自动化专业英语论文SpaceVectorPWMT翻译
空间矢量脉宽调制技术在交流感应电机控制中的使用
前言：由于交流感应电机的可靠性、坚固耐用、相对的低成本，它在许多应用领域已经渐渐地取代了直流电机。现在在许多工厂中的空气压缩机都是用交流感应电机来驱动的。速度控制交流感应电机可以节省大量的电能。在交流电机的中，空间矢量脉宽调制技术已经变成了流行的技术。其控制方法与仿真如下所述。
关键词：空间矢量脉宽调制；交流感应电机；仿真。
I. 绪论
随着可关断晶体管、大功率管、隔离栅双极晶体管等晶体管工作特性的的进步，频率转换方法使用在电机速度控制中正在变得越来越流行。脉宽调制变流器使在电机中控制电压和电流的频率和大小的数量级成为了可能。因此，相对于固定频率的电机驱动，脉宽调制换流电机驱动可以提供更好的效率和更高的性能。现在有正弦曲线、过度、和相对空间矢量脉宽调制等几种技术。空间矢量脉宽调制方法不仅可以产生转动磁场而且可以更好地提高电压的利用率。
此外，在如今仿真技术已经变成了一种解决一些重要工程问题的技术方MA TLAB/simulink仿真软件是一个非常重要的仿真软件，在我们产生产品之前，很有必要利用仿真软件去实现产品的可行性。
II. 空间矢量脉宽调制技术
A. 空间矢量脉宽调制技术的简介：
空间矢量脉宽调制引用了由三相功率转换器是最上面的三个功率三极管组成的一个特殊矩阵。和直接正弦曲线调制技术相比，在应用于交流电机调相中时,空间矢量脉宽调制电压和电流的输出端可以产生极少的波形失真，并且可以提供更高效率的电压补给。
典型的三相电压源功率变流器的结构如图In Fig 所示。在应用于应用于电机的绕组中时V a, Vb and Vc时电压的输出端。Q1到Q6六个功率晶体管形成输出端，他们由a, a’, b, b’, c and c’六段控制。在交流感应电机的控制中，当最上端的功率管转换时，相应的下面的功率管是关断的。开和关的状态对于上端Q1，Q3和Q5是等同的，a，b和c端在电压输出端的估值是很足够的。
Fig.1 三相功率转换器图
转换可变矢量[a, b, c]t之间的关系、行与行之间的的电压矢量之间的关系[V ab Vbc
Vca]t、输出相电压矢量之间的关系如下（1）、（2）式所示。
B. 转换方式和基本空间矢量
如图in Fig.1 所示。在上部的三个功率晶体管的开和关的组合状态有八种可能的组合。注意到下部的功率管的开关状态和上部的功率管的是相反的，所以一旦上部的三个功率管的开关状态确定了，下部的功率管的状态就可以完全确定了。根据式（1）、（2），在直流电源下的八种组合开关管的状态组合和行与行之间的输出矩阵和相电压如Tab.1. 所示。
Tab.1 设备的开关状态和相应的输出电压
C.定子电压的(α, β) 结构表达
在FOC的运算法则中，控制变量可表达在一个转置结构中。电流矢量Isref 可以直接控
制在规定的参考电压矢量中经过Park-1转换的矩阵。这个基准电压矢量可以在(α, β) 结构中表达。三相电V a, Vb and Vc之间的电压和基准参考电压三相电压之间的关系同样可以在(α, β) 结构中实现。
三相电压在(α, β) 结构中用克拉克转换方程表达如下所示。
由于在功率转换中八种状态组合都是有可能的，根据晶体管控制信号a，b，c的状态，V sα和V sβ在(α, β) 结构表达中可以取一串有限的数值。他们之间的关系表达如表2 所示。
Tab.2定子电压
此处的U0, U60, U120, U180, U240, U300, O000 和O111被称作基本空间向量。V sα和V sβ被称作基本空间向量的分量。
D.输出电压的α, β分解
八个基本空间向量通过联合转换的定义如图Fig 2 所示
空间向量脉宽调制技术的目的在于使用八个基本空间向量去估算输出的参考电压值。
在八个可能转换状态下使用去估算定子参考电压期望值的方法就是联合邻近的定子参考电压和调节每两个邻近定子的运行时间。参考电压Uout 和Uα,Uβ与基本空间向量之间的关系如图Fig .3.所示。
参考基准电压向量
在图.Fig .3中参考电压Uout 在基本空间向量U0 和U60 与相邻定子之间的运行时间之间的关系如（4）所示：
T1和T3周期的数量如（5）式所示:
显而易见，所有基本空间向量的行列值都是2VDC/3.最大的相电压是空间向量电压值的2/ 3VDC，所以基本空间向量在组合的绝对值是60 0 = = U U。。从上面的方程中我推断出T1和T3.
