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关键词： 互联变换器   ADRC控制器   下垂控制   交直流微电网  

摘要： 【目的】为确保交直流子网之间能量稳定平滑流动，解决由于大功率交流或直流负荷不确定投切而导致互联变换器控制效果恶化的问题，提出了一种基于二阶线性自抗扰控制器的互联变换器功率协调控制策略。【方法】在计及变换器传输功率的基础上，通过利用电流观测器估计交流或直流子网中大负荷投切扰动，然后在控制回路反馈通道中补偿扰动量，以实现在大功率负荷投切时交流子网频率、直流子网母线电压均始终能够在允许范围内变化。最后，基于MATLAB/Simulink搭建了独立交直流混合微电网的电磁暂态仿真模型，验证了本文所提功率协调自抗扰控制策略的有效性。【结果】与传统控制策略对比表明，所提控制策略使得微电网的可靠性与稳定性增加。【结论】所提控制策略对具有重要参考价值。

关键词： Batteries   Heating systems   Heat transfer   Electromagnetic heating   Discharges (electric)   Compounds   Resistance   MOSFET   Pulse width modulation   Oscillators   Battery self-heating   compound heating   LC parallel oscillation   low temperature  

摘要： At low temperature, it is challenging for existing battery heating methods to simultaneously achieve efficient and safe self-heating. For this reason, a compound self-heater (CSH) based on electromagnetic induction is proposed, which is capable of heating batteries safely and efficiently without an external power supply. Particularly, a pulse width modulation (PWM)-driven inductor capacitor (LC) parallel oscillation topology and a special inductive winding structure are proposed, to achieve the combined heating of noncontact electromagnetic induction heating and battery internal ohm heating. Further, the heating topology operation principle is revealed and the electrothermal model (ETM) is developed, providing theoretical guidance for the optimal design of the heater and the development of the heating strategy. The experimental results verify the validity of the CSH and ETM. In the full SOC range, the average heating rate of the CSH is 9.1 degrees C/min, and the battery can be heated from -20 to 0 degrees C in 100 s, with only 2.3% of battery energy consumed. Moreover, compared to existing discharge and alternating-current heating methods, the CSH is shown to exhibit better generalizability on LiFePO4 (LFP) and nickel-cobalt-manganese (NCM) batteries.

关键词： 故障诊断   特征偏移   标志性特征   时频滤波器   偏移注意  

摘要： 针对轴承故障数据分布不一致导致特征偏移、标志性特征提取困难的问题，提出一种基于时频滤波器和偏移注意神经网络的轴承故障诊断方法，从离线和在线两个方向分别对故障信号进行处理。在离线部分，提出时频滤波器，分别从时域和频域提取故障信号的标志性特征;提出兼顾全局特征和局部特征的空间采样方法。在线部分提出偏移注意神经网络，与自注意相比，偏移注意更有利于偏移特征的提取，从而降低数据分布不一致造成的影响。在西安交通大学和凯斯西储大学的轴承数据集上进行实验，达到了100%的精度，证明了所提方法能够很好的提取故障信号的标志性特征，并且能够有效抑制特征偏移对故障识别精度的影响。而在凯斯西储大学轴承数据集上的对比实验则证明了所提方法的优越性。除此之外，还在工业现场采集的燃气轮机主轴承数据集上进行了实验，结果证明所提方法具有实际应用意义。

关键词： 功率开关开路   故障诊断   共模电压残差   三相四线制   T型逆变器  

摘要： 功率开关开路故障是影响逆变器可靠性的关键因素之一。有效的故障诊断方法有利于保障容错控制的精准实施，对系统的安全运行至关重要。针对现有三相四线制T型逆变器功率开关开路故障诊断策略诊断变量多、流程复杂的问题，提出基于共模电压残差单类型诊断变量的开路故障定位方法。首先，分析三相四线制T型逆变器单管故障特征，并基于其简化电路，构建故障共模电压残差；同时，通过研究故障模态，引入“脉冲面积”度量，对不同开关故障下逆变器的共模电压残差进行精准量化；此外，为区分各开关故障下的差异性，刻画自适应阈值诊断区域并设计故障检测变量以实现故障开关精准定位。最后，搭建一台10 kW的三相四线制T型逆变器样机进行实验，结果验证了所提诊断方法的有效性与鲁棒性。

