电气工程及其自动化专业英语第三单元课件

1、Chapter 3 Power Electronic Technology,Section 1 Semiconductor Switches,semiconductor n. 半导体 power electronicn. 电力电子 lossn. 损耗，损失 windingn. 绕组，线圈 一圈，一转 transformer n 变压器，变换器，变量器 dielectric n. 介质，电介质，绝缘材料；a. 绝缘的，介电的，介质的，不导电的,Words,eddyn. 涡流，旋涡； a. 涡流的，涡旋的；v. 涡流，起旋涡 hysteresis n. 磁滞，滞后，迟滞 on-state a. 通

2、态的，接通的，开态 off-state a. 关态的，断开的，断态的 microamp n. 微安 milliamp n. 毫安,Words,waveform n. 波形 zero-voltage 电压过零的 zero-current 电流过零的,Words,1The switching losses are significant and can be managed. They can be further divided into three components: (a) the on-state losses, (b) the off-state losses and the los

3、ses in the transition states.,开关损耗是很大的，但可以控制。开关损耗进一步可以分解成三个部分：接通状态、关断状态和变换状态的损耗。,Notes,2The practical switching devices have limited capabilities of rate of voltage transition and the rate of current steering. These nonabrupt transition ratesgive rise to power losses in the switching devices. We wil

4、l examine these switching losses in two cases separately: the inductive and capacitive loads.,实际开关装置限制了电压变换速率和电流换向速率。非突变引起了开关装置的功率损失。我们将分别从感性负载和容性负载两种情况来分析开关损耗。,Notes,3The switching power losses increase linearly with the switching frequency like in the resistive case but about six times more. The u

5、pper bound on the switching frequency is also about half.,类似于电阻负载的情况，开关功率损耗随着开关频率线性增大，但大约为电阻负载情况的6倍多。开关频率的上限也约为一半。,Notes,4The capacitor is assumed to be large so that the voltage through it in steady state is nearly constant Uo. Assume that initially the switch is on, hence, the current through the

6、switch is IS. The capacitor voltage is Uo, the voltage across the switch is zero and the diode V1 is reverse biased. .,假设电容器很大，致使在稳态状态下其两端的电压接近为常数Uo。假使开关开始处于闭合状态，则通过开关的电流为IS。电容器的电压为Uo，开关两端的电压为零，二极管V1反向偏置。,Notes,Exercises,课内完成section 1中的Exercises I, II and III,电力电子器件Power Electronic Device,Power Elec

7、tronics Technology 电力电子技术 Analog Electronic Techniques 模拟电子技术,Semiconductors 半控型器件： Thyristor 晶闸管 (SCR: Silicon Controlled Rectifier),全控型器件： GTR 晶体管 (Giant Transistor) IGBT 绝缘栅双极晶体管 (Insulated-Gate Bipolar Transistor) Power MOSFET 电力场效应晶体管 (Metal Oxide Semiconductor Field Effect Transistor) GTO 门极可关

8、断晶闸管 (Gate-Turn-Off Thyristor) 不可控器件： Power Diode (Semiconductor Rectifier),电力电子器件Power Electronic Device,Transition of Part of Speech,词类转换是指把原文语言中的某一词类转译为汉语的另一词类。,一、转换为汉语动词 1、名词转换成动词 英语中表达动作概念的动名词、具有动作意义的抽象名词、由动词派生出来的名词、动词加名词构成的固定短语、介词加名词构成的固定短语等，往往可以根据具体情况译成汉语动词。 (1) The application of electronic

9、computers makes for a tremendous rise in labor productivity. 使用电子计算机可以大大提高劳动生产率。,Transition of Part of Speech,(2) Computers can provide analysis of every operation in a factory. 计算机能对工厂的每道工序进行分析。 (3) Primary forces have certain valuations that must be considered in any design. 在任何设计中，对于数值能确切计算的主要作用力

10、都必须加以考虑。 (4) Integrated circuits are fairly recent development. 集成电路是近年来发展起来的。,Transition of Part of Speech,(5) Rockets have found application for the exploration of the universe.,(6) The sight and sound of our jet planes filled me with special longing.,火箭已经用来探索宇宙。,看到我们的喷气式飞机，听见隆隆的机声，令我心驰神往。,Transit

