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Unified power quality conditioner based on a three-level NPC inverter using fuzzy control techniques

Salim CHENNAI,M-T BENCHOUIA

《能源前沿（英文）》 2014年第8卷第2期页码 221-239 doi: 10.1007/s11708-014-0317-7

摘要： This paper presents a novel and efficient control scheme for unified power quality conditioner (UPQC) based on three-level neutral point clamped (NPC) inverter using fuzzy logic techniques. The proposed UPQC is capable of mitigating source current harmonics and compensate all voltage disturbances such as voltage sags, swells, unbalances and harmonics. It is designed by the integration of series and shunt active filters (AFs) sharing a common DC bus capacitor. The DC voltage is maintained constant using proportional integral voltage controller. The synchronous reference frame (SRF) theory is used to get the reference signals for shunt active power filters (APFs) and the power reactive theory (p-q theory) for series APFs. The shunt and series APF reference signals derived from the control algorithm and sensed signals are injected in two controllers to generate switching signals. To improve the UPQC capability, fuzzy logic techniques are introduced to control the series APF. The performances of the proposed UPQC system are evaluated in terms of power factor correction, mitigation of voltage or current harmonics and all other voltage disturbances compensation using Matlab-Simulink software and SimPowerSystem toolbox. The simulation results illustrate the performance of the proposed UPQC at the common connection point of the nonlinear load to improve the power energy quality.

关键词： three-level neutral point clamped (NPC) inverter unified power quality conditioner (UPQC) current harmonics mitigation fuzzy logic controller voltage disturbance compensation shunt active filter series active filter power quality energy improvement

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Fault-tolerant control of an open-winding brushless doubly-fed wind power generator system with dual three-level

Shi JIN, Long SHI, Sul ADEMI, Yue ZHANG, Fengge ZHANG

《能源前沿（英文）》 doi: 10.1007/s11708-020-0711-2

摘要： To improve the fault redundancy capability for the high reliability requirement of a brushless doubly-fed generation system applied to large offshore wind farms, the control winding of a brushless doubly-fed reluctance generator is designed as an open-winding structure. Consequently, the two ends of the control winding are connected via dual three-phase converters for the emerging open-winding structure. Therefore, a novel fault-tolerant control strategy based on the direct power control scheme is brought to focus in this paper. Based on the direct power control (DPC) strategy, the post-fault voltage vector selection method is explained in detail according to the fault types of the dual converters. The fault-tolerant control strategy proposed enables the open-winding brushless doubly-fed reluctance generator (BDFRG) system to operate normally in one, two, or three switches fault of the converter, simultaneously achieving power tracking control. The presented results verify the feasibility and validity of the scheme proposed.

关键词： open-winding brushless doubly-fed reluctance generator (BDFRG) direct power control fault-tolerant control multi-level converter wind power

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Fundamental frequency and testing mode of complicated elastic clamped-plate vibration

QI Hongyuan, GUAN Yiduo

《机械工程前沿（英文）》 2008年第3卷第4期页码 360-364 doi: 10.1007/s11465-008-0084-4

摘要： Aimed at the modal analysis of complicated elastic clamped-plates, a trigonometric interpolation method of conformal mapping is applied to set up the mapping function between a complicated region and a unit dish region, and the fundamental frequency of the complicated vibrating region is analyzed with the help of the Galerkin method. Taking an elastic rectangle-plate with arc radius as an example, the testing mode frequency band of plates is determined by analyzing the fundamental frequency; meanwhile, according to hamming testing method of multi-point excitation to the single-point response, and by signal processing technology and its software programming, modal parameter recognition of the elastic clamped-plate is completed. Comparing the first order modal frequency with the theoretical fundament frequency, the validity of the testing mode method and theoretical analysis are verified.

