电气工程及其自动化专业英语第一章课文翻译

Section 1 Introduction 第一节介绍The modern society depends on the electricity supply more heavily than ever before.现代社会比以往任何时候对电力供应的依赖更多。

It can not be imagined what the world should be if the electricity supply were interrupted all over the world. 如果中断了世界各地的电力供应，无法想像世界会变成什么样子Electric power systems (or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world. 电力系统（或电力能源系统），提供电力到现代社会，已成为产业界的不可缺少的组成部分。

The first complete electric power system (comprising a generator, cable, fuse, meter, and loads) was built by Thomas Edison –the historic Pearl Street Station in New York City which began operation in September 1882. 托马斯爱迪生建立了世界上第一个完整的电力系统（包括发电机，电缆，熔断器，计量，并加载）它就是位于纽约市具有历史意义的珍珠街的发电厂始于1882年9月运作。

This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius. The load, which consisted entirely of incandescent lamps, was supplied at 110 V through an underground cable system. 这是一个直流系统，由一个蒸汽发动机驱动的直流发电机其供电面积约1.5公里至59范围内的客户。

第一章 电路基本原理第一节 电流与电压u （t ）和i （t ）这两个变量是电路中最基本的概念，描述了电路中各种不同的关系。

电荷与电流电荷与电流的概念是解释一切电气现象的基础原则。

而电荷也是电路的最基本的量。

电荷是构成物质的原子的电气属性，单位是库仑（C ）。

通过基础物理学，我们了解到一切物质都是由被称为原子的基本粒子构造而成的，每个原子中都包含电子、质子和中子。

我们还知道电子上的电荷带负电，每个电子上的电量是1.60210×10-19库仑。

质子带与电子相等的正电荷。

原子上质子与电子的数目相等，使其呈中性。

我们来考虑电荷的运动。

电或电荷的独特之处就是它们可以移动，也就是说电荷可以从一个地方移动到另一个地方，从而转换成另外一种形式的能量。

当把一根导线接在电池（一种电源）的两端时，电荷受迫而运动；正电荷与负电荷分别向相反的两个方向移动。

这种电荷的移动产生了电流。

习惯上，我们把正电荷移动的方向或负电荷移动的反方向称为电流的方向，如图1-1所示。

这种说法是由美国科学家、发明家本杰明·富兰克林提出的。

即使我们知道金属导体中的电流是由于带负电荷的电子（运动）而产生的，（我们）也使用默认的习惯，将正电荷运动的方向定义为电流的方向。

因此，电流是单位时间内电荷的变化率，单位是安培（ampere ，A ）。

在数学上，电流i 、电荷q 和时间t 的关系为i=dtdq （1-1） 将等式的两边同时进行积分，则可得到电荷在时间t 和t 0之间的变化。

有q== 0t t idt （1-2）在等式（1-1）中我们给电流i 的定义表现了电流不是一个定值量，电荷随时间的变化不同，电流也与之呈不同的函数关系。

电压、电能与电功率使电子在导体中定向运动需要做功或能量转换。

功由外电动势提供，最典型的就是图1-1中的电池。

外电动势也可理解为电压或电位差。

电路中，a 、b 两点之间的电压U ab 等于从a 到b 移动单位电荷所需能量（所做的功），有U ab =dqdw （1-3） w 代表电能，单位是焦耳（J ）；q 代表电量。

第一章第一篇sectiongTwo variables u(t) and i(t) are the most basic concepts in an electric circuit, they characterize the various relationships in an electric circuitu(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。

Charge and CurrentThe concept of electric charge is the underlying principle for explaining all electrical phenomena. Also, the most basic quantity in an electric circuit is the electric charge. Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C). 电荷和电流电荷的概念是用来解释所有电气现象的基本概念。

也即，电路中最基本的量是电荷。

电荷是构成物质的原子微粒的电气属性，它是以库仑为单位来度量的。

We know from elementary physics that all matter is made of fundamental building blocks known as atoms and that each atom consists of electrons, protons, and neutrons. We also know that the charge e on an electron is negative and equal in magnitude to 1.60210×10 19C, while a proton carries a positive charge of the same magnitude as the electron. The presence of equal numbers of protons and electrons leaves an atom neutrally charged. 我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。

