This study examines the influence of magnetic field and temperature on the transient voltage of a polycrystalline silicon radial junction solar cell in a dynamic regime under multispectral illumination. Radial junctio...This study examines the influence of magnetic field and temperature on the transient voltage of a polycrystalline silicon radial junction solar cell in a dynamic regime under multispectral illumination. Radial junction solar cells represent a major advancement in photovoltaic technologies, as they optimize light absorption and charge collection efficiency. The focus is on the impact of the magnetic field and temperature on the decay of transient voltage, which provides crucial information on recombination processes and the lifetime of minority carriers. The results reveal that the magnetic field tends to increase the transient voltage by directly affecting the transient electron density. Indeed, for B > 7 × 10−5 T, the magnetic field prolongs the relaxation time by increasing the transient voltage amplitude. Additionally, rising temperatures accelerate (ranging from 290 K to 450 K) recombination processes, thereby reducing the transient voltage, although this effect is moderated by the presence of a magnetic field. The study highlights the complex interaction between magnetic field and temperature, with significant impacts on the transient behaviour.展开更多
The power module of the Insulated Gate Bipolar Transistor(IGBT)is the core component of the traction transmission system of high-speed trains.The module's junction temperature is a critical factor in determining d...The power module of the Insulated Gate Bipolar Transistor(IGBT)is the core component of the traction transmission system of high-speed trains.The module's junction temperature is a critical factor in determining device reliability.Existing temperature monitoring methods based on the electro-thermal coupling model have limitations,such as ignoring device interactions and high computational complexity.To address these issues,an analysis of the parameters influencing IGBT failure is conducted,and a temperature monitoring method based on the Macro-Micro Attention Long Short-Term Memory(MMALSTM)recursive neural network is proposed,which takes the forward voltage drop and collector current as features.Compared with the traditional electricalthermal coupling model method,it requires fewer monitoring parameters and eliminates the complex loss calculation and equivalent thermal resistance network establishment process.The simulation model of a highspeed train traction system has been established to explore the accuracy and efficiency of MMALSTM-based prediction methods for IGBT power module junction temperature.The simulation outcomes,which deviate only 3.2% from the theoretical calculation results of the electric-thermal coupling model,confirm the reliability of this approach for predicting the temperature of IGBT power modules.展开更多
The current-voltage characteristics of 4H-SiC junction barrier Schottky （JBS） diodes terminated by an offset field plate have been measured in the temperature range of 25-300℃. An experimental barrier height value ...The current-voltage characteristics of 4H-SiC junction barrier Schottky （JBS） diodes terminated by an offset field plate have been measured in the temperature range of 25-300℃. An experimental barrier height value of about 0.5 eV is obtained for the Ti/4H-SiC JBS diodes at room temperature. A decrease in the experimental barrier height and an increase in the ideality factor with decreasing temperature are shown. Reverse recovery testing also shows the temperature dependence of the peak recovery current density and the reverse recovery time. Finally, a discussion of reducing the reverse recovery time is presented.展开更多
The Shatsky Rise ridge-ridge-ridge triple junction is an ancient triple junction in the Western Pacific Ocean whose initial geodynamic process is poorly understood and can only be inferred based on indirect geological...The Shatsky Rise ridge-ridge-ridge triple junction is an ancient triple junction in the Western Pacific Ocean whose initial geodynamic process is poorly understood and can only be inferred based on indirect geological and geophysical constraints.In this paper,we present three-dimensional numerical models that simulate the Shatsky Rise triple junction and calculate its coupled mantle flow and temperature structure.The mantle flow velocity field shows several distinctive features:1)stronger mantle upwelling closer to the ridge axis and triple junction;2)greater upwelling velocity at the faster-spreading ridges;and 3)the most significant increase in upwelling velocity for the slowest-spreading ridge toward the triple junction.The calculated mantle temperature field also reveals distinctive characteristics:1)sharp increases in the mantle temperature with depth and increases toward the spreading ridges and triple junction;2)the faster-spreading ridges are associated with higher temperatures at depth and identical distances from the triple junction;and 3)the slowest-spreading ridge shows the greatest increase in the along-ridge-axis temperature toward the triple junction.Compared to many present-day triple junctions with slower spreading rates,the along-ridge-axis velocity and thermal fields of the Shatsky Rise are more altered due to the presence of the triple junction.展开更多
Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJ...Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJTCs(heated junction thermocouples)are widely used for this purpose due to their ability to withstand extreme temperatures and radiation conditions.This article explores the role of HJTCs in reactor water level measurement and compares the performance of 2-wire and 3-wire connections.While the 2-wire connection is simple and cost-effective,it can introduce measurement inaccuracies due to wire resistance.In contrast,the 3-wire connection compensates for lead resistance,offering more precise and reliable measurements,particularly in long-distance applications.This paper discusses the operational considerations of these wiring configurations in the context of nuclear reactors and highlights the importance of choosing the appropriate connection type to optimize safety and measurement accuracy in PWR and BWR reactors.展开更多
A universal and low-cost temperature thermometer is realized via a special circuit,integrated circuit chip with microprocessor and analog to digital converter,and digital bus interface.Various thermocouples and resist...A universal and low-cost temperature thermometer is realized via a special circuit,integrated circuit chip with microprocessor and analog to digital converter,and digital bus interface.Various thermocouples and resistance temperature detectors used for temperature sensing may be connected to same thermometer.A special signal condition circuitry is designed and a matching algorithm is proposed.A novel calibration method named disassembled calibration is proposed in order to enhance efficiency and flexibility for the whole system.Additionally,it presents a combination method of low order polynomial fitting and piecewise linearity for the nonlinearity calibration of the thermocouple and the resistance temperature detector.A cold junction compensation based on digital way is described.And the matching algorithm and calibration method may eliminate errors stemming from excitation voltage source and reference voltage source,and can weaken quantization error of analog to digital converter and drift of components,too.Furthermore,the 400 times oversampling is completed by sequential and equal interval sampling to upgrade accuracy of analog to digital converter from original 12 to 15 bits and to raise signal-to-noise ratio.Finally,during a long time monitoring,experiment results show that errors at each static point are less than±0.2°C for the thermocouple system and less than±0.1°C for the resistance temperature detector system.展开更多
This work deals with determining the optimum thickness of the lamella wafer of silicon solar cell. The (p) base region makes up the bulk of the thickness of the wafer. This thickness has always been a factor limiting ...This work deals with determining the optimum thickness of the lamella wafer of silicon solar cell. The (p) base region makes up the bulk of the thickness of the wafer. This thickness has always been a factor limiting the performance of the solar cell, as it produces the maximum amount of electrical charges, contributing to the photocurrent. Determining the thickness of the wafer cannot be only mechanical. It takes into account the internal physical mechanisms of generation-diffusion-recombination of excess minority carriers. They are also influenced by external factors such as temperature and magnetic field. Under these conditions, magneto transport equation is required to be applied on excess minority carrier in lamella base silicon solar cell. It yields maximum diffusion coefficient which result on Lorentz law and Umklapp process. Then from photocurrent, back surface recombination velocity expressions are derived, both maximum diffusion coefficient and thickness dependent. The plot of the back surface recombination calibration curves as function of lamella width, leads to its maximum values, trough intercept points. Lamella optimum width is then obtained, both temperature and magnetic field dependent and expressed in relationships to show the required base thickness in the elaboration process.展开更多
Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,...Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO_(2)(p-n junction)and Ti_(3)C_(2)T_(x) MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO_(2),forming in-situ p-n junctions on the surface of Sn O.The hamburger-like SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensor exhibited improved acetone gas sensing response of 12.1(R_(g)/R_(a))at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti_(3)C_(2)T_(x) and pristine SnO-SnO_(2),respectively.Moreover,it expressed a short recovery time(9 s)and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti_(3)C_(2)T_(x) nanosheets,acting as a hole accumulation layer(HALs)between Ti_(3)C_(2)T_(x) and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti_(3)C_(2)T_(x) MXene in SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensors was discussed in detail.展开更多
With the rapid development of the world economy,IGBT has been widely used in motor drive and electric energy conversion.In order to timely detect the fatigue damage of IGBT,it is necessary to monitor the junction temp...With the rapid development of the world economy,IGBT has been widely used in motor drive and electric energy conversion.In order to timely detect the fatigue damage of IGBT,it is necessary to monitor the junction temperature of IGBT.In order to realize the fast calculation of IGBT junction temperature,a finite element method of IGBT temperature field reduction is proposed in this paper.Firstly,the finite element calculation process of IGBT temperature field is introduced and the linear equations of finite element calculation of temperature field are derived.Temperature field data of different working conditions are obtained by finite element simulation to form the sample space.Then the covariance matrix of the sample space is constructed,whose proper orthogonal decomposition and modal extraction are carried out.Reasonable basis vector space is selected to complete the low dimensional expression of temperature vector inside and outside the sample space.Finally,the reduced-order model of temperature field finite element is obtained and solved.The results of the reduced order model are compared with those of the finite element method,and the performance of the reduced-order model is evaluated from two aspects of accuracy and rapidity.展开更多