11、ion of Part of Speech,(7) The lack of any special excretory system is explained in a similar way. （excretory：排泄的）,(8) The 1976 UN document calls for the settlement of the Middle East conflict on the basis of Israeli withdrawal from occupied territories and Arab acknowledgement of Israelis right to e

12、xist.（n. v.）,植物没有专门的排泄系统，可用同样的方式加以说明。（名词转译）（n.v.）,1976年联合国文件要求在以色列撤出所占的土地以及阿拉伯承认以色列的生存权利的基础上解决中东冲突。,Transition of Part of Speech,2、形容词转换成动词 英语中某些由动词转换来的形容词、同介词搭配构成句子表语或定语的形容词、与连系动词一起构成复合谓语的形容词，通常可译成汉语中的动词。 (1) Copper wire is flexible. 铜线容易弯曲。 (2) Television is different from radio in that it sends a

13、nd receives pictures. 电视不同于无线电在于能发送并接收图像。,Transition of Part of Speech,(3) If extremely low-cost power were ever to become available from large nuclear power plants, electrolytic hydrogen would become competitive. 如能从大型核电站获得成本极低的电力，电解氢的竞争能力就会增强。 (4) Heat is a form of energy into which all other form

14、s are convertible. 热是能的一种形式，其他一切能的形式都能转化为热能。,(5) The workers are confident that they will be able to build the modern factory in a short time.,工人们确信在短期内一定能建成这座现代化工厂。,Transition of Part of Speech,3、介词转换成动词 英语中的介词或介词短语在许多情况下可以译成汉语的动词，尤其是当它们用作表语或状语时。 The letter E is commonly used for electromotive forc

15、e. 通常用字母E表示电动势。 (2) Except for atomic energy, all forms of energy used by man are from the sun. 除原子能之外，人类所利用的一切形式的能量都来自太阳。,Transition of Part of Speech,(3) So long as we have means of producing heat we can keep the steam engine at work. 只要能产生热，就能使蒸汽机做功。,Transition of Part of Speech,4、 副词转换成动词 英语中有些作

16、表语的副词或复合宾语中的副词，往往可译成汉语的动词。 (1) The electric current flows through the circuit with the switch on. 如果开关接通，电流就流过线路。 (2) Open the valve to let air in. 打开阀门，让空气进入。,Transition of Part of Speech,(3) We are through with our test report. 我们的试验报告写完了。,我笔直地向前高速飞行，越过港口，飞临海面。,(4) I barreled straight ahead, acros

17、s the harbor and out over the sea. （barrel：v.装桶；俚高速开车/行驶；飞奔）,Transition of Part of Speech,二、转换为汉语名词 1、动词转换成名词 英语中有些动词在翻译成汉语时很难找到相应的动词，这时可将其转译成汉语名词 。 (1) The electronic computer is chiefly characterized by its accurate and rapid computations. 电子计算机的主要特点是计算准确而快速。 (2) An electric current varies directl

18、y as the electromotive force and inversely as the resistance. 电流的变化与电动势成正比，与电阻成反比。,Transition of Part of Speech,(3) The design aims at automatic operation, easy regulation, simple maintenance and high productivity. 设计的目的在于自动操作，调节方便，维护简易，生产率高。,(4) Formality has always characterized their relationship

19、. （formality：拘谨；礼节；俗套）,他们之间的关系，有一个特点，就是以礼相待。,Transition of Part of Speech,(5) The earth on which we live is shaped a ball. （shape：使成形；摹制；仿造）,(6) Most U.S. spy satellites are designed to burn up in the earths atmosphere after completing their missions.,我们居住的地球，形状象一个大球。（动词转译）,美国绝大多数间谍卫星，按其设计，在完成使命后，在大

20、气层中焚毁。,Transition of Part of Speech,2、形容词转换成名词 英语中有些形容词加上定冠词the表示某一类人或物，汉译时常译成名词。另外，英语中有些表示事物特征的形容词作表语时，往往可在其后加上“性”、“度”、“体”等词，译成名词。 (1) People are so much more flexible and inventive than robots. 人类比机器人更灵活而且更富有创造性。 (2) Some people think tomorrows computers will be intelligent. 有人认为未来的计算机就具有智能。,Trans

