中英文翻譯---2mw風(fēng)力雙饋異步電動機(jī)的研究設(shè)計

1、<p><b>　　外文翻譯</b></p><p>　　2MW風(fēng)力雙饋異步電動機(jī)的研究設(shè)計</p><p><b>　　摘要</b></p><p>　　一個設(shè)計為一個2 MW風(fēng)力發(fā)電機(jī)的商業(yè),驗(yàn)證了兩種連接方式為標(biāo)準(zhǔn)雙饋異步機(jī)可延長低速下范圍到80%滑動沒有增加的額定功率電子變換器。這遠(yuǎn)遠(yuǎn)超出了正常的30%的

2、下限。較低的速度連接被稱作異步發(fā)電機(jī)模式和機(jī)器操作與短路定子繞組和所有的功率流在轉(zhuǎn)子回路。有兩個回路逆變器控制系統(tǒng)方案設(shè)計和調(diào)整為每一個模式。本文的目的是當(dāng)前仿真結(jié)果,說明了該控制器的動態(tài)性能均為雙饋異步發(fā)電機(jī)的連接方法為2 MW風(fēng)力渦輪機(jī)。一個簡單的分析了雙轉(zhuǎn)子電壓為連接方法包括作為這個演示的優(yōu)勢的時候,需要考慮設(shè)計等先進(jìn)控制策略。</p><p>　　關(guān)鍵詞:雙饋電機(jī)、異步發(fā)電機(jī)、風(fēng)力發(fā)電機(jī)。</p&g

3、t;<p><b>　　1、介紹</b></p><p>　　興趣是持續(xù)風(fēng)力渦輪機(jī),尤其是那些擁有一個額定功率的許多兆瓦這個流行主要由既環(huán)保,也可用的化石燃料。立法鼓勵減少碳足跡的所謂的地方,所以目前正在感興趣的可再生能源。風(fēng)力渦輪機(jī)仍然被看作是一種建立完善的技術(shù),已形成從定速風(fēng)力渦輪機(jī),現(xiàn)在流行的調(diào)速技術(shù)基于雙饋異步發(fā)電機(jī)(DFIGs)。風(fēng)力是一DFIG變速與轉(zhuǎn)子變頻器控制使

4、轉(zhuǎn)子電壓相位和大小調(diào)整以保持最佳扭矩和必要的定子功率因數(shù)文[1]~[3]。DFIG技術(shù)是目前發(fā)達(dá),是常用的風(fēng)力渦輪機(jī)。定子的DFIG是直接連接到網(wǎng)格與電力電子轉(zhuǎn)子變換器之間,用以轉(zhuǎn)子繞組的網(wǎng)格。這個變量速度范圍是成正比的評級的轉(zhuǎn)子等通過變頻器調(diào)速范圍±30%[4、5、6、7]轉(zhuǎn)子轉(zhuǎn)換器只需要的DFIG總量的30%的力量而使全面控制完整的發(fā)電機(jī)輸出功率。這可能導(dǎo)致顯著的成本節(jié)省了轉(zhuǎn)子轉(zhuǎn)換器[4]?；瑒迎h(huán)連接,但必須保持轉(zhuǎn)子繞組,

5、性能安全可靠。電源發(fā)電機(jī)速度特性,如圖1所示為2 MWwind汽輪機(jī)。對于一個商業(yè)發(fā)電機(jī)速度隨風(fēng)速,然而這種關(guān)系是為某一特定地點(diǎn)。作為風(fēng)速,并因此機(jī)速度快、輸出功率下降了的風(fēng)力發(fā)電機(jī)減少直至關(guān)閉時提取風(fēng)是比損失的發(fā)電機(jī)和液力變矩器。操作模式已經(jīng)提出,風(fēng)</p><p>　　這個能力的現(xiàn)代DF風(fēng)力渦輪機(jī)不同的無功功率吸收或產(chǎn)生[6、第九條、第十條]讓風(fēng)渦輪參與無功功率平衡的格子里。無功功率在電網(wǎng)的連接中描述的工作,

