一种大容量IGBT的驱动和快速保护方法

提出的大容量绝缘栅双极型晶体管（ＩＧＢＴ）器件的驱动和快速保护方法能满足各种容量的ＩＧＢＴ器件和功率场效应晶体管（ＭＯＳＦＥＴ）器件对驱动和短路保护的要求。介绍了驱动电路和快速保护电路的原理，及保护电路响应时间的测量方法。给出了在不同基准电压下，模拟不同退饱和的集射电压下的保护响应时间。短路试验证明了保护电路的快速性。此驱动保护电路已用于由５０Ａ／６００Ｖ ＩＧＢＴ模块构成的逆变器和由４００Ａ／６００Ｖ ＩＧＢＴ模块构成的直流斩波器。工业运行结果表明保护方法响应时间快，抗干扰能力强。     

大功率高压输入的IGBT高频直-直变换器

在高频高压输入的情况下,开关器件绝缘门极双极晶体管（ＩＧＢＴ）的耐压不能满足要求．文中论述了一种逆变单元串联的结构,它将输入的高电压分成几部分,每一部分有一个ＤＣＡＣ逆变器．此时,ＩＧＢＴ的工作电压等于各部分电压．为了提高输出功率,输出整流二极管通常并联连接,变压器的副边漏电感作为二极管的均流电感．并分析了高压输入的大功率ＤＣＤＣ逆变器的工作情况,同时给出了模拟结果和实验结果．     

等离子喷涂逆变器功率增大的研究

针对等离子喷涂逆变器高电压、大电流的特点,重点研究高频变压器的功率增大、反馈控制系统及ＩＧＢＴ模块保护。试验表明：逆变器输出功率能满足等离子喷涂工艺的要求。这项技术对推动等离子喷涂技术的发展具有重要意义。     

IGBT1kW逆变电源的设计与实现

设计与实现了以ＩＧＢＴ为开关器件的ＰｗＭｌｋＷ逆变电源，同时对逆变电源的主回路、控制回路、驱动和保护电路等的工作原理做了介绍。最后给出逆变器的实测性能指标。     

变频电源中 IGBT 应用电路研究

介绍了ＩＧＢＴ器件的性能特点,提出了在设计ＩＧＢＴ应用电路中应注意的问题及解决方案。     

采用瞬时值反馈及谐波注入的UPS逆变器分析

分析了瞬时值反馈控制对ＰＷＭ调制信号波形的影响，给出了在瞬时值反馈ＰＷＭ逆变器电路中注入三次谐波以提高电压利用率的一种改进方法。计算机仿真结果表明所提出的方法是有效的和可行的。此方法用于４０ｋＶＡＩＧＢＴ逆变器，实验结果令人满意。     

采用瞬时值反馈及谐波注入的UPS逆变器分析

分析了瞬时值反馈控制对ＰＷＭ调制信号波形的影响，给出了在瞬时值反馈ＰＷＭ逆变器电路中注入三次谐波以提高电压利用率的一种改进方法。计算机仿真结果表明所提出的方法是有效的和可行的。此方法用于４０ｋＶＡ ＩＧＢＴ逆变器，实验结果令人满意。     

变频电源中IGBT应用电路研究

介绍了ＩＧＢＴ器件的性能特点，提出了在设计ＩＧＢＴ应用电路中应注意的问题及解决方案。     

IGBT电阻缝焊电源

本文介绍了采用电力电子器件ＩＧＢＴ（绝缘栅双极型晶体管）逆变器的电阻焊机。论述了焊机系统的组成、工作原理、开关控制电路及相关的保护装置，所研制的电阻焊机具有高效、节能、体积小、谐波污染低的特点。     

高频高压E类逆变电源

研制了可用于塑料薄膜表面电晕处理的高频高压Ｅ类逆变电器,逆变器的开关管为ＩＧＢＴ,最大输出电压峰值３０ｋＶ,频率３０ｋＨｚ最大电晕放电功率１ｋＷ,该电源已用工业生产,运行稳定,可靠。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has