周期的余下时间都是耗在零向量中。T0值的方程就是T0=T-T1-T3.
在每一部分中，每个交换周期都是可以计算出来的。时间矢量的运用数量都与如下的变量有关：
在上述的范例中第三部分中，t1=-Z, t2=X;
同理可证，在其他部分中的输出电压Uout 中，相应的t1和t2可以通过X、Y与Z表示出来。
表3.t1和t2的估值
为了知道上述中哪一个变量正在应用，上述关系在参考电压矢量中的值必须得到。E.关键部分和开关时间
为了确定这部分，一个简单的的方法就是计算参考电压矢量在(a, b, c)同一时刻的V a, Vb 和Vc 的发射电压。这些发射电压都是相对于参考电压0的。
发射电压V a, Vb 和Vc如下式所示：
现在a，b，c三个变量的关系如下，如果V a>0,则a=1，否则a=0；如果Vb>0,则b=1,否则b=0；如果Vc>0，则C=1，否则c=0。N=4c+2b+a。变量N与其他部分的关系如下表格所示：
表.4
下一步就是计算三个必须的占空比，其式子如下所示：
最后，根据上部分我们必须确定正确的转换时间。以下的表五，给出了确定关系：
表.5 Tcm1 Tcm2 Tcm3估值转换时间
III. 空间矢量脉宽调制的仿真
在Matlab/Simulink的仿真环境中，我们很容易去实现SVPWM 的运算。图Fig.4 是全部的模型结构。图Fig. 5 到Fig. 10时全部模型的内部结构。
图Fig.4 是全部的模型结构。
IV. 结果
如果我们设置交流感应电机的参数如下：
电机模型：5kw 500v 1460RPM
转子类型:鼠笼式
定子阻抗和感应系数[Rs(ohm)Lis(H)]:[0.2147,0.000991] 转子阻抗和感应系数[Rr(ohm)Lir(H)]:[0.2205,0.000991] 互感系数Lm(H): 0.06419
Vdc: 500v
初始条件[1,0 0,0,0 0,0,0 ]
根据以上，我们可以得到如下仿真结果.
在仿真中我们可以看见：在经过3/2 的转换后，我们可以得到基准参考电压，它们是理想的正弦波。根据转换时间，我们可以得到控制功率变流器和驱动电机的PMW波形。
在Fig.14中我们可以得到：在电机驱动时，定子的峰值电流可达到450A。在开始的时间段，当转矩恒定时，钉子电流大约是150A。定子达到恒定时的启动时间大约是0.7s。三相输出电压的波形接近于正弦波。因此，我能使用不对称的PWM信号，输出电压波形不是
那么地接近于正弦波。如果我们使用非对称的PWM信号，波形将会更好。此外，和正弦调制技术相比，在SVPWM 调制中，在输出电压和电流中我们可以在非零矢量中插入一些对称零的矢量去减少波形失真
和正弦调制技术相比。
SVPWM 技术可以使控制设备更加简易，脉冲冲击少，懆声小，在输出电压和电流产生更少的波形失真，提高电源的效率。因此，SVPWM对交流感应电机的控制非常不错并且广泛地使用。
致谢
非常感谢厦门大学的谢富鹏教授在研究和此文中对我的帮助。衷心感谢我的父母和我的女朋友张秋丽对我热心的支持。同时，非常谢谢我的妹妹张彩霞和她丈夫杨海东对的关怀与照顾。
自动控制论文 英文版
自动控制论文 作者洪劲松 专业电气工程及其自动化 学号120301628 指导教师赵国新
Automatic control is when no one is directly involved in the case, the use of additional equipment or control device, the machine, device, or a working state of the control object or parameters (charged) automatically according to the predetermined rules. The traditional industrial production process using dynamic control technology, can effectively improve the quality of the products and the enterprise economic benefit. In today's rapid development of science and technology, automatic control technology in the field of industrial and agricultural production, national defense and science and technology, has a very important role. In a short span of one hundred years, the development of automatic control theory has been surprising, has a huge impact on human society. Automatic control theory is the study of automatic control common law science and technology. It is both an ancient and has become a mature discipline, another door is developing, the strong vitality of the emerging disciplines. From 1868 maxwell J.C.M axwell low order system stability criterion is put forward to date more than one hundred years, the development of automatic control theory can be divided into four main stages: the first stage: the classical control theory (or) classical control theory of the formation, development and maturity; The second stage: the rise of modern control theory and development; The third stage: big system control the rise and development stage; The fourth stage: intelligent control stage of development. The basic characteristics of the first stage of the classical control theory is mainly used for linear time-invariant systems research, namely for describing the system of linear differential equation with constant coefficients of analysis and synthesis; It is used only for single input and single output feedback control system; Only discuss the relationship between the system input and output, and ignore the internal state of the system, is a method of external description of the system. The basic method used: root locus method, frequency method, PID regulator (frequency domain). Control theory in the early stage of development, the automatic adjustment principle is based on the feedback theory, mainly used in industrial control. Feedback