关键词： multi-point excitation rectangle-plate single-point processing technology trigonometric interpolation

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低调制度下二极管箝位型多电平逆变器新型PWM控制方法

辛想,张庆范,胡顺全,李瑞来

《中国工程科学》 2007年第9卷第10期页码 91-96

摘要：

二极管箝位型多电平逆变器作为一种应用于高压大功率变换场合的变换器，其PWM控制技术是研究的核心内容之一。本文针对已有载波PWM方法中低调制度下电平退化的问题，提出了一种新颖的载波PWM方法，既便是在低调制度下，所有的电平都能够得到应用。仿真结果表明，这种方法可以提高二极管箝位型逆变器在低调制度下的器件利用率，使得逆变器在低调制度下工作于较高频率。

关键词：二极管箝位型逆变器载波PWM 低调制度冗余状态

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Three-dimensional fluorescence spectral characterization of soil dissolved organic matters in the fluctuatingwater-level zone of Kai County, Three Gorges Reservoir

Fang FANG, Yan YANG, Jinsong GUO, Hong ZHOU, Chuan FU, Zhe LI

《环境科学与工程前沿（英文）》 2011年第5卷第3期页码 426-434 doi: 10.1007/s11783-010-0264-4

摘要： Three-dimensional fluorescence spectroscopy was used to investigate the fluorescent properties of soil dissolved organic matter (DOM) in the water-level-fluctuation zone (WLFZ) of Kai County, Three Gorges Reservoir (TGR). Most of the soil DOM analyzed in this study was found to contain four fluorescence peaks. Peaks A and C represent humic-like fluorescence, whereas peaks B and D represent tryptophan-like fluorescence. Peaks E and F, which represent tyrosine-like fluorescence, only appeared in certain soils. Soil humus was the main source of DOM in soil, and higher concentration of soil DOM was found in the exposed soil than submerged soil. Compared to the peaks A and B, the fluorescence intensities of peaks C and D were strongly influenced by the fluctuating water level. Analysis of fluorescence intensities of different peaks in soil DOM showed that WLFZ soil was not contaminated significantly. Soil DOM contained at least two types of humic-like fluorescence groups and two types of protein-like fluorescence groups. The proportion of the content of peak A in soil organic matter was quite stable. The soil DOM in exposed soil had relatively high humification and aromaticity, and periodic submerging and exposure of soil had an impact on the humification of soil DOM.

关键词： water-level-fluctuation zone (WLFZ) soil dissolved organic matter (DOM) three-dimensional fluorescence spectra

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A three-dimensional two-level gradient smoothing meshfree method for rainfall induced landslide simulations

Dongdong WANG, Jiarui WANG, Junchao WU, Junjun DENG, Ming SUN

《结构与土木工程前沿（英文）》 2019年第13卷第2期页码 337-352 doi: 10.1007/s11709-018-0467-5

摘要： A three-dimensional two-level gradient smoothing meshfree method is presented for rainfall induced landslide simulations. The two-level gradient smoothing for meshfree shape function is elaborated in the three-dimensional Lagrangian setting with detailed implementation procedure. It is shown that due to the successive gradient smoothing operation without the requirement of derivative computation in the present formulation, the two-level smoothed gradient of meshfree shape function is capable of achieving a given influence domain more efficiently than the standard gradient of meshfree shape function. Subsequently, the two-level smoothed gradient of meshfree shape function is employed to discretize the weak form of coupled rainfall seepage and soil motion equations in a nodal integration format, as provides an efficient three-dimensional regularized meshfree formulation for large deformation rainfall induced landslide simulations. The exponential damage and pressure dependent plasticity relationships are utilized to describe the failure evolution in landslides. The plastic response of soil is characterized by the true effective stress measure, which is updated according to the rotationally neutralized objective integration algorithm. The effectiveness of the present three-dimensional two-level gradient smoothing meshfree method is demonstrated through numerical examples.