21、ition of Part of Speech,(3) In fission processes the fission fragments are very radioactive. 在裂变过程中，裂变碎片具有强烈的放射性。,The doctor did his best to cure the sick and the wounded. 医生尽了最大的努力来治疗病号和伤员。（形容词转换） They were considered insincere. 他们被人认为是伪君子。（insincere：不诚恳的；虚伪的；不可信任的）,Transition of Part of Speech,3、代

22、词转换成名词 英语中的代词译成汉语，有时为了使译文规范，须转换为名词 。 (1) Radio waves are similar to light waves except that their wave-length is much greater. 无线电波与光波相似，只不过无线电波的波长更长一些。 (2) The specific resistance of iron is not so small as that of copper. 铁的电阻系数不如铜的电阻系数那样小。,Transition of Part of Speech,(3) Electricity may be produ

23、ced by a generator which is turned by a motor using any of the other forms of energy. 发电机可以发电，而发电机是由利用任何其他形式能量的原动机带动的。,Transition of Part of Speech,4、 副词转换成名词 英语中有些副词，在句子中用作状语，译成汉语时可根据具体情况转换成汉语的名词 。 (1) The quality of the operating system determines how useful the computer is. 操作系统的质量决定着计算机的应用效能。 (2

24、) Electromagnetic waves travel as fast as light. 电磁波传播的速度和光一样。 .,Transition of Part of Speech,4、 副词转换成名词 (3) The instrument is used to determine how fully the batteries are charged. 这种仪表用来确定电池充电的程度。 (4) The device is shown schematically in Figure 1. 图1所示为这种装置的简图。,Transition of Part of Speech,三、转换为汉语

25、形容词 1、副词转换成形容词 (1) Robotics is so closely associated with cybernetics that it is sometimes mistakenly considered to be synonymous. 机器人技术与控制论的联系如此密切，以致两者有时被错误地认为是同一回事。 (2) Miniature gas detector is chiefly featured by small size, light weight, complete functions and long continuous working time. 袖珍式瓦

26、斯检测器的主要特点是体积小、重量轻、功能齐全、连续工作时间长。,Transition of Part of Speech,(3) Gases and liquids are perfectly elastic. 气体和液体都是完全的弹性体。,(4) In science and engineering, it is of great importance to state the laws and principles accurately.,(5)The sun affects tremendously both the mind and body of a man.,在理工科方面，定律和原

27、理的准确叙述非常重要。,太阳对人的身体和精神都有极大的影响。,Transition of Part of Speech,2、名词转换成汉语形容词 (1) The nuclear power system designed in China is of great precision. 中国设计的核动力系统十分精确。 (2) Electronic computers and microprocessors are of great importance to us. 电子计算机和微处理器对我们来说十分重要。 (3) Single crystals of high perfection are a

28、n absolute necessity for the fabrication of integrated circuits. 高度完整的单晶对于制造集成电路来说是绝对必要的。,Transition of Part of Speech,(4)The security and warmth of the destroyers sick bay were wonderful. （destroyer：破坏者；驱逐舰；bay：湾；飞机的舱；sick bay：船上病室/医务室；船上医疗设施的总称）,(5) It is no use employing radar to detect objects i

29、n water.,驱逐舰的病室很安全也很温暖，好极了。,使用雷达探测水下目标是没有用的。,Transition of Part of Speech,四、转换成汉语副词 1、形容词转换成汉语副词 (1) The engine has given a constantly good performance. 这台发动机一直运转良好。 (2) The same principles of low internal resistance also apply to milliammeters. 低内阻的原理同样适用于毫安表。,Transition of Part of Speech,1、形容词转换成汉

30、语副词 (3) A graph gives a visual representation of the relationship. 图表可以直观地显示要说明的关系。 (4)It was a clear and unemotional exposition of the presidents reasons for willing to begin a Chinese-American dialogue. （n.v.） 这篇发言清楚明白地、心平气和地说明了总统希望开始中美对话的原因。（形容词转译成副词） （unemotional：无感情的；不易动感情的；exposition：事实、想法等的阐述，讲解；说明性的文章/讲话）,Transition of Part of Speech,2、其他词转换成副词 (1) Rapid evaporation at the heating-surface tends to make the steam wet. 加热面上的迅速蒸发，往往使蒸汽的湿度加大。 (2) The added device will ensure accessibility fo