Online temperature monitoring of IGBTs is a crucial means to enhance the reliability of high-power converters.In the existing thermal model methods,the junction temperature is derived through the device power loss,whi...Online temperature monitoring of IGBTs is a crucial means to enhance the reliability of high-power converters.In the existing thermal model methods,the junction temperature is derived through the device power loss,which is difficult to obtain accurately in real time.This paper proposes a power loss observer to estimate the real-time power loss accurately.Unlike conventional methods,the proposed method only needs measure the heatsink temperature.Moreover,the proposed technique is robust to disturbances such as wind speed fluctuations,solder aging,and temperature dependence of thermal parameters,which helps to improve the temperature estimation accuracy throughout the full life cycle of IGBT modules.This paper analyzes the proposed method’s mathematical principle,algorithm,and implementation steps,while the loss observer is validated by simulation and experiment.展开更多
In power electronics applications,the selection of condition monitoring methods significantly affects both the precision and complexity of the junction temperature evaluation,which is essential for the reliability ass...In power electronics applications,the selection of condition monitoring methods significantly affects both the precision and complexity of the junction temperature evaluation,which is essential for the reliability assessment of power semiconductor devices.This study begins with a failure mechanism analysis of state-of-the-art power semiconductor devices.Junction temperature measurement methods can be categorized into three distinct approaches:thermal image-based,thermal model-based,and temperature-sensitive electrical parameter(TSEP)-based methods.Their respective advantages and disadvantages are comprehensively compared.Moreover,condition monitoring of the ON-state voltage drop is summarized and benchmarked.ON-state voltage and junction temperature measurements are experimentally demonstrated in a standard three-phase converter,which provides superior measurement accuracy and rapid dynamic response characteristics.Additionally,this investigation is extended to measurement methods for TSEP in wide-bandgap semiconductors.展开更多
The Insulated-Gate Bipolar Transistor(IGBT)module is the core of the three-level(3L)traction converter.In order to improve the lifetime of the traction converter,a model predictive torque control(MPTC)based on the jun...The Insulated-Gate Bipolar Transistor(IGBT)module is the core of the three-level(3L)traction converter.In order to improve the lifetime of the traction converter,a model predictive torque control(MPTC)based on the junction temperature constraint is proposed.Firstly,the optimization range is reduced by judging the sector where the reference voltage vector locates,as the traditional MPTC needs to be optimized 27 times in each sampling period,which requires a large amount of calculation.Secondly,by simplifying the calculation of IGBT power loss and dynamically constraining it in the cost function,the performance of optimal voltage vector balancing control can be balanced with power loss.Simulation results show that the proposed method reduces the junction temperature of the power semiconductor and prolongs the converter lifetime compared with the traditional strategy.展开更多
It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentra...It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>展开更多
The ac recombination velocity of the excess minority carriers, in the back surface of a silicon solar cell with a vertical junction connected in series, is developed through Einstein’s law giving the diffusion coeffi...The ac recombination velocity of the excess minority carriers, in the back surface of a silicon solar cell with a vertical junction connected in series, is developed through Einstein’s law giving the diffusion coefficient of minority carriers according to temperature, through mobility. The frequency spectrum of both, amplitude and phase, are produced for the diffusion coefficient and the recombination velocity in the rear face, in order to identify the parameters of equivalent electric models.展开更多
文摘This study examines the influence of magnetic field and temperature on the transient voltage of a polycrystalline silicon radial junction solar cell in a dynamic regime under multispectral illumination. Radial junction solar cells represent a major advancement in photovoltaic technologies, as they optimize light absorption and charge collection efficiency. The focus is on the impact of the magnetic field and temperature on the decay of transient voltage, which provides crucial information on recombination processes and the lifetime of minority carriers. The results reveal that the magnetic field tends to increase the transient voltage by directly affecting the transient electron density. Indeed, for B > 7 × 10−5 T, the magnetic field prolongs the relaxation time by increasing the transient voltage amplitude. Additionally, rising temperatures accelerate (ranging from 290 K to 450 K) recombination processes, thereby reducing the transient voltage, although this effect is moderated by the presence of a magnetic field. The study highlights the complex interaction between magnetic field and temperature, with significant impacts on the transient behaviour.