关键词： meshfree method landslide rainfall three-dimensional two-level gradient smoothing nodal integration

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Performance investigation of artificial intelligence based controller for three phase four leg shunt

J. JAYACHANDRAN,R. MURALI SACHITHANANDAM

《能源前沿（英文）》 2015年第9卷第4期页码 446-460 doi: 10.1007/s11708-015-0378-2

摘要： In this paper, the choice of power quality compensator is a DSTATCOM which constitutes a three phase four leg voltage source converter (VSC) with a DC capacitor. The control strategy proposed for the DSTATCOM is a neural network based one cycle control (OCC). This control strategy involves neural network block, digital circuits and linear elements, which eliminates the sensors required for sensing the load current and coupling inductor current in addition to the multiplier employed in the conventional method. The calculation of harmonic and reactive currents for the reference current generation is also eliminated, thus minimizing the complexity in the control strategy. The control strategy mitigates harmonic/reactive currents, ensures balanced and sinusoidal source current from the supply mains that are nearly in phase with the supply voltage, compensates neutral current, and maintains voltage across the capacitor under unbalanced source and load conditions. The performance of the DSTATCOM with the proposed artificial neural network (ANN) controllers is validated and investigated through simulations using Matlab software. The simulation results prove the efficacy of the proposed neural network based control strategy under varying source and load conditions.

关键词： neural network DSTATCOM neutral current mitigation total harmonic distortion (THD) three phase four wire distribution system unbalanced and/or distorted source

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三维仿生支架平台的刚度和层尺寸对癌细胞分离的影响 Article

张维冠, 刘子玉, 彭慧芝

《工程（英文）》 2021年第7卷第10期页码 1426-1435 doi: 10.1016/j.eng.2020.09.010

摘要：本研究根据精确控制的设计参数（包括刚度、层数和结构布局），开发了三维（3D）仿生支架平台，用于分离鼻咽癌（NPC43）细胞与永生化鼻咽上皮（NP460）细胞。支架平台上NPC43细胞和NP460细胞的迁移特征表明，NPC43细胞可以挤进10 µm宽、15 µm深的沟槽，而NP460细胞不能。NPC43细胞具有丝状伪足样突触，而NP460细胞呈片状形态。使用这些3D仿生平台进行研究发现，在较硬的双层支架平台[顶层为40/10 μm沟脊/沟槽（R/T）栅格，底层为20/10 μm R/T网格]上，NPC43细胞与NP460细胞的分离效率可达89%

关键词：细胞分离细胞迁移鼻咽癌（NPC） 3D支架平台

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Isogeometric analysis based on geometric reconstruction models

《机械工程前沿（英文）》页码 782-797 doi: 10.1007/s11465-021-0648-0

摘要： In isogeometric analysis (IGA), the boundary representation of computer-aided design (CAD) and the tensor-product non-uniform rational B-spline structure make the analysis of three-dimensional (3D) problems with irregular geometries difficult. In this paper, an IGA method for complex models is presented by reconstructing analysis-suitable models. The CAD model is represented by boundary polygons or point cloud and is embedded into a regular background grid, and a model reconstruction method is proposed to obtain the level set function of the approximate model, which can be directly used in IGA. Three 3D examples are used to test the proposed method, and the results demonstrate that the proposed method can deal with complex engineering parts reconstructed by boundary polygons or point clouds.

关键词： isogeometric analysis reconstruction model level set function trimmed element point cloud

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Implementation of photovoltaic water pumping system with MPPT controls

