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排序方式: 共有433条查询结果,搜索用时 15 毫秒
41.
Minglei Zhou Xiaojie You Chenchen Wang 《IEEJ Transactions on Electrical and Electronic Engineering》2014,9(6):675-684
In high‐power, high‐speed traction drive systems, the traction motor usually operates under one‐pulse PWM (pulse width modulation) mode (square wave) during high‐speed operation. The constant output voltage in this condition makes the traditional vector control inoperative anymore. In this paper, a modified vector control strategy using open‐loop current control instead of closed‐loop current control is proposed. The modified control strategy is specially designed for an induction motor operating under one‐pulse PWM mode. As the field orientation is greatly affected by the deviation in the parameters, the influence of mistuned rotor time constant and mutual inductance (which are regarded as the most important parameters for field orientation) on the performance of modified vector control is studied comprehensively, including the influence on estimated angle and amplitude of rotor flux, d/q‐axis voltage, and output torque. Subsequently, based on the comparison between the different methods, a new slip frequency correction strategy is proposed to maintain proper field orientation for the modified vector control. The new correction strategy is based on the q‐axis current component error. It is independent of the motor parameters and can be easily realized through minor calculations. The simulation and experimental results show that the proposed slip frequency correction strategy can not only eliminate rotor flux angle error in steady state but also effect rapid torque response during the transient process under one‐pulse PWM mode. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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43.
Marion Balz Erhard Schulte Hans -Peter Thier 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1996,202(1):80-81
The quality of an q71l000715/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-tocopherol standard can be checked easily by measuring the UV absorbance at minimum (255 nm,A
min) and maximum (292 nm,A
max) wavelengths inn-hexane. If the quotientA
min/A
max exceeds 0.18, the standard contains less than 90% q71l000715/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-tocopherol and the determination at 292 nm will yield inaccurate results. 相似文献
44.
45.
An improved approach to updating the electric field in simulations of Coulomb gases using the local lattice technique introduced by Maggs and Rossetto [A.C. Maggs, V. Rossetto, Phys. Rev. Lett. 88 (2002) 196402] is described and tested. Using the Fast Fourier Transform (FFT) an independent configuration of electric fields subject to Gauss' law constraint can be generated in a single update step. This FFT based method is shown to outperform previous approaches to updating the electric field in the simulation of a basic test problem in electrostatics of strongly correlated systems. 相似文献
46.
BoD协议中 可以 通过充分利用按需分配后剩余的带宽来降低时延。首先针对如何高效地利用剩余带宽及其对反馈控制的影响,提出了一种新型的基于预测和星上反馈控制的BoD带宽请求分配算法。其次根据网络流量同时呈现长相关和短相关特性,提出采用ARFIMA(p,d,q)模型进行流量建模与预测,该模型根据参数d的取值不同既能表示长相关又能表示短相关。最后利用OPNET软件建立仿真系统。仿真结果表明,对于长相关和短相关业务流,基于ARFIMA(p,d,q)模型预测和星上反馈控制的BoD带宽请求分配方案能够最高效地利用剩余带宽来降低时延。 相似文献
47.
Two of the majorNuphar alkaloids, nupharolutine and 6,6q/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-dihydroxythiobinupharidine, were isolated from the aquatic perennial herbNuphar lutea (L.) Sibth. & Sm., yellow water lily. In a lettuce seedling bioassay of the two pure compounds, the former was inactive and the latter was highly inhibitory of radicle elongation at concentrations greater than 2 ppm. Structures and stereochemistry of the two compounds were confirmed by DEPT,1H-1H COSY,1H-13C COSY, and1H-1H NOESY experiments. 相似文献
48.
Mario Gleria Roberta Bertani Roger De Jaeger 《Journal of Inorganic and Organometallic Polymers》2004,14(1):1-28
A general survey of fluorinated phosphazene polymers starting from their synthesis in 1965 to recent times is presented. Various types of fluorinated phosphazenes are described depending on the way fluorine atoms are connected to the polyphosphazene skeleton. The characterization, properties and practical utilization of these compounds in different domains are critically discussed. 相似文献
49.
Nadezhda Todorova Miroslav Rangelov Vanya Bogoeva Vishnya Stoyanova Anna Yordanova Ginka Nikolova Hristo Georgiev Daniela Dimitrova Safa Mohedin Katerina Stoyanova Ivanka Tsacheva 《International journal of molecular sciences》2021,22(15)
We addressed the issue of C1q autoantigenicity by studying the structural features of the autoepitopes recognized by the polyclonal anti-C1q antibodies present in Lupus Nephritis (LN) sera. We used six fractions of anti-C1q as antigens and selected anti-idiotypic scFv antibodies from the phage library “Griffin.1”. The monoclonal scFv A1 was the most potent inhibitor of the recognition of C1q and its fragments ghA, ghB and ghC, comprising the globular domain gC1q, by the lupus autoantibodies. It was sequenced and in silico folded by molecular dynamics into a 3D structure. The generated 3D model of A1 elucidated CDR similarity to the apical region of gC1q, thus mapping indirectly for the first time a globular autoepitope of C1q. The VH CDR2 of A1 mimicked the ghA sequence GSEAD suggested as a cross-epitope between anti-DNA and anti-C1q antibodies. Other potential inhibitors of the recognition of C1q by the LN autoantibodies among the selected recombinant antibodies were the monoclonal scFv F6, F9 and A12. 相似文献
50.
选择了优化钻进的衡量参数(h/p)/q,并以此多数对具体岩石优选了钻头,对具体岩石和钻头优选了合理的钻头每转进尺范围。 相似文献