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4th International Symposium on Insulation and Discharge Computation for Power Equipment, IDCOMPU 2023

作者： Gui, Xianxian Wu, Chuanqi Yuan, Zhao Wang, Cao Liu, Liming Chen, Lixue State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Hubei Wuhan430074 China State Grid Hubei Electric Power Research Institute Hubei Wuhan430077 China

ISBN: (纸本)9789819974047

Based on the experimental phenomenon that the breakdown position of the CuCr contact head in a vacuum circuit breaker may be the Cu–Cr phase boundary, the Cu–Cr interfacial binding models have been developed. The work function, work of interfacial separation, interfacial energy, charge transfer, and charge density distribution of Cu, Cr and W, Fe, Ni and Mo doped Cu/Cr interfaces are calculated from the first principles. The CuCr interface junction was found to have a smaller work function than pure copper and pure chromium. The reduced work function is prone to field emission, thus increasing the possibility of electrical breakdown. Three interfacial binding models Cu(110)/Cr(110), Cu(111)/Cr(111) and Cu(110)/Cr(100) are established in this paper. By comparing the separation work and interfacial energy, it is found that Cu(111)/Cr(111) is relatively stable. The charge transfer is ordered as W > Mo > Ni > Fe from large to small. This order is roughly the same as the atomic numbers of the four metals. The doping of W, Fe, Ni and Mo to make their work function reach the expected value is ranked as W > Ni > Fe > Mo. In this paper, we provide a theoretical basis for increasing the voltage strength of vacuum circuit breakers. © Beijing Paike Culture Commu. Co., Ltd 2024.

关键词： Electric circuit breakers

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Ionization process and distinctive characteristic of atmospheric pressure cold plasma jet driven resonantly by microwave pulses

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Plasma Science and technology 2022年第10期24卷 45-53页

作者： Lingli HONG Zhaoquan CHEN Jie YANG Tao CHENG Sile CHEN Yuming ZHOU Bing WANG Xinpei LU Anhui Province Key Laboratory of Power Electronics and Electrical Control Anhui University of TechnologyMaanshan 243032People's Republic of China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074People's Republic of China

In the present study,a coaxial transmission line resonator is constructed,which is always capable of generating cold microwave plasma jet plumes in ambient air in spite of using argon,nitrogen,or even air,*** the different kinds of working gas induce the different discharge performance,their ionization processes all indicate that the ionization enhancement has taken place twice in each pulsed periods,and the electron densities measured by the method of microwave Rayleigh scattering are higher than the amplitude order of 10^(18)m^(-3).The tail region of plasma jets all contain a large number of active particles,like NO,O,emitted photons,etc,but without O_(3).The formation mechanism and the distinctive characteristics are attributed to the resonance excitation of the locally enhanced electric fields,the ionization wave propulsion,and the temporal and spatial distribution of different particles in the pulsed microwave plasma *** parameters of plasma jet could be modulated by adjusting microwave power,modulation pulse parameters(modulation frequency and duty ratio),gas type and its flow rate,according to the requirements of application scenarios.

关键词： pulsed microwave discharge cold plasma jet transient ionization process ionization enhancement

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Attention Pyramid Dilated Region-based Model for Metallurgical Defect Detection

Attention Pyramid Dilated Region-based Model for Metallurgic...

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2024 International Conference on Computational Intelligence and Communication System, CCICS 2024

作者： Cheng, Danpeng Sha, Wuxin Xu, Zuo Huang, Lixin Zhang, Zhendong Du, Yunpeng Zhu, Zhihua Cao, Yuan-Cheng State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China CITIC Dicastal Co. Ltd. Qinhuangdao066011 China

Defect recognition is the key to realizing automatic visual inspection and quality control in intelligent manufacturing. Deep learning (DL) has been widely applied to locate damaged areas in images, characterize impurities of materials and further analyze the quality of products. However, automatic defect detection by DL in practical industrial applications is still a challenge due to the lack of sufficient datasets and appropriate recognition methods. Here, a novel Attention Pyramid Dilated Region-based Convolutional Neural Network (ADRCNN) is proposed to realize the multi-scale defect recognition and pixel-level instance segmentation of metallographic images. We also collected a dataset containing 900 images of commercial A356 aluminum alloy with different casting defects. The ADRCNN model is evaluated on our dataset with an average detection accuracy of 87.2% and 93.3% on validation and test sets respectively. To address the overfitting problem, a pretraining fine-tuning strategy is implemented by using the pretraining weights from large-scale datasets and temporarily freezing the weights of the backbone network during the training process. The experimental results show that the proposed model can achieve satisfactory defect segmentation in metallographic images, promoting the development of intelligent manufacturing in alloy industries. © Published under licence by IOP Publishing Ltd.