注：电气工程及其自动化专业英语翻译 1~7面班级：1002班学号：20姓名：王定瑞PART 1 FUNDAMENTALS OF ELECTRIC ENGINEERINGChapter 1 Circuit Fundamentals第1部分的电气工程基础第1章电路原理Electrostatic Charges静电荷Protons and electrons are parts of atoms that make up all things in our world. The positive charge of a proton is similar to the negative charge of an electron. However, a positive charge is the opposite of a negative charge. These charges are called electrostatic charges. Each charged particle is surrounded by an electrostatic field.质子和电子部件的原子构成一切事物在我们的世界。

正电荷的质子是类似于负电荷的电子。

然而,一个正电荷的反面是一个负电荷。

这些指控被称为静电荷。

每个带电粒子周围是一个静电场。

The effect that electrostatic charges have on each other is very important. They either repel (move away) or attract (come together) each other. It is said that like charges repel and unlike charges attract.这个效应,静电指控对方是非常重要的。

他们要么排斥(离开)或吸引(一起)每个其他。

Section 1 Introduction 第一节介绍The modern society depends on the electricity supply more heavily than ever before.现代社会比以往任何时候对电力供应的依赖更多。

It can not be imagined what the world should be if the electricity supply were interrupted all over the world. 如果中断了世界各地的电力供应，无法想像世界会变成什么样子Electric power systems (or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world. 电力系统（或电力能源系统），提供电力到现代社会，已成为产业界的不可缺少的组成部分。

The first complete electric power system (comprising a generator, cable, fuse, meter, and loads) was built by Thomas Edison –the historic Pearl Street Station in New York City which began operation in September 1882. 托马斯爱迪生建立了世界上第一个完整的电力系统（包括发电机，电缆，熔断器，计量，并加载）它就是位于纽约市具有历史意义的珍珠街的发电厂始于1882年9月运作。

This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius. The load, which consisted entirely of incandescent lamps, was supplied at 110 V through an underground cable system. 这是一个直流系统，由一个蒸汽发动机驱动的直流发电机其供电面积约1.5公里至59范围内的客户。

1```In the generator mode ,it,s operating speed isslightly higger than it,s synchronous speed and ie needs magnetizing revctive pover form the symtem that it is connected to in order to suuply pover .在发电方式下他的工作速度比同步转速稍高些，并了解供电力，他需要他所连接的系统吸收磁化无功功率。

2```in the barking mode of operyetion ,a three –phase indection motor running at a steady –speedcan be brought to a quick stop by interchanging two of stator leads感应电机运行电动状态时，其转速低于同步转速，运行在发电状态时，其转速高于同步转速，这就需要从与之间相连的系统电源提供励磁的无功功率。

3```obviously ,dc machine applications are very significant,but the advantages of the dc machinemmust be weighed against its greatr initial investment cost and the maintenance problems associated with its brush-commutator system..同步是指状态运行时点击以恒定的转速和频率运行。

4```with a cylindyical rotor the reluctance of the magnetic circuit of the field is independent of itsactual diretion and relative to the direct axis.圆柱形转子的磁场磁路的磁阻与直轴有关，而与磁场的实际方向无关。