6、由英國,連接條件小節(jié)CC.6.3.2[11]從國家電網(wǎng)。無功要求風(fēng)電場的定義是由圖2。　</p><p>　　MVAr點(diǎn)——相當(dāng)于功率因數(shù)為0.95領(lǐng)先于額定兆瓦</p><p>　　MVAr B點(diǎn)——相當(dāng)于功率因數(shù)為0.95滯后于額定兆瓦</p><p>　　C - MVAr 5點(diǎn)的額定兆瓦</p><p>　　D點(diǎn)- MVAr 5%額定兆

7、瓦</p><p>　　E - MVAr 12點(diǎn)的額定兆瓦</p><p>　　摘要本文旨在探討控制器性能和IG模式為DF 2MW 690V,4-pole,DFIG使用機(jī)器參數(shù)由制造商。這是進(jìn)一步研究建立在先前的穩(wěn)態(tài)性能進(jìn)行了兩種操作的損耗,以及國際組模式[8]。在[8]探討了穩(wěn)態(tài)效率為雙方關(guān)系。工作說明的穩(wěn)態(tài)性能都有好處,這臺機(jī)器運(yùn)行一個連接方法相對于其他。摘要本文檢視(即瞬態(tài)性能)的2

8、千瓦風(fēng)力渦輪。結(jié)果全部動態(tài)控制器(電流調(diào)節(jié)、解耦控制方程和矢量控制方式,在DF)的方式顯示指定。配置程序做了詳細(xì)的分析,形成了轉(zhuǎn)子的電壓在整個操作范圍內(nèi)DFIG模式,給出了這種能夠主宰成分浮出水面。這是特別重要的先進(jìn)控制方案設(shè)計時充分概論的工作范圍內(nèi),能被確認(rèn)。仿真模型,它已經(jīng)被證實(shí)對7.5kW實(shí)驗(yàn)室鉆機(jī)[12],是應(yīng)用于現(xiàn)實(shí)的2千瓦風(fēng)力使結(jié)論是關(guān)于擬議中的使用IG模式在真實(shí)的風(fēng)力渦輪。</p><p><

9、b>　　2、連接方法</b></p><p>　　雙饋異步電機(jī)通常連接如圖3。GSI網(wǎng)格側(cè)逆變器(保持)是一個固定的直流環(huán)節(jié)電壓與給定的功率因數(shù)的網(wǎng)格(在我們的情況下,團(tuán)結(jié))。轉(zhuǎn)子側(cè)逆變器(勞損)的控制,從而使最大能量提取的動能的風(fēng)而使定子功率因數(shù)控制范圍內(nèi)統(tǒng)一要求,盡管網(wǎng)格的功率因數(shù)往往是可取的。另一種連接方式為雙饋電機(jī)如圖4,這叫了異步發(fā)電機(jī)(指定)連接。定子是脫離電網(wǎng)和短路。轉(zhuǎn)子回路圖3。

10、從不變。GSI一樣的控制方式。DF)目的是為了控制勞損定子磁鏈在吸收最大功率的動能,風(fēng)能。</p><p><b>　　3、控制器性能</b></p><p>　　閉環(huán)控制方式都和IG模式DF討論的前期準(zhǔn)備工作[12]但只有一個7.5億千瓦實(shí)驗(yàn)室試驗(yàn)平臺。2千瓦動力學(xué)系統(tǒng)會有所不同,本文討論了。動態(tài)控制器的性能和IG模式為DF中顯示的是這段2 MW風(fēng)力渦輪機(jī)。<

11、/p><p>　　3.1DFIG模式(T和Q控制)</p><p>　　參考價值的扭矩模式控制器DF(見圖1)和定子無功使網(wǎng)格代碼要求達(dá)到[11],圖2。摘要研究了兩種速度,使部分的控制性能表現(xiàn)出兩上方和下方的標(biāo)稱功率的20%限制電網(wǎng)的規(guī)范要求。一個命名可以達(dá)到3億千瓦,約1150轉(zhuǎn)(小于標(biāo)稱功率的20%)</p><p>　　一個額定功率是達(dá)到125千瓦1550轉(zhuǎn)(超