关键词： Aluminum alloys

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Characteristics of the SOL ion-to-electron temperature ratio on the J-TEXT tokamak with different plasma configurations

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Plasma Science and technology 2024年第2期26卷 13-21页

作者：李存凯梁云峰江中和周松华建坤阳杰杨庆虎 Alexander KNIEPS Philipp DREWS 徐鑫毛飞越谢伟杨雨桐郭金龙李杨波任正康陈志鹏王能超 the J-TEXT Team International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung—PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)Julich 52425Germany 不详

Accurate measurement of the average plasma parameters in the edge region,including the temperature and density of electrons and ions,is critical for understanding the characteristics of the scrape-off layer(SOL) and divertor plasma transport in magnetically confined fusion *** the J-TEXT tokamak,a multi-channel retarding field analyzer(RFA) probe has been developed to study average plasma parameters in the edge region under various poloidal divertor and island divertor *** edge radial profile of the ion-to-electron temperature ratio,τ_(i/e),has been determined,which gradually decreases as the SOL ion self-collisionality,v_(SOL)*,*** is broadly consistent with what has been observed previously from various tokamak ***,the comparison of experimental results under different configurations shows that in the poloidal divertor configuration,even under the same v_(SOL)*,τ_(i/e) in the SOL region becomes smaller as the distance from the X-point to the target plate *** the island divertor configuration,τ_(i/e) near the O-point is higher than that near the X-point at the same v_(SOL)*,and both are higher than those in the limiter *** results suggest that the magnetic configuration plays a critical role in the energy distributions between electrons and ions at the plasma boundary.

关键词： ion temperature island divertor poloidal divertor retarding field analyzer(RFA)probe

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Comparative Study of Four-Phase Flux Modulated Doubly-Salient Reluctance Motors With Different Winding Polarity Configurations 5

Comparative Study of Four-Phase Flux Modulated Doubly-Salien...

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5th IEEE International Electrical and Energy Conference, CIEEC 2022

作者： Yu, Zhiyue Gan, Chun Ni, Kai Qu, Ronghai Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (数字)9781665411042

ISBN: (纸本)9781665411042

To reduce the torque ripple and radial vibration, the flux modulated doubly-salient reluctance motor (FMDRM) drives are investigated, where the conventional quasi square current excitation scheme is replaced by the novel dc-biased sinusoidal current excitation scheme with the guidance of the flux modulation principle. However, the existing investigations mainly focus on the three-phase FMDRM. To evaluate the performance of the four-phase FMDRM, this paper proposes a comparative study of the four-phase FMDRMs with different winding polarity configurations. The electromagnetic characteristics of the four-phase 8/6 FMDRMs with commonly utilized 4N4S and NSNS winding polarity configurations are investigated in detail. The magnetomotive force (MMF), winding inductance, phase back electromotive force (back-EMF), torque output capability, and torque ripple are analyzed and compared. In addition, the corresponding finite element analysis (FEA) results are carried out for motor performance comparison. The results show that, compared to the NSNS winding polarity, the 4N4S polarity can achieve a better overall torque performance in the steady-state. However, the NSNS polarity can achieve better overload capacity. © 2022 IEEE.

关键词： Reluctance motors

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Online Junction Temperature Monitoring for Discrete SiC MOSFET Based on On-state Voltage at High Temperature

Online Junction Temperature Monitoring for Discrete SiC MOSF...

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2022 IEEE Transportation Electrification Conference and Expo, Asia-Pacific, ITEC Asia-Pacific 2022

作者： Hu, Haoran Wang, Zhiqiang Zhou, Yimin Zhou, Da Xin, Guoqing Shi, Xiaojie Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (数字)9781665492065

ISBN: (纸本)9781665492065

Junction temperature monitoring is crucial for condition monitoring and thermal management of power semiconductor devices. In this paper, the online monitoring of junction temperature for discrete SiC MOSFETs is achieved by simultaneous measurements of their on-state voltage and current. A dedicated calibration circuit that decouples switching and conduction losses is used to obtain a look-up table for the junction temperature. According to the test results, under the operating condition with current of 50 A and temperature of 175°C, a single pulse test of 10 μ can cause a temperature rise of 8-9 °C, due to the self-heating effect of the discrete SiC MOSFETs. This temperature rise of DUT during the calibration test is compensated by the Foster network thermal model of the device afterwards. © 2022 IEEE.

关键词： Junction temperature

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Directional Pilot Protection Method of Energy Ratio of Whole Frequency Band for VSC-HVDC grid based on improved HHT 11

Directional Pilot Protection Method of Energy Ratio of Whole...

