共查询到20条相似文献,搜索用时 31 毫秒
1.
Kari Lehtinen Markku Sipila Veikko Porra 《International Journal of Circuit Theory and Applications》1991,19(2):125-143
A higher-order diffusion model for a bipolar transistor has been developed. This model is based on the Padé approximation of the quasi-static expansions of the base and collector currents and gives improved accuracy for the simulation of fast transients and periodic operation at high frequencies. the effect of higher-order circuit elements on accuracy is demonstrated by calculating the transient response to a step excitation and by determining the scattering parameters of a transistor model with higher-order elements linearized about an operating point. the higher-order model is replaced by an equivalent circuit including only conventional elements, and the transient behaviour of these two models is compared. 相似文献
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Leon O. Chua Ellen W. Szeto 《International Journal of Circuit Theory and Applications》1983,11(2):187-206
Highei- and mixed-order non-linear circuit elements have been introduced to provide a logically complete formulation for non-linear circuit theory. In this paper, we analyse the circuit-theoretic properties of these elements, including reciprocity, passivity and losslessness. We have derived necessary and sufficient conditions for a higher- or mixed-order n-port element to be reciprocal or antireciprocal. We have shown that under very mild assumptions, most non-linear higher-order 2-terminal elements are active and not lossless. Finally, we show that the number of lossless linear higher-order 2-terminal elements far exceeds that of the passive linear elements. 相似文献
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基于高阶谱与支持向量机的电力电子电路故障诊断技术 总被引:3,自引:0,他引:3
针对现有电力电子电路故障诊断方法存在的不足,研究了采用高阶谱分析和支持向量机(support vector machine,简称SVM)的电力电子电路故障诊断和定位方法。首先利用高阶谱中的双谱技术分析、处理和提取电路状态的故障信息特征;然后设计和采用多类层次支持向量机分类器作为故障模式的训练和识别器,其中,分类器的结构利用模糊C-均值算法(fuzzy C-means,简称FCM)进行了优化;最后采用一个实际的Buck功率电路进行了建模、仿真和验证。结果表明,采用该方法对电力电子电路故障的诊断和定位率可达99%以上,达到了较为理想的诊断精度。 相似文献
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考虑发电机约束条件的潮流计算方法 总被引:4,自引:1,他引:3
由于当发电机满足励磁电流限制时,并不能保证发电机定子电流不越限,当发电机满足定子电流限制时,也不能保证发电机励磁电流不越限,因此,本文将受发电机定子和转子电流约束下的节点定义为PI节点,同时,基于凸极式同步发电机定子电流和转了电流约束方程组,采用牛顿法分别推导了极坐标和直角坐标系统下的功率偏并型潮流方程,并给出PI节点的潮流雅可比矩阵元素修正公式,当考虑了定子电流和转子电流约束条件后,潮流计算的计 相似文献
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In this paper, new topologies for quasi-Cuk converter are proposed. The proposed converters with different voltage and current transfer ratio and reduced voltage stress on capacitor can be employed in distributed generation (DG) systems. In this paper, steady-state analysis of two proposed quasi-Cuk converters in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is presented. Then, besides values designing of used elements, maximum and minimum values of their current and voltage are calculated. Moreover, critical inductances between CCM and DCM for the proposed converters are calculated. Unique features of the proposed converters are different transfer ratio without employing additional elements compared to the conventional Cuk converter. Comparison of the proposed converters with conventional converter in terms of voltage transfer ratio, voltage stress on capacitor, and voltage stress on switch demonstrates advantages of the proposed converters. Finally, experimental results to verify the accuracy of the proposed converters in different operating modes are presented. 相似文献
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新型恒定一次侧电流无接触电能传输系统的建模与优化 总被引:5,自引:0,他引:5
提出一种新型无接触式感应耦合电能传输系统(inductively coupled power transfer,ICPT),系统一次侧线圈与电感/电容/电容所组成的谐振槽谐振、二次侧线圈与补偿电容并联谐振。利用互感理论,分别建立相互分离的原边等效电路模型和负载等效电路模型,采用正弦交流分析法对其等效电路模型进行分析,获得谐振槽电容及电感元件的参数计算公式,导出系统向负载传输功率及输出电压的计算表达式,并对谐振槽元件参数进行优化设计, 以便减小装置体积, 降低成本。额定频率下系统一次侧线圈电流保持恒定而与负载大小无关,保证电能由电源向负载的稳定传输。同时谐振槽输入电流随负载的减小而减小,提高系统的部分负载能效值。PSpice仿真实验验证该系统的上述优点。 相似文献
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D. Sud 《International Journal of Circuit Theory and Applications》1975,3(2):211-216
