电力电子及电力系统常用翻译.doc

第一章电力电子技术
Semiconductor switches are very important and crucial components in power electronic 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。
1 开关损耗Switching losses
Power losses in the power electronic 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。
2通态损耗On-State Losses
The electrical switches conduct heavy current and have nonzero voltage across the switch in the on-state.The on-state power losses are given by Pon=Uson if。这个电子开关能导通大电流,并且在通态时有非零的压降。这个通态功率损耗的公式为Pon=Uson if。
The Uson and If are respectively the switch voltage in the on—state and the forward current through the switch.For example,the typical power diodes and the power transistors have nearly 0。5 to l volt across them in the on—state.The forward currents can be hundreds to thousands of amperes。The on—state power losses are very significant。 其中Uson是通态时开关上的压降,if是流过开关的电流。例如，典型的功率二极管和功率晶体管有近似0.5～1伏的通态压降。而电流会有数百到数千安培。这个通态损耗非常重要。
3 断态损耗Off—State Losses
The electrical switches withstand high voltages and have nonzero leakage current through the switch in the off-state。The off-state power lesses are given by Poh=Uoff ir在关断状态时，电子开关到经受得起高电压，并会有非零的漏电流。断态损耗的公式为Poh=Uoff ir.
The Usoff and Ir are respectively the reverse bias voltage in the off-state and the reverse current through the switch.For example,the typical power diodes and the power transistors have high reverse voltages in hundreds to thousands of volts and microamps to milliamps through them in the off state. 其中Uoff在断态时的反向偏置电压,ir是流过开关的反向漏电流。例如，典型的功率二极管和功率晶体管有很高的反向压降几百到几千伏和几微安到几毫安的漏电流。
4 转换损耗Transition—State Losses
The practical switching devices have limited capabilities of rate of voltage transition and the rate of current steering.These nonabrupt transition rates give rise to power losses in the switching devices.We will examine these switching losses in two cases separately：the inductive and capacitive loads. 在实际的开关装置限制了电压变换率和电流变化率。非突变引起了开关装置的功率损耗.我们测试开关损耗时分两种情况：感性负载和容性负载。
5 接感性负载的开关Switching with Inductive Load
The indutor is assumed to be large so that the current through it in steady state is nearly constant Io。Assume that initially the switch is off。The inductor current is +Io and freewheels through diode V1.When the switch is turned on,the current through the switch begins to build up linearly(an assumption)to+Io while the diode V1 is still on.The on diode has zero voltage across it（an ideal diode)，hence,the voltage on the switch is held constant at+Us.When the current buildup is over，the diode V1 ceases to conduct and the voltage on the switch ramps linearly(again an assumption)down to zero。 假设电感无穷大，即在稳定时流经电感的电流是恒定的Io，假定开始时开关处于关断状态。电感电流为+Io惯性流过二极管V1。当开关闭合后，电流流经开关开始建立线性上升+Io此时二极管扔导通.二极管压降为0，此时开关两端电压维持在+Us当电流建立完成后,二极管V1截止，开关两端电压线性下降为0。
When the switch is turned off ，the voltage begins to build up linearly to +us while the diode V1 is off。 while the diode is off the current through the switch equals the inductor current,which is constant I0 After the switch voltage reaches aero， the current through the switch begins to decrease below I0，as the remaining current is now steered through the diode V1 which has now turned on The current through the swithch ramps down to zero ultimately。 Switching waveforms with inductive load are shown in Fig.3-1开关打开后，开关两端电压线性上升至Us.此时二极管仍截止，二极管截止,流过开关的电流相当于流过电感的电流,维持在恒定的Io。开关电压到0时,通过开关的电流开始上升到Io以下。此时余留的电流正转向二极管V1，V1导通。最终通过开关的电流下降到0，开关过程的波形的电感负载波形见图3-1
The switching losses are given by ： Psw=1/2UsIo[……….］fs
6 开关损耗的公式
Psw=1/2UsIo[………。]fs
The switching power losses increase linearly with the switching frequency like in the resistive case but about six times more。 The upper bound on the switching frequency is also about half. 开关功率损耗线性增加随着开关频率 此时的损耗要比阻性负载损耗的6倍还多。当f取最大时 Psw=1/2UsIo.