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11th Annual Meeting of CSEE Study Committee of HVDC and Power Electronics, HVDC 2022

作者： Chen, Tiantian Zhao, Zhenting Li, Yinhong State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781839538568

A directional pilot protection method of energy ratio of whole frequency band based on improved HHT is proposed to solve the problems of flexible DC line backup protection which is easily affected by the distributed capacitance of transmission line, synchronous communication, high resistance and applicability of algorithm. Firstly, by analysing the amplitude frequency response characteristics of the line boundary under forward and reverse faults, the attenuation effect of the boundary on the energy of different frequency band is obtained;Then, the improved HHT algorithm based on EEMD is used to extract the voltage energy of each frequency band, and constructs the fault detection criterion, direction criterion and pole selection criterion;Finally, based on PSCAD/EMTDC simulation platform, the effectiveness of the protection scheme is verified. © 2222 IET Conference Proceedings

关键词： Frequency response

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A High-Efficiency Bidirectional LLC Resonant Converter Based on Current-Doubler Rectification Circuit 5

A High-Efficiency Bidirectional LLC Resonant Converter Based...

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5th IEEE International Electrical and Energy Conference, CIEEC 2022

作者： Dong, Mingyang Chen, Changsong Xu, Zhiwen Chen, Haowen Han, Dongtong Zhang, Jingyre Huazhong University of Science and Technology The State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (数字)9781665411042

ISBN: (纸本)9781665411042

With the development of microgrids, DC/DC converters for bidirectional energy transmission between DC bus and energy storage batteries have received more and more attention. In order to convert the high voltage of the DC bus and the low voltage of the batteries, the converters with high-ratio transformers are widely used. However, high transformation ratio brings large secondary winding current, which causes large loss. To improve this defect, the current-doubler rectifier circuit and the LLC resonant converter is combined to build a new bidirectional DC/DC converter. The proposed topology not only reduces the secondary winding current but also reduces the number of MOSFETs, thus improving the efficiency of the converter. The working principle of the proposed converter is introduced, and the problem of voltage spikes in reverse operation is solved by means of ideally inverse coupled inductors. Through comparison and analysis, the feasibility of the proposed topology is verified and the results show that the proposed converter has higher efficiency than the traditional bidirectional LLC converter. © 2022 IEEE.

关键词： Topology

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A Five-Level Space Vector Modulation for Interleaved Vienna Rectifier With Reduced Harmonic Distortion and Line Current Ripple 5

A Five-Level Space Vector Modulation for Interleaved Vienna ...

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5th IEEE International Electrical and Energy Conference, CIEEC 2022

作者： Liu, Xiaokui Duan, Shanxu Song, Xuan Fu, Han Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (数字)9781665411042

ISBN: (纸本)9781665411042

T-type Vienna rectifier are applied in various occasions due to fewer switching devices and lower line current ripple. Parallel converters with interleaved operation can achieve larger power capacity and improve the efficiency and power density of the converters. In interleaved Vienna rectifiers, the conventional 180° interleaved modulation can reduce harmonic distortion and line current ripple. However, since the parallel three-level converters can be considered as a single five-level converter, the performance of parallel converter is not fully exploited. A novel modulation for dual-channel interleaved Vienna rectifier is proposed, which can reduce the line current ripple and the current harmonic distortion. Compared with the conventional method, the proposed modulation strategy has better performance. Experimental results verify the system performance of the proposed modulation strategy. © 2022 IEEE.

关键词： Harmonic distortion

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Research on Capacity Configuration Method of Underwater Compressed Air Energy Storage Considering Offshore Wind Power 4

Research on Capacity Configuration Method of Underwater Comp...

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4th International Conference on Energy engineering and Power Systems, EEPS 2024

作者： Shao, Ming Lou, Suhua Wu, Yaowu Lin, Yong Wu, Weijie Zuo, Zhengmin Liu, Peiyu Mo, Mingshan Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430074 China Power grid planning research center Guangdong power grid corporation Guangzhou China

ISBN: (纸本)9798350366914

In order to cope with the challenges brought by the volatility and randomness of new energy output such as offshore wind power, underwater compressed air energy storage (UCAES) has been widely concerned and has broad development and application prospects. A capacity configuration model of underwater air compressor considering offshore wind power is presented in this paper. Firstly, the model of underwater compressed air energy storage and wind power output is established. Then, the capacity optimization configuration model of UCAES is constructed with the goal of optimal economic benefit. Finally, the model is analyzed according to the solving results, and the results show that the validity of the model is verified. © 2024 IEEE.

关键词： Windmill

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