, both gate and drain pulsing resulted in early catastrophic device failure     

基于单片机控制的DC/AC变换

本文主要介绍基于单片机控制的DC/AC变换.采用较流行的MCS-51单片机,利用其功能强、速度快、使用灵活的特点,在检测和部分逻辑电路配合下,直接将事先根据能量等效原则存放于EPROM 中的SPWM数据按一定规律输出,驱动功率开关管,实现DC/AC变换.本电路采用了较新颖独特的设计,用比较器代替传统的A/D转换,既保证了高速、低成本,又大大简化了电路结构.     

Benchmark of power packaging for DC/DC and AC/DC converters

This paper presents the first reported final results of a benchmarking project "StatPEP" which investigated the Status of Power Electronic Packaging used in commercial DC/DC and AC/DC switch mode power supplies. The methodology of the project is first described. Some of the salient results of a comprehensive benchmarking of DC/DC converters (rated power of 100 W) and AC/DC converters (rated power up to 576 W) are presented. Examples for figures-of-merit are presented. The results of the investigation are presented in a generic form, which does not identify individual products. A comparison of the performance of the units shows that the measured power density of the AC/DC units is approximately 10% that of the DC/DC while the thermal density based on footprint is 50%. Also the switching frequency of the AC/DC is 50% that of the DC/DC. Some of the reasons for these differences are discussed     

Quasi current resonant DC link AC/AC converter

A new quasi current resonant DC link (QCRDCL) topology has been developed in this paper. Although prototype current resonant DC link topologies for AC/AC power conversion have had such problems as irregular high current peaks, uncontrollable pulse width, etc., this new topology enables the AC/AC conversion system to have the properties wherein the current peak is limited and the pulse width is adjustable. The system begins to assume an adjustable-width flat-topped current shape, whereby the system becomes particularly suitable for high power application. With control of the pulse width a very fine load current regulation can be obtained. In this system, an open loop PWM control has been adopted and almost the same quality of output waveforms as the conventional current source inverter has been achieved     

A space vector-based rectifier regulator for AC/DC/AC converters

A voltage-sourced rectifier control scheme for use with AC/DC/AC variable speed drives is presented. A control scheme is derived that directly calculates the duration of time spent on the zero state and on each switching state adjacent to the reference vector, over a constant switching interval, in order to drive the line current vector to the reference vector. In addition, under transient conditions, when deadbeat control is not possible, a control scheme is presented that ensures that the line current vector is driven in the direction of the reference current vector. The current reference for the rectifier controller is derived from the bus voltage error and a feedforward term based on the estimated converter output power. The proposed space vector-based rectifier regulator is shown to exhibit improved harmonic and transient performance over existing per-phase duty cycle prediction methods, especially at modulation indices near unity. The deadbeat control of the rectifier input current is accomplished every half-cycle with constant switching frequency while still symmetrically distributing the zero state within the half-cycle period     

Optimising single-phase PFC pre-staged AC/DC/AC topology viacommon-neutral connection

A new topology for the single-phase PFC-pre-staged AC/DC/AC converter is presented. The introduction of a common-neutral connection simplifies the conventional connection of an AC/DC/AC structure, and gives a new topology that still has good performance, conforms with output safety regulations and has other advantages such as requiring fewer power devices and having lower conduction losses     

A single-stage power-factor-corrected AC/DC converter

This paper presents a single-stage isolated converter topology designed to achieve a regulated DC output voltage having no low-frequency components and a high-input power factor. The topology is derived from the basic two-switch forward converter, but incorporates an additional transformer winding, inductor and a few diodes. The proposed circuit inherently forces the input current to be discontinuous and AC modulated to achieve high-input power factor. The converter output is operated in discontinuous mode to minimize the bulk capacitor voltage variations when the output load is varied. Analysis of the converter is presented, and performance characteristics are given. Design guidelines to select critical components of the circuit are presented. Experimental results on a 150 W 50 kHz universal input (90-265 V) 54.75 V output AC/DC converter are given which confirm the predicted performance of the proposed topology     

Synthesis of input-rectifierless AC/DC converters

This paper discusses the basic construction procedure and topological possibilities of creating AC/DC converters out of simple DC/DC converters. It is shown that two separately controlled DC/DC converters are sufficient for producing a regulated DC output and shaping the input current, from an AC voltage source, without the need for input rectifiers. Some design constraints are discussed, emanating from the limitation of the conversion ratios that can be achieved by particular DC/DC converters. Selected topologies are verified experimentally. This kind of rectifierless converter find applications in airborne power supplies where zero-crossing distortions are significant because of the inevitable phase-lead effect of the input rectifier bridge.