钽电解电容器生产工艺和漏电流分析

钽电解电容器在电子元器件中占据着非常重要的地位,钽电容器是电容器中体积小而又能达到较大电容量的产品,最早在1956年由美国贝尔实验室首先研制成功的,它的性能稳定,可靠性优异,在将尽一个世纪以来没有哪种电容器通过完全替代钽电解电容器,钽电容器封装形式多种多样,体积尺寸设计多样化,其所具备的稳定性高、容量大、小型方便、高性能以及较强的自愈能力等优势使钽电容器不仅广泛在军事通讯,航空航天等领域应用,而且还在向工业控制,影视设备、通讯仪表、手机、电脑、飞机、工业控制电子线路或者火箭雷达等领域扩展,覆盖范围非常广,其地位和重要性在电子电路中可圈可点。文章主要针对钽电解电容器关键生产工艺流程以及漏电流情况做了简单阐述,希望能进一步提高钽电解电容器的生产制造水平。     

多电平变流器在大功率风电系统中的应用

在分析多电平变流器在大功率风电系统中应用的优势基础上,介绍了二极管钳位式多电平、飞跨电容式多电平、级联型多电平、Boost-TL、VIENNA、有源中点钳位式多电平这六种结构在风力发电系统的应用。文章最后对这六种拓扑结构进行了比较和总结。     

Quantum flux parametron: a single quantum flux device for Josephsonsupercomputer

A quantum flux parametron (QFP), a single quantum flux superconductive device that has a potential of up to 100-GHz switching with nW-order power dissipation, is considered. The potential of the QFP and key technologies when QFPs are applied to a Josephson supercomputer are described. Switching speed, stability, and power dissipation of a QFP are discussed. QFP gates, circuits, and systems are next described. Then, ultra-fast clock distribution using a standing wave is explained. High-speed operation at more than 10 GHz and 10¹⁴ error-free operations per QFP have been demonstrated. Finally described is a high-density packaging scheme by three-dimensional integration, which is very important for ultra-high speed circuits because the propagation delay becomes dominant in such circuits     

Design and experiment of wireless power transfer systems via electromagnetic field near-zone region

This paper presents the fundamental principle, circuit implementation and measurement of wireless power transfer (WPT) technology through both Colpitts and Hartley oscillation prototype circuits. The Colpitts and Hartley oscillation prototypes are used to convert DC voltages into AC ones. Meanwhile, both half- and full-wave rectification circuits are designed correspondingly for AC/DC voltage conversion. In addition, the orientation and distance effects between the transmitting and receiving coils are investigated. The self-inductance, mutual-inductance and coupling coefficient for the coupled inductors are extracted as a function of distance and frequency by using an equivalent T-circuit network and a derived Z-parameter matrix. The proposed WPT systems operate at around 3.6 MHz and the transferred voltage is measured at the WPT receiving terminal. The measured results indicate that the two proposed WPT systems can operate properly for potential short-distance applications.     

Superconductor electronic device applications

Superconductors are becoming important in many applications where high sensitivity or speed is required. A brief introduction to superconductive device physics is presented, and the role of high-temperature superconductors is considered. The basic principles of a number of applications in metrology, electromagnetic sensing, and analog and digital circuits are presented. The prospects for hybrid semiconductor-superconductor devices, circuits, and systems are discussed     

OFDM系统中基于信号分布函数的AGC算法

在正交频分复用系统中,传统自动增益控制(Automatic Gain Control,AGC)估计接收功率的误差很大。该文提出OFDM系统中基于信号分布函数的AGC算法,该算法通过统计模数变换器(Analog to Digital Converter,ADC)输出信号的分布函数来估计接收功率,克服了ADC截断效应的影响。仿真结果表明,在OFDM系统中,该文给出的AGC算法在一次估计后,估计误差小于0.23dB,而传统AGC算法的估计误差小于9dB。因此该文的AGC算法能更精确地估计接收功率,并能大幅度提高系统性能。     

Technical innovations for a high-gradient quadrupole electromagnet intended for high power proton drift tube linacs

The IPHI project includes a 352 MHz drift tube linac (DTL) to accelerate a 100 mA cw proton beam from 5 to 10 MeV (1 MW beam power). The main challenge of such a structure is to house a strong gradient quadrupole (QP) in the very reduced space of the first drift tubes (DT). Having chosen not to use permanent magnets, the goal is to design 4.70 T integrated-gradient QP less than 50 mm long with 90 mm maximum outer radius and an aperture as large as possible to minimize beam losses. Two DT have been designed and built with different QP magnets for the low energy end of the IPHI DTL. The first one is based on conventional magnets with hollow conductors and high-permeability cobalt-iron alloy for the poles and yoke. Two separate cooling circuits are used for the DT and the magnet coils. A second design has been done to make profit of the full space available inside the DT and to reduce their manufacturing cost as much as possible. A single water flow is used to cool simultaneously both DT body and QP coils made up of full (nonhollow) conductors.     

