Electrode material based on a novel core–shell structure consisting of NiCoS（NCS） solid fiber core and Mn S（MS） sheet shell（NCS@MS） in situ grown on carbon cloth（CC） has been successfully prepared by a simple...Electrode material based on a novel core–shell structure consisting of NiCoS（NCS） solid fiber core and Mn S（MS） sheet shell（NCS@MS） in situ grown on carbon cloth（CC） has been successfully prepared by a simple sulfurization-assisted hydrothermal method for high performance supercapacitor. The synthesized NiCoS@Mn S/CC electrode shows high capacitance of 1908.3 F gat a current density of 0.5 A gwhich is higher than those of NiCoSand Mn S at the same current density. A flexible all-solid-state asymmetric supercapacitor（ASC） is constructed by using NiCoS@Mn S/CC as positive electrode, active carbon/CC as negative electrode and KOH/poly（vinyl alcohol）(PVA) as electrolyte. The optimized ASC shows a maximum energy density of 23.3 Wh kgat 1 A g, a maximum power density of about7.5 kw kgat 10 A gand remarkable cycling stability. After 9000 cycles, the ASC still exhibited67.8% retention rate and largely unchanged charge/discharge curves. The excellent electrochemical properties are resulted from the novel core–shell structure of the NiCoS@Mn S/CC electrode, which possesses both high surface area for Faraday redox reaction and superior kinetics of charge transport. The NiCoS@Mn S/CC electrode shows a promising potential for energy storage applications in the future.展开更多
Li4Ti5O(12)(LTO)has drawn great attention due to its safety and stability in lithium-ion batteries(LIBs).However,high potential plateau at 1.5 V vs.Li reduces the cell voltage,leading to a limited use of LTO.Dual-ion ...Li4Ti5O(12)(LTO)has drawn great attention due to its safety and stability in lithium-ion batteries(LIBs).However,high potential plateau at 1.5 V vs.Li reduces the cell voltage,leading to a limited use of LTO.Dual-ion batteries(DIBs)can achieve high working voltage due to high intercalation potential of cathode.Herein,we propose a DIB configuration in which LTO is used as anode and the working voltage was 3.5 V.This DIB achieves a maximum specific energy of 140 Wh/kg at a specific power of 35 W/kg,and the specific power of 2933 W/kg can be obtained with a remaining specific energy of 11 Wh/kg.Traditional LIB material shows greatly improved properties in the DIB configuration.Thus,reversing its disadvantage leads to upgraded performance of batteries.Our configuration has also widened the horizon of materials for DIBs.展开更多
The paper deals with the power quality analysis of interlaced four quadrant (4Q) converters with constant switching frequency. These are in fact the input stages of the locomotives and high speed trains supplied by 25...The paper deals with the power quality analysis of interlaced four quadrant (4Q) converters with constant switching frequency. These are in fact the input stages of the locomotives and high speed trains supplied by 25 kV, 50 Hz and 15 kV, 16.7 Hz lines. Due to the high power needed for the trains circulation, the 4Q converter can absorb distorted currents, whose harmonic content can affect the signaling systems and communication devices. The presence of more converters gives the opportunity, using dedicated commutation strategy, to interlace them in order to reduce the harmonic content in the absorbed current. In the paper a suitable model of more 4Q converters is developed. The control logic implemented in the model allows the evaluation of the harmonic contribution of both single converter and the interlaced configuration. The analysis is carried out through electromagnetic transient simulations.展开更多
高压直挂电池储能系统(battery energy storage system,BESS)采用H桥电路串联的方法升高电压后接入电网,将电池簇分散接入级联H桥变换器的直流侧,具有高度模块化的结构,对比低压方案具有单机容量大、效率高、响应速度快等明显优势。高...高压直挂电池储能系统(battery energy storage system,BESS)采用H桥电路串联的方法升高电压后接入电网,将电池簇分散接入级联H桥变换器的直流侧,具有高度模块化的结构,对比低压方案具有单机容量大、效率高、响应速度快等明显优势。高压直挂BESS若能兼具无功补偿能力,实现系统四象限运行,将具有更大的成本优势和经济效益。电池簇接单相H桥变换器的结构,使得系统运行在高比例无功补偿工况时,电池簇电流在一个二倍基频的周期中会出现两次反向,导致电池运行在高频充放电的工况,这会对电池寿命和电池状态监测造成较大的影响。为解决这一问题,提出一种基于零序电压注入的高比例无功补偿控制方法,避免了二倍基频脉动电流对电池进行高频充放电,再通过优化零序电压的幅值和相位,最大程度上降低对电池的影响。展开更多
License plate recognition system plays an important role in many applications. An automatic recognizer for Iraqi License Plates using ELMAN Neural network is proposed in this manuscript. The processing procedures are ...License plate recognition system plays an important role in many applications. An automatic recognizer for Iraqi License Plates using ELMAN Neural network is proposed in this manuscript. The processing procedures are developed in several stages. Experimental results are reported in the end of the paper to illustrate the performance of the proposed method.展开更多