12、過20%的額定功率)。參考和實(shí)際的扭矩、網(wǎng)球、定子無功功率,Qs,都顯示,兩者的速度在圖5。</p><p>　　參考扭矩,越富有,因?yàn)檫@兩者都是具體的名義轉(zhuǎn)矩速度對于一個給定的速度計算出圖1;?2672海里為1150轉(zhuǎn)速和?7701海里的1550轉(zhuǎn)速。200海里的速度在雙方的動態(tài)響應(yīng),說明了一步,改變扭矩。參考定子無功功率,Qs *,螺桿轉(zhuǎn)速變化之間的1150年所指定的范圍柵格規(guī)程的要求;最初?5%的生成與更進(jìn)

13、了一步,在t = + 5%的3.5s產(chǎn)生電力。在1550轉(zhuǎn)定子動力因素、pfs *,最初0.95并逐步改變在t = 3s團(tuán)結(jié)pfs和最后一步,在t = 0.95滯后4s pfs)。矢量控制回路的調(diào)整為一個時間常數(shù)的0.9s 0.1秒,為特和Qs循環(huán)。矢量控制的設(shè)計是為了有一個較慢的帶寬比當(dāng)前的規(guī)定。</p><p>　　實(shí)際轉(zhuǎn)子電流直接、irds、正交、irqs、部件對應(yīng)figure6圖5中顯示。這個步驟的影響是

14、明顯的變化對Te * irqs(上標(biāo)s指出變量是指在定子)。這個irqs *元件包含小瞬態(tài)響應(yīng)1550 rpm在t =三分球和t = 4s是由于步改變Qs價值。這個步驟改變Qs *,如圖5,導(dǎo)致快速變化的irds *,圖6,如有初步的誤差和實(shí)際Qs作為參考一會兒,管理作為回應(yīng)。現(xiàn)行規(guī)定,確保帶寬防止控制器對這樣的流動而不斷地獲得適當(dāng)?shù)姆磻?yīng)速度這個方程為基礎(chǔ)的調(diào)諧用來控制器的設(shè)計出相似的比例和積分所得的值為現(xiàn)行規(guī)定直接和正交循環(huán)的Hold

15、sworth魏厚[10]。</p><p>　　3.2 IG模式(T和流量控制)</p><p>　　參考價值的IG模式控制器是定子磁鏈和轉(zhuǎn)矩。摘要研究了兩種條件下2千瓦發(fā)電在IG模式中,啟動和扭矩步反應(yīng),以400轉(zhuǎn)(最低IG模式速度[12])和1420轉(zhuǎn)(所產(chǎn)生的力量以這樣的速度與轉(zhuǎn)子上游的額定功率轉(zhuǎn)換器,600億千瓦)。參考和實(shí)際的扭矩、網(wǎng)球、定子磁鏈,λsr(上標(biāo)' r”表明

16、變量是指兩個方面對轉(zhuǎn)子)的速度如圖7。</p><p>　　穩(wěn)態(tài)Te標(biāo)稱值處理的速度、?320海里為400轉(zhuǎn)速和?4081海里,源自公元1420年轉(zhuǎn)圖1。一個啟動順序必須建立在額定λsr機(jī)器,對于一個給定的速度,通過一段斜坡,圖7,機(jī)器可以產(chǎn)生電力。</p><p>　　一旦該控制器參考λsr已建立了機(jī)械,特*增加通過控制的名義價值斜坡給定的速度,然后一階躍響應(yīng)50海里在400轉(zhuǎn)速與200

17、海里時轉(zhuǎn)速適用。公元1420年,該控制器控制機(jī)器來跟蹤Te *果然,參看圖7。</p><p>　　矢量控制回路的確定值的參考轉(zhuǎn)子電流如圖8。最初的成分迅速上升到建立λsr,大約三倍公稱穩(wěn)態(tài)值對于一個給定的負(fù)荷點(diǎn)。當(dāng)前在額定的限制。最初的解碼器能夠顯著降低,如果一個較慢的反應(yīng)λsr實(shí)現(xiàn)。</p><p>　　這個硬中斷請求優(yōu)先級別組成,是由扭矩環(huán)使渴望權(quán)力產(chǎn)生。最初有輕微的誤差影響高解碼器

