電氣專業(yè)外文翻譯--變頻技術(shù)的發(fā)展

1、<p><b>　　中文4337字</b></p><p>　　畢業(yè)設(shè)計(jì)（外文翻譯）</p><p>　　英文題目 The Development of Frequency </p><p>　　Variation Speed Control </p><p>　　中文題目

2、 變頻技術(shù)的發(fā)展 </p><p>　　系 （院） 電氣工程系 </p><p>　　專 業(yè) 電氣工程與自動(dòng)化 </p><p>　　學(xué)生姓名 </p><p>　　學(xué)

3、 號(hào) </p><p>　　指導(dǎo)教師 </p><p>　　職 稱 講 師 </p><p><b>　　二〇一四年六月</b></p>

4、<p>　　The Development of Frequency Variation Speed Control</p><p>　　1. The Popularity and Prospect of Frequency Variation Speed Control</p><p>　　The electrical machinery exchange frequency

5、 conversion velocity modulation technology is the electricity saving, the improvement technical process improves the product quality and the improvement environment, the impetus technology advancement one main method now

6、 The frequency conversion velocity modulation by its outstanding velocity modulation and the braking quality, the high efficiency, the high power factor and the electricity saving effect, the widespread applicable scope

7、and other many me</p><p>　　In recent years exchanged in the velocity modulation most to be active, to develop quickest is the frequency conversion velocity modulation technology, the frequency conversion vel

8、ocity modulation is exchanges the velocity modulation foundation and the branch content. The last century transformer appearance causes the change voltage to become very much easy, thus has accomplished a huge electric p

9、ower profession. Since long ago, the alternating current frequency always is fixed, the frequency co</p><p>　　In this recent 10 years, the frequency conversion technology application has the very big develop

10、ment in our country, and obtained the good effect to be possible to say, the frequency conversion technology has accepted for the majority users, but had no alternative but to point out, our country in frequency conversi

11、on technology application aspect, with developed country level Shang You very big disparity. At present, the AC motors we are using now use frequency variation speed control only abou</p><p>　　And with the c

12、onstant development of control technique and control avenue, frequency variation speed controlled has developed the vector controlled frequency variation velocity modulation, by controlling the AC motor inside act for sh

13、unt DC motor field coper’s flux, to enhance the permanent torque output scope and static and dynamic character, make the AC motor frequency variation speed controlled system superior to DC motor voltage variation speed c

14、ontrolled system. For simplifying the control </p><p>　　Frequency variation speed control is the best way in the motor speed modulation, it is the perfect gear in the company’s technical reform and product r

15、enewal, it is the essential composition in the industrial automatic system, it is the assumption of realizing the automatic of product proceed and management, it is also the precondition in the development of information

16、ization. In our country’s traditional estate, using the DC motor speed control actuation account about 85%~90% in the speed contr</p><p>　　2. Our Country’s Development Condition in Speed Controlled Technique

17、</p><p>　　Our country is a developing country, so many product’s research ability has behind the developed countries. From now on, the product of frequency variation speed controlled that ourselves made only

18、 act for last century 90s in the international. With the reform and opening, rapid development of economic, forms a large market, it opens to the country companies, also the foreign companies. Many products are exported

19、from the developed countries, and runs well in our country, satisfied our need in f</p><p>　　As early as in the country "85" technical attack plan, the alternating velocity modulation technique was

20、 listed as the key technical attack project, but because our country’s electric power and electronic device aggregate level is very low, although the production of IGBT、GTO component has introduced the overseas technique

21、, it has not formed the economies of scale benefit, almost does not have the independent development ability of new frequency converter production, this has affected the domest</p><p>　　Therefore, the AC fre

22、quency variation speed control technique has the following sides:</p><p>　　(1) The basic research of control strategy in frequency converter has a large gap compares with the foreign level.</p><p&

23、gt;　　(2) The technical level of the whole machine is low in the frequency converter, although we had input certainly people, material resources, but because of the disperse power, did not form a certainly technique and p