电气工程及其自动化专业英语翻译．Electric Power Systems.The modern society depends on the electricity supply more heavily thanever before. It can not be imagined what the world should be if the electricity supply were interrupted all over the world. Electric power systems (or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world. The first complete electric power system (comprising a generator, cable, fuse, meter, and loads) was built by Thomas Edison –the historic Pearl Street Station in New York City which began operation in September 1882. This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius. The load, which consisted entirely of incandescent lamps, was suppliedat 110 V through an underground cable system.. Within a few years similar systems were in operation in most large cities throughout the world. Withthe development of motors by Frank Sprague in 1884, motor loads were addedto such systems. This was the beginning of what would develop into oneof the largest industries in the world. In spite of the initial widespreaduse of DC systems, they were almost completely superseded by AC systems. By 1886, the limitations of DC systems were becoming increasingly apparent. They could deliver power only a short distance from generators. To keep transmission power losses ( I 2 R ) and voltage drops to acceptable levels, voltage levels had to be high for long-distance power transmission. Such high voltages were not acceptable for generation and consumption of power; therefore, a convenient means for voltage transformation became a necessity.The development of the transformer and AC transmission by L. Gaulard and JD Gibbs of Paris, France, led to AC electric power systems. In 1889, the first AC transmission line in North America was put into operation in Oregon between Willamette Falls and Portland. It was a single-phase line transmitting power at 4,000 V overa distance of 21 km. With the development of polyphase systems by Nikola Tesla, the AC system became even more attractive. By 1888, Tesla held several patents on AC motors, generators, transformers, and transmission systems. Westinghouse bought the patents to these early inventions, and they formed the basis of the present-day AC systems. In the 1890s, there was considerable controversy over whether the electric utility industry should be standardized on DC or AC. By the turn of the century, the AC system had won out over the DC system for the following reasons:（1）V oltage levels can be easily transformed in AC systems, thus providing the flexibility for use of different voltages forgeneration, transmission, and consumption.（2）AC generators are much simpler than DC generators.（3）AC motors are much simpler and cheaper than DC motors.The first three-phase line in North America went into operation in 1893．——a 2,300 V, 12 km line in southern California. In the early periodof AC power transmission, frequency was not standardized. This poses a problem for interconnection. Eventually 60 Hz was adopted as standardin North America, although 50 Hz was used in many other countries. The increasing need for transmitting large amounts of power over longer distance created an incentive to use progressively high voltage levels.To avoid the proliferation of an unlimited number of voltages, theindustry has standardized voltage levels. In USA, the standards are 115, 138, 161, and 230 kV for the high voltage (HV) class, and 345, 500 and 765 kV for the extra-high voltage (EHV) class. In China, the voltage levels in use are 10, 35, 110 for HV class, and 220, 330 (only in Northwest China) and 500 kV for EHV class . The first 750 kVtransmission line will be built in the near future in Northwest China. With the development of the AC/DC converting equipment, high voltage DC (HVDC) transmission systems have become more attractive and economical in special situations. The HVDC transmission can be used for transmissionof large blocks of power over long distance, and providing an asynchronouslink between systems where AC interconnection would be impracticalbecause of system stability consideration or because nominal frequenciesof the systems are different. The basic requirement to a power systemis to provide an uninterrupted energy supply to customers with acceptablevoltages and frequency. Because electricity can not be massively storedunder a simple and economic way, the production and consumption ofelectricity must be done simultaneously. A fault or misoperation in anystages of a power system may possibly result in interruption ofelectricity supply to the customers. Therefore, a normal continuousoperation of the power system to provide a reliable power supply to the customers is of paramount importance. Power system stability may bebroadly defined as the property of a power system that enables it to remainin a state of operating equilibrium under normal operating conditionsand to regain an acceptable state of equilibrium after being subjectedto a disturbance.. Instability in a power system may be manifested inmany different ways depending on the system configuration and operatingmode. Traditionally, the stability problem has been one of maintaining synchronous operation. Since power systems rely on synchronous machinesfor generation of electrical power, a necessary condition forsatisfactory system operation is that all synchronous machines remainin synchronism or, colloquially in step. This aspect of stability isinfluenced by the dynamics of generator rotor angles and power-angle relationships, and then referred to rotor angle stability译文：电力系统现代社会比以往任何时候更多地依赖于电力供应。

