检索结果-南通市图书馆

Chinese Physics B 2010年第10期19卷 505-509页

作者：南雅公蒲红斌曹琳任杰 Department of electric Engineering Faculty of Automation and Information Engineering Xi'an University of Technology Department of Physics and Electronics Hexi University

This paper stuides the structures of 4H SiC floating junction Schottky barrier diodes. Some structure parameters of devices are optimized with commercial simulator based on forward and reverse electrical characteristics. Compared with conventional power Schottky barrier diodes, the devices are featured by highly doped drift region and embedded floating junction layers, which can ensure high breakdown voltage while keeping lower specific on-state resistance, and solve the contradiction between forward voltage drop and breakdown voltage. The simulation results show that with optimized structure parameter, the breakdown voltage can reach 4.36 kV and the specific on-resistance is 5.8 mΩ.cm2 when the Baliga figure of merit value of 13.1 GW/cm2 is achieved.

关键词： 4H SiC floating junction Schottky barrier diode optimization

High-accuracy and Low-complexity Phasor Estimation Method for PMU Calibration

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2021年第6期7卷 1202-1212页

作者： Jinsong Li Sudi Xu Hao Liu Tianshu Bi North China electric Power University and China electric Power Research Institute Beijing 102206China State Key Lab of Alternate electric Power System With Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

Due to the increasing development of renewables in power systems,the requirements for phasor measurement units(PMUs)becomes higher.A PMU calibrator is an important tool to test and calibrate PMUs to ensure their measurement *** device can provide accurate reference values for error analysis of *** this paper,a phasor algorithm with low computational complexity and high accuracy is proposed for the PMU *** method reduces the processor requirements and development costs of the calibrator,thereby facilitating its *** first,an enhanced discrete Fourier transform(DFT)method is put forward:1)the frequency response of the windowed DFT method is analyzed to reveal its large measurement errors under dynamic conditions;2)the parameter requirements of the DFT window that is regarded as a lowpass filter are analyzed,and thus a lowpass filter with better filtering performance is designed as the window coefficients to improve the estimation ***,based on the enhanced DFT algorithm,a calibrator algorithm framework consisting of two-stage filters and a signal recognition module is *** algorithm can consider the anti-interference ability and dynamic measurement accuracy at a low reporting *** and experimental test results show that the proposed calibrator algorithm provides high-accuracy measurements of the static and dynamic signals with low computational complexity.

关键词： Phasor measurement unit(PMU) PMU calibrator PMU test windowed DFT algorithm

Wind power prediction based on variational mode decomposition multi-frequency combinations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2019年第2期7卷 281-288页

作者： Gang ZHANG Hongchi LIU Jiangbin ZHANG Ye YAN Lei ZHANG Chen WU Xia HUA Yongqing WANG Institute of Water Resources and Hydro-electric Engineering Xi’an University of TechnologyXi’an 710048China State Grid Gansu electric Power Company Gansu Electric Power Research InstituteLanzhou 730050China State Grid Shaanxi electric Power Company Shaanxi Electric Power Research InstituteXi’an 710054China

Because of the uncertainty and randomness of wind speed, wind power has characteristics such as nonlinearity and multiple frequencies. Accurate prediction of wind power is one effective means of improving wind power integration. Because the traditional single model cannot fully characterize the fluctuating characteristics of wind power, scholars have attempted to build other prediction models based on empirical mode decomposition(EMD) or ensemble empirical mode decomposition(EEMD) to tackle this problem. However, the prediction accuracy of these models is affected by modal aliasing and illusive components. Aimed at these defects, this paper proposes a multi-frequency combination prediction model based on variational mode decomposition(VMD). We use a back propagation neural network(BPNN),autoregressive moving average(ARMA)model, and least square support vector machine(LS-SVM) to predict high, intermediate,and low frequency components,respectively. Based on the predicted values of each component, the BPNN is applied to combine them into a final wind power prediction ***,the prediction performance of the single prediction models(ARMA,BPNN and LS-SVM)and the decomposition prediction models(EMD and EEMD) are used to compare with the proposed VMD model according to the evaluation indices such as average absolute error, mean square error,and root mean square error to validate its feasibility and accuracy. The results show that the prediction accuracy of the proposed VMD model is higher.