Fitting VFC's Output Using Functionally Connected High-Order Neural Networks

1　IntroductionIntheprocessofdesigningandapplyingamea surementsystem ,weshouldoftendeterminetheex actoutputfunctionsofA/Dconvertersorsensors.FormostADC ,theoutputfunctionofA/Dcanberegardedasalinearfunctionwithinthepermittedprecision .However,fortheVoltage to FrequencyConverter (VFC)chip ,theoutputfunctionisoftennonlinearbecauseofthenon linearityoftheintegralcircuitinitsintegratedcircuit.ForthesameVFC ,thehigherthefull scaleoutputfrequencyis ,thelargerthenon linearityis.However,itiswellk…     

A Gated Clock Scheme for Low Power Testing of Logic Cores

Test power is now a big concern in large core-based systems. In this paper, we present a general approach for minimizing power consumption during test of integrated circuits or embedded cores. The proposed low power/energy technique is based on a gated clock scheme that can be used in a test-per-scan or a test-per-clock environment. The idea is to reduce the clock rate on the scan path (test-per-scan) or the test pattern generator (test-per-clock) without increasing the test time. Numerous advantages can be found in applying such a technique.     

A Novel Algebraic Technique for the Construction of Strong Substitution Box

Magnetic induction applications mostly rely on resonance for inducing maximum magnetic fields to system loads and hence for each resonant frequency dedicated circuits are required. Unfortunately, the frequency responses of such inductive systems manifest several peaks (frequency splitting) when their coupling coefficients are equal to or larger than critical coupling. Such frequency responses with several peaks are detrimental when the objective is to transfer maximum energy. Frequency splitting between inductive coils have been seen to date as detrimental to wireless power transfer and inductive communication systems. In this paper it is demonstrated that frequency splitting is a welcome phenomenon with advantage in the design of inductive filter banks and multi-frequency inductive systems. The centre frequencies of the filter banks result from split bands of inductive systems. This phenomenon is applied in conjunction with an innovative recursive algorithm to design inductive filter banks. The filters straddle both sides of the resonant frequency position and can be resolved individually.     

A taxonomy of ADC architectures for ICT engineering curricula

This paper presents the various Analog to Digital Converter (ADC) architectures within a structured frame in order to outline the basic design choices and to point out some additional degrees of freedom beyond the classic ADC circuits. The parameters for a detailed analysis of performance, speed, precision, costs are identified and discussed. Within this frame, the paper identifies variations to the classic ADC structures, which provide additional speed/cost tradeoffs. The aim is to provide students an understanding of various ADC techniques, allowing a motivated choice of the most suitable structure for each specific application at the systems design level. This approach has been used in teaching ADCs for several years, and the paper includes a discussion of results and student feedback.     

Ellipsoidal harmonic (Lame) MRI shims

Ellipsoidal harmonics are presented as a basis function set for the design of shim coils for magnetic resonance imaging (MRI) or spectroscopy. MR shim coils may be either superconductive or resistive. Ellipsoidal harmonics form an orthogonal set over an ellipsoid and hence are appropriate in circumstances where the imaging or spectroscopic region of a magnet more closely conforms to an ellipsoid rather than a sphere. This is often the case in practice. The Cartesian form of ellipsoidal harmonics is discussed. A method for the design of streamline coil designs is detailed and patterns for third-order ellipsoidal (Lame) shims wound on a cylindrical surface are presented.     

Use of Satellite Technologies for Power System Measurements, Command, and Control

This paper analyzes the use of wide-area measurement technologies including satellite-based methods for the command and control of power systems. The methods studied include the global positioning system (GPS) and low earth orbit satellites (LEOS). Satellite technologies have been used in a variety of applications requiring precise timing between geographically diverse locations. The deregulation of the electric power industry is placing increased demands on power transmission system utilization. Because deregulated power systems utilize long-distance high-power exchanges, satellite-based communication systems are useful in control of geographically large interconnected power systems. In this paper, the satellite-based measurements and commands are introduced for wide-area control. With the support of wide-area signals, a multiagent supervisory-level power system stabilizer is proposed here as a potential wide-area control structure. Increased loading of transmission facilities is an impetus for accurate dynamic thermal overhead electrical conductor ratings. The application of satellite-based measurement for improving the dynamic thermal rating of overhead transmission circuits is suggested.     

