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Electrical engineering and Control Technologies (CEECT), Conference on

作者： Yunpeng Zhou Wei He Jiabing Hu State Key Laboratory of Advanced Electromagnetic Engineering and Technology and School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

Oscillations in current control (CC) timescale caused by the large-scale integration of voltage-source converters (VSCs) have gained more and more attention from both academy and industry. In view of this problem, a comparative study is conducted to investigate the stability difference between gridfollowing (GFL) and grid-forming (GFM) converters in CC timescale. Firstly, the unified linearized model of GFL and GFM converters is established. Secondly, the impact paths of other control loops on the current control loop are extracted based on the proposed model. Thirdly, the characteristics of the corresponding paths in GFL and GFM converter are studied. By comparing the impact of the corresponding paths on the current control loop, the root cause of the stability difference between GFL and GFM in CC timescale is revealed. All results are verified through time-domain simulations.

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A Hybrid Method for Estimating the State of Health of Lithium-ion Batteries Based on Health Indicators during the Constant-Voltage Charging Stage

A Hybrid Method for Estimating the State of Health of Lithiu...

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Power Systems and Electrical technology (PSET), IEEE International Conference on

作者： Zhuohao Li Qionglin Shi Maoshu Xu Kangli Wang Kai Jiang School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798350353204

ISBN: (纸本)9798350353211

The electrochemical energy storage technologies, with lithium-ion batteries at the forefront, have made significant contributions to alleviating the global energy crisis and environmental pollution. Assessing the state of health (SOH) of lithium-ion batteries is of paramount importance for their longterm safe and stable operation. Moreover, the constant voltage (CV) charging stage, known for its stability and significantly influences aging. Therefore, this paper proposes a hybrid health state estimation method based on health features extracted during the CV charging stage. Firstly, the CV stage of lithiumion batteries is analyzed, and five health indicators (HIs) are extracted. Pearson correlation analysis is then conducted to assess the interrelationships between the HIs and SOH. Subsequently, a PSO-SVR hybrid model is established to estimate the SOH, where Particle Swarm Optimization (PSO) is employed to tune the parameters of the Support Vector Regression (SVR) model. Finally, the accuracy of the method is validated using battery data from the Tongji University Clean Energy Vehicle engineering Center, resulting in an estimated root mean square error (RMSE) and mean absolute percentage error (MAPE) of less than 1.5%.

关键词： Lithium-ion batteries Support vector machines Accuracy Voltage Aging Feature extraction Stability analysis State estimation Root mean square Testing

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Structure,far-infrared spectroscopy,microwave dielectric properties,and improved low-temperature sintering characteristics of tri-rutile Mg_(0.5)Ti_(0.5)TaO_(4) ceramics

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Journal of advanced Ceramics 2023年第2期12卷 296-308页

作者： Hongyu YANG Liang CHAI Guangchao LIANG Mengjiang XING Zixuan FANG Xing ZHANG Tianying QIN Enzhu LI Academy of Advanced Interdisciplinary Research Xidian UniversityXi’an 710071China National Engineering Research Center of Electromagnetic Radiation Control Materials University of Electronic Science and Technology of ChinaChengdu 610054China Key Laboratory of Multi-Spectral Absorbing Materials and Structures of Ministry of Education University of Electronic Science and Technology of ChinaChengdu 610054China Yangtze Delta Region Institute(Huzhou) University of Electronic Science and Technology of ChinaHuzhou 313001China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China Sichuan Province Key Laboratory of Information Materials and Devices Application Chengdu University of Information TechnologyChengdu 610225China

In this study,tri-rutile type Mg_(0.5)Ti_(0.5)TaO_(4) ceramics were synthesized,where the structure–property relationship,especially the structural configuration and intrinsic dielectric origin of Mg_(0.5)Ti_(0.5)TaO_(4) ceramics,and the low-firing characteristics were *** is found that the tri-rutile structural type is unambiguously identified through the Rietveld refinement analysis,the selected area electron diffraction(SAED),and the high-resolution transmission electron microscopy(HRTEM)along the[110]zone *** the increase in sintering temperature,the densification and uniformity of crystal growth play important roles in regulating the microwave dielectric properties of Mg_(0.5)Ti_(0.5)TaO_(4) ***,theoretical dielectric properties calculated by the far-infrared reflective spectra approached the experimental values,indicating the importance of structural features to dielectric ***,a glass additive with high matching relevance with ceramics has been developed to decrease the high sintering temperature of Mg_(0.5)Ti_(0.5)TaO_(4) ceramics,where 2–4 wt%Li_(2)O–MgO–ZnO–B_(2)O_(3)–SiO_(2)(LMZBS)glass frit was adopted to reduce the suitable temperature from 1275 to 1050℃ without significantly deteriorating the microwave dielectric ***,Mg_(0.5)Ti_(0.5)TaO_(4) ceramics containing 2 wt% glass addition sintered at 1050℃for 4 h possess excellent microwave dielectric properties:dielectric constant(ε_(r))=44.3,quality factor multiplied by resonant frequency(Q×f)=23,820 GHz(f=6.2 GHz),and the temperature coefficient of resonant frequency(τ_(f))=123.2 ppm/℃.