关键词： Wind power prediction Variational mode decomposition Multi-frequency combination prediction Back propagation neural network Autoregressive moving average model Least square support vector machine

Coordinated optimal dispatch and market equilibrium of integrated electric power and natural gas networks with P2G embedded

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2018年第3期6卷 495-508页

作者： Zexing CHEN Yongjun ZHANG Tianyao JI Zexiang CAI Licheng LI Zhiheng XU Key Laboratory of Clean Energy Technology of Guangdong Province School of Electric Power South China University of Technology

As power to gas(P2 G) technology gradually matures, the coupling between electricity networks and natural gas networks should ideally evolve *** the intent of characterizing market behaviors of integrated electric power and natural gas networks(IPGNs)with P2 G facilities, this paper establishes a steady-state model of P2 G and constructs optimal dispatch models of an electricity network and a natural gas network separately. In addition, a concept of slack energy flow(SEF) is proposed as a tool for coordinated optimal dispatch between the two networks. To study how the market pricing mechanism affects coordinated optimal dispatch in an IPGN, a market equilibrium-solving model for an IPGN is constructed according to game theory, with a solution based on the Nikaido-Isoda function. Case studies are conducted on a joint model that combines the modified IEEE 118-node electricity network and the Belgian 20-node gas *** results show that if the game between an electric power company and a natural gas company reaches market equilibrium, not only can both companies maximize their profits, but also the coordinated operation of the coupling units, i.e., gas turbines and P2 G facilities, will contribute more to renewable energy utilization and carbon emission reduction.

关键词： Integrated electric power and natural gas networks(IPGNs) Market equilibrium Power to gas(P2G) Slack energy flow(SEF)

Multi-objective interval prediction of wind power based on conditional copula function

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2019年第4期7卷 802-812页

作者： Gang ZHANG Zhixuan LI Kaoshe ZHANG Lei ZHANG Xia HUA Yongqing WANG Institute of Water Resources and Hydro-electric Engineering Xi’an University of TechnologyXi’an 710048China State Grid Shaanxi Baoji electric Power Company Baoji 721000China State Grid Gansu electric Power Company Gansu Electric Power Research InstituteLanzhou 730050China State Grid Shaanxi electric Power Company Shaanxi Electric Power Research InstituteXi’an 710054China

Interval prediction of wind power,which features the upper and lower limits of wind power at a given confidence level,plays a significant role in accurate prediction and stability of the power grid integrated with wind ***,the conventional methods of interval prediction are commonly based on a hypothetic probability distribution function,which neglects the correlations among various variables,leading to the decrease of prediction ***,we improve the multi-objective interval prediction based on the conditional copula function,through which we can fully utilize the correlations among variables to improve prediction accuracy without an assumed probability distribution *** use the multi-objective optimization method of nondominated sorting genetic algorithm-II(NSGA-II)to obtain the optimal solution *** particular best solution is weighted by the prediction interval average width(PIAW)and prediction interval coverage probability(PICP)to pick the optimized solution in practical ***,we apply the proposed method to three wind power plants in different cities in China as examples forvalidation and obtain higher prediction accuracy compared with other methods,i.e.,relevance vector machine(RVM),artificial neural network(ANN),and particle swarm optimization kernel extreme learning machine(PSO-KELM).These results demonstrate the superiority and practicability of this method in interval prediction of wind power.

关键词： Wind power prediction Interval prediction Conditional copula function Empirical distribution function Multi-objective optimization algorithm

Experiments and analysis for rheological properties of MRF

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2008年第S1期15卷 284-287页

作者：王海霞阮予明孔笋王捷 Fujian electric Vocational and Technical College Department of Mechanical and Electric Engineering

The work principle of flat-plate structure under shearing mode is expounded based on a vertical type rheometer for MRF which combined data acquisition with treatment and result *** formula to calculate shearing stress is *** on different recipe for MRF,experiments under different working gap length were done by altering the intensity of magnetic *** rheological model for MRF was established and the relationships between shearing stress,viscosity and magnetic field intensity were *** indicate that MRF has the flowing characters:with an increase of the magnetic induction and the nominal shear rate,the shear stress of MRF ***,as the working gap decreases,the shear stress *** has shear thinning property under magnetic field.

关键词： magneto-rheological fluid constitutive equation rheometer experiment

Multi-objective optimization strategy for distribution network considering V2Genabled electric vehicles in building integrated energy system

在线全文

学校读者我要写书评

暂无评论

Protection and Control of Modern Power Systems 2020年第1期5卷 48-55页

作者： Zhao Huang Baling Fang Jin Deng Hunan college of information ChangshaChina College of electric and information engineering Hunan university of technologyZhuzhouChina

Based on the large-scale penetration of electric vehicles(EV)into the building cluster,a multi-objective optimal strategy considering the coordinated dispatch of EV is proposed,for improving the safe and economical operation problems of distribution *** system power loss and node voltage excursion can be effectively reduced,by taking measures of time-of-use(TOU)price mechanism bonded with the reactive compensation of energy storage ***,the coordinate charging/discharging load model for EV has been established,to obtain a narrowed gap between load peak and ***,a multi-objective optimization model of the distribution grid is also defined,and the active power loss and node voltage fluctuation are chosen to be the objective *** improving the efficiency of optimization process,an advanced genetic algorithm associated with elite preservation policy is ***,reactive compensation capacity supplied by capacitor banks is dynamically determined according to the varying building *** proposed strategy is demonstrated on the IEEE 33-node test case,and the simulation results show that the power supply pressure can be obviously relieved by introducing the coordinated charging/discharging behavior of EV;in the meantime,via reasonable planning of the compensation capacitor,the remarkably lower active power loss and voltage excursion can be realized,ensuring the safe and economical operation of the distribution system.