电气工程及其自动化专业英语翻译（精选多篇）第一篇：电气工程及其自动化专业英语翻译Electric Power Systems.The modern society depends on the electricity supply more heavily than ever before.It can not be imagined what the world should be if the electricity supply were interrupted all over the world.Electric power systems(or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world.The first complete electric power system(comprising a generator, cable, fuse, meter, and loads)was built by Thomas Edison – the historic Pearl Street Station in New York City which began operation in September 1882.This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius.The load, which consisted entirely of incandescent lamps, was supplied at 110 V through an underground cable system..Within a few years similar systems were in operation in most large cities throughout the world.With the development of motors by Frank Sprague in 1884, motor loads were added to such systems.This was the beginning of what would develop into one of the largest industries in the world.In spite of the initial widespread use of DC systems, they were almost completely superseded by AC systems.By 1886, the limitations of DC systems were becoming increasingly apparent.They could deliver power only a short distance from generators.To keep transmission power losses(I 2 R)and voltage drops to acceptable levels, voltage levels had to be high for long-distance power transmission.Such high voltages were not acceptable for generation and consumption of power;therefore, a convenient means for voltage transformationbecame a necessity.The development of the transformer and AC transmission by L.Gaulard and JD Gibbs of Paris, France, led to AC electric power systems.In 1889, the first AC transmission line in North America was put into operation in Oregon between Willamette Falls and Portland.It was a single-phase line transmitting power at 4,000 V over a distance of 21 km.With the development of polyphase systems by Nikola Tesla, the AC system became even more attractive.By 1888, Tesla held several patents on AC motors, generators, transformers, and transmission systems.Westinghouse bought the patents to these early inventions, and they formed the basis of the present-day AC systems.In the 1890s, there was considerable controversy over whether the electric utility industry should be standardized on DC or AC.By the turn of the century, the AC system had won out over the DC system for the following reasons:（1）Voltage levels can be easily transformed in AC systems, thusproviding the flexibility for use of different voltages for generation, transmission, and consumption.（2）AC generators are much simpler than DC generators.（3）AC motors are much simpler and cheaper than DC motors.The first three-phase line in North America went into operation in 1893——a 2,300 V, 12 km line in southern California.In the early period of AC power transmission, frequency was not standardized.This poses a problem for interconnection.Eventually 60 Hz was adopted as standard in North America, although 50 Hz was used in many other countries.The increasing need for transmitting large amounts of power over longer distance created an incentive to use progressively high voltage levels.To avoid the proliferation of anunlimited number of voltages, the industry has standardized voltage levels.In USA, the standards are 115, 138, 161, and 230 kV for the high voltage(HV)class, and 345, 500 and 765 kV for the extra-high voltage(EHV)class.In China, the voltage levels in use are 10, 35, 110 for HV class, and 220, 330(only in Northwest China)and500 kVforEHVclass.Thefirst750kVtransmission line will be built in the near future in Northwest China.With the development of the AC/DC converting equipment, high voltage DC(HVDC)transmission systems have become more attractive and economical in special situations.The HVDC transmission can be used for transmission of large blocks of power over long distance, and providing an asynchronous link between systems where AC interconnection would be impractical because of system stability consideration or because nominal frequencies of the systems are different.The basic requirement to a power system is to provide an uninterrupted energy supply to customers with acceptable voltages and frequency.Because electricity can not be massively stored under a simple and economic way, the production and consumption of electricity must be done simultaneously.A fault or misoperation in any stages of a power system may possibly result in interruption of electricity supply to the customers.Therefore, a normal continuous operation of the power system to provide a reliable power supply to the customers is of paramount importance.Power system stability may be broadly defined as the property of a power system that enables it to remain in a state of operating equilibrium under normal operating conditions and to regain an acceptable state of equilibrium after being subjected to a disturbance..Instability in a power system may be manifested in many different ways depending on the system configurationand operating mode.Traditionally, the stability problem has been one of maintaining synchronous operation.Since power systems rely on synchronous machines for generation of electrical power, a necessary condition for satisfactory system operation is that all synchronous machines remain in synchronism or, colloquially “in step”.This asp ect of stability is influenced by the dynamics of generator rotor angles and power-angle relationships, and then referred to “ rotor angle stability ”译文：电力系统现代社会比以往任何时候更多地依赖于电力供应。

