電氣工程及其自動化專業(yè)英語期末復(fù)習(xí)資料整理

1、This simple circuit made up of a source,a load and two wires is seldom,if ever,met with in practice.Practical circuits may contain a large number of sources and loads interconnected in a variety of ways.這種由一個電源、一個負(fù)載和兩根導(dǎo)線組成的簡單電路，在實踐中即使能 碰到也是很少見的。實際電路可能包括許多按不同方式 連接的電源和負(fù)載。The direct ion of curre nt flo

2、w may be show n either by a hollow arrowhead or by suppl ying the curre nt symbol with a double subscriptwhose first digit identifies the junction at a higher potential and the second 省略了 identifies) the junction at a lower potential.電流的方向既可用一個空心箭頭來表示，又可用帶有雙下標(biāo)的電流符號來表示，且第一個下標(biāo)認(rèn)定為高電位點，第二個下標(biāo)為低電位點。In a p

3、ote ntial-distributi on diagram it is represe nted( on a suitable scale)by the slopeof the respective curve at any poi nt,the slope bei ng defi ned as the tangent of the angle that the line tangent to the curve at that point make with the x-axis.在電勢分布圖中，電流由曲線上該點相應(yīng)的 斜率表示，斜率定義為切線與x坐標(biāo)軸夾角的正切。It follow t

4、hat the r.m.s.(effective) value of an alternating current is numerically equal to the magnitude of the steady direct curre nt that would produce the same heat ing effect in the same resista nee and over the same period of time.由此得出：交流電流的均方根(有效值)大小上等于在相同電阻上和同一時間內(nèi)產(chǎn)生相同的熱 效應(yīng)的恒穩(wěn)直流電流。The operational volta

5、ge amplifier is representedschematically by the triangular symbol .AO is the voltage gain from differe ntial in put to sin gle-e ndrd output and is always a positive nu mber . Phase reversals are taken into account at the in put termi nal， which is the reas on why these are labeled ” +” andThe volta

6、ge at each terminal，including the output ,may be referred to common reference ,usually ground ,and uni ess otherwise stated ,this com mon refere nee will be assumed . Thus ,lett ing V(+) represe nt the voltage of the positive in put term inal with respect to the com mon refere nee ,and V(-),that of

7、the n egative in put term inal ,we may defi ne the differential input voltage as V 二V( ) -V (-) ,and the output voltage is V0 = A0Vid.電壓運算放大器可用三角形符號來表示。A0表示從差動輸入端到單一輸出端的電壓增益，并恒為正值。考慮到在輸入端可能會有反相輸入的情況，所以要標(biāo)上“ +號與號。每個端口包括端口的輸出端口的電壓，都可以選一個共同的參考點，通常選大地，除非另有說明，否則所假 定的參考點就是地。這樣，用 V(+)代表正向輸入端對參考點的電壓，而V(-)則代表

8、負(fù)向輸入端對參考點的電壓，我們可以將差動輸入電壓定義為二V)-V(-)，輸出電aa壓V。二Ay。The significance of this result is that the terminal voltage gain ,which is the usable voltage gain , is in depe ndent of the parameters of the amplifier ,and depe nds only on the exter nal comp onent R1 and 這個結(jié)論的意義在于端電壓增益(這是很有用的電壓增益)與放大器的參數(shù)無關(guān)，而只取決于 外部

9、元件R1和R2。A truth table is a list of all of the possible in put variable state combinations of a circuit listed in binary-sequential order with the corresponding output state for each combination listed in an adjace nt colu mn. Tablei shows the binary nu mberacorresponding tothe decimal nu mbers from

10、zero to fiftee n.真值表是這樣的一個表格，電路中可能輸入的所有不同狀態(tài)組合按二進制順序連續(xù)排列，輸出狀態(tài)與輸入端的每種組合對應(yīng)，表1表示了與十進制015對應(yīng) 的二進制數(shù)。The truth table is used as the begi nning point in desig ning or an alyz ing a logic circuitThe sequential listing makes it easy to recog nize if any in put comb in ati ons were missed. It is made up of eith

11、er from the problem specificati ons or by seque ntial testi ng of an assembled circuit. A logic equati on can be formulated from the truth table and a logic circuit can be developed from the equation. Truth tables are used in defining the basic AND,OR and NOT functions below在設(shè)計或分析一個邏輯電路時，首先要列寫真值表。這種