基金supported by the Science and Technology Project of the Headquarters of the State Grid Corporation of China(52199922001U).
文摘The power module of the Insulated Gate Bipolar Transistor(IGBT)is the core component of the traction transmission system of high-speed trains.The module's junction temperature is a critical factor in determining device reliability.Existing temperature monitoring methods based on the electro-thermal coupling model have limitations,such as ignoring device interactions and high computational complexity.To address these issues,an analysis of the parameters influencing IGBT failure is conducted,and a temperature monitoring method based on the Macro-Micro Attention Long Short-Term Memory(MMALSTM)recursive neural network is proposed,which takes the forward voltage drop and collector current as features.Compared with the traditional electricalthermal coupling model method,it requires fewer monitoring parameters and eliminates the complex loss calculation and equivalent thermal resistance network establishment process.The simulation model of a highspeed train traction system has been established to explore the accuracy and efficiency of MMALSTM-based prediction methods for IGBT power module junction temperature.The simulation outcomes,which deviate only 3.2% from the theoretical calculation results of the electric-thermal coupling model,confirm the reliability of this approach for predicting the temperature of IGBT power modules.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61006060)the 13115 Innovation Engineering of Shaanxi, China (Grant No. 2008ZDKG-30)the Key Laboratory Fund of Ministry of Education, China (Grant No. JY0100112501)
文摘The current-voltage characteristics of 4H-SiC junction barrier Schottky （JBS） diodes terminated by an offset field plate have been measured in the temperature range of 25-300℃. An experimental barrier height value of about 0.5 eV is obtained for the Ti/4H-SiC JBS diodes at room temperature. A decrease in the experimental barrier height and an increase in the ideality factor with decreasing temperature are shown. Reverse recovery testing also shows the temperature dependence of the peak recovery current density and the reverse recovery time. Finally, a discussion of reducing the reverse recovery time is presented.
基金This research was supported by the National Key R&D Program of China(No.2018YFC0309800)the China Ocean Mineral Resources R&D Association(No.DY135S2-1-04)+4 种基金the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD 0205)the Guangdong Basic and Applied Basic Research Foundation(Nos.2021B1515020098 and 2021A1515012227)the National Natural Science Foundation of China(Nos.41776058,41890813,41976066,91858207 and 41806067)the Chinese Academy of Sciences(Nos.ISEE2019ZR01,QYZDY-SSW-DQC005,133244KYSB20180029,131551KYSB20200021,Y4SL021001,and XDB41000000)the China National Space Administration(No.D020303).
文摘The Shatsky Rise ridge-ridge-ridge triple junction is an ancient triple junction in the Western Pacific Ocean whose initial geodynamic process is poorly understood and can only be inferred based on indirect geological and geophysical constraints.In this paper,we present three-dimensional numerical models that simulate the Shatsky Rise triple junction and calculate its coupled mantle flow and temperature structure.The mantle flow velocity field shows several distinctive features:1)stronger mantle upwelling closer to the ridge axis and triple junction;2)greater upwelling velocity at the faster-spreading ridges;and 3)the most significant increase in upwelling velocity for the slowest-spreading ridge toward the triple junction.The calculated mantle temperature field also reveals distinctive characteristics:1)sharp increases in the mantle temperature with depth and increases toward the spreading ridges and triple junction;2)the faster-spreading ridges are associated with higher temperatures at depth and identical distances from the triple junction;and 3)the slowest-spreading ridge shows the greatest increase in the along-ridge-axis temperature toward the triple junction.Compared to many present-day triple junctions with slower spreading rates,the along-ridge-axis velocity and thermal fields of the Shatsky Rise are more altered due to the presence of the triple junction.