One operating system might be better suited to some computing tasks than others.To provide clues to their strengths and weaknesses,operating systems are informally categorized and characterized using one or more of the following terms:(1) A single-user operating system expects to deal with oneset of input devices -those that can be controlled by one user at a time.Operating systems for handheld computers and many personal computers fit into the single-user category.(2)A multiuser operating system is derigned to deal with input,output,and processing requests from many users-all atthe same time.One of its most difficult responsibilities is to schedule all of the processing requests that must be performed by a centralized computer-often a mainframe.(3)A network operating system(also referred to as a “server operating system”) provides communications and routing services that allow compoters to share data,programs,and peripheral devices.Novell Netware,for example,is almost always referred to as a network operating system。

第一章第一篇sectiongTwo variables u(t) and i(t) are the most basic concepts in an electric circuit, they characterize the various relationships in an electric circuitu(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。

Charge and CurrentThe concept of electric charge is the underlying principle for explaining all electrical phenomena. Also, the most basic quantity in an electric circuit is the electric charge. Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C).电荷和电流电荷的概念是用来解释所有电气现象的基本概念。

也即，电路中最基本的量是电荷。

电荷是构成物质的原子微粒的电气属性，它是以库仑为单位来度量的。

We know from elementary physics that all matter is made of fundamental building blocks known as atoms and that each atom consists of electrons, protons, and neutrons. We also know that the charge e on an electron is negative and equal in magnitude to 1.60210×10 19C, while a proton carries a positive charge of the same magnitude as the electron. The presence of equal numbers of protons and electrons leaves an atom neutrally charged.我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。

翻译翻译Electric Power Systems.The modern society depends on the electricity supply more heavily than ever before. It can not be imagined what the world should be if the electricity supply were interrupted all over the world. Electric power systems (or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world. The first complete electric power system (comprising a generator, cable, fuse, meter, and loads) was built by Thomas Edison – the historic Pearl Street Station in New York City which began operation in September 1882. This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius. The load, which consisted entirely of incandescent lamps, was supplied at 110 V through an underground cable system.. Within a few years similar systems were in operation in most large cities throughout the world. With the development of motors by Frank Sprague in 1884, motor loads were added to such systems. This was the beginning of what would develop into one of the largest industries in the world. In spite of the initial widespread use of DC systems, they were almost completely superseded by AC systems. By 1886, the limitations of DC systems were becoming increasingly apparent. They could deliver power only a short distance from generators. To keep transmission power losses ( I 2 R ) and voltage drops to acceptable levels, voltage levels had to be high for long-distance power transmission. Such high voltages were not acceptable for generation and consumption of power; therefore, a convenient means for voltage transformation became a necessity.The development of the transformer and AC transmission by L. Gaulard and JD Gibbs of Paris, France, led to AC electric power systems. In 1889, the first AC transmission line in North America was put into operation in Oregon between Willamette Falls and Portland. It was a single-phase line transmitting power at 4,000 V over a distance of 21 km. With the development of polyphase systems by Nikola Tesla, the AC system became even more attractive. By 1888, Tesla held several patents on AC motors, generators, transformers, and transmission systems. Westinghouse bought the patents to these early inventions, and they formed the basis of the present-day AC systems. In the 1890s, there was considerable controversy over whether the electric utility industry should be standardized on DC or AC. By the turn of the century, the AC system had won out over the DC system for the following reasons: （1）Voltage levels can be easily transformed in AC systems, thus providing the flexibility for use of different voltages for generation, transmission, and consumption.（2）AC generators are much simpler than DC generators.（3）AC motors are much simpler and cheaper than DC motors.The first three-phase line in North America went into operation in 1893——a 2,300 V, 12 km line in southern California. In the early period of AC power transmission, frequency was not standardized. This poses a problem for interconnection. Eventually 60 Hz was adopted as standard in North America, although 50 Hz was used in many other countries. The increasing need for transmitting large amounts of power over longer distance created an incentive to use progressively high voltage levels. To avoid the proliferation of an unlimited number of voltages, the industry has standardized voltage levels. In USA, the standards are 115, 138, 161, and 230 kV for the high voltage (HV) class, and 345, 500 and 765 kV for the extra-high voltage (EHV) class. In China, the voltage levels in use are 10, 35, 110 for HV class, and 220, 330 (only in Northwest China) and 500 kV for EHV class . The first 750 kVtransmission line will be built in the near future in Northwest China. With the development of the AC/DC converting equipment, high voltage DC (HVDC) transmission systems have become more attractive and economical in special situations. The HVDC transmission can be used for transmission of large blocks of power over long distance, and providing an asynchronous link between systems where AC interconnection would be impractical because of system stability consideration or because nominal frequencies of the systems are different. The basic requirement to a power system is to provide an uninterrupted energy supply to customers with acceptable voltages and frequency. Because electricity can not be massively stored under a simple and economic way, the production and consumption of electricity must be done simultaneously. A fault or misoperation in any stages of a power system may possibly result in interruption of electricity supply to the customers. Therefore, a normal continuous operation of the power system to provide a reliable power supply to the customers is of paramount importance. Power system stability may be broadly defined as the property of a power system that enables it to remain in a state of operating equilibrium under normal operating conditions and to regain an acceptable state of equilibrium after being subjected to a disturbance.. Instability in a power system may be manifested in many different ways depending on the system configuration and operating mode. Traditionally, the stability problem has been one of maintaining synchronous operation. Since power systems rely on synchronous machines for generation of electrical power, a necessary condition for satisfactory system operation is that all synchronous machines remain in synchronism or, colloquially "in step". This aspect of stability is influenced by the dynamics of generator rotor angles and power-angle relationships, and then referred to " rotor angle stability "译文：电力系统现代社会比以往任何时候更多地依赖于电力供应。