12、連續(xù)的表格很容易辨認(rèn)出是否遺漏了任何一種組合，她可有問題的具體情況或?qū)σ患呻娐愤M行連續(xù)測試來建立。由真值表可建立 邏輯等式，由此等式就可構(gòu)造一邏輯電路。在下面定義基本邏輯與”、或”和 非”的函數(shù)中就用到了真值表。The logic AND fun cti on can be expa nded to any nu mber of in puts ,simply by appl yin gthe basic defi niti on. Thus a 5-i nput logic AND gate will produce an output only if the in put comb in

13、 atio n ABCDE=11111 exists,and providing the physical circuit will still function properly with that many in put attached.只要運用基本定義，邏輯與函數(shù)便可擴展到任意一個輸入。因此一個五輸入的邏輯與門只有在 ABCDE=11111且具體電路與那些連接的輸入量有恰當(dāng)?shù)暮瘮?shù)關(guān)系時才等于一。Today moti on con trol is an area of tech no logy that embraces many diverse discipli nes,such as

14、 electrical mach in es,power semic on ductor devices, conv erter circuits,dedicated hardware sig nal electronics,control theory,and microcomputers,more recently,the advent of VLSI/ULSI circuits and sophisticated computer-aided desig n tech niq ues has added nelimen sio nsto the tech no logy.當(dāng)今世界的運動控

15、制是這么一個綜合性的技術(shù)領(lǐng)域，其包括諸如電機、電力半導(dǎo)體裝置、轉(zhuǎn)換 器電路、專門的硬件信號電子學(xué)、控制理論、微型計算機等方方面面的眾多技術(shù)領(lǐng)域。最近出 現(xiàn)的超大規(guī)模集成電路，甚至特大規(guī)模集成電路，再加上日漸程序的計算機輔助設(shè)計技術(shù)出現(xiàn)， 又進一步拓寬了運動控制技術(shù)領(lǐng)域新的運用范圍。Mechanical motion control systemSound widespread acceptanee in industry since the invention of the steam engine started the first in dustrial revoluti on in ei

16、ghtee nth cen tury,whe n mass in dustry manu facturi ng replaced manu al labor.18世紀(jì)蒸汽機的發(fā)明開啟了第一次工業(yè)革命，當(dāng)時大規(guī)模的工業(yè)生產(chǎn)化代替了手工勞動，從此 以后，運動機械的運動控制系統(tǒng)便在工業(yè)領(lǐng)域得到廣泛地應(yīng)用。The con cept of computer-i ntegrated manu facturi ng(CIM),in which bus in ess decisi ons are tran slated to desig ns, which are the n tran slated to m

17、anu facturi ng through a hierarchy of computers and moti on con trol systems, will become a reality in the n ear future.計算機集成制造的概念，將在不遠(yuǎn)的將來成為現(xiàn)實，所謂計算機集成制造，就是首先將商務(wù)決 策轉(zhuǎn)化為產(chǎn)品設(shè)計，然后又通過計算機和運動控制系統(tǒng)將其轉(zhuǎn)化為產(chǎn)品制造Bernd M.Bauma nn has dem on strated the suitability of fuzzy con trol tech niq ues for the power-train ma

18、n ageme nt of hybrid electric vehicles.However,his operati on strategyepresentshow the in dividual comp onents of the drive train will in teract with one ano ther, and emphasizes the mea ns for controlling the power flow： such as ransmissions or clutchesand dependency of the components on each other

19、.Bernd Baumann已經(jīng)證明了模糊控制技術(shù)對混合式電動車的傳動的控制是適宜的。然而，更重 要的是其在文中說明了，在驅(qū)動系統(tǒng)的整個鏈條中各部件將會是怎樣相互作用的，以及在諸如 傳遞或提取功率這樣的過程中的控制的方法，還有系統(tǒng)中各部件之間的相互依存的關(guān)系。The direct-axis synchronous reactanee is the ratio of the fundamental component of reactive armature voltage, due to the fun dame ntal direct-axis comp onent of armature

20、curre nt. to this comp onent of curre nt un der steady-state con diti ons and at rated freque ncy.同步電機的直軸同步電抗，是由電樞反應(yīng)電流的直軸基波分量所產(chǎn)生的電樞反應(yīng)基波電壓與額 定頻率穩(wěn)態(tài)條件下的基波電流分量的比值Major data acquisition and control elements found in substation automation and their typical relati on ship to each other and to corporate dat

