检索结果-南通市图书馆

Stability Analysis and Control of DC Distribution System with Electric Vehicles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy Engineering 2023年第3期120卷 633-647页

作者： Zhijie Zheng Song Zhang Xiaolei Zhang Bo Yang Fang Yan Xiaoning Ge state Grid Shandong Electric Power company Economic and Technological research institute JinanChina state Grid Shandong Electric Power company limited JinanChina state Nuclear Electric Power Planning Design&research institute company limited BeijingChina

The DC distribution network system equipped with a large number of power electronic equipment exhibits weak damping characteristics and is prone to low-frequency and high-frequency unstable *** current interpretation of the oscillation mechanism has not been ***,this paper established the complete statespace model of the distribution system consisting of a large number of electric vehicles,characteristic equation of the distribution network system is derived by establishing a state-space model,and simplified reduced-order equations describing the low-frequency oscillation and the high-frequency oscillation are ***,based on eigenvalue analysis,the oscillation modes and the influence of the key system parameters on the oscillation mode are ***,impacts of key factors,such as distribution network connection topology and number of dynamic loads,have been discussed to suppress oscillatory instability caused by inappropriate design or dynamic ***,using the DC distribution example system,through model calculation and time-domain simulation analysis,the correctness of the aforementioned analysis is verified.

关键词： DC distribution network system oscillation instability reduced-order equivalent model damping control sensitivity analysis

Parameter Estimation of Sub-/Super-synchronous Oscillation Based on Interpolated All-phase Fast Fourier Transform with Optimized Window Function

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 2024年第4期12卷 1031-1041页

作者： Bo Sun Xi Wu Xi Chen Zixiao Zou Qiang Li Bixing Ren School of Electrical Engineering Southeast UniversityNanjingChina state Grid Jiangsu Electric Power company limited research institute NanjingChina

In recent years,with increasing amounts of renewable energy sources connecting to power grids,sub-/super-synchronous oscillations(SSOs)occurred more *** to the time-variant nature of SsO magnitudes and frequencies,as well as the mutual interferences among SsO modes with close frequencies,the accurate parameter estimation of SsO has become a particularly challenging *** solve this issue,this paper proposes an improved spectrum analysis method by improving the window function and a spectrum correction method to achieve higher ***,by aiming at the sidelobe characteristics of the window function as evaluation criteria,a combined cosine function is optimized using a genetic algorithm(GA).Furthermore,the obtained window function is self-convolved to extend its excellent characteristics,which have better performance in reducing mutual interference from other SSO ***,a new form of interpolated all-phase fast Fourier transform(IpApFFT)using the optimized window function is proposed to estimate the parameters of *** method allows for phase-unbiased estimation while maintaining algorithmic simplicity and *** performance of the pro-posed method is demonstrated under various conditions,com-pared with other estimation *** results validate the effectiveness and superiority of the proposed method.

关键词： Sub-/Super-synchronous oscillation(SSO) window function parameter estimation interpolated all-phase fast Fourier transform(ApFFT)

Prediction and controlling for welding deformation of propeller base structure

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2021年第4期6卷 410-416页

作者： Junan Yi Jian Lin Zhen Chen Tianyu Chen state Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China shipbuilding Technology research institute Shanghai200032China china state shipbuilding Corporation limited Beijing 100097China

Welding deformation often brings about manufacturing problems such as dimensional inaccuracies during assembly and reduces fabrication *** and controlling welding deformation can help to improve the quality of welded *** this paper,the welding deformation of propeller base struc-tures is predicted by means of numerical approaches and mechanical constraints are proposed to control deformations in welding *** elasto-plastic finite element method(TEP FEM)is employed to simulate welding process of the base *** accuracy of welding deformation by TEP FEM analysis is verified by comparing with experimental data of tee joint *** show that welding deformations of the base mainly comprise out-of-plane distortion of ring fringe and radial distortion of cylindrical *** mechanical constraints of fixed points at fringe and rigid supports inside cylin-der can decrease out-of-plane and radial distortions *** numerical approach adopted in this article can serve as an effective tool to optimize welding process planning in integrated design method.