文摘Accurate water level measurement in nuclear reactors,particularly in PWRs(pressurized water reactors)and BWRs(boiling water reactors),is essential for ensuring the safety and efficiency of reactor operations.K-type HJTCs(heated junction thermocouples)are widely used for this purpose due to their ability to withstand extreme temperatures and radiation conditions.This article explores the role of HJTCs in reactor water level measurement and compares the performance of 2-wire and 3-wire connections.While the 2-wire connection is simple and cost-effective,it can introduce measurement inaccuracies due to wire resistance.In contrast,the 3-wire connection compensates for lead resistance,offering more precise and reliable measurements,particularly in long-distance applications.This paper discusses the operational considerations of these wiring configurations in the context of nuclear reactors and highlights the importance of choosing the appropriate connection type to optimize safety and measurement accuracy in PWR and BWR reactors.
基金the Beijing Municipal Education Commission Science Technology Fund(No.KM201411232015)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges Under Beijing Municipality(No.IDHT20130519)the National Natural Science Foundation of China(No.61272375)
文摘A universal and low-cost temperature thermometer is realized via a special circuit,integrated circuit chip with microprocessor and analog to digital converter,and digital bus interface.Various thermocouples and resistance temperature detectors used for temperature sensing may be connected to same thermometer.A special signal condition circuitry is designed and a matching algorithm is proposed.A novel calibration method named disassembled calibration is proposed in order to enhance efficiency and flexibility for the whole system.Additionally,it presents a combination method of low order polynomial fitting and piecewise linearity for the nonlinearity calibration of the thermocouple and the resistance temperature detector.A cold junction compensation based on digital way is described.And the matching algorithm and calibration method may eliminate errors stemming from excitation voltage source and reference voltage source,and can weaken quantization error of analog to digital converter and drift of components,too.Furthermore,the 400 times oversampling is completed by sequential and equal interval sampling to upgrade accuracy of analog to digital converter from original 12 to 15 bits and to raise signal-to-noise ratio.Finally,during a long time monitoring,experiment results show that errors at each static point are less than±0.2°C for the thermocouple system and less than±0.1°C for the resistance temperature detector system.
文摘This work deals with determining the optimum thickness of the lamella wafer of silicon solar cell. The (p) base region makes up the bulk of the thickness of the wafer. This thickness has always been a factor limiting the performance of the solar cell, as it produces the maximum amount of electrical charges, contributing to the photocurrent. Determining the thickness of the wafer cannot be only mechanical. It takes into account the internal physical mechanisms of generation-diffusion-recombination of excess minority carriers. They are also influenced by external factors such as temperature and magnetic field. Under these conditions, magneto transport equation is required to be applied on excess minority carrier in lamella base silicon solar cell. It yields maximum diffusion coefficient which result on Lorentz law and Umklapp process. Then from photocurrent, back surface recombination velocity expressions are derived, both maximum diffusion coefficient and thickness dependent. The plot of the back surface recombination calibration curves as function of lamella width, leads to its maximum values, trough intercept points. Lamella optimum width is then obtained, both temperature and magnetic field dependent and expressed in relationships to show the required base thickness in the elaboration process.
基金supported financially by the National Natural Science Foundation of China(Nos.,51572158 and 51972200)the Graduate Innovation Fund of Shaanxi University of Science&Technology+2 种基金funded by the Japan Society for the Promotion of Science(JSPS)Grant-in-Aid for the Scientific Research(KAKENHI Nos.20H00297 and Innovative Area“Mixed Anion”(No.16H06439))the Nippon Sheet Glass Foundation for Materials Science and Engineeringby the Dynamic Alliance for Open Innovations Bridging Human,Environment and Materials,the Cooperative Research Program of“Network Joint Research Center for Materials and Devices”。
文摘Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO_(2)(p-n junction)and Ti_(3)C_(2)T_(x) MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO_(2),forming in-situ p-n junctions on the surface of Sn O.The hamburger-like SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensor exhibited improved acetone gas sensing response of 12.1(R_(g)/R_(a))at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti_(3)C_(2)T_(x) and pristine SnO-SnO_(2),respectively.Moreover,it expressed a short recovery time(9 s)and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti_(3)C_(2)T_(x) nanosheets,acting as a hole accumulation layer(HALs)between Ti_(3)C_(2)T_(x) and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti_(3)C_(2)T_(x) MXene in SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensors was discussed in detail.
