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(上接2009年第3期79页)
3.5.11浪涌抑制器件的组合应用
有时候靠一个浪涌抑制器件(SPD)很难满足所有的需求,为了优化SPD的浪涌抑制性能,同时减小生产成本,可以将多个SPD组合使用。图3AT是一个能够承受高功率的气体放电管(GDT)和一个箝位动作迅速的金属氧化物压敏电阻(MOV)的组合应用情况。GDT被触发后可以吸收大部分浪涌能量,当产生过压时,串联电感可以使GDT触发,而MOV可以保护负载不受GDT触发电压的影响。 相似文献
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GaN高电子迁移率晶体管(HEMT)以其复杂的器件特性使其大信号建模变得十分困难,尽管EEHEMT、Angelov等模型结构曾经成功应用于GaAs HEMT/MESFET的大信号模型,但当它们被用于GaN HEMT建模时却不再准确和完备.面向GaN HEMT器件的大信号模型,本文提出了一种紧凑的模型拓扑,此模型拓扑综合了GaN HEMT器件的直流电压-电流(I-V)特性、非线性电容、寄生参数、栅延迟漏延迟与电流崩塌、自热效应以及噪声等特性.经验证此模型拓扑在仿真中具有很好的收敛性,适用于GaN HEMT器件的大信号模型的建立,满足GaN基微波电路设计对器件模型的需求. 相似文献
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周继昆 《太赫兹科学与电子信息学报》2014,12(6):817-820
通过建立系统的互感耦合模型,对串并联(LCL)型感应电能传输系统的频率特性进行分析,结果表明,系统的软开关频率会因负载的变化而改变.针对这种特性,基于FPGA 设计了一种闭环频率跟踪方法,经实验验证,当负载在较宽范围内发生变化时,该方法可使系统原边逆变器的工作频率跟踪系统的软开关频率,确保了逆变器开关管工作在零电流开关(ZCS)切换模式. 相似文献
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MESFET和PHEMT大信号建模 总被引:1,自引:0,他引:1
分析了 MESFET和 PHEMT大信号建模的现状 ,提出了在 DC和脉冲两种状态下通用于 MESFET和 PHEMT的精确 I-V模型 ;提出了具有二维 C-V模型精度的一维C-V模型和负载线 S参数测量提取方法 ;提出了采用改进 Cold FET测量与提取技术进行管壳封装器件建模的方法。本文的大信号模型具有很好的数值收敛性和标准的等效电路。提出的模型精确地模拟了器件的 DC I-V、脉冲 I-V、偏置相关 S参数、 C-V特性和电路的功率、增益、效率以及线性特性 ,并用几个实例证实了其精度和通用性。 相似文献
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变阻抗相对论返波管的研究 总被引:4,自引:0,他引:4
根据相对论返波管(RBWO)的非线性理论,数值模拟了耦合阻抗单步跃变型RBWO效率与束流参量、耦合阻抗跃变位置、高低耦合阻抗比值的依赖关系,结果表明器件最优化效率可达到50%,设计制造了一个X波段高功率耦合阻抗单步跃变型RBWO,运用全电磁粒子模拟程序仿真了器件中注波互作用过程,预见出器件功率、效率、频率等性能参量,在电子注电流、注加速电压、互作用区长度相同的实验条件下,测得变阻抗器件实验效率约为均匀阻抗型器件效率的2倍。 相似文献
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宽禁带(WBG)器件与传统的硅基器件相比具有优越的材料性能,在器件开关性能方面具有更大的优势,可以实现更高的开关速度、更低的开关损耗,从而提升电力电子模块的整体效率.但快速开关的瞬态过程也带来了许多问题,其中之一就是电磁干扰噪声的增加.在传导型电磁干扰上,为实现电力电子模块的可靠运行,已有许多针对WBG器件的相关研究,包括开关瞬态机理、噪声源及传播路径的建模、噪声抑制和电磁兼容滤波器设计等.而要设计出可靠的、且有高开关速度和高容量的电力电子系统,还需要解决电磁辐射干扰的问题.文章综述了电力电子系统中电磁辐射干扰的研究成果,其内容涵盖了 WBG器件的电磁干扰源及噪声传播路径的建模、电磁干扰导致的可靠性问题分析,以及减小近场耦合的解决方案及设计原则. 相似文献
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Hammi O. Sirois J. Boumaiza S. Ghannouchi F.M. 《Microwave Theory and Techniques》2006,54(8):3246-3254
An active load-pull-based large-signal modeling approach, suitable for designing and optimizing load modulated amplifiers such as Doherty or linear amplification using nonlinear components based amplifiers, is proposed. A Doherty amplifier was designed by optimizing the dynamic loads seen by the amplifier's transistor using a large-signal load-pull-based behavior model built into computer-aided-design software. Simulation and measurement results showed good agreement, while results obtained using an empirical model of this transistor demonstrated discrepancies. The load-pull-based model was then used to study performance degradation of the Doherty amplifier when load impedance was moved out from the perfect 50 /spl Omega/. It has been shown that the load mismatch can greatly affect the linearity and efficiency performance of the amplifier unless its phase is controlled and kept within a specific range. A load mismatch system level compensator scheme, capable of restituting the linearity loss and maintaining the power-added efficiency close to its maximum range, is proposed. 相似文献
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为揭示通信电台电磁脉冲阻塞效应机理,在受试电台正常工作状态下,借助注入耦合模块实验研究了阶跃脉冲串和双指数脉冲串对数字通信电台误码率的影响规律。引入电磁脉冲对受试设备影响时间的概念,建立了与连续波阻塞效应等价的电磁脉冲阻塞敏感判据。实验结果表明:电磁脉冲对受试设备的影响时间取决于脉冲波形,可通过效应试验测试确定。在电磁脉冲重复率较低时,受试电台的临界干扰电平与脉冲重复率无关,属于单脉冲效应;当脉冲重复率大于电磁脉冲影响时间的倒数时,受试电台的临界干扰电平随脉冲重复率增加而降低,属于多脉冲累加效应。将电磁脉冲在影响时间窗口内进行频谱分析,采用连续波带内多频阻塞效应模型进行验证,误差在2dB以内。 相似文献