21、a in frastructure. Regardless of size and complexity of the n etwork, the basic eleme nt of substati on automati on are gen erally those described in the followi ng subsectio ns主要的數(shù)據(jù)采集和控制元件，是變電所自動化，及其相互之間的，還有其他共同數(shù) 據(jù)底層之間的通常關(guān)系的基礎(chǔ)。無論網(wǎng)絡(luò)的規(guī)模和復(fù)雜程度如何，變電所綜合自動化系統(tǒng)的基 本要素不外乎如下幾點。The purpose of a power system is

22、to deliver the power the customers require in real time, on dema nd, within acceptable voltage and frequency limits, and in a reliable and economic manner. In normal operation of a power system ,the total power generation is balaneed by the total load and transmission losses. The system frequency an

23、d voltage on all the buses are within the required limits, while no overloads on li nes or equipme nt are resulted .However ,loads電力系統(tǒng)運行的目的就是一旦用戶需要，便能以適時的、可靠的、經(jīng)濟的方式，向用戶按其所 要求的電壓和頻率的范圍提供其所需的電力。在電力系統(tǒng)正常運行時，其所發(fā)總電量與負(fù)荷及 輸電損耗之和是相平衡的。由于線路和設(shè)備沒有出現(xiàn)過載，因而系統(tǒng)中的所有母線的電壓和頻 率均在所需的范圍之內(nèi)。然而，負(fù)荷總是經(jīng)常在或大或下的變化，因而必須采取一定控制手段，以使

24、電力系統(tǒng)維持在一個穩(wěn)定而經(jīng)濟的運行狀態(tài)。Power system control is very important issue to maintain the normal operation of a system.System voltage levels,frequency,tie-line flows,line currents,and equipment loading must be kept within limits determ ined to be safe in order to provide satisfactory service to the power sys

25、tem customers.翻譯：電力系統(tǒng)控制是維持電力系統(tǒng)正常運行非常重要的問題。為了給電力系統(tǒng)的用戶提供令 人滿意的服務(wù)，系統(tǒng)的電壓、頻率、連接線處的涌流、線電流，以及設(shè)備負(fù)荷率，必須要限制 在安全的范圍之內(nèi)。AGC is an effective means for power and frequency control in large-scale power systems. In an in terc onn ected power system, the primary objectives of AGC are to regulate freque ncy to the spe

26、cified nominal value and to maintain the in tercha nge power betwee n con trol areas at the scheduled values by adjusted the output of the selected gen erators. This fun ctio n is com mon ly referred to as load-freqe ncy con trol.A sec on dary objective is to distributed cha nge in gen erati on amon

27、g un its to mi ni mize operati ng costs.將電壓維持在必需的范圍內(nèi)的難題，又被電力系統(tǒng)的現(xiàn)實復(fù)雜化了，這個現(xiàn)實就是系統(tǒng)為其提 供電能負(fù)荷的數(shù)量不計其數(shù)，且為其提供的發(fā)電機組的數(shù)量也是最大的。當(dāng)負(fù)荷變化時，輸電 系統(tǒng)的無功功率的需求也是變化的。由于無功功率不能長距離傳輸，因而電壓控制的功能，就 不得不采用在整個系統(tǒng)中分散布局的某種專用的裝置來完成。這就與頻率控制時的情形截然相 反，頻率控制是取決于系統(tǒng)總的有功平衡的。恰當(dāng)?shù)剡x擇和布局控制無功功率和電壓的裝置， 是電力系統(tǒng)工程所面臨的主要挑戰(zhàn)之一。In an interconnected power syste

28、m,the primary objectives of AGC are to regulate frequency to the specified nominal value and to maintain the interchange power between control area at the scheduled values by adjust the output of the selected gen erators.在相互連接的電力系統(tǒng)中，發(fā)電自動化控制的首要的目標(biāo)有兩個，一將頻率調(diào)節(jié)到指定的額定 值，二是通過調(diào)節(jié)所選定的發(fā)電機的輸出功率，維持各控制區(qū)域之間的計劃發(fā)電量之間的交換。The problem of maintaining voltages within the required limits is complicated by the fact that the power system supplies power to a vast nu mber of