18、的交叉耦合正交循環(huán)系統(tǒng)的條款。一旦名義λsr于機(jī)器直接和正交環(huán)路的解耦。又一特步引起短暫飆升的硬中斷請求優(yōu)先級別*雖然被調(diào)諧到這個變化是慢于參考價值。</p><p><b>　　4、轉(zhuǎn)子的電壓元件</b></p><p>　　雙方的性能和IG模式DF已經(jīng)在上一節(jié)。兩者都是基于內(nèi)部控制電流環(huán)和外部控制回路為轉(zhuǎn)矩和定子無功功率損耗的案例和轉(zhuǎn)矩和定子磁鏈的IG。再加上解耦

19、方程的PI控制器的影響,降低產(chǎn)量之間的交叉耦合循環(huán)。最后一部分工作的研究做出貢獻(xiàn)的穩(wěn)態(tài)組件的轉(zhuǎn)子電壓,全部在方程式(1和2),2千瓦機(jī)器來評估的重要性,在不同的速度方程式解耦。轉(zhuǎn)子電壓、工具、轉(zhuǎn)子電流、國稅局,居于萬物的工具和組件由方程式(1和2)進(jìn)行了DF轉(zhuǎn)速范圍內(nèi)(1000年到1950年轉(zhuǎn)矩確定)的正常從圖表1),和定子動力因素、pfs、范圍的0.9落后領(lǐng)先到0.9%。只有pfs被視為GSI可能保持團(tuán)結(jié)酚醛風(fēng)輪變頻器連接到網(wǎng)格的獨(dú)立

20、的勞損。</p><p>　　圖9所示的是變化的速度和vrdqs定子無功功率范圍的調(diào)查。vrds組件的主導(dǎo)的穩(wěn)態(tài)的ωsfσirqs?的壓降和λsq后被忽略的是零組件選擇參考幀。這可以比較圖9和數(shù)字。在一個2千瓦的vrqs機(jī)床主導(dǎo)下的ωsf(Lm / Ls)λsd期限為低的總泄漏,降低電感、σirds交叉耦合效應(yīng)的術(shù)語和λs取向的λsq構(gòu)件框架設(shè)置為零。在vrqs變化在恒定的速度(并因此轉(zhuǎn)矩)是由于從irds交叉耦

21、合的定子無功功率調(diào)節(jié),Qs,因此pfs這個工具vrqs統(tǒng)治級的組件和對稱1500rpm;thesynchronous速度4-pole機(jī)。這是經(jīng)公園等[13]。</p><p>　　在穩(wěn)態(tài)變化直接,irds、正交、irqs、轉(zhuǎn)子電流部件對速度和Qs如圖10。irds元件的功率因數(shù)、調(diào)節(jié)定子無,通過控制Qs和太少</p><p>　　s組件調(diào)節(jié)。irds確定的價值的比例提供發(fā)電機(jī)無功功率的定子

22、和轉(zhuǎn)子回路。irds增加越來越積極的比例從轉(zhuǎn)子回路Q同時減少了問從出口到Q的靜定。越來越消極irds增加問從,減少了定子電路的轉(zhuǎn)子的一面,直到Q是由轉(zhuǎn)子出口。Qs隨維持理想Te,因此irds組件無會持續(xù)pfs在更高的速度。大致上是恒定的irqs元件恒速恒轉(zhuǎn)矩的力量,積極為產(chǎn)生的定位框架和直接和正交軸排成一線國稅局的大小是為所有的額定內(nèi)部條件圖10。</p><p>　　其余的這部分說明了轉(zhuǎn)子的電壓,vrdqs、穩(wěn)

23、態(tài)部件從方程式(1和2)。這個Rrsirds術(shù)語及術(shù)語vrds Rrsirqs vrqs僅僅是irdqs,如圖10,攀登通過后,所以不顯示。</p><p>　　jσωsfirdqs的交叉耦合條件vrdqs如圖11所示， jσωsfirdqs有助于vrds和σωsfirds從 vrqs。Σωsfirds由組成隨既速度和定子無功功率為定子無功成正比,與轉(zhuǎn)矩對于一個給定的定子動力因素。σωsfirds隨著年齡的增長而