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Applications of transient electromagnetics include nonnuclear electromagnetic pulse (EMP) effects on electronic systems to evaluate system vulnerability. A basic component used in the mathematical modeling of systems for EMP vulnerability is the linear dipole antenna. Wu has derived an approximate analytical solution for the pulse reflected from the feed point of a linear dipole antenna for an incident ideal step function of current. The solution does not include the part associated with the very high frequency components because of an approximation used in evaluating the integral describing the reflected pulse. The approximation is eliminated and a simple analytical solution is given that describes that portion of the step function response associated with the very high frequency components. Numerical evaluation of the solution demonstrates convergence with Wu's approximate solution. 相似文献
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A bound on EMP coupling 总被引:1,自引:0,他引:1
A bound on the energy coupled to a load by means of an antenna or aperture subjected to a step function electromagnetic pulse (EMP) is given by the polarizabilities of the antenna or aperture. Examples of coupling bounds for a slender electric dipole antenna, a circular aperture, and a narrow slot aperture with depth are given. It is demonstrated, by use of the bound on the integral of the effective area over all frequencies, that the maximum energy absorbed by an object subjected to a step function EMP is bounded in terms of the static polarizabilities of the object. (The energy spectrum of the step function EMP bounds the spectrum of EMP described by the double exponential over all frequencies.) It is demonstrated that this bound can be used on apertures in infinite ground planes for which Babinet's principle fails to apply (apertures having depth and cavity backed apertures), where the requirement is simply to use the polarizabilities on the incident side of the aperture.<> 相似文献
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Energy saving is one of the most important research hotspots, by which operational expenditure and CO2 emission can be reduced. Optimal cooling capacity scheduling in addition to temperature control can improve energy efficiency. The main contribution of this work is modeling the telecommunication building for the fabric cooling load to schedule the operation of air conditioners. The time series data of the fabric cooling load of the building envelope is taken by simulation by using Energy Plus, Building Control Virtual Test Bed (BCVTB), and Matlab. This pre-computed data and other internal thermal loads are used for scheduling in air conditioners. Energy savings obtained for the whole year are about 4% to 6% by simulation and the field study, respectively. 相似文献
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电源浪涌保护电路的正确运用 总被引:2,自引:0,他引:2
介绍了常用浪涌保护器件(如气体放电管、金属氧化物压敏电阻、电压瞬变抑制二极管)的特性和用法。以电源端口的防护为例,列举了几种应用中常见的认识误区和错误用法,并提出使用滤波器作为缓冲级与SPD组合使用实现多级防护的抑制措施。 相似文献
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为提高系统抗强电磁脉冲毁伤能力,采用时域有限差分法(Finite Difference Tim
e Domain,FDTD)和通用电路仿真器(SPICE)相结合的协同仿真方法,以圆柱腔内由单导线、
双绞线、普通双线和同轴线组成的线束为研究对象,重点研究了导线类型、导线间距、捆扎
和RC滤波电路对耦合特性的影响。结果表明:耦合系数受腔体和传输线的双重影响,同轴线
耦合系数较其他两类线缆降低约40 dB;线间相互屏蔽是捆扎降低耦合系数的主要原因
;随着导线间距增大,耦合系数幅值增大;RC滤波电路是降低电磁耦合的有效手段。所得结
论对电子系统进行抗电磁脉冲加固具有重要意义。 相似文献