theory for feedback control. Feedback control is one of the most basic is the most important control mode, after the introduction of feedback signal, system response to come from the external and internal interference become very dull, so as to improve the anti-interference ability and the control precision of the system. Feedback effects, meanwhile, brings the problem of system stability, which was once the system stability problem in people inspired people to conduct the thorough research to the feedback control system in the enthusiasm, promote the development of the theory of automatic control and improvement. So in a sense, the classical feedback control theory is accompanied by the emergence and development of control technology and gradually improve and mature. During the second world war, in order to design and manufacture of aircraft and Marine autopilot, artillery positioning system, radar tracking system based on feedback principle of military equipment, to further promote and perfect the development of automatic control theory. In 1868, maxwell (J.C.M axwell) lower order algebraic criterion of the stability of the system are put forward. In 1875 and 1896, mathematicians rous (Routh) and hull weitz (Hurwitz) respectively independently the stability criterion of high order system was put forward, namely the Routh Hurwitz criterion. During the second world war (1938-1945), Nyquist (H.N yquist) in 1948, proposed the theory of frequency
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电气自动化专业毕业论文英文翻译
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Building construction concrete crack of prevention and processing Abstract The crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure. Keyword: Concrete crack prevention processing Foreword Concrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and
自动化专业英语_考试版的文章翻译
UNIT 1 A 电路 电路或电网络由以某种方式连接的电阻器、电感器和电容器等元件组成。如果网络不包含能源，如 电池或发电机，那么就被称作无源网络。换句话说，如果存在一个或多个能源，那么组合的结果为有源网络。在研究电网络的特性时，我们感兴趣的是确定电路中的电压和电流。因为网络由无源电路元件组成，所以必须首先定义这些元件的电特性. 就电阻来说，电压-电流的关系由欧姆定律给出，欧姆定律指出：电阻两端的电压等于电阻上流过的电流乘以电阻值。在数学上表达为: u=iR (1-1A-1)式中 u=电压，伏特；i =电流，安培；R = 电阻，欧姆。 纯电感电压由法拉第定律定义，法拉第定律指出：电感两端的电压正比于流过电感的电流随时间的 变化率。因此可得到：U=Ldi/dt 式中 di/dt = 电流变化率，安培/秒； L = 感应系数，享利。 电容两端建立的电压正比于电容两极板上积累的电荷q 。因为电荷的积累可表示为电荷增量dq的和或积分，因此得到的等式为 u= ，式中电容量C是与电压和电荷相关的比例常数。由定义可知，电流等于电荷随时间的变化率，可表示为i = dq/dt。因此电荷增量dq 等于电流乘以相应的时间增量，或dq = i dt，那么等式 (1-1A-3) 可写为式中 C = 电容量，法拉。 归纳式(1-1A-1)、(1-1A-2) 和 (1-1A-4)描述的三种无源电路元件如图1-1A-1所示。注意，图中电流的参考方向为惯用的参考方向，因此流过每一个元件的电流与电压降的方向一致。 有源电气元件涉及将其它能量转换为电能，例如，电池中的电能来自其储存的化学能，发电机的电能是旋转电枢机械能转换的结果。 有源电气元件存在两种基本形式：电压源和电流源。其理想状态为：电压源两端的电压恒定，与从 电压源中流出的电流无关。因为负载变化时电压基本恒定，所以上述电池和发电机被认为是电压源。另一方面，电流源产生电流，电流的大小与电源连接的负载无关。虽然电流源在实际中不常见，但其概念的确在表示借助于等值电路的放大器件，比如晶体管中具有广泛应用。电压源和电流源的符号表示如图1-1A-2所示。 分析电网络的一般方法是网孔分析法或回路分析法。应用于此方法的基本定律是基尔霍夫第一定律，基尔霍夫第一定律指出：一个闭合回路中的电压代数和为0，换句话说，任一闭合回路中的电压升等于电压降。网孔分析指的是：假设有一个电流——即所谓的回路电流——流过电路中的每一个回路，求每一个回路电压降的代数和，并令其为零。 考虑图1-1A-3a 所示的电路，其由串联到电压源上的电感和电阻组成，假设回路电流i ，那么回路总的电压降为因为在假定的电流方向上，输入电压代表电压升的方向，所以输电压在（1-1A-5）式中为负。因为电流方向是电压下降的方向，所以每一个无源元件的压降为正。利用电阻和电感压降公式，可得等式(1-1A-6)是电路电流的微分方程式。 或许在电路中，人们感兴趣的变量是电感电压而不是电感电流。正如图1-1A-1指出的用积分代替式(1-1A-6)中的i，可得1-1A-7 UNIT 3 A 逻辑变量与触发器
机械类数控车床外文翻译外文文献英文文献车床.doc
Lathes Lathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod. The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle. The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up
英语专业毕业论文翻译类论文
英语专业毕业论文翻译 类论文 Document number：NOCG-YUNOO-BUYTT-UU986-1986UT
毕业论文（设计）Title:The Application of the Iconicity to the Translation of Chinese Poetry 题目:象似性在中国诗歌翻译中的应用 学生姓名孔令霞 学号 BC09150201 指导教师祁晓菲助教 年级 2009级英语本科（翻译方向）二班 专业英语 系别外国语言文学系
黑龙江外国语学院本科生毕业论文（设计）任务书 摘要
