检索结果-内蒙古大学图书馆

International Conference on Electrical Machines and Systems (ICEMS)

作者： Xiaotao Tu Chenglin Gu State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

Novel transverse flux permanent magnet motor (TFPMM) with Brushless DC drive is expected to be applied to direct-drive electric vehicles. To reduce torque ripple and obtain faster torque response, direct torque control (DTC) with position sensors instead of flux linkage observer has been employed. The voltage vectors are determined by position of magnetic poles as well as torque hysteresis comparator. In consideration of much longer commutation process caused by the features of novel TFPMM, phase advance commutation has been brought in DTC to achieve maximum torque per ampere. Simulation results have been presented to verify the effectiveness of the proposed method.

关键词： Torque Commutation Couplings Stators Vectors Torque control Rotors

来源：评论

学校读者我要写书评

暂无评论

A sympathetic inrush detection method based on on-line magnet flux calculation

A sympathetic inrush detection method based on on-line magne...

引用

International Conference on Power System technology (POWERCON)

作者： Fei Wang Xuanwei Qi Yi Wang Hang Luo Jian Zhang Zhe Zhang Xianggen Yin State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

The sympathetic inrush is a hot issue in the field of differential protection research, due to its characteristic of concealment, diversity, and complexity. The mal-operation of differential protection probably caused by sympathetic inrush is still a difficult problem to be solved. This paper proposed a new sympathetic inrush detection method based on the on-line magnet flux calculating by integrating the measuring voltages on the tips of transformer. This method can completely overcome the negative influence of CT saturation on the differential protection from principle. The EMTDC-based simulation results prove the effectiveness of the proposed method and also verify that this method would not decrease the sensitivity of differential protection under the condition of internal fault.

关键词： Circuit faults Surges Surge protection Magnetic flux Saturation magnetization Voltage measurement

来源：评论

学校读者我要写书评

暂无评论

Mechanism Analysis of Instability in Grid-Connected PV Systems With Volt-Var Control

Mechanism Analysis of Instability in Grid-Connected PV Syste...

引用

International Conference on Power Electronics and Motion Control (IPEMC)

作者： Shuxuan Yan Xiaojie Shi Xuhua Liu Qiong Chen Lei Lin State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

Utilizing the flexible reactive power regulation capability of PV inverters for voltage support is proved to be an effective solution to voltage fluctuation and violation, which however can induce control of instability. To address this issue, this paper focuses on the dq-frame admittance modeling of three-phase grid-tied inverters with volt-var control, which behaves as a multi-input-multi-output (MIMO) system. It is found that the volt-var control can reshape the q-d channel output admittance in the low-frequency range and increase the risk of oscillation instability. To explore its mechanism, the MIMO model is transformed into a single-input-single (SISO) model from I qd to U d . Applying the impedance-based stability criterion, this paper analyzes in detail the effect of volt-var control, grid-following (GFL) control and the grid impedance on the system stability. Finally, simulations and semi-physical experiments results validate the above analysis.

关键词： Analytical models Voltage fluctuations Stability criteria Power system stability Control systems Admittance Voltage control

来源：评论

学校读者我要写书评

暂无评论

A Novel Preliminary Design Method of PMSM Drive System for Minimizing Acceleration Time of High-Speed and Large-Inertia Flywheel Rotor Load

A Novel Preliminary Design Method of PMSM Drive System for M...

引用

International Conference on Electrical Machines and Systems (ICEMS)

作者： Jiakang Yao Kexun Yu Xianfei Xie Lizheng Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

In the research field of pulsed power system (PPS), high-power and high-energy pulse alternator is used for providing intense pulses of electrical power, whose rotor is designed large to store enough energy for satisfying multi-shot requirement, which can be regarded as a high-speed and large-inertia flywheel. How to design a suitable mechanical drive system with a compact volume for minimizing the acceleration time (AT) from rest to target speed is one of the most concerned issues. The design of motor drive system is an iterative process, especially when co-designing of the motor and its converter. An accurate initial parameter estimate can greatly reduce the costs. Therefore, in this paper, a novel preliminary design method of permanent magnet synchronous motor (PMSM) drive system is proposed. Firstly, a special base value system (BVS) of PMSM drive system is introduced in this paper, and the equations of maximum torque control (MTC) are normalized. Secondly, the design method based on minimum acceleration time curve (MATC) is proposed, and a MATC of turn number design is derived. Thirdly, considering the influence of windage and eddy current losses on the output torque of motor, the corresponding MATCs in low and high vacuum environment are studied respectively. Finally, it is concluded that the optimal turn number coefficient should be greater than 3.5 in the design.