24、增長速度的組件負(fù)載力矩增加如圖1。σωsfirqs組件是主導(dǎo)學(xué)期在vrds組成eqn(1),在不同步性的速度。在極性的結(jié)果ωsf定義和大小的扭矩。irdqs大小是由頻率升高而升高，ωsf與總漏電感。圖12表明vrdqs由j(Lm/Ls)和ωsf和λsdq組成，(Lm/Ls)ωsfλsq有助于vrds，這個學(xué)期大致上是零因定位框架。 (Lm/Ls)ωsfλsd抑制 vrqs 的組成，(Lm/Ls)ωsfλsd的形狀組成完全由ωsf.決定。

25、</p><p><b>　　5、討論</b></p><p>　　分析vrds和vrqs組成的可行性是由占統(tǒng)治地位的條款。λs定位框架的結(jié)果λsq和vrds前饋術(shù)語被忽略所以穩(wěn)態(tài)vrds組件的結(jié)果是Rrsirds?σωsfirqs。三種截然不同的區(qū)域,然后可以識別sub-synchronous速度，關(guān)于同步速度，和超同步速度。vrds的瞬態(tài)響應(yīng)的對于一個步驟irds

26、*主導(dǎo)下的pσirds. p(Lm/Ls)λsd作為一個微不足道的效果了λsd 術(shù)語是恒定的,假設(shè)一個僵硬的網(wǎng)格。irds*的脈沖一步穩(wěn)態(tài)值影響的vrqs在vrds的穩(wěn)態(tài)條款，vrqs穩(wěn)定的狀態(tài)是由主導(dǎo)下的λsd 期限，Vrqs的瞬態(tài)響應(yīng)由irqs*來的是由pσirqs周期正如步驟irqs最初是高的。p(Lm/Ls)λsq有一個最大的作用時λsq約等于零，在vrqs的vrds周期和步驟周期所有的經(jīng)驗(yàn)值變化的irqs *。</p&g

27、t;<p><b>　　6、結(jié)論</b></p><p>　　摘要首先分析了控制器的響應(yīng)和IG模式DF連接DFIG MW風(fēng)力渦輪機(jī)。2這臺機(jī)器參數(shù)為2千瓦機(jī),為商用WRIM用于風(fēng)力渦輪機(jī),由制造商。2千瓦機(jī)參數(shù)用于這項(xiàng)工作并不僅僅是一種線性比例的前期準(zhǔn)備工作在7.5萬千瓦的特性與不相同的兩個人之間的機(jī)器。</p><p>　　兩個方面進(jìn)行了調(diào)查分析,對2

28、千瓦DFIG。已經(jīng)存在的仿真模型用于評估可控性和穩(wěn)態(tài)和瞬態(tài)行為DFIG 2千瓦的IG模式和DF)。</p><p>　　結(jié)果表明,IG模式是一種可控的運(yùn)作模式,這將擴(kuò)大低速運(yùn)行電壓降低轉(zhuǎn)子速度降低(電壓),所以IGBTs限制會被尊為將當(dāng)前的和權(quán)限的機(jī)器和液力變矩器。電壓的組成進(jìn)行了轉(zhuǎn)子損耗模式DFIG 2千瓦。這顯示了重要的解耦方程中的表現(xiàn)DFIG隨速度。</p><p><b>

29、;　　外文原文</b></p><p>　　Design Study of Doubly-Fed Induction Generators</p><p>　　for a 2MW Wind Turbine</p><p><b>　　ABSTRACT</b></p><p>　　A design study

30、for a 2 MW commercial wind turbine is presented to illustrate two connection methods for a standard doubly-fed induction machine which can extend the low speed range down to 80% slip without an increase in the rating of

31、the power electronic converter. This far exceeds the normal 30% lower limit. The low speed connection is known as induction generator mode and the machine is operated with a short circuited stator winding with all power

