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Reliability evaluation of IGBT power module on electric vehicle using big data

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Journal of Semico.ductors 2024年第5期45卷 50-60页

作者： Li Liu Lei Tang Huaping Jiang Fanyi Wei Zonghua Li Changhong Du Qianlei Peng Guocheng Lu The School of Electrical Engineering Chongqing UniversityChongqing 400044China The Deepal Automobile Technology co. Ltd.Chongqing 400023China

There are challenges to the reliability evaluation for insulated gate bipolar transistors(IGBT)on electric vehicles,such as junction temperature measurement,co.putational and storage resources.In this paper,a junction temperature estimation approach based on neural network without additional co.t is proposed and the lifetime calculation for IGBT using electric vehicle big data is performed.The direct current(DC)voltage,operation current,switching frequency,negative thermal co.fficient thermistor(NTC)temperature and IGBT lifetime are inputs.And the junction temperature(T_(j))is output.With the rain flow co.nting method,the classified irregular temperatures are brought into the life model for the failure cycles.The fatigue accumulation method is then used to calculate the IGBT lifetime.To solve the limited co.putational and storage resources of electric vehicle co.trollers,the operation of IGBT lifetime calculation is running on a big data platform.The lifetime is then transmitted wirelessly to electric vehicles as input for neural network.Thus the junction temperature of IGBT under long-term operating co.ditions can be accurately estimated.A test platform of the motor co.troller co.bined with the vehicle big data server is built for the IGBT accelerated aging test.Subsequently,the IGBT lifetime predictions are derived from the junction temperature estimation by the neural network method and the thermal network method.The experiment shows that the lifetime prediction based on a neural network with big data demonstrates a higher accuracy than that of the thermal network,which improves the reliability evaluation of system.

关键词： IGBT junction temperature neural network electric vehicles big data

Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

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Journal of Magnesium and Alloys 2024年第4期12卷 1449-1460页

作者： Guishang Pei Cheng Pan Dapeng Zhong Junyi Xiang Xuewei Lv co.lege of Materials Science and Engineering Chongqing UniversityChongqing 400044China chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China Pangang group Research Institute co. Ltd.Panzhihua 617000China

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted co.siderable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air atmosphere.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kJ/mol.The endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kJ/mol,which is related to the inco.gruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high temperatures.The cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is co.trolled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating rate.Additionally,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(J mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

关键词： MgV_(2)O_(6) Crystal structure Phase transitions Thermodynamic functions

Three-dimensional parametric co.tact analysis of planetary roller screw mechanism and its application in grouping for selective assembly

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Frontiers of Mechanical Engineering 2024年第1期19卷 53-72页

作者： Huilin HE Peitang WEI Huaiju LIU Xuesong DU Rui HU Genshen LIU Yajun WU State Key Laboratory of Mechanical Transmission for Advanced Equipment Chongqing UniversityChongqing 400044China Taiyuan Heavy Machinery group co. Ltd.Taiyuan 030024China

The planetary roller screw mechanism(PRSM)is a novel precision transmission mechanism that realizes the co.version between linear and rotary motions.The co.tact characteristics of helical surfaces directly determine PRSM’s performance in load-carrying capacity and transmission accuracy.Therefore,studying the co.tact characteristics of PRSM forms the fundamental basis for enhancing its transmission performance.In this study,a three-dimensional parametric analysis method of co.tact characteristics is proposed based on the PRSM meshing principle and PyVista(a high-level API to the Visualization Toolkit).The proposed method co.siders the influence of machining errors among various thread teeth.The effects of key machining errors on co.tact positions and axial clearance,as well as their sensitivities,are analyzed.With excellent solution accuracy,this method exhibits higher calculation efficiency and stronger robustness than the analytical and numerical meshing models.The influence of nominal diameter and pitch errors of the screw,roller,and nut on the axial clearance follows a linear relationship,whereas flank angle errors have negligible effects on the axial clearance.The co.responding influence co.fficients for these three machining errors on the axial clearance are 0.623,0.341,and 0.036.The variations in co.tact positions caused by individual errors are axisymmetric.Flank angle errors and roller diameter errors result in linear displacements of the co.tact points,whereas pitch errors cause the co.tact points to move along the arc of the roller diameter.Based on the proposed threedimensional parametric co.tact characteristics analysis method,the Fuzzy C-Means clustering algorithm co.sidering error sensitivity is utilized to establish a co.ponent grouping technique in the selective assembly of critical PRSM co.ponents,ensuring the rational and co.sistent clearances based on the given co.ponent’s machining errors.This study provides effective guidance for analyzing co.tact characteristics and grouping in selective ass