Duality between superconducting and semiconducting electronics

The existence of a formal analogy between semiconductive and superconductive circuits is pointed out. A sampling of circuits in both technologies is analyzed and compared on the basis of the analogy, and a new FET circuit is described which is the analog of a known superconductive circuit. The heuristic value of the analogy is emphasized.     

基于交替方向惩罚法的低精度量化MIMO雷达恒模波形设计方法

在MIMO雷达中配备大量有源天线单元可以获得优异的波束形成性能,但会导致系统能耗大、电路复杂及成本高等问题。采用低精度的DAC组件可有效克服上述问题,但现有基于无限精度DAC条件所设计的MIMO雷达波形往往难以直接适用于低精度DAC系统。为此,该文提出了一种离散相位约束下基于最小化积分副主瓣比的低精度量化MIMO雷达恒模波形设计方法。该方法首先采用丁克尔巴赫(Dinkelbach)算法将目标函数二次分数形式转换成减法形式,再利用交替方向惩罚法求解非凸恒模离散相位约束问题。最后通过数值仿真与其他方法进行对比,分析了所提方法的发射方向图与积分副主瓣比性能,验证了该方法的有效性。      

Power transfer capability and bifurcation phenomena of loosely coupled inductive power transfer systems

Loosely coupled inductive power transfer (LCIPT) systems are designed to deliver power efficiently from a stationary primary source to one or more movable secondary loads over relatively large air gaps via magnetic coupling. In this paper, a general approach is presented to identify the power transfer capability and bifurcation phenomena (multiple operating modes) for such systems. This is achieved using a high order mathematical model consisting of both primary and secondary resonant circuits. The primary compensation is deliberately designed to make the primary zero phase angle frequency equal the secondary resonant frequency to achieve maximum power with minimum VA rating of the supply. A contactless electric vehicle battery charger was used to validate the theory by comparing the measured and calculated operational frequency and power transfer. For bifurcation-free operation, the power transfer capability and controllability are assured by following the proposed bifurcation criteria. Where controllable operation within the bifurcation region is achievable, a significant increase in power is possible.     

电压控制型BUCK变换器DCM的精确离散模型及分叉稳定性分析

本文建立了不连续运行模式下电压反馈型BUCK变换器精确的离散数学模型,在此基础上分析了BUCK 变换器的分叉稳定性问题,得到了变换器参数之间相互关系的解析表示式,改进了已有近似模型的结论,界定了变换器主要参数的稳定运行范围,并展现了BUCK 变换器从稳定到倍周期分叉甚或混沌的过程.本文的研究方法具有一般性,为DC/DC功率变换器非线性现象的分析建立数学模型基础.     

Linearity improvement for the switched-capacitor DAC

Capacitor mismatch is the major source of nonlinearity for switched-capacitor data conversion circuits. A new approach to eliminate this effect is described. It is shown that this method provides almost inherent linearity     

CMOS-based near zero-offset multiple inputs max–min circuits and its applications

CMOS-based near zero-offset multiple inputs maximum circuit and minimum circuits are proposed. The analog signal building blocks including shunt-feedback buffer, voltage-subtraction circuits and current mirrors are deployed for obtained the good performances. This achieved circuit is a simply scheme and able to work with low-power supplies. The input range is obtained around ±600 mV within ±1.5 V power supplies. Near zero-offset and low-output impedance are provided by proposed circuit. The delay of output is less than 5 ns for THD less than 1% and frequency response up to 500 MHz. Half-wave, full-wave rectifiers and 4 bits linear combination Digital-to-Analog Converter (DAC) are raised up to confirm the realistic applications. All performances including the DC-characteristic, frequency response, high-frequency wave output are simulated by PSpice.     

Recognition of dynamic patterns in DC-DC switching converters

Techniques for analyzing the dynamic patterns of power flow in high-frequency DC-DC switching power converters are developed. Emphasis is placed on exploring methods for developing reduced-order instantaneous and averaged models. of power electronic circuits for simulation, analysis, and control design. Tools from selective modal analysis are used to develop the dynamic pattern recognition algorithm that facilitates the classification of circuit modules