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关键词： Nanowire MOSFET   spacer   underlap   fringing fields   halo doping  

摘要： This paper presents a novel design and analysis of a low-k source-side asymmetrical spacer halo-doped nanowire MOSFET. The utilization of high-k spacer materials in MOSFETs enhances electrostatic control and minimizes short-channel effects in nanoscale devices. However, the performance of dynamic circuits suffers, with higher fringe capacitance brought on by high-k spacers. Our method focuses on reducing gate capacitance by promising utilization of high-k spacer material. The proposed device is constructed in Silvaco TCAD software, and results show that the low-k source-side asymmetrical spacer halo-doped nanowire MOSFET design exhibits noticeably lower gate capacitance and intrinsic delay, with values of 1.23x10-17\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.23\user2{ } \times \user2{ }10<^>{-17}$$\end{document} F and 1.11x10-12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.11\user2{ } \times \user2{ }10<^>{-12}$$\end{document} s, respectively. The CMOS inverter delay and three-stage ring oscillator operating frequency for the proposed device are 1.82x10-12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.82\user2{ } \times \user2{ }10<^>{-12}$$\end{document} s and 91.61 GHz, respectively. The proposed device demonstrates better performance than other spacer engineering devices, making it a strong candidate for digital applications.

关键词： 低压台区   光伏功率预测   模糊C均值聚类   时间卷积网络   压缩和激励网络  

摘要： 现有光伏功率预测的方法在应对低压台区分布式光伏时，存在初始数据过于冗余、预测特征提取困难，进而导致预测精度不足的问题，对此，本文提出一种基于FCM-SENet-TCN的低压台区光伏超短期功率预测方法。首先，利用模糊C均值聚类算法（fuzzy Cmeans，FCM）充分挖掘多源气象环境数据，将初始数据集以不同天气进行聚类，降低初始数据冗余度；其次，将压缩和激励网络（Squeeze-and-Excitation Networks，SENet）融入时间卷积网络（temporal convolutional network，TCN），高效提取复杂特征并提高预测精度；最后，应用平均绝对百分比误差和均方根误差作为评价指标，对预测结果进行评估。仿真结果表明：所提预测方法可以充分利用初始气象数据，能够针对低压台区分布式光伏发电机组出力特点，做出更为精确的超短期功率预测。

关键词： 水平轴风力机   大气边界层   空气动力学   湍流  

摘要： 该文风洞中构建出两种平均风切变指数和湍流强度的大气边界层风场，并开展均匀来流和大气边界层条件下风力机载荷及功率特性的实验研究。结果表明：风力机偏航运行时，机组轴向载荷减小，疲劳载荷增大，随着偏航角增大，风轮功率系数减小，最优叶尖速比降低。在大气边界层来流条件下，风轮平均倾覆力矩系数和功率系数较均匀来流增大，机组疲劳载荷、极端载荷，及输出功率的非定常特性显著增加，且功率系数的概率分布更符合高斯分布。风轮功率系数谱与大气边界层来流速度谱存在一定程度的关联性，在耦合区间出现Φp/Φu～f-2的幂率关系。在超过约3倍转频后，功率系数谱曲线基本呈水平趋势，表明湍流来流与输出功率的调制作用开始解耦，解耦后风力机功率输出受湍流来流的影响较弱，其功率谱响应主要取决于风轮的自身特性。

关键词： 全柔性隔振系统   有限元方法   功率流   可视化   隔振器布置  

摘要： 在对船舰等大型复杂结构上的动力设备进行减振设计和分析时,传统隔振模型无法充分考虑基础和机器柔性、隔振器质量、隔振器布置形式等对振动传递的影响,也无法直观显示振动能量在整个系统的传递情况,因此不适用于大型复杂结构的建模和分析。分别将柔性的机器和基础视为形状不规则的板结构,隔振器用空间梁模拟,建立了考虑机器、基础和隔振器柔性的隔振系统模型。将有限元方法引入隔振系统的振动计算,避免了计算机器和基础机械导纳的复杂过程,给出了柔性隔振系统的传递功率流表达式。将系统的振动传递进行可视化处理,得到了结构的能量分布及功率流传递路径,对机械设备的振动传递预测和隔振设计具有重要的指导意义。

关键词： 对称型双芯移相变压器   本体保护   复合型差动保护   电平衡差动   故障定位  

摘要： 对称型双芯移相变压器(该文简称“移相变”)，能够实现输电线路传输功率的动态调节，提高系统潮流输送的灵活性。然而由于对称型双芯移相变压器拓扑结构复杂，内部故障特征耦合交错，为其本体保护方案的设计和配置优化带来了挑战。为解决这一问题，该文在分析移相变磁路结构的基础上，基于基尔霍夫电流定律、电磁感应定律等基本电路原理建立了一种适应于对称双芯移相变压器的复合型差动保护方案。该方案仅通过一套继电器便可以反映串联变压器和励磁变压器的匝间、匝地故障及其之间引线的短路故障。进一步的，通过附加电平衡差动，实现了移相变区内故障的定位功能，相较于已有保护方案，反映的故障类型更为全面的同时减少了电流互感器的配置数量，提高了经济性。最后，基于MATLAB/Simulink仿真平台搭建了对称型双芯移相变压器仿真模型，通过大量仿真实验，验证了该文所提方案的可行性和有效性。