索绪尔提出的语言符号任意性，近些年不断受到质疑，来自语言象似性的研究是最大的挑战。语言象似性理论是针对语言任意性理论提出来的，并在不断发展。象似性是当今认知语言学研究中的一个重要课题，是指语言符号的能指与所指之间的自然联系。本文以中国诗歌英译为例，探讨象似性在中国诗歌翻译中的应用，从以下几个部分阐述：（1）象似性的发展；（2）象似性的定义及分类；（3）中国诗歌翻译的标准；（4）象似性在中国诗歌翻译中的应用，主要从以下几个方面论述：声音象似、顺序象似、数量象似、对称象似方面。通过以上几个方面的探究，探讨了中国诗歌翻译中象似性原则的重大作用，在诗歌翻译过程中有助于得到“形神皆似”和“意美、音美、形美”的理想翻译效果。 关键词：象似性；诗歌；翻译
Abstract The arbitrariness theory of language signs proposed by Saussure is severely challenged by the study of language iconicity in recent years. The theory of iconicity is put forward in contrast to that of arbitrariness and has been developing gradually. Iconicity, which is an important subject in the research of cognitive linguistics, refers to a natural resemblance or analogy between the form of a sign and the object or concept. This thesis mainly discusses the application of the iconicity to the translation of Chinese poetry. The paper is better described from the following parts: (1) The development of the iconicity; (2) The definition and classification of the iconicity; (3) The standards of the translation to Chinese poetry; (4) The application of the iconicity to the translation of Chinese poetry, mainly discussed from the following aspects: sound iconicity, order iconicity, quantity iconicity, and symmetrical iconicity. Through in-depth discussion of the above aspects, this paper could come to the conclusion that the iconicity is very important in the translation of poetry. It is conductive to reach the ideal effect of “the similarity of form and spirit” and “the three beauties”. Key words: the iconicity; poetry; translation
机械类英语论文及翻译翻译
High-speed milling High-speed machining is an advanced manufacturing technology, different from the traditional processing methods. The spindle speed, cutting feed rate, cutting a small amount of units within the time of removal of material has increased three to six times. With high efficiency, high precision and high quality surface as the basic characteristics of the automobile industry, aerospace, mold manufacturing and instrumentation industry, such as access to a wide range of applications, has made significant economic benefits, is the contemporary importance of advanced manufacturing technology. For a long time, people die on the processing has been using a grinding or milling EDM (EDM) processing, grinding, polishing methods. Although the high hardness of the EDM machine parts, but the lower the productivity of its application is limited. With the development of high-speed processing technology, used to replace high-speed cutting, grinding and polishing process to die processing has become possible. To shorten the processing cycle, processing and reliable quality assurance, lower processing costs. 1 One of the advantages of high-speed machining High-speed machining as a die-efficient manufacturing, high-quality, low power consumption in an advanced manufacturing technology. In conventional machining in a series of problems has plagued by high-speed machining of the application have been resolved. 1.1 Increase productivity High-speed cutting of the spindle speed, feed rate compared withtraditional machining, in the nature of the leap, the metal removal rate increased 30 percent to 40 percent, cutting force reduced by 30 percent, the cutting tool life increased by 70% . Hardened parts can be processed, a fixture in many parts to be completed rough, semi-finishing and fine, and all other processes, the complex can reach parts of the surface quality requirements, thus increasing the processing productivity and competitiveness of products in the market. 1.2 Improve processing accuracy and surface quality High-speed machines generally have high rigidity and precision, and other characteristics, processing, cutting the depth of small, fast and feed, cutting force low, the workpiece to reduce heat distortion, and high precision machining, surface roughness small. Milling will be no high-speed processing and milling marks the surface so that the parts greatly enhance the quality of the surface. Processing Aluminum when up Ra0.40.6um, pieces of steel processing at up to Ra0.2 ~ 0.4um.