关键词： Torque Reluctance motors Permanent magnet motors Rotors Acceleration Flywheels

来源：评论

学校读者我要写书评

暂无评论

Analysis and Suppression of Mutual Inductive Couplings of the CM EMI Filter in Motor Drive

Analysis and Suppression of Mutual Inductive Couplings of th...

引用

International Conference on Power Electronics (ICPE)

作者： Zhihao Fang Dong Jiang Zaidong Hu State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781728116129

This paper gives an analysis of mutual inductive couplings of the CM EMI filter in motor drive. First, the high-frequency model of L-C EMI filter is proposed, then, equivalent decoupling circuits are established based on the method of transferring controlled voltage source. It is concluded by calculation that some mutual inductive couplings have an effect on the transfer gain of EMI filter in the whole frequency spectrum of EMI current. While some mutual inductive couplings influence the transfer gain only at high frequency range. Finally, in order to drop the EMI current below the standard, the combination of an optimized EMI filter and an advanced method are adopted.

关键词： electromagnetic interference Couplings Inductance Capacitors Motor drives Inductors Impedance

来源：评论

学校读者我要写书评

暂无评论

Improved Longitudinal Protection for T-connected Inverter Interfaced Distributed Generation Distribution Network

Improved Longitudinal Protection for T-connected Inverter In...

引用

Sustainable Power and Energy Conference (iSPEC)

作者： Shengyuan Guan Jian Qiao Wenting Weng Shaoxiang Ma State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665414401

Inverter interfaced distributed generator (IIDG) is connected to the distribution network in the form of T-connected, which changes the operating characteristics of single power flow direction in the traditional distribution network, and makes the traditional three-stage current protection no longer applicable. Therefore, this paper proposes an improved longitudinal protection method for T-connected inverter distributed power distribution networks. The control strategy of IIDG is analyzed, and the analysis method in a distribution network is given. On this basis, an improved criterion of longitudinal protection is proposed. The proposed criterion can sensitively identify internal and external faults that is not affected by DGs. Simulation results of PSCAD verify the effectiveness of the proposed method.

关键词： Resistance Performance evaluation Simulation Distribution networks Information processing Inverters Generators

来源：评论

学校读者我要写书评

暂无评论

Density Functional Theory for Electrocatalysis

引用

Energy & Environmental Materials 2022年第1期5卷 157-185页

作者： Xiaobin Liao Ruihu Lu Lixue Xia Qian Liu Huan Wang Kristin Zhao Zhaoyang Wang Yan Zhao State Key Laboratory of Silicate Materials for Architectures International School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China Zhejiang University Hangzhou 310058China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Center of Smart Materials and DevicesSchool of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China Lynbrook High School San Jose CA 95129USA The Institute of Technological Sciences Wuhan UniversityWuhan 430072China

It is a considerably promising strategy to produce fuels and high-value chemicals through an electrochemical conversion process in the green and sustainable energy *** for electrocatalytic reactions,including hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),nitrogen reduction reaction(NRR),carbon dioxide reduction reaction(CO_(2)RR),play a significant role in the advanced energy conversion technologies,such as water splitting devices,fuel cells,and rechargeable metal-air *** low-cost and highly efficient electrocatalysts is closely related to establishing the composition-structure-activity relationships and fundamental understanding of catalytic *** functional theory(DFT)is emerging as an important computational tool that can provide insights into the relationship between the electrochemical performances and physical/chemical properties of *** article presents a review on the progress of the DFT,and the computational simulations,within the framework of DFT,for the electrocatalytic processes,as well as the computational designs and virtual screenings of new *** useful descriptors and analysis tools for evaluating the electrocatalytic performances are highlighted,including formation energies,d-band model,scaling relation,egorbital occupation,and free energies of ***,the remaining questions and perspectives for the development of DFT for electrocatalysis are also proposed.

关键词： analysis tools density functional theory descriptors electrocatalysis

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation on dynamic and static holdups of powder inside pre-reduction shaft furnace

Numerical simulation on dynamic and static holdups of powder...