7 开关接有容性负载Switching with capacitive Load
The capacitor is assumed to be large so that the voltage through is in stedy state is nearly constant U0.Assume that initially the switch is on，hence,the cuttent through the switch is IS。The capacitor voltage is U the voltage across the switch is zero and the diode V1is reverse biased.When the switch is turned off,the switch voltage begins to ramp up to+U0 while the diode V1 is still off.During this buildup，the current through the switch is held constant at Is.Wheng the voltage buildup is over，the diode V1begins to conduct and the voltage on the switch is clamped at U0，and the current through the switch ramps linearly(again an assumption）down to zero。 假设电容器很大，致使在稳定状态下其两端电压接近为常数Uo。假使开关初始状态为闭合，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。当开关打开后，开关两端电压开始上升到Uo，此时二极管一直关断。当电压等于Uo时，二极管V1开始导通并且开关两端电压被钳位在Uo。流过开关的电流线性下降到零。
When the switch is closed，the current begins to build up linearly to Is while the diode V1 is still on 。The voltage on the switch remains clamped at U0.After the switchcurrent reaches Is ，the diode turns off and the voltage on the switch begins to ramp down to zero. 当开关闭合，电流开始上升至Is，此时V1仍然导通,开关两端电位被钳位在Uo.当开关电流等于Is时，二极管关断并且开关两端电压线性下降至0。
The switching power losses in the case of capacitive load also have similar dependence as in the case of inductive loads。 当开关闭合，电流开始上升至Is，此时V1仍然导通,开关两端电位被钳位在Uo。当开关电流等于Is时，二极管关断并且开关两端电压线性下降至0.
The switching power losses in the case of capacitive load also have similar dependence as in the case of inductive loads. 接容性负载情况下的开关功率损耗的决定因素与感性负载情况下有相似之处。
The switching losses can be usually minimized in two ways； 1divert the energy from the switch to a loss or non-loss circuit or 2switch at either zero current or at zero voltage。The first is called snubbering and the later is known as zero—voltage and zero-current swithching. 开关损耗一般被归为两点：1。开关的能量转化成了损耗或无损耗电流或开关的过0电流或过0电压，第一个被称为缓冲，最后一个被成为过0电流或过0电压的开关。
第二章Electric Power Systems 电力系统
1 介绍 Introduction
The modern society depends on the electricity supply more heavily than ever before。 现代社会的电力供应依赖于更多地比以往任何时候。 It can not be imagined what the world should be if the electricity supply were interrupted all over the world. 它无法想象的世界应该是什么，如果电力供应中断了世界各地。 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，已成为不可缺少的组成部分产业界的。
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. 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）的托马斯爱迪生所建-站纽约市珍珠街的历史始于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. 这是一个半径直流系统组成的一个蒸汽发动机驱动的直流发电机面积约1。5公里至59供电范围内的客户。负载，其中包括完全的白炽灯，为V提供110通过地下电缆系统. 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。
在一个类似的系统在大多数大城市在世界各地运行数年。随着马达的弗兰克斯普拉格发展在1884年,电机负载被添加到这些系统。这是什么开始发展成为世界上最大的产业之一。在最初的直流系统广泛使用尽管如此，他们几乎完全被空调系统所取代。到1886年，直流系统的局限性也日益明显。他们可以提供功率只有很短的距离从发电机。
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。 为了保持发射功率损失(我2 R）和电压下降到可接受的水平,电压等级，必须长途输电高。如此高的电压不发电和电力消耗可以接受的，因此,电压转换成为一个方便的手段的必要性。
The development of the transformer and AC transmission by L. Gaulard and JD Gibbs of Paris, France, led to AC electric power systems. 在发展的变压器,法国和交流输电由L。巴黎戈拉尔和JD吉布斯导致交流电力系统。
In 1889， the first AC transmission line in North America was put into operation in Oregon between Willamette Falls and Portland. 1889年，第一次在北美交流传输线将在俄勒冈州波特兰之间威拉梅特大瀑布和实施。
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.这是一个单相线路传输功率为4,000公里，超过21 V系统的距离。随着交流的发展多相系统由尼古拉特斯拉，成为更具吸引力的。通过1888年,特斯拉举行交流多项专利电动机，发电机，变压器和输电系统.西屋公司购买了这些早期的发明专利，并形成了系统的基础，现在的交流。
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： 在19世纪90年代，有很大的争议或交流电力行业是否应该统一于直流。到了世纪之交的，在交流系统赢得了原因出在下面的直流系统为:
（1）Voltage levels can be easily transformed in AC systems， thus providing the flexibility for use of different voltages for generation, transmission, and consumption. （1）电压水平可以很容易地改变了空调系统，从而提供了传输的灵活性，发电用不同的电压和消费。
（2)AC generators are much simpler than DC generators。 （2）交流发电机简单得多比直流发电机。
（3）AC motors are much simpler and cheaper than DC motors. (三）交流电机和电机便宜简单得多,比直流。
The first three—phase line in North America went into operation in 1893——a 2,300 V, 12 km line in southern California。 前三个阶段的美国北线投产于1893年- 1 2300五，南加州12公里路线研究。 In the early period of AC power transmission， frequency was not standardized. 在电力传输初期交流,频率不规范。 Many different frequencies were in use： 25, 50, 60， 125， and 133 Hz。 有许多不同频率的使用：25，50，60，125，和133赫兹。 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。 这对互连的问题。最后60赫兹标准获得通过，成为美国在北美，虽然是50赫兹在许多其他国家使用。
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 . 较长的距离越来越需要大量的电力传输多激励他们逐步使用高压的水平。为了避免电压增殖数量无限,业界标准电压水平。在美国，标准是115，138， 161，和230千伏的高电压（高压)类，345，500和765千伏级的特高电压(超高压）。在中国，各级使用电压为10，35,110级高压, 220，中国330（仅在西北）和500千伏超高压类。
The first 750 kVtransmission line will be built in the near future in Northwest China. 第一个750 kVtransmission线将建在不久的将来在中国西北地区。
With the development of the AC/DC converting equipment， high voltage DC （HVDC) transmission systems have become more attractive and economical in special situations. 随着交流的发展/直流转换设备,高压直流高压直流（HVDC）传输系统已经成为更具吸引力的经济和情况特殊。 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. 在高压直流输电可用于输电块以上的大长途电话,并提供不同系统间的异步连接在AC联网系统将是不切实际的,因为稳定考虑，或因标称频率的系统。
The basic requirement to a power system is to provide an uninterrupted energy supply to customers with acceptable voltages and frequency. 基本要求到电源系统是提供一个不间断的能源供应,以客户可接受的电压和频率。 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. 由于电力无法大量储存在一个简单的方法和经济，电力的生产和消费必须同时进行.系统的故障或误操作的权力在任何阶段可能导致电力供应中断给客户。 Therefore， a normal continuous operation of the power system to provide a reliable power supply to the customers is of paramount importance. 因此，一个正常的电力系统连续运行的，提供可靠的电力供应给客户的重要性是至关重要的。
翻译
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。 电力系统稳定，可广泛定义为干扰财产的权力系统，可继续经营的状态下正常运行的平衡条件和后向遭受恢复一个可以接受的平衡状态.
Instability in a power system may be manifested in many different ways depending on the system configuration and operating mode. 在电力系统的不稳定可能会表现在经营方式和多种不同的方式取决于系统配置。
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 "。 传统上，稳定性问题一直是一个保持同步运行.由于电力系统的发电电力，一个令人满意的系统运行的必要条件是，依靠同步电机同步电机都留在同步或通俗的“步骤”。这一方面是受稳定的发电机转子的动态角度和功角的关系，然后提到“转子角稳定”。
2 电力系统的组成部分 Components of Power Systems
Modern power systems are usually large—scale, geographically distributed, and with hundreds to thousands of generators operating in parallel and synchronously. 现代电力系统通常规模大,地域分布,并与数百名，并同步在数以千计的发电机并联运行。 They may vary in size and structure from one to another， but they all have the same basic characteristics: 他们可能会有所不同的规模和结构从一个到另一个，但它们都具有相同的基本特征：
（1)Are comprised of three—phase AC systems operating essentially at constant voltage. （1）是由三个三相交流电压恒定系统经营本质上。 Generation and transmission facilities use three-phase equipment 。 发电和输电设施使用三个阶段的设备.
Industrial loads are invariablythree—phase; single—phase residential and commercial loads are distributed equally among the phases so as to effectively form a balanced three-phase system. 工业负荷总是三相,单相负载的住宅和商业之间平等分配的阶段，从而有效地形成一个平衡的三相系统。
(2）Use synchronous machines for generation of electricity. （2）使用电力同步一代机器。 Prime movers convert the primary energy （fossil， nuclear， and hydraulic） to mechanical energy that is, in turn, converted to electrical energy by synchronous generators. 牵引车转换的一次能源(化石,核能和水力）为机械能就是反过来，中,转换为电能的同步发电