检索结果-内蒙古大学图书馆

Research on Topology and Modulation Control Method of a Novel Three-Level Current-Fed DCDC Converter

IOP Conference Series: Materials science and Engineering 2019年第4期612卷

作者： Kai Ji Tingyang Chen Wenfeng Long Jinping He National Key Laboratory of Science and Technology on Vessel Integrated Power System Wuhan Institute of Marine Electric Propulsion Wuhan China

Multilevel current source converter has the benefits of high output capacity, low current switching stress and low harmonic or ripple content. This paper presents a new topology of three-level current-fed DC/DC converter for superconducting magnetic energy storage application. In this topology, a superconducting inductance acting as a constant current source and a shunt inductance acts as current divider ensure current flows through the power switch components equally to generate immediate level of current. A novel kind of pulse width modulation (PWM) switching strategy for the current instantaneous control of the current source converter was proposed. The modulation switching strategy proposed is able to effectively control the DC current output of the converter. Also, due to the both of proposed topology and control method are quite a simple, it can be easily realized in the practice. Simulation results prove the feasibility and validity of the proposed topology and modulation strategy

关键词：

来源：评论

学校读者我要写书评

暂无评论

Analysis of Eddy-Current Loss and its Reduction in a Conduction-Cooled HTS Magnet

引用

IOP Conference Series. Earth and Environmental science 2019年第4期300卷 042126-042126页

作者： Ji, Kai Long, Wenfeng He, Jinping Zheng, Jun National Key Laboratory of Science and Technology on Vessel Integrated Power System Wuhan Institute of Marine Electric Propulsion Wuhan China

Since conduction cooling system is environmental friendly and easy operating, the conduction-cooled method is widely used in cryogenic cooling system of high-temperature superconducting (HTS) magnet. The eddy-current losses are generated in the cooling structures when HTS magnet is charging and discharging or the current in the magnet is alternating. In this paper, a 3D model of analyzing the eddy-current loss was built. The eddy-current losses of a HTS magnet with different cooling structures were calculated. Thermal analysis of the HTS magnet was carried out together with the electromagnetic analysis. The effect of the cooling structures’ geometric parameters on the eddy-current losses was discussed. The methods of reducing the eddy-current loss were proposed. The analysis results demonstrate that the optimization of the geometric parameters would greatly benefit the reduction of the eddy-current losses.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A 10b 1.25GS/s Residue Post-Amplified Pipelined-SAR ADC with Supply-and-Temperature Stabilized Open-Loop Residue Amplifier

A 10b 1.25GS/s Residue Post-Amplified Pipelined-SAR ADC with...

引用

IEEE International Symposium on Circuits and systems (ISCAS)

作者： Xinsheng Wang Maosong Shi Peizhe Li Jianwei Liu Zhangcheng Huang Chixiao Chen Wenning Jiang Frontier Institute of Chip and System Fudan University Shanghai China Herbin Insitute of Technology at Weihai Weihai China State Key Laboratory of Intergrated Chips and Systems Fudan University Shanghai China National Laboratory of Science and Technology on Analog Integrated Circuit Chongqing China

This paper presents a single-channel two-stage pipelined-SAR ADC with ping-pong switched half of capacitor-digital-to-analog-converter (CDAC) moving the residue amplification into 2 nd stage to lighten the timing burden of the 1 st stage. Besides, a dynamic open-loop residue amplifier (RA) is employed to improve the energy efficiency and amplification speed. In order to enhance the ADC robustness, the gain variation under the supply and temperature drift are suppressed through the supply-and-temperature compensation bias. The simulation results shows gain variation is less than 5% under the temperature range from -20 °C to 100 °C and supply voltage variation of $\pm \mathbf{5}\%$ , which ensure the above 56 dB ADC SNDR under process-voltage-temperature (PVT) variation. The ADC is simulated with a 40 nm CMOS process and 1V supply voltage, it achieves 59 dB SNDR with Nyquist input frequency at 1.25 GS/s sampling rate. The power consumption is 5.6mW, leading to a Walden FoM (FoMw) of 6.2 fJ/conversion-step and a Schreier FoM (FoMs) of 169.5 dB.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Significantly Improving Mechanical Properties of Cf/Pai Composites: The Influence of Interfacial Modification Coupled with Post Heat Treatment