Najet REBEI,Ali HMIDET,Rabiaa GAMMOUDI,Othman HASNAOUI

《能源前沿（英文）》 2015年第9卷第2期页码 187-198 doi: 10.1007/s11708-015-0359-5

摘要： To increase the output efficiency of a photovoltaic (PV) system, it is important to apply an efficient maximum power point tracking (MPPT) technique. This paper describes the analysis, the design and the experimental implementation of the tracking methods for a stand-alone PV system, using two approaches. The first one is the constant voltage (CV) MPPT method based on the optimum voltage, which was deduced experimentally, and considered as a reference value to extract the optimum power. The second one is the increment conductance (Inc-Cond) MPPT method based on the calculation of the power derivative extracted by the installation. The output controller can adjust the duty ratio to the optimum value. This optimum duty ratio is the input of a DC/DC boost converter which feeds a set of Moto-pump via a DC/AC inverter. This paper presents the details of the two approaches implemented, based on the system performance characteristics. Contributions are made in several aspects of the system, including converter design, system simulation, controller programming, and experimental setup. The MPPT control algorithms implemented extract the maximum power point (MPP), with satisfactory performance and without steady-state oscillation. MATLAB/Simulink and dSpace DS1104 are used to conduct studies and implement algorithms. The two proposed methods have been validated by implementing the performance of the PV pumping systems installed on the roof of the research laboratory in INSAT Tunisia. Experimental results verify the feasibility and the improved functionality of the system.

关键词： photovoltaic generator (PVG) maximum power point tracking (MPPT) boost DC/DC converter DC/AC inverter moto-pump

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一种新型的部分遮挡和非匹配条件下最大功率点跟踪光伏子模块级功率平衡拓扑结构 Article

Mustafa GOKDAG,Mehmet AKBABA

《信息与电子工程前沿（英文）》 2016年第17卷第12期页码 1388-1396 doi: 10.1631/FITEE.1500322

摘要：部分遮挡和串联模块（或子模块）的非匹配条件可在整个光伏系统中导致功率曲线非凸且出现多个局部极值和峰值功率下降的现象。通过功率传输，可将各子模块的工作电压拉平；这样的功率收集操作可生成凸功率曲线，提升光伏系统的峰值功率。本文所述拓扑结构受益于开关电容（Switched capacitor, SC）转换器的概念，是一种子模块级功率平衡概念的具体应用。与现有研究成果相比，其创新点包含无遮挡时停止开关操作、串联线路级可拓展性以及减少功率电子元件使用量。功率电子元件使用量的减少是通过两个子模块共享一个SC转换器的方式实现的，这也能带来降低功率器件能量损耗、降低成本和电路体积的优势。本文给出了所述拓扑结构的插入损耗的理论式，并通过PSpice仿真和原型电路的实验评估，证明了损耗理论解的正确性。这也表明，通过使用所述拓扑结构，有可能提取出部分遮挡的光伏线路的几乎所有可用能量，并将其传输至负载端。

关键词：子模块级最大功率点跟踪（Sub-module-level maximum power point tracking MPPT）；差分功率处理（Differential power processing

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Probabilistic stability analysis of Bazimen landslide with monitored rainfall data and water level fluctuationsin Three Gorges Reservoir, China

Wengang ZHANG, Libin TANG, Hongrui LI, Lin WANG, Longfei CHENG, Tingqiang ZHOU, Xiang CHEN

《结构与土木工程前沿（英文）》 2020年第14卷第5期页码 1247-1261 doi: 10.1007/s11709-020-0655-y

摘要： Landslide is a common geological hazard in reservoir areas and may cause great damage to local residents’ life and property. It is widely accepted that rainfall and periodic variation of water level are the two main factors triggering reservoir landslides. In this study, the Bazimen landslide located in the Three Gorges Reservoir (TGR) was back-analyzed as a case study. Based on the statistical features of the last 3-year monitored data and field instrumentations, the landslide susceptibility in an annual cycle and four representative periods was investigated via the deterministic and probabilistic analysis, respectively. The results indicate that the fluctuation of the reservoir water level plays a pivotal role in inducing slope failures, for the minimum stability coefficient occurs at the rapid decline period of water level. The probabilistic analysis results reveal that the initial sliding surface is the most important area influencing the occurrence of landslide, compared with other parts in the landslide. The seepage calculations from probabilistic analysis imply that rainfall is a relatively inferior factor affecting slope stability. This study aims to provide preliminary guidance on risk management and early warning in the TGR area.