24、roduction scale.</p><p>　　(3) All the semiconductor power device product in the frequency converter is blank.</p><p>　　(4) Correlative Industries and relative Industries drop behind.</p>

25、<p>　　(5) Few production and sale, low reliable and technological standards.</p><p>　　With the development and improvement in the power electronic technique, power divert based on power electronic circu

26、it technique and various control technique, the AC frequency variation speed controlled technique is mature day by day, and sure to be the main way in the future. With the constant development of power electronic techniq

27、ue, reliable character, well adoption, cheap price that the frequency converter have will become true. This technique will gain widely, popularity application .At p</p><p>　　3. Frequency Variation Speed Cont

28、rolled Mode</p><p>　　The alternating frequency conversion velocity modulation technique obtained the rapid development in 20th century. This is related with some crucial technical which gain unprecedented pr

29、ogress, they are Motor vector control technique, Direct torque control technique, PWM technique, Entire numerical control technique and self-setting technique which based on microcomputer and large scale integrated circu

30、it, and so on.</p><p>　　(1) Vector Control Technique</p><p>　　Vector transformation control technique is a one kind of new control thought and control theory which posed by SIEMENS CO. in 1971.

31、It is realizing the stator current excitation component and the torque component solution lotus root by rotor magnetic field direction detection, and vector transformation, achieved the goal that separately control the m

32、otor flux linkage and the electric current, as a result, obtain finely static, dynamic performance. Until now, the vector control technique has obta</p><p>　　(2) Vector Control Without Velocity Generator Tec

33、hnique</p><p>　　Vector control without velocity generator technique abolish the problems that the environment compatibility、install and maintenance bring on, reduce the cost, enhance the system reliability,

34、at the same time, union vector control, has the fine performance of vector control. The speed estimate method in vector control technique without velocity generator, besides basis mathematical model computation electric

35、motor rotational speed, at present the more applied are the model to refer auto-adapted m</p><p>　　(3) Direct Torque Control Technique</p><p>　　In1985, Germany's M. Depen-block proposes the

36、direct torque control technique（DTC） for the first time，The direct torque control technique analyzes the motor mathematical model directly under the stator coordinate system. Uses the stator magnetic field direction dete

37、ction but not to need the solution lotus root electric current，directly control the electric motor flux linkage and torque, enable the torque to obtain the fast response, in order to obtain the highly effective control p

38、erformance.</p><p>　　Direct torque control technique is another kind of new、high performance alternating frequency conversion velocity modulation technique after vector control technique in the nearly 10 yea

39、rs, this kind of control technique is insensitive to the electrical machinery parameter, not influence by the rotor parameter, easy and feasible, it has the broad development and the application prospect.</p><

40、p>　　(4) PWM (pulse width modulation) Control Technique</p><p>　　In1964, Germany's A. Schonung and some people took the lead to propose the pulse-duration modulation (PWM -pulse width modulation) frequ

41、ency conversion thought, opened the recent development domain for the modern alternating velocity modulation system. The PWM control technique controls the inversion output alternating fundamental wave voltage peak-to-pe

42、ak value by changing the rectangle pulse width, controls its output frequency through changing the modulation cycle, in order to carry on the ou</p><p>　　(5) Numerical Control Technique</p><p>　

43、　The digitalize in control technique is the key technique of static frequency conversion installment, also will be the next development tendency, at present in the market frequency conversion installment nearly comprehen

44、sively has realized the numerical control. Has realized the fast operation and the high accuracy control by using the DSP and the ASIC technique, and could gain a fine current wave, reduce the noise of the frequency conv

45、erter in a large scale, and the scanning time also be reduced</p><p>　　(6) Self-setting Technique</p><p>　　The self-setting technique is widespread used in the frequency conversion velocity modu

46、lation system day by day, it may accord to the speed and the load to auto adjust the parameter of the control system, enable the system with rapid dynamic response. The self-setting technique divides into off-line and th