32、flow being through the rotor circuit. A two l</p><p>　　Keywords: Doubly-fed, Induction generator, Wind turbine</p><p>　　1. INTRODUCTION</p><p>　　There is continuing interest in wind

33、 turbines, especially those with a rated power of many megawatts.This popularity is largely driven by both environmental concerns and also the availability of fossil fuels. Legislation to encourage the reduction of the s

34、o called carbon footprint is currently in place and so interest in renewables is currently high. Wind turbines are still viewed as a well established technology that has developed from fixed speed wind turbines to the no

35、w popular variable speed</p><p>　　The power – generator speed characteristic shown in figure 1 is fora commercial 2 MWwind turbine. The generator speed varies with wind speed however this relation is set for

36、 a specific location. As wind speed, and therefore machine speed, falls the power output of the generator reduces until the wind turbine is switched off when the power extracted from the wind is less than the losses of t

37、he generator and converter. An operating mode has been proposed by a wind turbine manufacturer that is clai</p><p>　　The reference torque required by both controllers (DF and IG mode) can easily be derived f

38、rom this curve. The torque – speed data can then be stored in a look-up table so the reference torque is automatically varied with speed.</p><p>　　The capability of modern DF wind turbines to vary the reacti

39、ve power absorbed or generated [6, 9, 10] allows a wind turbine to participate in the reactive power balance of the grid. The reactive power at the grid connection considered in this work is described, for the UK, by the

40、 Connection Conditions Section CC.6.3.2 [11] available from the National Grid. The reactive power requirement for a wind farm is defined by figure 2.</p><p>　　Point A - MVAr equivalent for 0.95 leading power

41、 factor at rated MW</p><p>　　Point B - MVAr equivalent for 0.95 lagging power factor at rated MW</p><p>　　Point C - MVAr -5 % of rated MW</p><p>　　Point D - MVAr 5 % of rated MW<

42、/p><p>　　Point E - MVAr -12 % of rated MW</p><p>　　The objective of this paper is to investigate the controller performance of DF and IG mode for a 2MW, 690V, 4-pole DFIG using machine parameters p

43、rovided by the manufacturer. This is further research building on a previous paper which demonstrated the steady-state performance of the two modes of operation, DF and IG mode [8]. In [8] the authors discussed the stead

44、y-state efficiency for both connections. The steady-state performance work illustrated that there were benefits to operating the machi</p><p>　　This paper examines the controllability (i.e. transient perform

45、ance) of the 2 MW wind turbine. Results of the full dynamic controller (current regulation, decoupling equations and vector control) in both DF mode and IG mode are shown. A detailed analysis of thecomponents that form t

46、he rotor voltage over the full operating range in DFIG mode is presented as this enables the dominant control components to be identified. This is particularly important when designing advanced control schemes as an o<

47、;/p><p>　　2. CONNECTION METHODS</p><p>　　Doubly-fed induction machines are commonly connected as shown in figure 3. The grid side inverter (GSI) is controlled to maintain a fixed dc link voltage wi

48、th a given power factor at the grid (in our case unity). The rotor side inverter (RSI) is controlled so the maximum energy is extracted from the kinetic energy of the wind whilst enabling the stator power factor to be co

49、ntrolled within the limits of the grid requirements though unity power factor is often desirable.</p><p>　　An alternative connection method for a doubly-fed machine is shown in figure 4, here called the indu

50、ction generator (IG) connection. The stator is disconnected from the grid and is short-circuited. The rotor circuit is unchanged from figure 3. The GSI is controlled as in DF mode. The objective of the RSI is to control

51、the stator flux linkage while extracting the maximum power from the kinetic wind energy.</p><p>　　3. CONTROLLER PERFORMANCE</p><p>　　A closed loop controller for both DF mode and IG mode has bee

52、n discussed in prior work [12] but only for a 7.5 kW laboratory test rig. The dynamics of a 2 MW system are somewhat different and are investigated in this paper. The performance of the dynamic controller for both DF and