Adaptive noise data filtering in real-time requires dedicated hardware to meet demanding time requirements. Both DSP processors and FPGAs were studied with respect to their performance in power consumption, hardware a...Adaptive noise data filtering in real-time requires dedicated hardware to meet demanding time requirements. Both DSP processors and FPGAs were studied with respect to their performance in power consumption, hardware architecture, and speed for real time applications. For testing purposes, real time adaptive noise filters have been implemented and simulated on two different platforms, Motorola DSP56303 EVM and Xilinx Spartan III boards. This study has shown that in high speed applications, FPGAs are advantageous over DSPs with respect of their speed and noise reduction because of their parallel architecture. FPGAs can handle more processes at the same time when compared to DSPs, while the later can only handle a limited number of parallel instructions at a time. The speed in both processors impacts the noise reduction in real time. As the DSP core gets slower, the noise removal in real time gets harder to achieve. With respect to power, DSPs are advantageous over FPGAs. FPGAs have reconfigurable gate structure which consumes more power. In case of DSPs, the hardware has been already configured, which requires less power consumption? FPGAs are built for general purposes, and their silicon area in the core is bigger than that of DSPs. This is another factor that affects power consumption. As a result, in high frequency applications, FPGAs are advantageous as compared to DSPs. In low frequency applications, DSPs and FPGAs both satisfy the requirements for noise cancelling. For low frequency applications, DSPs are advantageous in their power consumption and applications for the battery power devices. Software utilizing Matlab, VHDL code run on Xilinix system, and assembly running on Motorola development systems, have been used for the demonstration of this study.展开更多
分布式储能(distributed energy storage system,DESS)可通过功率四象限运行以高效服务于配电网电压管理。现有以改善电压质量为导向的DESS优化配置研究缺乏对储能功率四象限运行和配网三相不平衡状态的全面考虑。为此,提出一种适用于...分布式储能(distributed energy storage system,DESS)可通过功率四象限运行以高效服务于配电网电压管理。现有以改善电压质量为导向的DESS优化配置研究缺乏对储能功率四象限运行和配网三相不平衡状态的全面考虑。为此,提出一种适用于不平衡配电网的功率四象限DESS两阶段优化配置方法。在选址阶段,基于三相牛顿-拉夫逊潮流算法提出全维电压灵敏度分析方法,从提升系统电压质量的角度深入探究DESS的最优选址。在定容阶段,考虑系统运行经济效益,以年均投运成本最低和节点电压偏差最小为优化目标建立了DESS经济运行模型,通过粒子群-灰狼优化算法进行求解。以改进IEEE33节点三相配电网为例开展算例分析,仿真结果验证了所提方法的有效性。展开更多
基金supported by the Grant-in-Aid for Scientific Research (KAKENHI) program, Japan (C, Grant Number 15K05597)Takahashi Industrial and Economic Research Foundation (Takahashi Grant Number 06-003-154)
文摘Electrode material based on a novel core–shell structure consisting of NiCoS（NCS） solid fiber core and Mn S（MS） sheet shell（NCS@MS） in situ grown on carbon cloth（CC） has been successfully prepared by a simple sulfurization-assisted hydrothermal method for high performance supercapacitor. The synthesized NiCoS@Mn S/CC electrode shows high capacitance of 1908.3 F gat a current density of 0.5 A gwhich is higher than those of NiCoSand Mn S at the same current density. A flexible all-solid-state asymmetric supercapacitor（ASC） is constructed by using NiCoS@Mn S/CC as positive electrode, active carbon/CC as negative electrode and KOH/poly（vinyl alcohol）(PVA) as electrolyte. The optimized ASC shows a maximum energy density of 23.3 Wh kgat 1 A g, a maximum power density of about7.5 kw kgat 10 A gand remarkable cycling stability. After 9000 cycles, the ASC still exhibited67.8% retention rate and largely unchanged charge/discharge curves. The excellent electrochemical properties are resulted from the novel core–shell structure of the NiCoS@Mn S/CC electrode, which possesses both high surface area for Faraday redox reaction and superior kinetics of charge transport. The NiCoS@Mn S/CC electrode shows a promising potential for energy storage applications in the future.
基金the financial supports from the National Natural Science Foundation of China (51932003, 51902050, 51872115 & 51802110)Program for the Development of Science and Technology of Jilin Province (20190201309JC)+4 种基金the Open Project Program of Wuhan National Laboratory for Optoelectronics (2018WNLOKF022)the Jilin Province/Jilin University co-Construction Project-Funds for New Materials (SXGJSF2017-3, Branch-2/440050316A36)Program for JLU Science and Technology Innovative Research Team (JLUSTIRT, 2017TD-09)the Fundamental Research Funds for the Central Universities JLU“Double-First Class” Discipline for Materials Science & Engineering.