47、e on-line. The research results in the kind of off-line has been applied in the most production, before the system program operate, it operate a block self-setting program, recognize the correl</p><p><b&

48、gt;　　變頻技術(shù)的發(fā)展</b></p><p>　　1.變頻技術(shù)的普及前景</p><p>　　電機(jī)交流變頻調(diào)速技術(shù)是當(dāng)今節(jié)電、改善工藝流程以提高產(chǎn)品質(zhì)量和改善環(huán)境、推動(dòng)技術(shù)進(jìn)步的一種主要手段。變頻調(diào)速以其優(yōu)異的調(diào)速和起制動(dòng)性能，高效率、高功率因數(shù)和節(jié)電效果，廣泛的適用范圍及其它許多優(yōu)點(diǎn)而被國內(nèi)外公認(rèn)為最有發(fā)展前途的調(diào)速方式。電氣傳動(dòng)控制系統(tǒng)通常由電動(dòng)機(jī)、控制裝置和信息裝置3

49、部分組成，電氣傳動(dòng)關(guān)系到合理地使用電動(dòng)機(jī)以節(jié)約電能和控制機(jī)械的運(yùn)轉(zhuǎn)狀態(tài)，實(shí)現(xiàn)電能-機(jī)械能的轉(zhuǎn)換，達(dá)到優(yōu)質(zhì)、高產(chǎn)、低耗目的。電氣傳動(dòng)分成不調(diào)速和調(diào)速兩大類，調(diào)速又分交流調(diào)速和直流調(diào)速兩種方式。不調(diào)速電動(dòng)機(jī)直接由電網(wǎng)供電，但隨著電力電子技術(shù)的發(fā)展這類原本不調(diào)速的機(jī)械越來越多地改用調(diào)速傳動(dòng)以節(jié)約電能(節(jié)約15%~20%或更多)，改善產(chǎn)品質(zhì)量，提高產(chǎn)量。在我國60%的發(fā)電量是通過電動(dòng)機(jī)消耗的，因此調(diào)速傳動(dòng)是一個(gè)重要行業(yè)，已經(jīng)得到國家重視，目前已

50、有一定規(guī)模。</p><p>　　近年來交流調(diào)速中最活躍、發(fā)展最快的就是變頻調(diào)速技術(shù)，變頻調(diào)速是交流調(diào)速的基礎(chǔ)和主干內(nèi)容。上個(gè)世紀(jì)變壓器的出現(xiàn)使改變電壓變得很容易，從而造就了一個(gè)龐大的電力行業(yè)。長期以來，交流電的頻率一直是固定的，變頻調(diào)速技術(shù)的出現(xiàn)使頻率變?yōu)榭梢猿浞掷玫馁Y源。</p><p>　　這10年來，變頻技術(shù)的應(yīng)用在我國有很大的發(fā)展，并取得了良好的效果可以說，變頻技術(shù)已為大多數(shù)用

51、戶所接受，但是不能不指出，我國在變頻技術(shù)的應(yīng)用方面，與發(fā)達(dá)國家的水平尚有很大差距，目前，我國在用的交流電動(dòng)機(jī)使用變頻調(diào)速運(yùn)行的僅6%左右，而下業(yè)發(fā)達(dá)國家已達(dá)(60%~70%)，日本在風(fēng)機(jī)、水泵上變頻調(diào)速的采用率已達(dá)10% ,而我國還不足0.01%.在日本，空調(diào)器的70%采用了變頻調(diào)速，而我國才剛剛起步。從這個(gè)現(xiàn)實(shí)出發(fā)，變頻技術(shù)尚有很大的發(fā)展空間，應(yīng)該鍥而不舍地做好推廣應(yīng)用工作。</p><p>　　而且隨著控制技