基金supported in part by Heilongjiang Provincial Natural Science Foundation of China under Project TD2021E004in part by Ningbo Science and Technology Bureau under S&T Innovation 2025 Major Special Programme with project code 2019B10071。
文摘With the rapid development of the world economy,IGBT has been widely used in motor drive and electric energy conversion.In order to timely detect the fatigue damage of IGBT,it is necessary to monitor the junction temperature of IGBT.In order to realize the fast calculation of IGBT junction temperature,a finite element method of IGBT temperature field reduction is proposed in this paper.Firstly,the finite element calculation process of IGBT temperature field is introduced and the linear equations of finite element calculation of temperature field are derived.Temperature field data of different working conditions are obtained by finite element simulation to form the sample space.Then the covariance matrix of the sample space is constructed,whose proper orthogonal decomposition and modal extraction are carried out.Reasonable basis vector space is selected to complete the low dimensional expression of temperature vector inside and outside the sample space.Finally,the reduced-order model of temperature field finite element is obtained and solved.The results of the reduced order model are compared with those of the finite element method,and the performance of the reduced-order model is evaluated from two aspects of accuracy and rapidity.
基金supported by the National Key Research and Development Program of China(No.2022YFE 0138400)the National Nature Science Foundation of China(No.51925702)Zhejiang Provincial Key R&D Program Project(No.2023C01061).
文摘Online temperature monitoring of IGBTs is a crucial means to enhance the reliability of high-power converters.In the existing thermal model methods,the junction temperature is derived through the device power loss,which is difficult to obtain accurately in real time.This paper proposes a power loss observer to estimate the real-time power loss accurately.Unlike conventional methods,the proposed method only needs measure the heatsink temperature.Moreover,the proposed technique is robust to disturbances such as wind speed fluctuations,solder aging,and temperature dependence of thermal parameters,which helps to improve the temperature estimation accuracy throughout the full life cycle of IGBT modules.This paper analyzes the proposed method’s mathematical principle,algorithm,and implementation steps,while the loss observer is validated by simulation and experiment.
文摘In power electronics applications,the selection of condition monitoring methods significantly affects both the precision and complexity of the junction temperature evaluation,which is essential for the reliability assessment of power semiconductor devices.This study begins with a failure mechanism analysis of state-of-the-art power semiconductor devices.Junction temperature measurement methods can be categorized into three distinct approaches:thermal image-based,thermal model-based,and temperature-sensitive electrical parameter(TSEP)-based methods.Their respective advantages and disadvantages are comprehensively compared.Moreover,condition monitoring of the ON-state voltage drop is summarized and benchmarked.ON-state voltage and junction temperature measurements are experimentally demonstrated in a standard three-phase converter,which provides superior measurement accuracy and rapid dynamic response characteristics.Additionally,this investigation is extended to measurement methods for TSEP in wide-bandgap semiconductors.
基金supported by the following funding:Hunan Provincial Department of Education Outstanding Youth Project(Grant No.24B0025)Regional Joint Fund Project of Hunan Province(Grant No.2025JJ70036)National Natural Science Foundation of China(Grant No.52002409).
文摘The Insulated-Gate Bipolar Transistor(IGBT)module is the core of the three-level(3L)traction converter.In order to improve the lifetime of the traction converter,a model predictive torque control(MPTC)based on the junction temperature constraint is proposed.Firstly,the optimization range is reduced by judging the sector where the reference voltage vector locates,as the traditional MPTC needs to be optimized 27 times in each sampling period,which requires a large amount of calculation.Secondly,by simplifying the calculation of IGBT power loss and dynamically constraining it in the cost function,the performance of optimal voltage vector balancing control can be balanced with power loss.Simulation results show that the proposed method reduces the junction temperature of the power semiconductor and prolongs the converter lifetime compared with the traditional strategy.
文摘It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>
文摘The ac recombination velocity of the excess minority carriers, in the back surface of a silicon solar cell with a vertical junction connected in series, is developed through Einstein’s law giving the diffusion coefficient of minority carriers according to temperature, through mobility. The frequency spectrum of both, amplitude and phase, are produced for the diffusion coefficient and the recombination velocity in the rear face, in order to identify the parameters of equivalent electric models.