SSRN

引用

SSRN 2023年

作者： Zhang, Shouchun Zhou, Fang Zhao, Zhenbo Jing, Deqi Zhang, Xinghua Wang, Peng Su, Weiguo CAS Key Laboratory for Carbon Materials Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan030001 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan430033 China Research Center of Advanced Thermoplastic Composites Engineering Institute of Coal Chemistry Chinese Academy Sciences Taiyuan030001 China

Carbon fiber reinforced polyamide-imide (CF/PAI) composites is a potential candidate for high temperature applications under high stress conditions. However, the structure-property relationships of CF/PAI are not clear. This work presented an experimental investigation into the influence of interfacial modification and heat modification on the microstructures and mechanical properties of CF/PAI composites. The CF/PAI interfacial interactions was improved by the combined effect of chemical bonding between PAI-compatible sizing and CF as well as hydrogen bonding between the sizing and matrix. Meanwhile, heat modification enhanced the modulus of matrix, which was beneficial to stress transfer in the interfacial region. Therefore, the interlaminar shear strength (ILSS), flexural strength and flexural modulus of RS0.6-CF/PAI composites were remarkably improved by 81.3%, 23.7% and 39.1% compared with the control specimen. Microstructure examinations of modified and unmodified CF/PAI composites showed that both interfacial modification and heat modification played an important role in transitions of failure mode under interlaminar shear loading and flexural loading. These findings provide an effective method to tailor the microstructures of CF/PAI composites in achieving desired properties. © 2023, The Authors. All rights reserved.

关键词： Polyamideimides

来源：评论

学校读者我要写书评

暂无评论

Field-Harmonic-Oriented Design of Vernier Permanent Magnet Machine Towards High Torque Density and Low Torque Ripple

Field-Harmonic-Oriented Design of Vernier Permanent Magnet M...

引用

International Conference on Electrical Machines and systems (ICEMS)

作者： Li Fang Dawei Li Yuanzhi Zhang Jiewen Wu School of Electrical and Electronics Engineering Huazhong University of Science and Technology Wuhan China School of Electricla Engineering and Automation (Hubei Key Laboratory of Power Equipment and System Security for Integrated Energy) Wuhan University Wuhan China College of Design and Engineering National University of Singapore Singapore

Vernier permanent magnet machine (VPMM) has been a promising candidate for low-speed large-torque applications owing to high torque density based on multiple-magnetic field-harmonics working principle However, rich field harmonics also cause large torque ripple, meanwhile the regular reducing methods will also undermine torque density. In this paper, the field-harmonic-oriented design approach is proposed for the VPMM towards high torque density and low torque ripple. Based on the permeance unit model, the mapping relationship between torque output and field harmonics is built. Explicit design regulations are established for the airgap structure so as to modulate the optimal field harmonics composition. Via the proposed method, a surface-mounted VPMM is purposely designed and the electromagnetic performance is verified by FEA. Finally, a prototype of the proposed machine has been manufactured and tested. Both analytical and experimental results validate the feasibility of the proposed design method.

关键词：

来源：评论

学校读者我要写书评

暂无评论

First Demonstration of Wafer-Level Arrayed β-Ga2O3 Thin Films and MOSFETs on Diamond by Transfer Printing technology

First Demonstration of Wafer-Level Arrayed β-Ga2O3 Thin Fil...