52、術(shù)和控制手段的不斷提高，變頻調(diào)速又由變壓變頻控制的變頻調(diào)速發(fā)展到了矢量控制變頻調(diào)速，通過控制交流電動(dòng)機(jī)里相當(dāng)于并勵(lì)直流電動(dòng)機(jī)勵(lì)磁繞組的磁通變化，提高變頻器的恒轉(zhuǎn)矩輸出范圍和動(dòng)靜態(tài)特性，使得交流電動(dòng)機(jī)變頻調(diào)速系統(tǒng)的性能超過了直流電動(dòng)機(jī)調(diào)壓調(diào)速系統(tǒng)的性能。為了簡化控制系統(tǒng)，減少設(shè)備故障率，在矢量控制變頻調(diào)速的基礎(chǔ)上又發(fā)展了無速度傳感器的矢量控制變頻調(diào)速。在一些對動(dòng)靜態(tài)特性要求不太高的應(yīng)用中，無速度傳感器的矢量控制變頻調(diào)速己完全可以和有速度傳

53、感器的矢量控制變頻調(diào)速相媲美。矢量控制對交流電機(jī)調(diào)速具有劃時(shí)代的意義。</p><p>　　變頻調(diào)速是電機(jī)調(diào)速的最佳方式，是企業(yè)技術(shù)改造和產(chǎn)品更新?lián)Q代的理想設(shè)備，是工業(yè)自動(dòng)化系統(tǒng)必不可少的組成部分，是實(shí)現(xiàn)生產(chǎn)過程和管理自動(dòng)化的前提，也是信息化發(fā)展的先決條件。在我國傳統(tǒng)產(chǎn)業(yè)中，采用直流電機(jī)拖動(dòng)的調(diào)速系統(tǒng)約占調(diào)速系統(tǒng)總量的85%~90%，而交流調(diào)速系統(tǒng)僅占10%~15%。效率低、質(zhì)量差、消耗大、故障率高己成為制約企業(yè)

54、發(fā)展的瓶頸。因此，必須積極推廣先進(jìn)的交流變頻調(diào)速技術(shù)，用先進(jìn)的設(shè)備武裝傳統(tǒng)產(chǎn)業(yè)，促進(jìn)自動(dòng)化、工業(yè)化和信息化的進(jìn)一步發(fā)展。</p><p>　　2. 變頻調(diào)速發(fā)展趨勢</p><p>　　如果說以第一個(gè)晶閘管的出現(xiàn)作為交流電動(dòng)機(jī)變頻調(diào)速的起點(diǎn)，可以認(rèn)為它的發(fā)展歷史己40多年了。而變頻調(diào)速技術(shù)真正高速發(fā)展時(shí)期，應(yīng)該是在PWM調(diào)制技術(shù)的出現(xiàn)和微機(jī)控制技術(shù)發(fā)展之后。特別是最近20年來，隨著交流調(diào)速

55、技術(shù)的應(yīng)用普及，交流變頻調(diào)速在化工、火電廠、礦山、油田、機(jī)械制造、城市建設(shè)、水處理、甚至家電等行業(yè)己經(jīng)全面推廣使用，一般主要用于節(jié)能及控制。隨著變頻技術(shù)的普及和深入，以及國際、國內(nèi)電器設(shè)備使用的有關(guān)標(biāo)準(zhǔn)意識(shí)的強(qiáng)化，電力系統(tǒng)行業(yè)和用戶對變頻技術(shù)的質(zhì)量要求也越來越高。變頻調(diào)速的發(fā)展趨勢主要圍繞下面幾個(gè)方而展開。</p><p>　　（1） 高性能的智能控制變頻器</p><p>　　380V系

56、統(tǒng)的低壓變頻器是國內(nèi)的主要研究對象，應(yīng)用交流調(diào)速的基本理論，結(jié)合神經(jīng)網(wǎng)絡(luò)控制、魯棒控制、模糊控制，或其他智能控制等手段，實(shí)現(xiàn)電機(jī)運(yùn)行參數(shù)的自動(dòng)辨識(shí)，以期達(dá)到自適應(yīng)、自調(diào)整的最優(yōu)控制。這方面己有一定的研究成</p><p>　?。?）速度傳感器研究</p><p>　　從前面所述的各種變頻調(diào)速的理論可知，一般系統(tǒng)都要用到轉(zhuǎn)速傳感器。在實(shí)際使用中，由于變頻設(shè)備和被控電動(dòng)機(jī)有一定的距離，而高精度

