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Solid-state transformer-based new traction drive system and control

Jianghua FENG, Jing SHANG, Zhixue ZHANG, Huadong LIU, Zihao HUANG

《机械工程前沿（英文）》 2018年第13卷第3期页码 411-426 doi: 10.1007/s11465-018-0467-0

摘要：

A new type of traction drive system consisting of solid-state traction transformer (SSTT), inverter unit, auxiliary inverter, traction motor and other key components is built in order to suit the demand of developing the next-generation electric traction system which will be efficient and lightweight, with high power density. For the purpose of reducing system volume and weight and improving efficiency and grid-side power quality, an efficient SSTT optimized topology combining high-voltage cascaded rectifiers with high-power high-frequency LLC resonant converter is proposed. On this basis, an integrated control strategy built upon synchronous rotating reference frame is presented to achieve unified control over fundamental active, reactive and harmonic components. The carrier-interleaving phase shift modulation strategy is proposed to improve the harmonic performance of cascaded rectifiers. In view of the secondary pulsating existing in a single-phase system, the mathematical model of secondary power transfer is built, and the mechanism of pulsating voltage resulting in beat frequency of LLC resonant converter is revealed, so as to design optimum matching of system parameters. Simulation and experimental results have verified that the traction system and control scheme mentioned in this paper are reasonable and superior and that they meet the future application requirements for rail transit.

关键词： solid-state traction transformer high-voltage cascaded rectifier LLC resonant converter synchronous rotating reference frame carrier-interleaving phase shift control secondary pulsating voltage beat frequency

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高压VDMOS的一种高精度静态物理模型

鲍嘉明,孙伟锋,赵野,陆生礼

《中国工程科学》 2008年第10卷第2期页码 72-78

摘要：

提出了高压VDMOS的一种高精度静态物理模型(HASPM)。在该模型中，基于更为合理的假设而使得用解析方法求得了双扩散沟道区中的电场和电压；通过深入研究VDMOS 内部的物理特性，给出了一个关于漂移区电场的微分方程，并在整个漂移区都用解析方法求解了该微分方程，由此求得了漂移区的电压降。计算结果表明，该模型在漏端电流接近饱和处的稳定性有较大提高，具有较高的计算精度，特别是在栅电压与漏电压都比较大的情况下，其计算精度有较大程度的提高。

关键词：垂直双扩散MOS场效应晶体管静态物理模型解析方法

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Recent advances toward high voltage, EC-free electrolytes for graphite-based Li-ion battery

Tong Zhang, Elie Paillard

《化学科学与工程前沿（英文）》 2018年第12卷第3期页码 577-591 doi: 10.1007/s11705-018-1758-z

摘要：

Lithium-ion batteries are a key technology in today’s world and improving their performances requires, in many cases, the use of cathodes operating above the anodic stability of state-of-the-art electrolytes based on ethylene carbonate (EC) mixtures. EC, however, is a crucial component of electrolytes, due to its excellent ability to allow graphite anode operation–also required for high energy density batteries–by stabilizing the electrode/electrolyte interface. In the last years, many alternative electrolytes, aiming at allowing high voltage battery operation, have been proposed. However, often, graphite electrode operation is not well demonstrated in these electrolytes. Thus, we review here the high voltage, EC-free alternative electrolytes, focusing on those allowing the steady operation of graphite anodes. This review covers electrolyte compositions, with the widespread use of additives, the change in main lithium salt, the effect of anion (or Li salt) concentration, but also reports on graphite protection strategies, by coatings or artificial solid electrolyte interphase (SEI) or by use of water-soluble binder for electrode processing as these can also enable the use of graphite in electrolytes with suboptimal intrinsic SEI formation ability.

关键词： lithium-ion electrolyte solid electrolyte interphase additives high voltage graphite

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Parameter identification of interconnected power system frequency after trip-out of high voltage transmission

Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG

《能源前沿（英文）》 2014年第8卷第3期页码 386-393 doi: 10.1007/s11708-014-0323-9

摘要： Accurate modeling and parameters of high voltage (HV) grid are critical for stability research of system frequency. In this paper, simulation modeling of the system frequency was conducted of an interconnected power system with HV transmission lines in China. Based on recorded tripping data of the HV transmission lines, system parameters were identified by using genetic algorithm (GA). The favorable agreement between simulation results and recorded data verifies the validity of gird models and the accuracy of system parameters. The results of this paper can provide reference for the stability research of HV power grid.