引用

International Electron Devices Meeting (IEDM)

作者： Tiancheng Zhao Xinxin Yu Wenhui Xu Yang He Zhenyu Qu Rui Shen Ruize Wang Huaixin Guo Huarui Sun Zhonghui Li Min Zhou Tiangui You Xin Ou State Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai China CETC Key Laboratory of Carbon-based Electronics Nanjing Electronic Devices Institute Nanjing China School of Science and Ministry of Industry and Information Technology Key Laboratory of Micro-Nano Optoelectronic Information System Harbin Institute of Technology Shenzhen China National Key Laboratory of Solid-State Microwave Devices and Circuits Nanjing China

ISBN: (数字)9798350365429

ISBN: (纸本)9798350365436

We, for the first time, fabricated wafer-level arrayed β-Ga 2 O 3 single crystal thin films on diamond substrate using transfer printing technology. The transfer-printed β-Ga 2 O 3 thin film possesses a thickness of 260 nm, a XRD rocking curve FWHM of ∼78 arcsec, and a surface roughness of 0.36 nm. The amorphous interface layer after post-annealing is less than 2 nm. The thermal boundary resistance is extracted to 21.7 m 2 .K/GW, which is the lowest value reported for single-crystal β-Ga 2 O 3 integrated with diamond. Thanks to the high thermal conductivity of diamond and the high-quality hetero-interface, the performance of β-Ga 2 O 3 -on-diamond RF MOSFETs is significantly enhanced. The maximum on-state current is 810 mA/mm, and the $f_{\max}$ before de-embedding reaches 61 GHz, which is the highest recorded value to date. Infrared thermal imaging shows that integrating with diamond significantly reduces the junction temperature of β-Ga 2 O 3 devices. The $\mathrm{R}_{\text{th}}$ of β-Ga 2 O 3 -on-diamond devices is merely 5.52 K·mm/W, setting a new record for β-Ga 2 O 3 -based devices. These results demonstrate that hetero-integration with diamond via wafer-level transfer printing technology provides an effective thermal management platform for β-Ga 2 O 3 , facilitating its advancement in high-power and RF devices.

关键词： Radio frequency Printing Temperature measurement MOSFET X-ray scattering Voltage measurement Thermal resistance Logic gates Diamond Substrates

来源：评论

学校读者我要写书评

暂无评论

Supermaneuverable Flipping Control and Planning Based on Multi-Rotor Mode of Tilt-Rotor UAVs

Supermaneuverable Flipping Control and Planning Based on Mul...

引用

IEEE International Conference on Robotics and Biomimetics

作者： Hongpeng Wang Qinghao Zhang Yue Fei Kun Deng Jun Liang Chuanyu Sun Li Xu The Key Laboratory of Civil Aviation Smart Airport Theory and System Civil Aviation University of China College of Artificial Intelligence Nankai University Tianjin China Laboratory of Science and Technology on Integrated Logistics Support National University of Defense Technology Changsha China Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute of Nankai University Shenzhen China China Nuclear Power Technology Research Institute Co. Ltd Shenzhen China

ISBN: (数字)9798331509644

ISBN: (纸本)9798331509651

Maneuverability is a critical factor for UAV s to survive in high-intensity combat scenarios. Traditional UAV s typically operate in a stable motion state to ensure flight safety. However, in highly contested environments, special missions require high mobility while maintaining safety. Tilt-rotor UAV s, which combine the characteristics of fixed-wing and multi-rotor UAVs, can perform extreme maneuvers, such as high angles of attack and post-stall maneuvers, to rapidly change posture and complete tasks like positioning and defense. Therefore, integrating and optimizing safety and maneuverability metrics is necessary for enabling UAV s to achieve extreme maneuverability. In this paper, extreme maneuver planning and control for tilt-rotor UAV s are realized through a method based on third-order Bezier curve planning of body angular velocity. Experimental results demonstrate tilt-rotor UAVs can perform extreme super-maneuverable flips while maintaining overall process control.