关键词： Distribution network electric vehicles Multi-objective optimization Coordinated dispatch Advanced genetic algorithm

Efficiency-oriented vehicle relocation of shared autonomous electric fleet in station-based car-sharing system

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2024年第4期11卷 681-699页

作者： Ning Wang Hangqi Tian Jiahui Guo Huahua Wu Jian Lyu School of Automotive Studies Tongji UniversityShanghai 201804China State Grid Zhejiang electric Power Co. Ltd.Hangzhou 310007China State Grid Zhejiang electric Vehicle Service Co. Ltd.Hangzhou 310012China

Long waiting delays for users and significant imbalances in vehicle distribution are bothering traditional station-based one-way electric car-sharing system *** address the problems above,a“demand forecast-station status judgement-vehicle relocation”multistage dynamic relocation algorithm based on the automatic formation cruising technology was proposed in this *** stage one,a novel trip demand forecast model based on the long short-term memory network was established to predict users'car-pickup and car-return order volumes at each *** stage two,a dynamic threshold interval was determined by combining the forecast results with the actual vehicle distribution among stations to evaluate the status of each *** vehicle-surplus,vehicleinsufficient,vehicle-normal stations,and the number of surplus or insufficient vehicles for each station were *** stage three,setting driving mileage and carbon emission as the optimization objectives,an integer linear programming mathematical model was constructed and the optimal vehicle relocation scheme was obtained by the commercial solver *** 43 stations and 187 vehicles in Jiading District,Shanghai,China,as a case study,results showed that rapid vehicle rebalancing among stations with minimum carbon emissions could be realized within 15 min and the users’car-pickup and car-return demands could be fully satisfied without any refusal.

关键词： Sustainable transportation One-way car-sharing Shared autonomous electric fleet Multistage dynamic relocation algorithm

Study on operation voltage monitoring and electrothermal coupling simulation of electric multiple unit(EMU)roof arrester

在线全文

学校读者我要写书评

暂无评论

High Voltage 2022年第2期7卷 357-368页

作者： Qizhe Zhang Shenghui Wang Kaixuan Sun Xinghao Dong Mingliang Liu Fangcheng Lü State Key Laboratory of Alternate electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina

The roof arrester of electric multiple units(EMU)can efficiently limit the overvoltage,and ensure the safe operation of the EMU electrical *** the process of high‐speed operation,the traction power supply system is often affected by *** addition,roof arrester explosion accidents occasionally *** this paper,the on‐line voltage measurement system of the EMU arrester is *** analysing a large number of voltage waveforms,the abnormal voltage is divided into three categories:over‐phase voltage,high harmonic voltage and steep impulse *** charac-teristics of abnormal voltage waveforms are then *** electrothermal coupling simulation model of the arrester is developed,and the current response and temperature distribution of the arrester under abnormal voltage are *** impact of the impulse voltage energy on the arrester temperature is studied by applying a triangular wave voltage to the ***,some suggestions are proposed for the operation and maintenance of the roof arrester.

关键词： operation traction coupling

Artificial Neural Network Maximum Power Point Tracker for Solar electric Vehicle

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2005年第2期10卷 204-208页

作者： Theodore Amissah OCRAN 曹军义曹秉刚孙兴华 Research and Development Center for electric Vehicle Xi’an Jiaotong University Xi’an 710049 China

This paper proposes an artificial neural network maximum power point tracker (MPPT) for solar electric vehicles. The MPPT is based on a highly efficient boost converter with insulated gate bipolar transis- tor (IGBT) power switch. The reference voltage for MPPT is obtained by artificial neural network (ANN) with gradient descent momentum algorithm. The tracking algorithm changes the duty-cycle of the converter so that the PV-module voltage equals the voltage corresponding to the MPPT at any given insolation, tempera- ture, and load conditions. For fast response, the system is implemented using digital signal processor (DSP). The overall system stability is improved by including a proportional-integral-derivative (PID) controller, which is also used to match the reference and battery voltage levels. The controller, based on the information sup- plied by the ANN, generates the boost converter duty-cycle. The energy obtained is used to charge the lith- ium ion battery stack for the solar vehicle. The experimental and simulation results show that the proposed scheme is highly efficient.

关键词： artificial neural network maximum power point tracker (MPPT) photovoltaic module digital signal processor solar electric vehicle