关键词： planetary roller screw mechanism(PRSM) co.tact position axial clearance machining error grouping for selective assembly

Interfacial reaction between AZ91D magnesium alloy melt and mild steel under high temperature

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China Foundry 2024年第2期21卷 159-167页

作者： Jia-hong Dai Jian-yue Zhang Bin Jiang Xiang-jun Xu Zhong-tao Jiang Hong-mei Xie Qing-shan Yang Guo-qing Zhang co.lege of Materials Science and Engineering Yangtze Normal UniversityChongqing 408100China National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China chongqing Jiulongyuan High-tech Industry group co. Ltd.Chongqing 400080China Loncin Industry co. Ltd.Chongqing 400080China Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA chongqing Key Laboratory of Materials Surface&Interface Science Chongqing University of Arts and SciencesChongqing 402160China School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing 401331China

The metallurgical quality co.trol of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and co.rosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting process.Therefore,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is necessary.In the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild steel.Meanwhile,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and AZ91D.AlFe_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg matrix.It is found that the growth of the intermetallic layer is co.trolled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction process.By measuring the thickness of different layers,the growth co.stant was calculated.It increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the co.tent of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe co.tent of AZ91D than holding time.

关键词： AZ91D mild steel interface reaction intermetallic growth kinetics

co.pled heat and moisture transfer in walls featuring moisture-buffering materials and ventilating layers:An Experimental study

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Energy and Built Environment

Energy and Built Environment 2024年第1期5卷 97-109页

作者： Xueqiong He Chi Feng Huibo Zhang School of Design Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Research Institute of Building Sciences group co. LtdShanghai 200032China School of Architecture and Urban Planning Chongqing UniversityChongqing 400045China

The moisture performance of building envelopes largely depends on the building materials,co.struction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can help dehumidify the wall and indoor air.This paper presents an experimental study of the heat,air,and moisture variations within the envelope wall of a chamber featuring different air interlayer settings under real outdoor air co.ditions during the summer of 2020 in Shanghai,China.Self-developed humidity-co.trolling building mate-rials were applied to the inner building envelope.Temperature,humidity,wind velocity,and heat-flow sensors were placed at different positions in the middle of the wall.These parameters were measured and reco.ded in real-time under three working co.ditions:humidification,dehumidification,and ventilation.The experimental results show that under the ventilation working co.ditions,moisture co.tent of 0.52 kg can be removed after a 2-h air layer ventilation,which can benefit the design strategy for the humidification and ventilation of dehu-midification walls.

关键词： Ventilated wall Heat and humidity co.pling transfer Moisture-buffering materials Experimental research

Laminar Flame Instability of n-Hexane,n-Octane,and n-Decane in Spherical Expanding Flames

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Journal of Thermal Science 2024年第3期33卷 1189-1199页

作者： YIN Geyuan HU Erjiang LI Xiaotian LV Xin HUANG Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China United Automotive Electronic Systems co. LtdShanghai201206China chongqing Changan Automobile co. Ltd.Chongqing401120China

This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and n-decane.The experiment was carried out in a co.stant volume co.bustion bomb to get the flame images.The critical radius under different co.ditions was extracted using the image processing program.co.bined with the existing critical Peclet number theory,the dominant factors of flame instability under current co.ditions for three n-alkanes can be figured out.Moreover,the average cell size(equivalent cell radius,R_(cell))was extracted to provide quantitative analysis of the flame cellular structure,based on the method developed in this work.The theoretical R_(cell)were also calculated and co.pared with the experimental results to validate the proposed method.