关键词： high voltage (HV) grid frequency stability parameter identification primary frequency regulation (PFR)

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Experimental study of pollution effect on the behavior of high voltage insulators under alternative current

Hani BENGUESMIA, Nassima M’ZIOU, Ahmed BOUBAKEUR

《能源前沿（英文）》 2021年第15卷第1期页码 213-221 doi: 10.1007/s11708-017-0479-1

摘要： In this paper, the impact of the conductivity and the distribution of pollution on the behavior of the high voltage insulator cap and pin 1512L, artificially polluted is described. An experimental model in form of a disc is proposed. This experimental model reproduces the real model which is the 1512L insulator. Besides, a comparative study is presented. For this comparative study, different solutions are adopted to s`imulate the pollution (containing NaCl+ distilled water) that has different conductivities for a discontinuous distribution of the pollution on the insulator under an AC voltage. Furthermore, the influence of the pollution on the flashover voltage and the leakage current is studied. Finally, the behavior of real and experimental model of the insulator is investigated.

关键词： 1512L insulator circular model artificial pollution flashover leakage current discontinuous pollution high voltage

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Development and advances in modular multilevel converter based HVDC projects in China

《工程管理前沿（英文）》页码 183-189 doi: 10.1007/s42524-022-0248-7

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关键词： high voltage direct current power converter power systems renewable energy ultra-high voltage

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大中功率节能调速传动的合理电压等级

马小亮

《中国工程科学》 2001年第3卷第11期页码 80-84

摘要：

大中功率风机和泵采用变频调速可节约大量电能，大部分功率在0.2～2 MW范围中。我国现在200 kW以上的电机多是中压，现行中压电网多为10 kV，选用10 kV直接变频从技术和经济角度看都不太合理。由于变频器输入侧都有变压器，因此电机和变频器没有必要和电网一致。文章讨论不同功率段的合理电压等级以及在电机电压和电网电压不同情况下当变频器出现故障时如何实现旁路工作。

关键词：大中功率节能调速合理电压等级低压变频中压变频旁路

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High purity Mn

Xiaoqiang SHAN, Fenghua GUO, Wenqian XU, Xiaowei TENG

《能源前沿（英文）》 2017年第11卷第3期页码 383-400 doi: 10.1007/s11708-017-0485-3

摘要： Developing electrodes with high specific energy by using inexpensive manganese oxides is of great importance for aqueous electrochemical energy storage (EES) using non-Li charge carriers such as Na-or K-ions. However, the energy density of aqueous EES devices is generally limited by their narrow thermodynamic potential window (~1.23 V). In this paper, the synthesis of high purity layered Mn O nanoparticles through solid state thermal treatment of Mn O spinel nanoparticles, resulting in a chemical formula of [Mn ][Mn O ], evidenced by Rietveld refinement of synchrotron-based X-ray diffraction, has been reported. The electro-kinetic analyses obtained from cyclic voltammetry measurements in half-cells have demonstrated that Mn O electrode has a large overpotential (~ 0.6 V) towards gas evolution reactions, resulting in a stable potential window of 2.5 V in an aqueous electrolyte in half-cell measurements. Symmetric full-cells fabricated using Mn O electrodes can be operated within a stable 3.0 V potential window for 5000 galvanostatic cycles, exhibiting a stable electrode capacity of about 103 mAh/g at a C-rate of 95 with nearly 100% coulombic efficiency and 96% energy efficiency.

关键词： manganese oxides Mn₅O₈ high voltage aqueous Na-ion storage

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一种低电流纹波的低压大电流DC-DC变换器的研究

王萍,孙栩,宋良瑜

《中国工程科学》 2005年第7卷第4期页码 59-63

摘要：

通过n个倍流整流结构交错并联方式用以进一步减小纹波电流。给出了电路的开关信号波形和仿真模型，并使用Pspice仿真软件对该模型进行仿真，取得满意效果。最后通过实验验证。这种结构特别适用于通信设备、计算机、宇航等领域的电源。

关键词：低压大电流DC-DC变换器倍流整流交错并联

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A pseudocapacitive molecule-induced strategy to construct flexible high-performance asymmetric supercapacitors

《化学科学与工程前沿（英文）》 2023年第17卷第9期页码 1208-1220 doi: 10.1007/s11705-023-2304-1

摘要： The combination of high-voltage windows and bending stability remains a challenge for supercapacitors. Here, we present an “advantage-complementary strategy” using sodium lignosulfonate as a pseudocapacitive molecule to regulate the spatial stacking pattern of graphene oxide and the interfacial architectures of graphene oxide and polyaniline. Flexible and sustainable sodium lignosulfonate-based electrodes are successfully developed, showing perfect bending stability and high electronic conductivity and specific capacitance (521 F·g⁻¹ at 0.5 A·g^–1). Due to the resulting rational interfacial structure and stable ion-electron transport, the asymmetric supercapacitors provide a wide voltage window reaching 1.7 V, outstanding bending stability and high energy-power density of 83.87 Wh·kg^–1 at 3.4 kW·kg^–1. These properties are superior to other reported cases of asymmetric energy enrichment. The synergistic strategy of sodium lignosulfonate on graphene oxide and polyaniline is undoubtedly beneficial to advance the process for the construction of green flexible supercapacitors with remarkably wide voltage windows and excellent bending stability.