电气工程及其自动化专业英语课后翻译The pony was revised in January 2021——电流之比才是恒定的，并且这个比值也取决于温度以及其它环境因素。

我们通常应当把线性电阻器仅仅称为电阻器。

只有当需要强调元件性质的时候才使用更长的形式称呼它。

而对于任何非线性电阻器我们应当始终这么称呼它，非线性电阻器不应当必然地被视为不需要的元件。

如果一个电路有两个或多个独立源，求出具体变量值（电流或电压）的一种方法是使用节点分析法或网孔分析法。

另一种方法是求出每个独立源对变量的作用然后把它们进行叠加。

而这种方法被称为叠加法。

叠加法原理表明线性电路某个元件两端的电压（或流过元件的电流）等于每个独立源单独作用时该元件两端的电压（或流过元件的电流）的代数和。

相电压与相电流之比等于电路的阻抗，符号为字母Z ，阻抗是一个具有量纲为欧姆的复数量。

阻抗不是一个相量，因此不能通过把它乘以 并取其实部把它转换成时域形式。

但是，我们把电感器看作是通过其电感量L 表现为时域形式而通过其阻抗jwL 表现为频域形式，电容在时域里为电容量C 而在频域里为 ，阻抗是某种程度上的频域变量而非时域变量。

无论是星型连接的电源还是三角形连接的电源都有重要的实际应用意义。

星型连接的电源用于长距离电力传输，此时电阻损耗(I2R)将达到最小。

这是由于星型连接的线电压是三角形连接的线电压的 倍，于是,对于相同的功率来说，三角型连接的线电流是星形连接的线电流的 倍。

三角形连接的电源使用在根据三相电源而需要的三个单相电路中。

这种从三相到单相的转变用在住宅布线中因为家用照明和设备使用单相电源。

三相电33源用在需要大功率的工业布线中。

在某些应用场合，无论负载是星形连接还是三角形连接并不重要。

模拟电子电路是关于其中电压和电流是对物理量进行模拟的且连续变化那些系统。

复制音乐的电子电路必须具有与声音成正比的电压和电流。

一个高保真的放大系统要尽可能保持模拟量不失真，我们要仔细地设计模拟电子电路以使电压和电流反映输入信号。

Semiconductor switches are very important and crucial components inpower electronic systems.these switches are meant to be the substitutionsof the mechanical switches,but they are severely limited by the properties of the semiconductor materials and process of manufacturing.在电力电子系统，中半导体开关是特别重要和重点零件。