53、 IG mode are shown in this section for a 2 MW wind turbine.</p><p>　　3.1. DFIG Mode (T and Q Control)</p><p>　　The reference values for the controller in DF mode are torque (see figure 1) and st

54、ator reactive power to enable the grid code requirement [11] to be achieved, figure 2. Two speeds are investigated in this section to enable the performance of the controller to be shown both above and below the 20% of r

55、ated power limit from the grid code requirements. A nominal generated power of 320 kW is achieved at 1150 rpm (less than 20% of rated power) and</p><p>　　a nominal power of 1.25 MW is achieved at 1550 rpm (g

56、reater than 20% of the rated power). The reference and actual torque, Te, and stator reactive power, Qs, are shown for both speeds</p><p>　　in figure 5.</p><p>　　The value of reference torque, T

57、e*, for both speeds is the specific nominal torque for a given speed calculated from figure 1; ?2672 Nm for 1150 rpm and ?7701 Nm for 1550 rpm. A step of 200 Nm is applied at both speeds to illustrate the dynamic respons

58、e to a step change in torque. The value of reference stator reactive power, Qs*, at 1150 rpm is varied between the limits specified by the grid code requirements; initially ?5% of the generated power with a step at t=3.5

59、s to +5% of the generated po</p><p>　　The actual rotor current direct, irds, and quadrature, irqs, components corresponding to figure 5 are shown in figure6. The effect of the step change in Te* is apparent

60、on the irqs (the superscript ‘s’ indicates that the variable is referred to the stator) as expected. The irqs* component at 1550 rpm contains small transient responses at t=3s and t=4s that are due to the step changes in

61、 the Qs value. The step change in Qs*, shown in figure 5, causes a fast change in irds*, figure 6, as there is </p><p>　　3.2. IG Mode (T and Flux Control)</p><p>　　The reference values for the c

62、ontroller in IG mode are stator flux linkage and torque. Two conditions are investigated for the 2 MW generator in IG mode, start-up and torque step responses, at 400 rpm (minimum IG mode speed [12]) and 1420 rpm (genera

63、ted power at this speed corresponds to the upper power rating of rotor converter, 600 kW). The reference and actual torque, Te, and stator flux linkage, λsr (the superscript ‘r’ indicates that the variable is referred to

64、 the rotor), for both speeds a</p><p>　　The steady-state Te is the nominal value for the speed of operation, ?320 Nm for 400 rpm and ?4081 Nm for 1420 rpm derived from figure 1. A start-up sequence is requir

65、ed to establish the rated λsr in the machine, for a given speed, by means of a ramp, figure 7, before the machine can generate power.</p><p>　　Once the controller reference λsr has been established in the ma

66、chine, the Te* is increased by means of a controlled ramp to the nominal value for a given speed and then a step response of 50 Nm step at 400 rpm and 200 Nm at 1420 rpm is applied. The controller regulates the machine t

67、o track Te* as expected, see figure 7.</p><p>　　The vector control loops determine the reference rotor current values that are shown in figure 8. The ird component initially increases rapidly to establish th

68、e λsr and is approximately 3 times the nominal steady-state value for a given load point. The current is within the rated limit at all times. The initial ird can be significantly reduced if a slower response of λsr is im

69、plemented.</p><p>　　The irq component is regulated by the torque loop to enable the desired power to be generated. Initially there is a slight error due to the high ird which affects the quadrature loop by t

70、he cross coupling terms. Once nominal λsr is established in the machine the direct and quadrature loops are decoupled. Again a Te step causes a transient spike in irq* though the control is tuned to be slower than this c

71、hange in reference value.</p><p>　　4. CONTRIBUTION OF ROTOR VOLTAGE COMPONENTS</p><p>　　The performance of both DF and IG mode has been illustrated in the previous section. Both controllers are

72、based on an inner current loop and an outer control loop for torque and stator reactive power in the DF case and torque and stator flux linkage in the IG case. Decoupling equations were then added to the PI controller ou

73、tputs to reduce the effect of cross coupling between the loops. The final part of this work studies the contribution of the steady state components of rotor voltage, given in</p><p>　　of the RSI.</p>