This paper presents a method for the calculation of first- and higher-order differential sensitivities of the response of a linear reciprocal or non-reciprocal network following large changes to one or more elements. The method requires only one nodal matrix inversion per frequency. The same inverted matrix can be used when different elements are chosen for large change, providing the original changed element(s) is returned to its nominal value. 相似文献
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部分线性核估计方法在谐波责任分摊问题中的应用 总被引:1,自引:1,他引:0
准确评估公共连接点处的背景谐波电压和等效谐波阻抗是研究谐波责任分摊问题的前提。为准确评估背景谐波电压波动情况下受关注谐波源分摊的谐波责任,文中研究应用了部分线性核估计方法。为求解背景谐波电压,将背景谐波电压在受关注时段内的某一时刻按照泰勒级数展开,并把高阶项看做误差项,为保证求解的准确性,选取的目标函数在误差平方和最小的基础上考虑了展开时刻的有效邻域范围和各误差项所占权重不同对估计的影响,并利用窗宽参数控制展开时刻的邻域范围和对应误差项所占权重的大小。利用IEEE 14节点系统进行了仿真验证,并将计算结果与两种线性方法进行了比较,证明了该方法的有效性。 相似文献
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Leon O. Chua Chwen-Cher Chang 《International Journal of Circuit Theory and Applications》1988,16(2):157-190
Circuit models for both long-base and short-base p-n junction diodes which are valid for non-linear high-speed and high-frequency operations are presented. the diode model consists of a parallel connection of higher-order dynamic elements and includes the conventional diffusion model as a special case. the new dynamic model can be used for simulating arbitrary p-n junction diode circuits under all operating conditions. In particular, it is capable of simulating realistically the diode's reverse transient behaviour and providing an increasingly accurate approximation to the diffusion equation as the order of the model gets higher. the model is also shown to be capable of reproducing the frequency-dependent small-signal characteristics of p-n junction diodes. The model is based mainly upon the device's physical operating principles. Perhaps the most significant implication of the model is the fact that it illustrates the important roles played by higher-order and dynamic elements in highspeed and high-frequency non-linear device modelling. 相似文献
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Giancarlo Storti‐Gajani Amedeo Premoli Angelo Brambilla 《International Journal of Circuit Theory and Applications》2009,37(1):67-85
Power electronic elements are often built employing arrays of devices designed to evenly share high currents over a large number of single devices. In some situations, mismatch in current sharing can occur causing temperature differences between elements of the array. These differences can trigger electrothermal instability phenomena and even device destruction. In this paper, we consider the electrothermal dynamic behavior of arrays composed of identical one‐port elements. We first introduce a simplified model of the thermal paths and of the elements composing the array that allows the analysis of the behavior of the electrothermal system. Then, we investigate from a mathematical standpoint dynamic effects governing current sharing and possible situations causing hot spots with consequent device destruction. These results are compared with simulations of detailed non‐linear models confirming predictions given by the simplified model. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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风电、光伏、储能、柔性高压直流输电等通过电压源/电流源型变流器接口取代了传统的机械开关并网,将给电力系统的既有频率动态特性、有功平衡原理及相关控制方法带来改变。首先回顾了近年电力电子接口相关的系统频率事件,从惯量角度分析了规模化电力电子接口对系统频率控制的影响。总结了提高频率支撑能力的接口控制技术,分析了接口外特性在惯性响应和一次调频环节与同步机组等价性。基于能量守恒原理讨论了大规模电力电子接口接入下电力系统有功平衡机理,最后从机理、模型、方法层面提出了电力电子化该领域内值得探索问题。 相似文献
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无功补偿投切元件的选择 总被引:1,自引:0,他引:1
吴家庆 《广东输电与变电技术》2006,(4):34-36
无功补偿投切元件多种多样,本文分别从投切速度,响应速度、合闸涌流、过电压以及功耗等方面讨论了几种投切元件的特性和一般的选择原则。 相似文献
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基于变频保护功能的单片DC/DC变换芯片 总被引:1,自引:0,他引:1
设计并推出了一种具有变频保护功能的降压型单片DC/DC开关电源芯片。该芯片具有独特的过热、限流和短路保护功能,只需外接3只元件就可构成一个高性能的DC/DC开关电源。芯片的限流和短路保护功能分为两级:一级为降压限流,二级为降频截流。当输出短路时.占空比和工作频率同时变小.大大减小了短路电流和短路损耗,保证了用户系统的安全。当芯片工作温度过高时,芯片的过热保护电路将关断功率开关管,确保芯片安全可靠工作。仿真和应用实例证明了该芯片的可行性。 相似文献