关键词： reliability analysis Bazimen landslide rainfall reservoir water level slope stability

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黏聚裂纹阻抗的弯曲梁承载力

王利民,徐世,任传波

《中国工程科学》 2007年第9卷第2期页码 30-35

摘要：

在混凝土类软化材料断裂研究中，裂纹端部损伤区被简化为具有黏聚应力分布的非线性裂纹，该黏聚力对裂纹扩展有阻抗作用。裂纹体的应力强度因子是断裂力学标志载荷作用与几何构型因素的量化表达指标；黏聚力形成的阻抗强度因子数值，与黏聚裂纹长度和材料极值拉伸应力存在数量关系。通过双K断裂判据，以带切口的三点弯曲梁为断裂力学模型，分析了裂纹黏聚阻力对断裂过程的影响规律，计算该弯曲梁结构断裂试样的最大承担载荷；其结果比较符合实验数据。

关键词：黏聚裂纹三点弯曲梁混凝土双K断裂参数结构承载力

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A simple digital control algorithm for three phase shunt active filter: simulation and experimentation

Subbaraman SRINATH, Chandan KUMAR, M. P. SELVAN

《能源前沿（英文）》 2014年第8卷第1期页码 119-128 doi: 10.1007/s11708-013-0288-0

摘要： A novel and simple control algorithm using digital signal processor (DSP) has been proposed and realized for a three phase shunt active filter (SAF). The simulation and prototype construction of SAF is conducted to compensate the reactive power and harmonics in a distribution system. The major feature of the proposed algorithm is that it does not require unit vector templates and any transformations for the reference current generation of SAF. This reduces the computational complexity and makes the control flexible and faster. The simulation is conducted in MATLAB/SIMULINK while DSP TMS320LF2407 is employed in the digital implementation of hysteresis current control (HCC) for experimentation. The hardware results correlate with the simulation results in reducing the total harmonic distortion (THD) of the source current and achieving unity power factor.

关键词： shunt active filter (SAF) power quality voltage source inverter (VSI) digital signal processor (DSP) total harmonic distortion (THD) power factor improvement

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SOIL ORGANIC CARBON SEQUESTRATION MATTERS BUT IS NO PANACEA FOR CARBON-NEUTRAL AGRICULTURE

《农业科学与工程前沿（英文）》 doi: 10.15302/J-FASE-2022470

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标题作者时间类型操作

Unified power quality conditioner based on a three-level NPC inverter using fuzzy control techniques

Salim CHENNAI,M-T BENCHOUIA

期刊论文

Fault-tolerant control of an open-winding brushless doubly-fed wind power generator system with dual three-level

Shi JIN, Long SHI, Sul ADEMI, Yue ZHANG, Fengge ZHANG

期刊论文

Fundamental frequency and testing mode of complicated elastic clamped-plate vibration

QI Hongyuan, GUAN Yiduo

期刊论文

低调制度下二极管箝位型多电平逆变器新型PWM控制方法

辛想,张庆范,胡顺全,李瑞来

期刊论文

Three-dimensional fluorescence spectral characterization of soil dissolved organic matters in the fluctuatingwater-level zone of Kai County, Three Gorges Reservoir

Fang FANG, Yan YANG, Jinsong GUO, Hong ZHOU, Chuan FU, Zhe LI

期刊论文

A three-dimensional two-level gradient smoothing meshfree method for rainfall induced landslide simulations

Dongdong WANG, Jiarui WANG, Junchao WU, Junjun DENG, Ming SUN

期刊论文

Performance investigation of artificial intelligence based controller for three phase four leg shunt

J. JAYACHANDRAN,R. MURALI SACHITHANANDAM

期刊论文

三维仿生支架平台的刚度和层尺寸对癌细胞分离的影响

张维冠, 刘子玉, 彭慧芝

期刊论文

Isogeometric analysis based on geometric reconstruction models