引用

6th International Congress on the Science and technology of Ironmaking 2012, ICSTI 2012

作者： Xu, Jian Wu, Sheng-Li Guo, Xin-Ying Du, Kai-Ping State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing China

ISBN: (纸本)9781627480215

In some non-blast furnace ironmaking processes, such as COREX smelting reduction process, the reducing gas, introduced into the upper pre-reduction shaft furnace, usually contains a considerable quantity of dust or powder as a result of coal gasification and iron-bearing burden decomposition in melter gasifier, and the powder distribution behaviors make direct and important influences on gas flow as well as burden reduction inside pre-reduction shaft furnace. Based on momentum exchange among gas-solid-powder phases and empirical equations, a two-dimensional mathematical model was established in the present work to simulate both dynamic and static holdups of powder. There were two blockade zones existing in the centre and edge regions near the bottom respectively. The dynamic holdup of powder firstly increased to 3.0e-3 and then decreased to 7.0e-4 as the gas ascended from the inlet to the top. At the bottom of the shaft furnace, the relatively low gas velocity gave rise to dynamic powder accumulation. By contrast, the static holdup of powder generally increased from 2.0e-5 near the edge to as high as 1.8e-4 near the centre at the gas inlet level and the trend was further promoted to 5.0e-3 in the central inactive zone or even to 1.0e-1 at the bottom below the gas inlet. In addition, the influences of the powder density, the feed rate and the man-made deadman shape on powder distribution behaviors inside pre-reduction shaft furnace were also investigated in this work.

关键词： Gases

来源：评论

学校读者我要写书评

暂无评论

Effect of particle morphology of iron ore on moisture segregation in sinter mixture

Effect of particle morphology of iron ore on moisture segreg...

引用

6th International Congress on the Science and technology of Ironmaking 2012, ICSTI 2012

作者： Zhang, Guo-Liang Wu, Sheng-Li Zhu, Juan Wang, Yong-Zhi Liu, Xin-Liang Chen, Shao-Guo Fan, Jia-Xin State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing China

ISBN: (纸本)9781627480215

Suitable content and distribution of sinter mix moisture plays an important role in promoting particle growth and improving granulated particle strength. Previous researches mainly concerned the effects of water absorption and saturated water amount of iron ore on moisture addition. However, rare researches covered the effect of particle morphology of iron ore on moisture segregation in sinter mixture. By application of immersion method and capillary water suction method, experiments are conducted to study the effects of porosity, size distribution and particle shape on water absorption rate. Moreover, water absorption characteristics of iron ore at different stages are investigated, thus relationship between particle morphology and moisture segregation is obtained, and moisture segregation mechanism is explored. The results are as follows: (1) Iron ore which has larger porosity, smaller particle size and plate structure has larger water absorption rate, thus this typical iron ore can obtain more segregated water. (2) The process-water absorption rate of iron ore is mainly influenced by particle shape in the earlier stage while affected mainly by porosity in the later stage. (3) The size and amount of capillary pores among iron ore particles are mainly determined by particle morphology of iron ore which produces the different capillary effects and all these results in the moisture segregation.

关键词： Mixtures

来源：评论

学校读者我要写书评

暂无评论

Multi-stage Process Analysis and Modelling based Online Monitoring for Chip Packaging Process

引用

IFAC-PapersOnLine 2015年第28期48卷 993-998页

作者： Qin, Yan Zhao, Chunhui Gao, Furong State Key Laboratory of Industrial Control Technology Department of Control Science and Engineering Zhejiang University Hangzhou310027 China Key Laboratory of Advanced Control and Optimization for Chemical Processes Shanghai20023 China Department of Chemical and Biomolecular Engineering The Hong Kong University of Science and Technology Cleary Water Bay Kowloon Hong Kong

As one of the crucial semiconductor manufacturing steps, chip packaging process plays an important role to provide a phys ical protection, electric interconnection environment for naked wafer. In the present work, the chip packaging process is analyzed in detail for process understanding and monitoring. First, detailed description of the chip packaging process is given to help better understand the process. Then, the underlying process characteristics are explored and multi-stage nature of chip packaging process is revealed by t racking changes of process variable correlat ions. The whole process is divided into several modeling phases using a step-wise sequential phase partition algorithm, agreeing well with the real process. Stage-based online monitoring and fault diagnosis is performed to analyze some common abnormal behaviors in this process. The stage-based analysis results not only provide reliable online monitoring and fault diagnosis performance but also provide enhanced process understanding. © 2015

关键词： Chip scale packages Batch data processing Failure analysis Fault detection Packaging Partial discharges Process monitoring Semiconductor device manufacture Batch process Chip packaging Diagnosis performance Electric interconnection Multi stage Process characteristics Process understanding Semiconductor manufacturing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：