关键词： 馈电网络   波束赋型   宽带天线阵列   波束稳定   频变  

摘要： 为了在宽带的天线阵列中实现两个固定的波束方向，本文提出了一种相位差随频率变化的馈电网络设计方法。所设计馈电网络的相位差与工作频率之比在整个频率范围内保持恒定，这意味着在f0时相位差为φ，在2f0时相位差为2φ。馈电网络的传输线结构为带状线。天线阵列中的辐射单元为维瓦尔第天线。设计并加工了该馈电网络，测量结果与仿真结果基本吻合。由所设计的馈电网络馈电的天线阵列能在2～4GHz频率范围内实现两个固定方向波束，与理论分析结果具有较好的一致性。所设计的宽带天线阵列系统具有在宽带范围内保持波束方向稳定的功能，为双区域覆盖提供了一种潜在的解决方案。

关键词： 多端口DC-DC变换器   光伏直流汇集   功率失配   电压均衡  

摘要： 多端口输入独立输出串联（IIOS）型直流变换器具有独立最大功率点跟踪控制（MPPT）、高升压比和高效率等优点，适用于分布式光伏中压直流汇集场合。针对分布式光伏系统输入功率不匹配会造成子模块输出电压不均匀，导致器件过电压和系统最大输出功率损失的问题，本文提出了一种基于功率解耦多绕组变压器（PD-MWT）的多端口输入独立输出串联型双半桥IIOS变换拓扑结构，与现有其它多端口IIOS变换器相比，该拓扑结构将子模块变换器中的隔离变压器和用于电压均衡的多绕组变压器集成在一个PD-MWT中，可以显著减小整个IIOS系统体积和尺寸。此外，该变换器仅需在电路中配置较少的传感器就能实现MPPT控制和输出均压均衡，且网侧开关管比其他IIOS变换器具有更低的电流应力，最后通过MATLAB/Simulink仿真和三模块900W小型样机实验验证了该拓扑的工作原理和相关性能。

关键词： Radiation hardened   MOSFET   Interfacial electron trapped   Radiation resistance   Electron radiation shielding  

摘要： The radiation resistance of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is of great significance when applied in aerospace. However, it is still challenging to obtain MOSFETs with excellent radiation resistance. In this work, the radiation hardened MOSFETs were realized by GdF3-Al2O3@Bi-Ti3C2Tx/epoxy (MBAG/EP) polymer-based composite coating with function of trapped interfacial electrons. The radiation resistance of resultant packed MOSFET is significantly improved, showing the lower threshold voltage negative drift value (0.41 V) than the bare MOSFET (7.89 V). This is mainly attributed to the introduction of ultra-thin Al2O3 intermediate layer between Bi and GdF3, which effectively tailor electron dense and distribution for an effective electron attenuation, and thus improve the radiation resistance of the MOSFET. Theoretical calculations further reveal that the packed MOSFETs present the less shifted voltage and trapped charges compared with the pristine one. This work provides an interface engineering strategy for developing radiation hardened MOSFETs.

关键词： Double-gate metal-oxide-semiconductor field-effect transistors (DG MOSFETs)   switching speed   analog/RF performance parameters  

摘要： Graded-channel gate-stack double-gate metal-oxide-semiconductor field-effect transistors (GC-GS-DG-MOSFETs) with symmetric single-material-gate-metal (D1), asymmetric single-material-gate-metal (D2 and D3), dual-material-gate-metal (D4 and D5), and triple-material-gate-metal (D6 and D7) have been investigated to optimize the best structure for ultra-fast digital logic circuit and RF microwave circuit applications. The work function (phi m=4.7 +/- 0.2eV)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\varphi }_{m}=4.7\pm 0.2 eV)$$\end{document} of the gate electrodes has been determined based on key performance indicators, such as offset current, the ION/IOFF ratio, and threshold voltage. This study identifies the designs that offer improved switching speed and overall device performance by evaluating ION/IOFF, subthreshold swing, and threshold voltage. It also illustrates the electric field distribution, surface potential, and energy band diagram of the channel for all proposed configurations. Analog/ RF performance has been estimated by investigating the transconductance (gm), output conductance (gd), early voltage (VEA), output resistance Ro), transconductance generation factor (TGF), cut-off frequency (fT), intrinsic device delay (s), transconductance frequency product (TFP), and gain-bandwidth product (GBP). Additionally, linearity parameters, such as higher-order transconductance (gm2, gm3), VIP2, VIP3, third-order intercept point (IIP3), and third-order intermodulation distortion (IMD3)) have also been assessed.