关键词： Mg0.5Ti0.5TaO4 ceramics crystal structure low-temperature sintering

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Constructing Br-Doped Li_(10)SnP_(2)S_(12)-Based All-Solid-State Batteries with Superior Performances

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Energy Material Advances 2023年第1期4卷 500-511页

作者： Qiyue Luo Liang Ming Dong Zhang Chaochao Wei Zhongkai Wu Ziling Jiang Chen Liu Shiyu Liu Kecheng Cao Long Zhang Chuang Yu Shijie Cheng State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074P.R.China School of Chemistry and Chemical Engineering Huazhong University of Science and TechnologyWuhan 430074P.R.China School of Physical Science and Technology&Shanghai Key Laboratory of High-resolution Electron Microscopy Shanghai Tech UniversityShanghai 201210P.R.China Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074P.R.China College of Physics and Energy Fujian Normal UniversityFuzhou 350117P.R.China

Ionic conductivity and electro/chemical compatibility of Li_(10)SnP_(2)S_(12) electrolytes play crucial roles in achieving superior electrochemical performances of the corresponding solid-state ***,the relatively low Li-ion conductivity and poor stability of Li_(10)SnP_(2)S_(12) toward high-voltage layered oxide cathodes limit its ***,a Br-substituted strategy has been applied to promote Li-ion *** optimal composition of Li_(9.9)SnP_(2)S_(11.9)Br_(0.1) delivers high conductivity up to 6.0 mS cm^(−1).7Li static spin-lattice relaxation(T1)nuclear magnetic resonance(NMR)and density functional theory simulation are combined to unravel the improvement of Li-ion diffusion mechanism for the modified *** mitigate the interfacial stability between the Li_(9.9)SnP_(2)S_(11.9)Br_(0.1) electrolyte and the bare LiNi_(0.7)Co_(0.1)Mn_(0.2)O_(2) cathode,introducing Li_(2)ZrO_(3) coating layer and Li_(3)InCl_(6) isolating layer strategies has been employed to fabricate all-solid-state lithium batteries with excellent electrochemical *** Li_(3)InCl_(6)-LiNi_(0.7)Co_(0.1)Mn_(0.2)O_(2)/Li_(3)InCl_(6)/Li_(9.9)SnP_(2)S_(11.9)Br_(0.1)/Li-In battery delivers much higher discharge capacities and fast capacity degradations at different charge/discharge C rates,while the Li_(2)ZrO_(3)@LiNi_(0.7)Co_(0.1)Mn_(0.2)O_(2)/Li_(9.9)SnP_(2)S_(11.9)Br_(0.1)/Li-In battery shows slightly lower discharge capacities at the same C rates and superior cycling *** characterization methods are conducted to reveal the differences of battery *** poor electrochemical performance of the latter battery configuration is associated with the interfacial instability between the Li_(3)InCl_(6) electrolyte and the Li_(9.9)SnP_(2)S_(11.9)Br_(0.1) *** work offers an effective strategy to constructing Li_(10)SnP_(2)S_(12)-based all-solid-state lithium batteries with high capacities and superior cyclabilities.

关键词： battery electrolyte conductivity

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Design of a 13 Tesla Hybrid Magnet

Design of a 13 Tesla Hybrid Magnet

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International Conference on Applied Superconductivity and electromagnetic Devices, ASEMD

作者： Zhixing Yang Li Ren Pu Duan Ying Xu Jing Shi The State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

The Iron-based superconductors(IBS) have high upper critical field, low anisotropy and strong current carrying capacity, which are expected to be the next-generation high temperature superconductors. This paper describes a 13 Tesla hybrid magnet using YBCO tapes and iron-based tapes. The design approach is aimed at verifying the superiority of Iron-based superconducting tapes using a shorter length of IBS tapes. The support structure is designed to improve the mechanical stability of magnets. Through mechanical analysis, it is verified that the magnet meets the design requirements and the operation stability.

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High Efficiency Hybrid Synchronous Motor Design with Loss Analysis for a Two-Speed e-Powertrain System in Electric Vehicle

High Efficiency Hybrid Synchronous Motor Design with Loss An...