关键词： molecular synergy pseudocapacitive lignosulfonate flexible electronic devices asymmetric supercapacitor wide voltage windows

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形状空间下基于级联回归的三维人脸重建 Article

Feng LIU, Dan ZENG, Jing LI, Qi-jun ZHAO

《信息与电子工程前沿（英文）》 2017年第18卷第12期页码 1978-1990 doi: 10.1631/FITEE.1700253

摘要：最近，级联回归方法在基于二维图像的三维人脸重建中取得了良好的效果。本文主要探究了基于级联回归三维人脸重建中四个未解决的重要问题：（1）二维特征点数量的影响；（2）三维点云数量的影响；（3）自动二维特征点的检测方法；（4）算法的收敛。本文专门设计了一个简单有效的基于形状空间的级联回归三维重建算法。该算法有效利用各类独立的自动二维特征点检测算法，且重建的三维人脸具有和输入图像相同的姿态和表情。同时在训练中，本文设计了一种随机扰动检二维特征点位置信息的策略，使得算法更有效且更鲁棒。最后，通过大量的对比实验证明了该算法不仅有着良好的精度和计算效率，而且对加深级联回归三维重建方法的理解有着启发意义。

关键词：三维人脸重建；级联回归；形状空间；实时

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基于沃尔什特征的增强型AdaBoost 人脸快速检测算法

郭志波,杨静宇,刘华军,严云洋

《中国工程科学》 2008年第10卷第7期页码 125-131

摘要：然后提出一种双阈值增强型AdaBoost 算法，其中双阈值的快速搜索方法大大节约了训练时间，并且在训练Cascaded 检测器过程中，前层分类器的训练结果对后层分类器的训练具有指导作用，加强了总体检测器的性能

关键词：沃尔什特征增强型AdaBoost Cascaded 型检测器人脸检测

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一种具有高电压传输比的新型Cuk矩阵变换器

张小平,朱建林,唐华平,张炳根,柳莎莎

《中国工程科学》 2008年第10卷第4期页码 78-83

摘要：

对传统矩阵变换器存在电压传输比低的缺陷进行研究，提出一种新型的称为Cuk矩阵变换器的电路拓扑结构。介绍了该拓扑结构的基本构成及其工作原理，推导了其电压传输比与占空比之间函数关系的解析表达式，阐述了所采用的双闭环控制策略的基本设计方法，并通过仿真对其有效性和可行性进行了验证。结果表明：该拓扑结构能实现输出电压和频率的任意调节，其电压传输比可大于1，也可小于1，且直接输出标准的正弦波而无需滤波环节，有效地解决了传统矩阵变换器电压传输比低的难题，具有一定的应用价值。

关键词： Cuk矩阵变换器电路拓扑电压传输比双闭环控制仿真

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用于无线供电物联网感知的电小尺寸惠更斯整流天线综述 Review

蔺炜, Richard W. Ziolkowski

《工程（英文）》 2022年第11卷第4期页码 42-59 doi: 10.1016/j.eng.2021.08.025

摘要：

远场无线电力传输（WPT）是一项重大突破性技术，它将支持许多预期中泛在的物联网（IoT）应用，而这些应用与第五代（5G）、第六代（6G）及以上无线生态系统相关。整流天线是整流电路和天线的组合，是远场WPT系统中最关键的组件。然而，紧凑型应用设备需要更小的集成整流天线，这些天线要同时具有大的电磁波捕获能力、高交流（AC）到直流（DC）转换效率，及促进多功能无线性能的作用。本文综述了各种整流天线的小型化技术，如曲折平面倒F天线（PIFA）整流天线、小型化的基于单极和偶极的整流天线、分形环和贴片整流天线、介质负载整流天线和电小尺寸近场谐振寄生整流天线。文中总结了它们的性能特征，并与我们之前开发的被证明更适合IoT 应用的电小尺寸惠更斯整流天线进行比较。例如，如本文所演示，它们经过定制可以成为无电池IoT 传感器。与电池供电设备相比，无电池的无线供电设备体积更小、重量更轻。此外，它们对环境友好，因此具有显著的社会效益。本文介绍了一系列高性能电小型惠更斯整流天线，包括惠更斯线极化（HLP）和圆极化（HCP）整流天线、基于这些设计的无线供电IoT 传感器以及双功能HLP整流天线和天线系统。最后，考虑两个线性均匀HLP整流天线阵列系统，以获得更为显著的大型无线电力捕获。示例阵列说明了如何有效将它们与DC或射频（RF）功率进行合成，从而促进IoT的实际应用。

关键词： Antenna Array Cardioid pattern Electrically small antenna Huygens dipole antenna Internet of Things (IoT) Rectenna Rectifier circuit Wireless power transfer

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Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

《能源前沿（英文）》 2022年第16卷第6期页码 943-955 doi: 10.1007/s11708-021-0793-5

摘要： This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

关键词： weak grids voltage source (VS) control wind turbine (WT) stabilization control wind farm inertial response