74、<p>　　Figure 9 shows the variation of vrdqs for the speed and stator reactive power range investigated. The vrds component is dominated in the steady-state by the ?ωsfσirqs term as the voltage drop across Rrs is neg

75、ligible and the λsq component is zero due to the choice of reference frame. This can be confirmed by comparing figure 9 with figures 11. The vrqs in a 2 MW machine is dominated by the ωsf(Lm/Ls)λsd term as the low total

76、leakage inductance, σ, reduces the effect of the irds cross coupling te</p><p>　　The steady-state variation in the direct, irds, and quadrature, irqs, rotor current components with respect to speed and Qs is

77、 shown in figure 10. The irds component regulates the stator power factor, pfs, by controlling Qs and the ird</p><p>　　s component regulates Te. The value of irds determines the proportion of the generator r

78、eactive power supplied by the stator and rotor circuits. An increasingly positive irds increases the proportion of Q from the rotor circuit while decreasing the Q from the stator until Q is exported by the stator. An inc

79、reasingly negative irds increases the Q from the stator circuit, reducing the Q from the rotor side until Q is exported by the rotor. Qs increases with Te to maintain the desired pfs and so th</p><p>　　The r

80、emainder of this section illustrates the rotor voltage, vrdqs, steady-state components from eqns (1 and 2). The Rrsirds term in vrds and the Rrsirqs term in vrqs are simply irdqs, figure 10,scaled by Rrs and so are not s

81、hown.</p><p>　　The jσωsfirdqs cross coupling terms of vrdqs are shown in figure 11. The jσωsfirqs term contributes to vrds and σωsfirds forms part of vrqs. The σωsfirds component varies with both speed and s

82、tator reactive power as stator reactive power is proportional to torque for a given stator power factor. The σωsfirds component increases with speed as the load torque increases,figure 1. The ?σωsfirqs component is the d

83、ominant term in the vrds component, eqn (1), at non-synchronous speeds; the polarity is </p><p>　　5. DISCUSSION</p><p>　　This analysis enables the vrds and vrqs components to be characterised by

84、 the dominant terms. The λs orientation frame results in the λsq feed forward term in vrds being negligible and so the steady state vrds component is a result of Rrsirds?σωsfirqs. Three distinct regions can then be ident

85、ified, sub-synchronous speed (low irqs due to low load so vrds is approximately Rrsirds), about synchronous speed (ωsf is around 0 so vrds is approximately Rrsirds) and supersynchronous speed (irds and irqs </p>&

86、lt;p>　　The steady state vrqs component is dominated by the λsd term, confirmed by Hopfensperger et al [9] (with the exception of synchronous speed when the steady state vrqs is dependent on the Rrsirqs term). The tran

87、sient response of vrqs to an irqs* step is dominated by the pσirqs term as the differential of the step change in irqs is initially high.The p(Lm/Ls)λsq term has a negligible effect as λsq is approximately zero. The vrd

88、s term and the steady-state terms in vrqs all experience a change in v</p><p>　　6. CONCLUSIONS</p><p>　　This paper has investigated the controller response for the DF and IG mode connections for

89、 a 2 MW DFIG wind turbine. The machine parameters for the 2 MW machine were provided, for a commercially available WRIM used in wind turbines, by the manufacturer. The 2 MW machine parameters used in this work are not si

90、mply a linear scaling of prior work on a 7.5 kW machine and so the characteristics are not identical between the two machines.</p><p>　　Two areas of analysis have been investigated with respect to the 2 MW D

91、FIG. Existing simulation models have been used to evaluate the controllability and steady-state and transient behaviour of a 2 MW DFIG in DF and IG mode. The outcome shows that IG mode is a controllable mode of operation

92、 which will extend the low speed operation as rotor voltage decreases (as speed reduces) and so the voltage limit of the IGBTs will be respected as will the current and power limits of the machine and converte</p>

93、<p>　　ACKNOWLEDGEMENTS</p><p>　　The authors are grateful to FKI Industrial Drives and the EPSRC for their support.</p><p>　　REFERENCES</p><p>　　1. Pena R, Clare J and Asher GM

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