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IEEE International Conference on Electric Machines and Drives (IEMDC)

作者： Shun Feng Ronghai Qu School of Electrical and Electronic Engineering State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

With high efficiency and high flux-weakening capability, hybrid synchronous motor (HSM) is a competitive alternative as a cost-effective solution for traction applications. This paper presents a cascaded and systematic method to define specifications of target motor and design a high efficiency 172 kW, 18000 rpm HSM for a two-speed e-Powertrain system. Vehicle-level specifications and gear ratio combinations are taken into consideration to determine motor requirements. Four concept rotor typologies are investigated to obtain efficiency maps for comparisons in simulation models. Detailed loss analyses are done at both base speed and maximum speed for a selected HSM. 0.2 mm stator lamination and 4 segmented magnets in each magnet slot have been applied to further improve motor maximum efficiency. Performance tests are completed in the dyne bay to show that 97.5% maximum efficiency is achieved.

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Research on Direct Voltage Control of High-Speed FESS Based on Low SFFR 3

Research on Direct Voltage Control of High-Speed FESS Based ...

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3rd IEEE China International Youth Conference on Electrical engineering, CIYCEE 2022

作者： Zhao, Sifeng Ye, Caiyong Wan, Shanming State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China Dunshi Magnetic Energy Technology Co. Ltd. Shijiazhuang050000 China

ISBN: (数字)9781665477321

ISBN: (纸本)9781665477321

The low switching-to-fundamental frequency ratio (SFFR) control strategy is adopted when the high-speed flywheel energy storage system (FESS) is used in urban rail transit system to provide network stability and regenerative braking energy recovery. The performance of the current control will be deteriorated or even the system instability may occur under low SFFR strategy. In this paper, a Low SFFR based direct voltage control strategy is proposed according to the unique characteristics of the high-speed FESS. The feasibility of the proposed method is analyzed, and the control parameters and the midpoint voltage balance method are designed. The effectiveness of the current stability and midpoint voltage balance is verified through simulations and experiments. © 2022 IEEE.

关键词： Light rail transit

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A Novel Variable Impedance Design Concept of PM Fault Tolerant Machine

A Novel Variable Impedance Design Concept of PM Fault Tolera...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Runyu Wang Dawei Li Xinggang Fan Ronghai Qu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

A novel variable impedance fault tolerant design concept is proposed in this paper for high reliable PM machines. The special fault tolerant ring structure realizes the automatic transformation of the machine from low impedance in healthy operation to ultra-high impedance in fault operation, which effectively suppresses the short-circuit current. First, the design guidelines for fault tolerant ring and the fault tolerance mechanism of variable impedance are introduced. Subsequently, two variable impedance machine topologies with separated and integrated fault tolerant rings are investigated. Finally, the prototypes are fabricated and the experimental results show that the proposed variable impedance topology has a turn-to-turn short-circuit current suppression capability that far exceeds that of the conventional fault tolerant topology.

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Nonlinear Multiscale Modeling of Multi-Machine Power Systems Integrated with Photovoltaics

Nonlinear Multiscale Modeling of Multi-Machine Power Systems...

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PELS Students and Young Professionals Symposium (SYPS), IEEE

作者： Jiaqi Wu Miao Han Meng Zhan School of Electrical and Electronic Engineering State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

Large-scale photovoltaics (PVs) connected to the power grid through power electronic equipment have greatly changed the dynamics of the traditional power systems dominated by synchronous generators (SGs), bringing significant challenges to modeling and analysis of modern power systems. In this paper, a nonlinear model of multi-machine power systems integrated with PVs is established to reveal the multi-timescale transient synchronization characteristics using the singular perturbation technique. The fast subsystem containing the dynamics of the DC voltage control, terminal voltage control, and phase-locked loop, and the slow subsystem containing the dynamics of the rotor swing can effectively reflect the dynamics of multi-machine power systems integrated with PVs within the electromagnetic and electromechanical timescales, respectively. The proposed model provides a clearer physical picture of dynamics in the multi-machine power systems integrated with PVs within the electromagnetic and electromechanical timescales, and serves as the foundational model for further stability analysis. Finally, simulation results verify the validity of the proposed model.

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Efficiency Estimates of Integrated Two-Speed e-Powertrain System under WLTP Driving Cycle for Electric Vehicle

Efficiency Estimates of Integrated Two-Speed e-Powertrain Sy...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Shun Feng Ronghai Qu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

Efficiency is always one of key metrics for electric powertrain system to make the most of battery stored energy and boost electric vehicle’s range. This paper presents a systematic method to estimate efficiency capability for an integrated two-speed e-Powertrain system. Overall system is modelled in MATLAB/Simulink. Inverter power, voltage and current requirements are defined from system specifications. Inverter losses, efficiencies and thermal conditions are investigated at switching frequencies of SkHz and 12kHz. With both traction motor and gearbox efficiency maps, 93.2% system peak efficiency and 90.2% Worldwide Harmonized Light Vehicle Test Procedure (WLTP) Class 3b driving cycle efficiency are obtained to verify that design targets are met in simulations. A prototype is built to validate system efficiency performance in the thermal chamber during tests.

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