关键词： Hole traps  

摘要： As implemented in the commercialized device modeling software, the four-state nonradiative multi-phonon model has attracted intensive attention in the past decade for describing the physics in negative bias temperature instability (NBTI) and other reliability issues of Si/SiO2MOSFET devices. It was proposed initially based on the assumption that the oxygen vacancy defects (VO) in SiO2dielectric layer are bistable in the Si-dimer and back-projected structures during carrier capture and emission. Through high-throughput first-principles structural search, we found VO on nonequivalent O sites in amorphous SiO2can take 4 types of structural configurations in neutral state and 7 types of configurations in +1 charged state after capturing holes, which produce a wide range of charge-state transition levels for trapping holes. The finding contrasts the structural-bistability assumption and makes the four-state model invalid for most of O sites. To describe the reliability physics accurately, we propose an all-state model to consider all these structural configurations as well as all the carrier capture/emission transitions and thermal transitions between them. With the all-state model, we show that the VO defects play important roles in causing NBTI, which challenges the recent studies that discarded VO as a possible hole trap in NBTI. Our systematical calculations on the diversified VO properties and the all-state model provide the microscopic foundation for describing the reliability physics of MOSFETs and other transistors accurately. Copyright © 2024, The Authors. All rights reserved.

关键词： MOSFET   Silicon carbide   Logic gates   Resistance   Frequency measurement   Power measurement   Electrical resistance measurement   Switches   Silicon   Impedance   Fast switching events   input impedance   internal gate resistance   silicon carbide (SiC) power MOSFETs  

摘要： This article presents an analysis of the internal gate resistance of silicon carbide (SiC) power MOSFETs and its influence on the dynamic device performance. The internal gate resistance of SiC power MOSFETs features a frequency and voltage dependency that is not observed for silicon (Si) power MOSFETs, and hence, not investigated in mature Si device technology. Using numerical device modeling based on experimental electrical characterization, the low-frequency (LF) behavior of the internal gate resistance is attributed to the defects at the SiC-oxide interface. The high-frequency (HF) behavior is explained by the gate signal propagation across the die area and incorporated in a proposed MOSFET model. In the example of a reference SiC power MOSFET design, the developed model is used to evaluate the differences between the simulated and the measured switching waveforms in more detail. The results do not only reveal the physics of the internal gate resistance of SiC power MOSFETs but also highlight how the standard SPICE models, which include the internal gate resistance as a lumped resistor, can be limited in modeling the switching waveforms of SiC power MOSFETs and estimating switching losses with high accuracy.

关键词： 油浸式变压器   温升试验   热点温度   动态演化规律   推演计算模型  

摘要： 变压器绕组动态温度信息可有效衡量其负载能力和服役寿命，基于此本文开展了油浸式变压器绕组热点动态温升演化规律及推演计算模型研究。首先，基于“电磁-流-热”多场耦合仿真获得了不同负载率下变压器绕组的稳态温度分布，并通过温升试验验证仿真模型的有效性；然后，仿真分析了绕组热点动态温升演化规律，研究了热点动态温升与负载率的关联关系；最后，采用差分进化算法对温升曲线进行预测，研究提出了绕组热点温升推演计算模型。结果表明，本文多场耦合温度仿真结果与实测结果的最大误差小于5%；绕组热点温升值随负载电流施加时间的增长呈现出饱和型指数函数增长规律，稳态温升值随负载率的增大呈幂函数规律增长，动态温升时间常数值随负载率增大呈幂函数下降规律；采用本文推演计算模型求解获得的绕组热点稳态温升值的最大误差百分比仅为2.83%，温升时间常数值的最大误差百分比仅为4.76%。本文成果为采用小负载率温升试验数据推演获得大负载率电流下的温升数据提供了可行性，为解决现场变压器温升试验实施难、检测时间长的问题提供了技术参考。

关键词： SiC MOSFET   结温波动   主动热管理   等效栅极电阻控制   可靠性  

摘要： 通常限制SiC MOSFET可靠性的根本因素是非平稳工况下的结温波动。本文提出的等效栅极电阻控制方法克服了在线连续修改驱动电阻的困难。在此基础上，提出一种主动热管理方法，通过改变开关损耗的方式来抑制结温波动，同时给出了结温调节范围的推导过程。最终，搭建逆变器实验平台，验证了理论分析的正确性。实验结果表明，该方法可显著降低SiC MOSFET各功率波动阶段的温度波动，最大波动范围由18.83℃降至9.85℃，SiC MOSFET的寿命延长约2.18倍。此外，本文考虑了系统的效率因素，提出温控操作区间和结温控制系数的概念。最后，通过实验验证了本文所提出的方法的有效性。

关键词： 新型电力系统   低压台区   智能电表   相别辨识   DistFlow模型   递推最小二乘法  

摘要： 低压台区中存在用户实际相别与标定值不一致的现象，对台区的主动调控与精细化管理构成了障碍。当前的相别辨识方法在面临高比例分布式光伏接入、拓扑结构信息及线路参数缺失的有源低压台区时，具有一定的局限性。为此，文中提出了一种基于电压与功率采集数据的有源低压台区用户相别辨识方法。首先，通过分析低压台区三相线性化DistFlow潮流模型，得到相别辨识的理论依据。然后，通过松弛0-1变量构建多元线性回归模型，并利用递推最小二乘法求解，实现相别辨识，避免了矩阵求逆。此外，还引入了相别隶属度指标强化计算结果。光伏台区试点应用结果显示，该方法的识别精度高，鲁棒性好，不易受电压平衡程度、节点数量和三相分布式光伏等因素的影响。