关键词： Measurement Biomimetics Process control Autonomous aerial vehicles Angular velocity Planning Safety Kalman filters Robots

来源：评论

学校读者我要写书评

暂无评论

Augmented Reality-Based Digital-Physical Space Registration and Projection for Cognitive Enhancement and Assessment

Augmented Reality-Based Digital-Physical Space Registration ...

引用

IEEE International Conference on Robotics and Biomimetics

作者： Hongpeng Wang Yue Fei Qinghao Zhang Kun Deng Jun Liang Chuanyu Sun Li Xu The Key Laboratory of Civil Aviation Smart Airport Theory and System Civil Aviation University of China College of Artificial Intelligence. Nankai University Tianjin China Laboratory of Science and Technology on Integrated Logistics Support National University of Defense Technology Changsha China Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute of Nankai University Shenzhen China China Nuclear Power Technology Research Institute Co. Ltd. Shenzhen China

ISBN: (数字)9798331509644

ISBN: (纸本)9798331509651

Driven by information technology, mod-ern warfare is more diverse and intelligent than traditional warfare, in which intelligent unmanned system plays an increasingly important role. To defend against distant threat of unmanned military arma-ments, it's essential to deploy radars, sonars, satellites, and other long-range detection equipment to build a multidimensional national defense monitoring system. Due to the unpredictable nature of battlefield, radar-based reconnaissance missions require operators to have extensive experience and maintain a high level of focus. However, prolonged radar operations may impose a heavy psychological burden on operators and even affect their mental functions. To address these challenges, this paper proposes a cognitive en-hancement and assessment system that projects virtual 3D battlefield scenarios onto the real world based on augmented reality and evaluates operators' mental state through eye-tracking technology.

关键词： Three-dimensional displays Satellites Spaceborne radar Virtual environments Sonar Reconnaissance Robot sensing systems Radar equipment Monitoring Sonar detection

来源：评论

学校读者我要写书评

暂无评论

Research on flexible control algorithm for acceleration/deceleration in heavy-duty motion

引用

Journal of Physics: Conference Series 2019年第1期1303卷

作者： Lei Yuan Mingjin Xu Zhenxing Wu Jin Xu Naval University of Engineering Wuhan 430033 China Nation Key Laboratory of Science and Technology on Vessel Integrated Power System Wuhan 430033 China

An algorithm for acceleration/deceleration control is proposed in this paper to improve the flexibility of the heavy-duty motion system. The algorithm is based on the five-segment S-type acceleration/deceleration curve. During the acceleration switching time, a circular arc is used to smooth the curve, and the running time of each stage could be reasonably allocated by cyclic iteration. A parameter is defined to quantify the degree of flexibility of the acceleration/deceleration process to match the actual project. This paper will build the model to compare the good and bad point of different algorithms. The result shows that the vibration and impact during the acceleration and deceleration process can be effectively reduced, which means that the flexibility of the system has been greatly improved.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Silulation on Parallel Control Mthods of Isoland Microgrid powered bylnverter and Diesel Generator

引用

Journal of Physics: Conference Series 2021年第1期1965卷

作者： Zhang Xiaolin Ma Fan Li Chun National Key Laboratory of Science and Technology on Vessel Intergrated Power System Naval University of Engineering Wuhan 430033 Hubei China

Aiming at the power quality problems caused by the large number of renewable energy access to the grid, three common parallel networking modes of inverters and diesel generators in the independent micro-grid were analyzed in this paper, this paper also makes a systematic and comprehensive comparsion from the control principle, control structure, control performance, overall resource occupation, deduced the equivalent conditions of droop control and virtual synchronous generator control. Secondly, the characteristic of different control methods was analyzed to test the stability and also point out the characteristic of voltage and current in this paper. Finally, the micro-grid model was builted on PSCAD/EMTDC platform to verify the performance of three methods from the conditions of parallel off grid switching, load mutation and three-phase short circuit fault, and also point out the application scope of different strategies, it has reference value for micro-grid engineering practice.

关键词：

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：