半导体开关将要替代机械开关,但半导体资料的性质和生产过程严重限制了他们。

Switching losses开关消耗Power losses in the power eletronic converters are comprised of the Switching losses and parasitic losses.电力电子变换器的功率消耗分为开关消耗和寄生消耗the parasitic losses account for the losses due to the winding resistances of the inductors and transformers,the dielectric losses ofcapacitors,the eddy and the hysteresis losses.寄生损失的绕组电感器、变压器的阻力、介电消耗的电容器, 涡流和磁滞消耗the switching losses are significant and can be managed.这个开关消耗是特别重要的, 能够被办理。

they can be further divided into three components:(a)the on-state losses,(b)the off-state losses and the losses in the transition states.他们能够分为三个部分:通态消耗，断态消耗和转换过程中产生的消耗。

Electric Power Systems.The modern society depends on the electricity supply more heavily than ever before. It can not be imagined what the world should be if the electricity supply were interrupted all over the world. Electric power systems (or electric energy systems), providing electricity to the modern society, have become indispensable components of the industrial world. The first complete electric power system (comprising a generator, cable, fuse, meter, and loads) was built by Thomas Edison – the historic Pearl Street Station in New York City which began operation in September 1882. This was a DC system consisting of a steam-engine-driven DC generator supplying power to 59 customers within an area roughly 1.5 km in radius. The load, which consisted entirely of incandescent lamps, was supplied at 110 V through an underground cable system.. Within a few years similar systems were in operation in most large cities throughout the world. With the development of motors by Frank Sprague in 1884, motor loads were added to such systems. This was the beginning of what would develop into one of the largest industries in the world. In spite of the initial widespread use of DC systems, they were almost completely superseded by AC systems. By 1886, the limitations of DC systems were becoming increasingly apparent. They could deliver power only a short distance from generators. To keep transmission power losses ( I 2 R ) and voltage drops to acceptable levels, voltage levels had to be high for long-distance power transmission. Such high voltages were not acceptable for generation and consumption of power; therefore, a convenient means for voltage transformation became a necessity.The development of the transformer and AC transmission by L. Gaulard and JD Gibbs of Paris, France, led to AC electric power systems. In 1889, the first AC transmission line in North America was put into operation in Oregon between Willamette Falls and Portland. It was a single-phase line transmitting power at 4,000 V over a distance of 21 km. With the development of polyphase systems by Nikola Tesla, the AC system became even more attractive. By 1888, Tesla held several patents on AC motors, generators, transformers, and transmission systems. Westinghouse bought the patents to these early inventions, and they formed the basis of the present-day AC systems. In the 1890s, there was considerable controversy over whether the electric utility industry should be standardized on DC or AC. By the turn of the century, the AC system had won out over the DC system for the following reasons: （1）Voltage levels can be easily transformed in AC systems, thus providing the flexibility for use of different voltages for generation, transmission, and consumption.（2）AC generators are much simpler than DC generators.（3）AC motors are much simpler and cheaper than DC motors.The first three-phase line in North America went into operation in 1893——a 2,300 V, 12 km line in southern California. In the early period of AC power transmission, frequency was not standardized. This poses a problem for interconnection. Eventually 60 Hz was adopted as standard in North America, although 50 Hz was used in many other countries. The increasing need for transmitting large amounts of power over longer distance created an incentive to use progressively high voltage levels. To avoid the proliferation of an unlimited number of voltages, the industry has standardized voltage levels. In USA, the standards are 115, 138, 161, and 230 kV for the high voltage (HV) class, and 345, 500 and 765 kV for the extra-high voltage (EHV) class. In China, the voltage levels in use are 10, 35, 110 for HV class, and 220, 330 (only in Northwest China) and 500 kV for EHV class . The first 750 kVtransmission line will be built in the near future in Northwest China. With the development of the AC/DC converting equipment, high voltage DC (HVDC) transmission systems have become more attractive and economical in special situations. The HVDC transmission can be used for transmission of large blocks of power over long distance, and providing an asynchronous link between systems where AC interconnection would be impractical because of system stability consideration or because nominal frequencies of the systems are different. The basic requirement to a power system is to provide an uninterrupted energy supply to customers with acceptable voltages and frequency. Because electricity can not be massively stored under a simple and economic way, the production and consumption of electricity must be done simultaneously. A fault or misoperation in any stages of a power system may possibly result in interruption of electricity supply to the customers. Therefore, a normal continuous operation of the power system to provide a reliable power supply to the customers is of paramount importance. Power system stability may be broadly defined as the property of a power system that enables it to remain in a state of operating equilibrium under normal operating conditions and to regain an acceptable state of equilibrium after being subjected to a disturbance.. Instability in a power system may be manifested in many different ways depending on the system configuration and operating mode. Traditionally, the stability problem has been one of maintaining synchronous operation. Since power systems rely on synchronous machines for generation of electrical power, a necessary condition for satisfactory system operation is that all synchronous machines remain in synchronism or, colloquially "in step". This aspect of stability is influenced by the dynamics of generator rotor angles and power-angle relationships, and then referred to " rotor angle stability "译文：电力系统现代社会比以往任何时候更多地依赖于电力供应。