关键词： Mechanical constraints Propeller base structure Thermal elasto-plastic finite element method Welding deformation

Non-cooperative target pose estimation based on improved iterative closest point algorithm

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 Systems Engineering and Electronics 2022年第1期33卷 1-10页

作者： ZHU Zijian XIANG Wenhao HUO Ju YANG Ming ZHANG Guiyang WEI Liang Department of Astronautics Harbin Institute of TechnologyHarbin 150006China Department of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150006China Systems Engineering research institute China State Shipbuilding Corporation LimitedBeijing 100036China

For localisation of unknown non-cooperative targets in space,the existence of interference points causes inaccuracy of pose estimation while utilizing point cloud *** address this issue,this paper proposes a new iterative closest point(ICP)algorithm combined with distributed weights to intensify the dependability and robustness of the non-cooperative target *** interference points in space have not yet been extensively studied,we classify them into two broad categories,far interference points and near interference *** the former,the statistical outlier elimination algorithm is *** the latter,the Gaussian distributed weights,simultaneously valuing with the variation of the Euclidean distance from each point to the centroid,are commingled to the traditional ICP *** each iteration,the weight matrix W in connection with the overall localisation is obtained,and the singular value decomposition is adopted to accomplish high-precision estimation of the target ***,the experiments are implemented by shooting the satellite model and setting the position of interference *** outcomes suggest that the proposed algorithm can effectively suppress interference points and enhance the accuracy of non-cooperative target pose *** the interference point number reaches about 700,the average error of angle is superior to 0.88°.

关键词： non-cooperative target pose estimation iterative closest point(ICP) Gaussian weight

A Parallel-type Load Damping Factor Controller for Frequency Regulation in Power Systems with High Penetration of Renewable Energy Sources

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 2024年第4期12卷 1019-1030页

作者： Zhe Zhang Siyang Liao Yuanzhang Sun Jian Xu Deping Ke Bo Wang Rui Chen Yibo Jiang Hubei Engineering and Technology research Center for AC/DC Intelligent Distribution Network School of Electrical Engineering and AutomationWuhan UniversityWuhan 430072China state Grid Hubei Electric Power company limited Economic research institute Wuhan 430074China state Grid(Suzhou)City&Energy research institute company limited Suzhou 215000China

Renewable energy sources(RESs)are rapidly devel-oping and their substitution for traditional power generation poses significant challenges to the frequency regulation in power *** load damping factor D characterizes the active power of load that changes with power system frequency,which is an important factor influencing the frequency ***,the value of D is small,resulting in the limitation in frequency regulation of the power *** paper proposes a parallel-type load damping factor controller to enhance load damping factor by utilizing static var generators(SVGs)in ***,it discusses the configuration method for the relevant parameters of the controller,evaluates its frequen-cy regulation capability,investigates the impact of large-scale application of the controller on static and dynamic loads,and conducts a comprehensive evaluation of the impact of the damping factor control process on the voltage stability of the main *** large-scale application of the proposed controller can significantly improve the frequency regulation capability,and almost have no influence on the working status of the *** can also significantly improve the dynamic performance of system *** proposed controller can provide technical support for the frequency regulation of new power systems with high proportion of RESs.

关键词： Load damping factor parallel-type load damping factor controller power system frequency regulation highproportion renewable energy system

Co-conversion of methanol and n-hexane into aromatics using intergrown ZSM-5/ZSM-11 as a catalyst

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2020年第5期14卷 783-792页

作者： Shumei Wei Yarong Xu Zhaoyang Jin Xuedong Zhu UNILAB State Key Laboratory of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China research institute of Urumqi Petrochemical company Petrochina Company LimitedUrumqi 830019China

The conversion of n-hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant *** this study,intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-1I *** physicochemical properties of ZSM-5/ZSM-l1 intergrown zeolite were analyzed using X-ray diffrac-tion,N2 isothermal adsorption-desorption,the tempera-ture-programmed desorption of ammonium,scanning clectron microscopy,Fourier transform infrared spectra of adsorbed pyridine,and nuclear magnetic resonance of 27AI,and compared with those of the ZSM-5 and ZSM-11 *** catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and n-hexane under the fixed bed conditions of 400℃,0.5 MPa(N2),methanol:n-hexane=7:3(mass ratio),and weight hourly space velocity=1 h 1(methanol).Com-pared to the ZSM-5 and ZSM-11 zeolites,the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area,a unique crystal structure,moderate acidity,and suitable Brensted/Lewis acid *** evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate,n-hexane conversion rate,and aromatic *** outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique *** benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.