关键词： cellular instability equivalent cell radius critical Peclet number spherical flame

Calcium-chelating peptides from rabbit bone co.lagen:characterization,identification and mechanism elucidation

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Food Science and Human Wellness 2024年第3期13卷 1485-1493页

作者： Fuhuan Yuan Yu Fu Liang Ma Hankun Zhu Yong Yu Xin Feng Yi Sun Hongjie Dai Xin Liu Zhengfang Liu Yuhao Zhang co.lege of Food Science Southwest UniversityChongqing 400715China chongqing Key Laboratory of Speciality Food co.Built by Sichuan and chongqing Chongqing 400715China Key Laboratory of Luminescence Analysis and Molecular Sensing(Southwest University) Ministry of EducationChongqing 400715China Angel Yeast co. Ltd.Yichang 443003China

This study aimed to characterize and identify calcium-chelating peptides from rabbit bone co.lagen and explore the underlying chelating mechanism.co.lagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)co.bined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode acco.nted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.

关键词： Rabbit bone co.lagen peptide Peptide-calcium chelate Chelation mechanism Liquid chromatography-tandem mass(LC-MS/MS)

Optimization of a Pipeline-Type Savonius Hydraulic Turbine

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1123-1146页

作者： Xiaohui Wang Kai Zhang Xiaobang Bai Senchun Miao Zanxiu Wu Jicheng Li School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou730050China Postdoctoral Station of Civil Engineering Lanzhou University of TechnologyLanzhou730050China Postdoctoral Research Station of Xinxiang Aviation Industry(group)co. Ltd.Xinxiang453000China chongqing Pump Industry co. Ltd.Chongqing404100China

This study focuses on a DN50 pipeline-type Savonius hydraulic turbine.The torque variation of the turbine in a rotation cycle is analyzed theoretically in the framework of the plane potential flow theory.Related numerical simulations show that the change in turbine torque is co.sistent with the theoretical analysis,with the main power zone and the seco.dary power zone exhibiting a positive torque.In co.trast,the primary resistance zone and the seco.dary resistance zone are characterized by a negative torque.Analytical relationships between the turbine’s internal flow angleθ,the deflector’s inclination angleα0,and the co.erage angleαof the power zone are introduced,and a method for calculating the optimal number of blades is proposed to maximize the power zone.Results are presented about performance tests co.ducted on five groups of hydraulic turbines with the blade number ranging from 3 to 7.Such results indicate that both the turbine’s reco.ery power and efficiency attain the highest values when the blade number is 4,which is in agreement with the number of blades calculated by the proposed method.Additionally,the study examines the effects of the flow rate on turbine parameters and the projected energy generation and co.t savings for a specific pipeline co.figuration.

关键词： Savonius turbine blade number numerical simulation experimental study benefit prediction

IHVFL: a privacy-enhanced intention-hiding vertical federated learning framework for medical data

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Cybersecurity 2024年第2期7卷 96-112页

作者： Fei Tang Shikai Liang Guowei Ling Jinyong Shan co.lege of co.puter Science and Technology Chongqing University of Posts and TelecommunicationsNo.2Chongwen RoadNan'an DistrictChongqing 400065China School of Cyber Security and Information Law Chongqing University of Posts and TelecommunicationsChongqing 400065China sudo Technology co. LTD.Beijing 100083China

Vertical Federated Learning(VFL)has many applications in the field of smart healthcare with excellent performance.However,current VFL systems usually primarily focus on the privacy protection during model training,while the preparation of training data receives little attention.In real-world applications,like smart healthcare,the process of the training data preparation may involve some participant's intention which co.ld be privacy information for this partici-pant.To protect the privacy of the model training intention,we describe the idea of Intention-Hiding Vertical Feder-ated Learning(IHVFL)and illustrate a framework to achieve this privacy-preserving goal.First,we co.struct two secure screening protoco.s to enhance the privacy protection in feature engineering.Seco.d,we implement the work of sample alignment bases on a novel private set intersection protoco..Finally,we use the logistic regression algorithm to demonstrate the process of IHVFL.Experiments show that our model can perform better efficiency(less than 5min)and accuracy(97%)on Breast Cancer medical dataset while maintaining the intention-hiding goal.

关键词： Medical data Vertical federated learning Privacy-presserving Intention-hiding Logistic regression