Numerical calculation of the current through a vibrating capacitor

Contents The measurement of the contact potential difference with the so-called Kelvin probe or vibrating capacitor technique is one of the most sensitive measuring procedures in surface physics. This article describes the influence of the shape of the Kelvin probe on the measured current. Two models are investigated: The most simple one, a parallel plate-capacitor and a more realistic one, a sphereplate capacitor.

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Numerische Berechnung des Stromes durch einen schwingenden Kondensator

Übersicht Die Messung der Kontaktpotential-Differenz mit Hilfe der Kelvin-Sonde oder der Methode des schwingenden Kondensators ist eine der empfindlichsten Meßmethoden in der Oberflächenphysik. In diesem Artikel wird der Einfluß der Form der Kelvin-Sonde auf den gemessenen Strom dargestellt. Zwei Modelle werden untersucht: Ein sehr einfaches, der parallele Platenkondensator, und ein etwas praxisnäheres, die Kapazität zwischen einer Kugel und einer Platte.

     

偏置电容法测量电容电流

电力系统中心点绝缘系统在确定是否要配置消弧线圈时,需要估算或测量系统的单相接地电流。用戴维南定理推导了偏置电容法测量电容电流的计算式,并分析了其产生误差的原因。     

Stray capacitance eliminating transformations for switched capacitor circuits

Transformations are given that eliminate the influence of part or all of the stray capacitances to ground in a switched capacitor circuit, while leaving the transfer functions and, conditionally, their sensitivities to nominal capacitor ratios invariant. the transformations increase the number of operational amplifiers to the minimum that is required, as we prove, for stray capacitance insensitive circuits. the number of capacitors usually also increases, giving rise to constraint equations.     

Hybrid switch with controlled switching for circuits with capacitor banks

An original scheme for constructing a hybrid switch (HSW) for switching capacitor banks is proposed and proven. The experimental studies of the transient processes during current commutation in the hybrid switch are conducted. The dependences of the transition time of the current between a vacuum arcquenching chamber (VDK) and a diode unit on the switching current are determined. A mathematical model of the current transition between the vacuum arc-quenching chamber and diode units under different switching modes is developed.     

A calculation method of chamberless thermal determination of intrinsic safety for electrical circuits

A mathematical model of electric ignition for methane-air mixture from a source of sustained power is applied to develop a reliable calculation method for determination of the intrinsic safety of electrical circuits of explosion-proof electrical equipment. A method for rapid calculating of the intrinsic safety for explosion-proof electrical equipment is developed that is suitable for evaluation of a wide class of circuits, including systems with reduced discharge time, based on regression relationships obtained by the preliminary pattern of thermal explosion field. The possibility of using the proposed method is shown by the example of determination of the intrinsic safety of electrical circuits of a dc power supply with high load capacity, which responds to the excess of the modulus for the rate of change of load current strength.     

优化模拟电流法计算超高压输电线路三维磁场

为了获得更准确的输电线路下方磁场的三维分布,使用智能优化算法对模拟电流法中模拟电流的个数与位置参数进行寻优,解决了普通模拟电流法中模拟电流的位置和个数只能依靠经验来确定的问题,从而提高计算精度.建立基于输电线路实际物理形状的三维计算模型,通过不同方法计算上海市松江区洞泾-泗泾500 kV线路的三维磁场分布.将计算结果与...     

Weighted average Q-factor calculation for single port filter-antenna measurement

Filter-antenna has many advantages like no need of match network, low insertion loss, ease of design, low cost and light weight. However, practical implementation of filter-antenna requires a precise value of \(Q\) -factor. Filter-antenna is a single device, handling radiating and filtering properties simultaneously, making it difficult to extract \(Q\) -factor for such device. Moreover, filter-antenna has single port and designer is required to calculate \(Q\) -factor from single port. As reported in literature that the available methods for calculation of \(Q\) -factor from single port seem inaccurate. This paper presents a novel \(Q\) -factor calculation method that outperforms existing methods for almost every case of filter-antenna. Experimental results verify the superior performance of proposed method relative existing methods.     

Power·delay product in COSMOS logic circuits

In this simulation work, we use COSMOS logic devices—a novel single gate CMOS architecture recently announced [1]—in multi-input logic gates, assessing its performance in terms of power·delay product. We consider three different multi-input logic circuits: a two-input NOR gate, a three-input NOR gate, and a three-input composite NOR/NAND (NORAND) gate. For this power·delay analysis, the transient TCAD simulations are employed in a mixed-mode approach where circuit and device simulations are coupled together, culminating in the delay response of the circuits as well as the static/dynamic current components. The analysis shows that all circuits, except the 3-input NOR gate, has acceptable characteristics at low-power applications and static leakage limits all COSMOS circuits at high-bias conditions.     