文摘Li4Ti5O(12)(LTO)has drawn great attention due to its safety and stability in lithium-ion batteries(LIBs).However,high potential plateau at 1.5 V vs.Li reduces the cell voltage,leading to a limited use of LTO.Dual-ion batteries(DIBs)can achieve high working voltage due to high intercalation potential of cathode.Herein,we propose a DIB configuration in which LTO is used as anode and the working voltage was 3.5 V.This DIB achieves a maximum specific energy of 140 Wh/kg at a specific power of 35 W/kg,and the specific power of 2933 W/kg can be obtained with a remaining specific energy of 11 Wh/kg.Traditional LIB material shows greatly improved properties in the DIB configuration.Thus,reversing its disadvantage leads to upgraded performance of batteries.Our configuration has also widened the horizon of materials for DIBs.
文摘The paper deals with the power quality analysis of interlaced four quadrant (4Q) converters with constant switching frequency. These are in fact the input stages of the locomotives and high speed trains supplied by 25 kV, 50 Hz and 15 kV, 16.7 Hz lines. Due to the high power needed for the trains circulation, the 4Q converter can absorb distorted currents, whose harmonic content can affect the signaling systems and communication devices. The presence of more converters gives the opportunity, using dedicated commutation strategy, to interlace them in order to reduce the harmonic content in the absorbed current. In the paper a suitable model of more 4Q converters is developed. The control logic implemented in the model allows the evaluation of the harmonic contribution of both single converter and the interlaced configuration. The analysis is carried out through electromagnetic transient simulations.
文摘高压直挂电池储能系统(battery energy storage system,BESS)采用H桥电路串联的方法升高电压后接入电网,将电池簇分散接入级联H桥变换器的直流侧,具有高度模块化的结构,对比低压方案具有单机容量大、效率高、响应速度快等明显优势。高压直挂BESS若能兼具无功补偿能力,实现系统四象限运行,将具有更大的成本优势和经济效益。电池簇接单相H桥变换器的结构,使得系统运行在高比例无功补偿工况时,电池簇电流在一个二倍基频的周期中会出现两次反向,导致电池运行在高频充放电的工况,这会对电池寿命和电池状态监测造成较大的影响。为解决这一问题,提出一种基于零序电压注入的高比例无功补偿控制方法,避免了二倍基频脉动电流对电池进行高频充放电,再通过优化零序电压的幅值和相位,最大程度上降低对电池的影响。
文摘License plate recognition system plays an important role in many applications. An automatic recognizer for Iraqi License Plates using ELMAN Neural network is proposed in this manuscript. The processing procedures are developed in several stages. Experimental results are reported in the end of the paper to illustrate the performance of the proposed method.
文摘Adaptive noise data filtering in real-time requires dedicated hardware to meet demanding time requirements. Both DSP processors and FPGAs were studied with respect to their performance in power consumption, hardware architecture, and speed for real time applications. For testing purposes, real time adaptive noise filters have been implemented and simulated on two different platforms, Motorola DSP56303 EVM and Xilinx Spartan III boards. This study has shown that in high speed applications, FPGAs are advantageous over DSPs with respect of their speed and noise reduction because of their parallel architecture. FPGAs can handle more processes at the same time when compared to DSPs, while the later can only handle a limited number of parallel instructions at a time. The speed in both processors impacts the noise reduction in real time. As the DSP core gets slower, the noise removal in real time gets harder to achieve. With respect to power, DSPs are advantageous over FPGAs. FPGAs have reconfigurable gate structure which consumes more power. In case of DSPs, the hardware has been already configured, which requires less power consumption? FPGAs are built for general purposes, and their silicon area in the core is bigger than that of DSPs. This is another factor that affects power consumption. As a result, in high frequency applications, FPGAs are advantageous as compared to DSPs. In low frequency applications, DSPs and FPGAs both satisfy the requirements for noise cancelling. For low frequency applications, DSPs are advantageous in their power consumption and applications for the battery power devices. Software utilizing Matlab, VHDL code run on Xilinix system, and assembly running on Motorola development systems, have been used for the demonstration of this study.
文摘分布式储能(distributed energy storage system,DESS)可通过功率四象限运行以高效服务于配电网电压管理。现有以改善电压质量为导向的DESS优化配置研究缺乏对储能功率四象限运行和配网三相不平衡状态的全面考虑。为此,提出一种适用于不平衡配电网的功率四象限DESS两阶段优化配置方法。在选址阶段,基于三相牛顿-拉夫逊潮流算法提出全维电压灵敏度分析方法,从提升系统电压质量的角度深入探究DESS的最优选址。在定容阶段,考虑系统运行经济效益,以年均投运成本最低和节点电压偏差最小为优化目标建立了DESS经济运行模型,通过粒子群-灰狼优化算法进行求解。以改进IEEE33节点三相配电网为例开展算例分析,仿真结果验证了所提方法的有效性。