57、的轉(zhuǎn)速傳感器都要使用專門的電源，被控電動(dòng)機(jī)有的是在戶外，運(yùn)行工況非常惡劣，要保證速度反饋的準(zhǔn)確性，有時(shí)不得不采取特別措施，因此也會(huì)增加額外費(fèi)用，運(yùn)行的可靠性和控制精度也會(huì)因此受到影響。無速度傳感器的變頻調(diào)速系統(tǒng)，是通過現(xiàn)場采集的電流電壓量，以及控制的實(shí)施策略，綜合出被控電機(jī)的實(shí)際轉(zhuǎn)速。這種控制方案要求計(jì)算機(jī)的控制速度較高，并有足夠的精度。</p><p>　?。?） 針對功率因數(shù)提高和諧波污染的研究</p&

58、gt;<p>　　低壓變頻調(diào)速系統(tǒng)的控制雖然己經(jīng)是非常成熟了，但目前國際、國內(nèi)的產(chǎn)品，一般都是矢量控制和直接轉(zhuǎn)矩控制，重點(diǎn)放在電機(jī)變頻控制理論的實(shí)現(xiàn)和完善上，而對變頻器的輸出波形、功率因數(shù)，以及諧波污染等問題還沒有引起足夠的重視。最近10多年來，國外在這一領(lǐng)域己有較深入的研究。有的針對功率因數(shù)，有的強(qiáng)調(diào)輸出波形。多重化技術(shù)就是為了解決輸出波形問題。最近幾年的研究表明，利用PWM輸出控制解決諧波輸出問題，是比較理想的方法，它

59、可以省去多重化中的變壓器，或過多的開關(guān)元器件，使變頻器的體積和重量減少，但這種方法不能解決所有諧波的消除問題，只能部分消除特定諧波。這方面的研究論文還不多，也還沒有成熟的類似低壓變頻器的產(chǎn)品出現(xiàn)。</p><p>　　（4） 高壓變頻器的研究</p><p>　　變頻器的主要作用之一是節(jié)能。而高壓電動(dòng)機(jī)的節(jié)能效果是比較明顯的，大功率的風(fēng)機(jī)和水泵用電動(dòng)機(jī)一般都是高壓電動(dòng)機(jī)。國內(nèi)，高壓變頻調(diào)速

60、和它的節(jié)能控制還是一個(gè)比較薄弱的環(huán)節(jié).它主要是針對6~10kV的交流電動(dòng)機(jī)進(jìn)行變頻調(diào)速控制。這種高壓電動(dòng)機(jī)廣泛應(yīng)用于火力發(fā)電廠的送風(fēng)機(jī)和引風(fēng)機(jī)上。同樣也可用于其他如石油化工、礦山、冶煉、機(jī)械制造等行業(yè)的變頻節(jié)能控制。從某種意義上講，由于目前國內(nèi)還不能完全生產(chǎn)高質(zhì)量的合格電力電子器件，而且，國外低壓變頻器的性能價(jià)格比也比國內(nèi)自己研究的變頻器高得多。因此,在這方面還有許多研究工作要做。 </p><p>　　隨著電力

61、電子技術(shù)最近20多年的飛速發(fā)展，功率半導(dǎo)體器件的成本逐年下降，技術(shù)工藝和性能也得到不斷改善.電力電子器件的應(yīng)用己從傳統(tǒng)的直流調(diào)速、直流屏、斬波器等領(lǐng)域延伸到交流調(diào)速和電力系統(tǒng)的質(zhì)量控制領(lǐng)域.并正朝著高電壓、大功率的方向發(fā)展.這也是千年之交和世紀(jì)之交我國電力電子技術(shù)應(yīng)用的發(fā)展趨勢。</p><p>　?。?）無換向器同步電機(jī)的變頻調(diào)速</p><p>　　無換向器電動(dòng)機(jī)也是在20世紀(jì)70年代