专业英语阅读 翻译文章
C o m m e n c e m e n t o f t h e Commercial Operation of 600M W U n i t , "H i ro n o N o. 5Thermal Power Station of The Tokyo Electric Power Co., Inc." Commercial operation of The Tokyo Electric Power Co., Inc. Hirono No. 5 Thermal Power Station commenced in July 2004. This plant is a 600 MW coal-fired supercritical power plant. The main line-up of the plant, which features a steam turbine and a boiler, are supplied by Mitsubishi Heavy Industries, Ltd. (MHI). MHI set up this plant with a range of such key equipment along with ancillary facilities such as control systems, a flue gas treatment system, a wastewater treatment system, and stacks. This report gives a brief overview of the advanced technologies applied to the steam turbine and boiler of this plant supplied by MHI. 1. Introduction The Hirono No. 5 Thermal Power Station began com-mercial operation in July 2004. It is a 600 MW coal-fired,supercritical power plant that operates under the high-est global standards for steam conditions (24.5MPa x 600/600o C). The steam turbine has various advanced MHI tech-nologies, including the first 600 MW class two-casing turbine, high- and intermediate-pressure combined cas-ing developed by utilizing high temperature materials and cooling structures to cope with the ultra supercritical steam condition, 48 inch steel integral shroud blade (ISB), a new type of condenser, and a single shell deaerator cum storage tank. The boiler adopted in this plant has MHI's advanced technologies. They are reduced emission of NOx and unburned carbon with the A-PM burner and MRS pul-verizer. In addition, the vertical waterwall furnace that uses high temperature compatible materials and rifled tubes are adopted. Further, the plant is very much streamlined through the use of such simple systems and equipment as de-scribed below: (1) unification of air duct and flue gas duct into a single line through the adoption of a maximum capacity class fan, (2) unification of all feed water heaters into a single line, (3) unification of circulating water pumps into a single line, and (4) adoption of a plant starting system that does not rely on the boiler circulating pump. Since the plant is located in a narrow site adjacent to existing units operated using oil and gas, the overall arrangement of the plant has been improved by consult-ing with the Owner and is arranged in a more compact manner. Advanced MHI technologies have also been adopted in ancillary facilities. This includes the use of a dry se-lective catalytic NOx removal system, a high performance flue gas treatment system based on the harmonious de-sign of a double contact flow scrubber type flue gas desulfurization system with a low-low temperature dry electrostatic precipitator, an overall waste water treat-ment system, and self-supporting group stacks. In this way, MHI has drawn upon all of its competencies in es-tablishing this plant. 2. Steam turbine Figure 1Figure 1 shows an external view of the Hirono No. 5 steam turbine. Fig. 1 View of the 600 MW Hirono No.5 steam turbine HIROMASA MOMMA*1 TAKAYUKI SUTO*1RYUJI IWAMOTO*3 JUNICHI ISHIGURO*1TOSHIHIRO MIYAWAKI*2TSUYOSHI NAKAHARA*4