关键词： ZSM-5/ZSM-11 methanol w-hexane cofeeding aromatics

Genetic model of hanging wall syncline and central dome in extensional fault

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2002年第5期45卷 440-448页

作者：刘德来丁贵明鲁兵 Exploration and Production company PetroChina Company Limited Beijing China institute of Geology State Seismological Bureau Beijing China

Hanging wall syncline and central dome are special extension structures, developing over the hanging wall in an extensional ramp-flat fault. Under the condition that the flat is sub-horizontal, the hanging wall syncline is separated from the half graben by the central dome. And on the dome forms an erosional surface. Both sediments in the half graben and erosional surface on the top of the central dome extended over the dome and entered into the hanging wall syncline with extension going on. Meanwhile, those having entered were overlapped by new sedimentary layers in the hanging wall syncline, so that there is a together-threaded, diachronic unconformity to form in the same epoch stratum. The layers in the hanging wall syncline also have an attribute of migrating laterally and getting tilted with extension. There is no sedimentation on the central dome. But sediments, which came from the half graben, got thicker over the dome in extension.

关键词： hanging wall syncline, central dome, extensional ramp-flat fault, extensional basin, Yilan-Yitong Graben.

A Missing Power Data Filling Method Based on Improved Random Forest Algorithm

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2019年第4期5卷 33-39页

作者： Wei Deng Yixiu Guo Jie Liu Yong Li Dingguo Liu Liang Zhu state Grid Hunan Power company limited research institute Changsha 410007China College of Electrical and Information Engineering Hunan UniversityChangsha 410082China state Grid Hunan Electric Power company limited Changsha 410004China

Missing data filling is a key step in power big data preprocessing,which helps to improve the quality and the utilization of electric power *** to the limitations of the traditional methods of filling missing data,an improved random forest filling algorithm is *** a result of the horizontal and vertical directions of the electric power data are based on the characteristics of time ***,the method of improved random forest filling missing data combines the methods of linear interpolation,matrix combination and matrix transposition to solve the problem of filling large amount of electric power missing *** filling results show that the improved random forest filling algorithm is applicable to filling electric power data in various missing ***’s more,the accuracy of the filling results is high and the stability of the model is strong,which is beneficial in improving the quality of electric power data.

关键词： Big data cleaning missing data filling data preprocessing random forest data quality

Effects of Bionic Volute Tongue on Aerodynamic Performance and Noise Characteristics of Centrifugal Fan Used in the Air-conditioner

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 Bionic Engineering 2020年第4期17卷 780-792页

作者： Liming Wu Xiaomin Liu Menghao Wang Department of Fluid Machinery and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China The 705 research institute China State Shipbuilding Corporation LimitedXi'an 710077China

The aerodynamic noise generated by the centrifugal fan used in the air conditioner is related to the comfort of human living and working,which can be controlled by using the bionic design and optimization of key components of centrifugal *** by the non-smooth leading edge of long-eared owl wing,eight kinds of volute tongues are proposed to reduce the aerodynamic noise of a centrifugal *** flow and sound characteristics are numerically investigated by incorporating computational fluid dynamics and computational *** optimal result exhibits a noise reduction of up to 1.5 dB with a slight increase in mass flow *** acoustic characteristics,with respect to the sound pressure level,power spectral density,and sound directivity are *** time-domain,frequency-domain,and root mean square values of pressure fluctuation are monitored and analyzed to assess the unsteady flow interaction between the volute tongue and *** intensity and scale of vortices in the centrifugal fan are suppressed in the upstream and downstream of the bionic volute tongue,and the turbulence effect on the surface of the volute tongue becomes even and weak.

关键词： bionic design volute tongue centrifugal fan noise reduction numerical simulation