Postbreakdown current in MOS structures: extraction of parameters using the Integral difference function method

This paper deals with the extraction of parameters and simulation of the postbreakdown leakage current in pMOS devices with ultrathin oxides. The model considered is based on the generalized diode equation, i.e., a diode-like equation with series resistance. The current-voltage (I-V) characteristic can be expressed in a closed-form expression, which makes it is suitable for circuit simulation environments. Model parameters are extracted using the integral difference function (IDF) method. Because the exact expression for the I-V characteristic is used for computing the IDF, the method does not involve any kind of approximation. The effect of including a nonlinear correction term to the voltage drop across the structure is also discussed.     

A companion macromodelling approach for the transient analysis of MOS large-scale integrated circuits

Purpose of this work is to present a new macromodelling approach for the simulation at the device level of large MOS integrated circuits, requiring only marginal modifications to be implemented in the widely used circuit simulator SPICE. This method results in a substantial saving in computing time and guarantees the same accuracy of SPICE. A prototype simulator based on this method has been developed and used to analyse several significant circuits. In addition, since the method is particularly suitable to be implemented in parallel computers, some results obtained with the CRAY-YMP/432 computer are provided.     

Operation of analog MOS circuits in the weak or moderate inversion region

In analog metal-oxide-semiconductor (MOS) circuit design, the ratio of channel width to channel length (W/L) can become very high, often exceeding a value of 1000. This high ratio may result either from wide channel devices, designed to achieve high transconductance, or from short-channel-length devices used in high-frequency circuits. Since drain current is generally proportional to the W/L ratio, the effective gate-to-source voltage to achieve a desired drain current is typically quite low. In many cases, this set of circumstances leads to operation in the weak or moderate inversion region accompanied by electrical behavior that differs significantly from that in the strong inversion region. In designing analog MOS circuits, an understanding of operation below the strong inversion region is necessary to relate design predictions to simulation results. In addition, biasing simple amplifier stages near the weak or moderate inversion region can be used to advantage. Such a bias can lead to maximum voltage gain, low device dissipation, and minimum total harmonic distortion.     

对低压补偿装置中并联电容器的过电流保护的分析

符合GB14048.4 接触器标准具有过载反时限动作特性的传统热继电器,却长期用于低压成套补偿柜中,作为需要门限式过电流保护的并联电容器的保护器.本文认为是根本不起保护作用的,仅是摆设而已.     

可直接分析与计算的变压器等效电路模型

针对电网中不同电压等级网络间分析和计算方法复杂,不能进行直接分析与计算的问题,依据电路的网络理论,提出了一种含理想运算放大器的变压器等效电路,采用理想运算放大器实现受控源的方式,建立了变压器工程化模型电路,并对电路的网络方程进行了理论推导和电路的模型进行了仿真.仿真结果表明,该工程化模型不但能模拟等效变压器电路,而且电路方程也满足变压器的网络方程,从而在含有变压器的电网中实现了不同电压等级网络间的直接仿真分析与模拟计算.     

数字化变电站级联网络时延上界计算方法

提出一种改进的数字化变电站级联网络时延上界计算方法,从级联系统末端开始逐步细化数据流,逐步求取其后端级联系统对级联入口数据流的服务曲线,达到了只需考虑单次突发的效果。运用多种方法对采用交换式以太网环形拓扑构建数据采集网和GOOSE网合并的变电站过程总线网络进行计算,结果表明所提出的方法比采用上级离开曲线即下级到达曲线思路的方法更有效。     

Generalized reluctances in eddy current magnetic circuits

Summary The concept of generalized—complex or operational—reluctances is introduced. It is shown that these reluctances simplify considerably the calculation of systems, containing magnetic circuits with eddy currents. Two simple applications are worked out. Some results from a numerical study of the magnetic flux on breaking a telephone relay are given.

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Übersicht Es wird gezeigt, wie der Begriff eines verallgemeinerten, komplexen oder operatorischen magnetischen Widerstandes (Reluktanz) eine bequeme Behandlung von Problemen über wirbelstrombehaftete magnetische Kreise zuläßt. Zwei einfache Beispiele werden durchgerechnet. Die Ergebnisse einer Untersuchung des magnetischen Flusses bei Ausschaltung eines Telephonrelais werden angedeutet.

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With 6 Figures

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To the memory of a great teacher of operational calculusHenning Pleijel (1873–1962) Professor of theoretical electrotechnics 1913–1934 at the Royal Institute of Technology, Stockholm

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Presented at the First International Conference on Electromagnetic Relays, held at Tohoku University, Sendai, Japan, Oct. 8–11, 1963.     

超级电容器在变电站直流系统中的应用

现在各类中小型终端变电站、枢纽变电站中使用的蓄电池直流屏,环境温度要求高、维护工作量大,蓄电池使用寿命短,如采用超级电容替代蓄电池将具有革命性的进步.     

A fast discrete method for voltage drop and current calculation formanufacturing facilities with intermittent loads

The author presents a numerical method of calculating voltage drops and thermal current ratings due to a large number of intermittent loads such as welders and robots. The welder and robot loads can have different currents and duty cycles and may connect at different points on a distribution network that is not necessarily radial. No lumping of welder loads is required. Regular loads such as motor loads and other process loads can also be represented simultaneously. The method can be easily extended to single-phase welders, i.e., for a three-phase distribution system analysis