62、發(fā)展起來的新型調(diào)速系統(tǒng)。它是一種變頻調(diào)速同步電動(dòng)機(jī).也可以認(rèn)為是一種用半導(dǎo)體電子開關(guān)線路代替換向器和電刷作用的直流電動(dòng)機(jī)。根據(jù)采用的控制方式不同.可分為直流無換向器電動(dòng)機(jī)和交流無換向器電動(dòng)機(jī)。直流無換向器電動(dòng)機(jī)采用交-直-交或直-交變頻控制系統(tǒng);交流無換向器電動(dòng)機(jī)采用交-交變頻控制系統(tǒng)。近10年來.國內(nèi)外雜志上有許多相關(guān)的研究論文。而且，也有一定的成果出現(xiàn)。</p><p>　　3. 變頻調(diào)速控制方式</p

63、><p>　　交流變頻調(diào)速技術(shù)在20世紀(jì)得到了迅速發(fā)展。這與一些關(guān)鍵性技術(shù)的突破性進(jìn)展有關(guān)，它們是交流電動(dòng)機(jī)的矢量控制技術(shù)、直接轉(zhuǎn)矩控制技術(shù)、PWM技術(shù)以及微型計(jì)算機(jī)和大規(guī)模集成電路為基礎(chǔ)的全數(shù)字化控制技術(shù)、自整定技術(shù)等。</p><p><b>　?。?）矢量控制技術(shù)</b></p><p>　　矢量變換控制技術(shù)是西門子公司于1971年提出的一種

64、新的控制思想和控制理論。它是以轉(zhuǎn)子磁場定向，采用矢量變換的方法實(shí)現(xiàn)定子電流勵(lì)磁分量和轉(zhuǎn)矩分量之間的解藕，達(dá)到對交流電動(dòng)機(jī)的磁鏈和電流分別控制的目的，從而獲得了優(yōu)良的靜、動(dòng)態(tài)性能。迄今為止，矢量控制技術(shù)己經(jīng)獲得了長足的發(fā)展，并得到了廣泛應(yīng)用。</p><p>　?。?）無速度傳感器矢量控制技術(shù)</p><p>　　無速度傳感器控制技術(shù)免去了傳感器帶來的環(huán)境適應(yīng)性、安裝維護(hù)等問題，降低了成本，

65、提高了系統(tǒng)的可靠性，同時(shí)結(jié)合矢量控制，具有矢量控制的優(yōu)良性能。無速度傳感器技術(shù)中速度估算的方法，除了根據(jù)數(shù)學(xué)模型計(jì)算電動(dòng)機(jī)轉(zhuǎn)速外，目前應(yīng)用較多的有模型參考自適應(yīng)法和擴(kuò)展卡爾曼濾波法。此外全維轉(zhuǎn)子磁通觀測器，齒諧波電勢(RSH)等理論也出現(xiàn)在無速度傳感器技術(shù)中。從1983年提出無速度傳感器矢量控制策略以來，一直受到學(xué)術(shù)界和產(chǎn)業(yè)界的高度重視，日立、安川電機(jī)等公司在1987年分別發(fā)表了研究成果，并相繼推出了產(chǎn)品。目前，無速度傳感器矢量控制變頻

66、器的調(diào)速范圍為1:50左右，個(gè)別廠商有1:75甚至更高的產(chǎn)品。</p><p>　?。?）直接轉(zhuǎn)矩控制技術(shù)</p><p>　　1985年.德國的M . Depen-block首次提出直接轉(zhuǎn)矩控制技術(shù)(DTC)。DTC控制直接在定子坐標(biāo)系下分析交流電動(dòng)機(jī)的數(shù)學(xué)模型。采用定子磁場定向而無需解藕電流，直接控制電動(dòng)機(jī)的磁鏈和轉(zhuǎn)矩，以使轉(zhuǎn)矩得到快速響應(yīng)，從而獲得高效的控制性能。</p>