Semiconductor switches are very important and crucial components in power electronicsystems.these switches are meant to be the substitutions of the mechanical switches,but they are severely limited by the properties of the semiconductor materials and process of manufacturing. 在电力电子系统，中半导体开关是非常重要和关键部件。

半导体开关将要替换机械开关,但半导体材料的性质和生产过程严重限制了他们。

Switching losses开关损耗Power losses in the power eletronic converters are comprised of the Switching losses and parasitic losses. 电力电子转换器的功率损耗分为开关损耗和寄生损耗the parasitic losses account for the losses due to the winding resistances of the inductors and transformers,the dielectric losses of capacitors,the eddy and the hysteresis losses. 寄生损失的绕组电感器、变压器的阻力、介电损耗的电容器,涡流和磁滞损耗the switching losses are significant and can be managed. 这个开关损耗是非常重要的,可以被处理。

they can be further divided into three components:(a)the on-state losses,(b)the off-state losses and the losses in the transition states. 他们可以分为三个部分: 通态损耗，断态损耗和转换过程中产生的损耗。

Semiconductor switches are very important and crucial components in powerelectronic systems.these switches are meant to be the substitutions of the mechanical switches,but they are severely limited by the properties of the semiconductor materials and process of manufacturing. 在电力电子系统，中半导体开关是非常重要和关键部件。

半导体开关将要替换机械开关,但半导体材料的性质和生产过程严重限制了他们。

Switching losses开关损耗Power losses in the power eletronic converters are comprised of the Switching losses and parasitic losses. 电力电子转换器的功率损耗分为开关损耗和寄生损耗the parasitic losses account for the losses due to the winding resistances of the inductors and transformers,the dielectric losses of capacitors,the eddy and the hysteresis losses. 寄生损失的绕组电感器、变压器的阻力、介电损耗的电容器,涡流和磁滞损耗the switching losses are significant and can be managed. 这个开关损耗是非常重要的,可以被处理。

they can be further divided into three components:(a)the on-state losses,(b)the off-state losses and the losses in the transition states. 他们可以分为三个部分: 通态损耗，断态损耗和转换过程中产生的损耗。

第一章第一篇sectiongTwo variables u(t) and i(t) are the most basic concepts in an electric circuit, they characterize the various relationships in an electric circuitu(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。

Charge and CurrentThe concept of electric charge is the underlying principle for explaining all electrical phenomena. Also, the most basic quantity in an electric circuit is the electric charge. Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C).电荷和电流电荷的概念是用来解释所有电气现象的基本概念。

也即，电路中最基本的量是电荷。

电荷是构成物质的原子微粒的电气属性，它是以库仑为单位来度量的。

We know from elementary physics that all matter is made of fundamental building blocks known as atoms and that each atom consists of electrons, protons, and neutrons. We also know that the charge e on an electron is negative and equal in magnitude to 1.60210×10 19C, while a proton carries a positive charge of the same magnitude as the electron. The presence of equal numbers of protons and electrons leaves an atom neutrally charged.我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。