67、<p>　　直接轉(zhuǎn)矩控制技術(shù)是近10年繼矢量控制技術(shù)之后發(fā)展起來的又一種新型的高性能交流變頻調(diào)速技術(shù)，這種控制技術(shù)與矢量控制技術(shù)相比，對電機(jī)參數(shù)不敏感，不受轉(zhuǎn)子參數(shù)的影響，簡單易行，具有廣闊的發(fā)展和應(yīng)用前景。</p><p>　　（4）PWM控制技術(shù)</p><p>　　1964年，德國的A. Schonung等率先提出了脈寬調(diào)制(PWM -pulse width modul

68、ation)變頻的思想，為近代交流調(diào)速系統(tǒng)開辟了新的發(fā)展領(lǐng)域。PWM控制技術(shù)通過改變矩形脈沖的寬度來控制逆變器輸出交流基波電壓的幅值，通過改變調(diào)制周期來控制其輸出頻率，從而在逆變器上同時(shí)進(jìn)行輸出電壓幅值和頻率的控制。PWM技術(shù)簡化了逆變器的結(jié)構(gòu)，能夠明顯的改善變頻器的輸出波形，降低電動(dòng)機(jī)的諧波損耗，并減小轉(zhuǎn)矩脈動(dòng)，同時(shí)提高了系統(tǒng)的動(dòng)態(tài)響應(yīng)性能。PWM技術(shù)還可用于整流器的控制，能夠?qū)崿F(xiàn)輸入電流非常接近正弦.。并可使電網(wǎng)功率因數(shù)為1。PWM

69、整流器因而被稱為“綠色”變流器。目前，PWM技術(shù)己成為變頻器中應(yīng)用最為廣泛的控制技術(shù)。交流電機(jī)調(diào)速性能的不斷提高在很大程度上是由于PWM技術(shù)的不斷進(jìn)步。目前廣泛應(yīng)用的是在規(guī)則采樣PWM的基礎(chǔ)上發(fā)展起來的準(zhǔn)優(yōu)化PWM法，即三次諧波疊加法和電壓空間矢量PWM法。</p><p>　?。?） 數(shù)字化控制技術(shù)</p><p>　　控制技術(shù)的數(shù)字化是靜止變頻裝置的核心技術(shù)，也是今后的發(fā)展趨勢。目前市

70、場上的變頻裝置幾乎全面實(shí)現(xiàn)了數(shù)字化控制。采用DSP和ASIC技術(shù)實(shí)現(xiàn)了快速運(yùn)算和高精度控制，可以得到良好的電流波形，使變頻器的噪音大幅度降低，并且掃描時(shí)間大幅度縮短，目前電流響應(yīng)為0.1~0.7ms，速度響應(yīng)為2~4 ms,足以滿足傳動(dòng)領(lǐng)域的控制要求。同時(shí)由于應(yīng)用微電子技術(shù)和ASIC技術(shù)，裝置的元器件數(shù)量得以大幅度減少，從而使變頻裝置的體積減小，可靠性得到大幅度提高。全數(shù)字控制方式使變頻器的信息處理能力大為增強(qiáng)。采用模擬控制方式無法實(shí)現(xiàn)

71、的復(fù)雜控制在今天都己成為現(xiàn)實(shí)，從而所謂的RAS概念即可靠性(Reliability)、可操作性(Availability)、可維修性(Serviceability)得以充實(shí)。</p><p><b>　　（6）自整定技術(shù)</b></p><p>　　自整定技術(shù)在變頻調(diào)速系統(tǒng)中的應(yīng)用日益廣泛，它可以根據(jù)速度和負(fù)載的變化自動(dòng)調(diào)整控制系統(tǒng)的參數(shù)，使得系統(tǒng)具有快速的動(dòng)態(tài)響應(yīng)。