電力牽引傳動(dòng)課程設(shè)計(jì)三相異步電動(dòng)機(jī)調(diào)速系統(tǒng)設(shè)計(jì)

1、目錄一、概述1、電機(jī)概述2、變頻器概述3、三相異步牽引電機(jī)變頻調(diào)速原理及其種類 3.1變頻調(diào)速原理及其機(jī)械特性3.2.基頻以下變頻調(diào)速3.3.基頻以上變頻調(diào)速二、異步電動(dòng)機(jī)在兩相靜止坐標(biāo)系下的數(shù)學(xué)模型三、 異步電動(dòng)機(jī)的仿真模型四、s-function程序五、電機(jī)系統(tǒng)模型六、仿真過(guò)程及其結(jié)果七、總結(jié)參考文獻(xiàn)摘 要由于變頻運(yùn)行下三相異步電動(dòng)機(jī)調(diào)速系統(tǒng)具有節(jié)能的重要優(yōu)點(diǎn),已在國(guó)內(nèi)外工業(yè)生產(chǎn)和日常生活許多領(lǐng)域得到越來(lái)越廣泛地應(yīng)用。目前在變頻調(diào)速系統(tǒng)中,隨著電力電子技術(shù)及變頻調(diào)速技術(shù)的迅速發(fā)展,交流調(diào)速技術(shù)日新月異，新的控制策略不斷涌現(xiàn)，這也使得交流調(diào)速開(kāi)始全面取代直流調(diào)速。在交流調(diào)速技術(shù)中，交流變頻調(diào)

2、速以其優(yōu)異的調(diào)速性能，高效節(jié)能和廣泛的應(yīng)用范圍等特點(diǎn)而被國(guó)內(nèi)外人為是最有前途的調(diào)速方式。關(guān)鍵詞：變頻；三相異步電動(dòng)機(jī)；調(diào)速abstractwith the important merit of saving energy for the timing system of three-phase induction motor under the supply of frequency converter, it has been widely used in more and more fields. now, with the rapid development of power elect

3、ronics and frequency-conversion technology.the technology of adjusting speed of ac induction electromotor changes quickly and new control method appears ceaselessly. dc electromotor by the ac induction electromotor is replaced by the ac induction electromotor in wide range. the ac variable frequency

4、 speed regulation is generally acknowledged by the home and abroad that it has a great future with excellent speed regulation, high efficiency saving energy, extensive scope of application and other merit. keywords: frequency converter; three-phase induction motor;change speed一、概述在變頻調(diào)速系統(tǒng)中異步電機(jī)是一個(gè)非線性、

5、強(qiáng)耦合、高階次的控制對(duì)象，如果忽略其非線性、強(qiáng)耦合、高階次的條件，近似求出線性單變量動(dòng)態(tài)結(jié)構(gòu)，得到的控制系統(tǒng)的動(dòng)態(tài)性能往往不高。要設(shè)計(jì)具有優(yōu)良動(dòng)態(tài)性能的異步電機(jī)調(diào)速系統(tǒng)，必須要深入分析異步電機(jī)的動(dòng)態(tài)數(shù)學(xué)模型。本文在分析異步電機(jī)數(shù)學(xué)模型的基礎(chǔ)上，利用matlab軟件中的simulink對(duì)異步電動(dòng)機(jī)進(jìn)行建模，通過(guò)給出異步電動(dòng)機(jī)正弦脈寬調(diào)制(spwmsinusoidal pulse width modulation)變頻調(diào)速系統(tǒng)的仿真結(jié)果來(lái)驗(yàn)證利用這三種方法對(duì)異步電機(jī)進(jìn)行建模的可行性。1電機(jī)概述1電機(jī)作為一種機(jī)電能量轉(zhuǎn)換裝置，在電力工業(yè)各類工礦企業(yè)，農(nóng)業(yè)國(guó)防，交通運(yùn)輸，日常生活各方面都占有重要地位。

6、隨著科學(xué)技術(shù)的發(fā)展和社會(huì)化大生產(chǎn)的需要，三相基本的電機(jī)形式：直流電機(jī)，感應(yīng)電機(jī)，同步電機(jī)在工業(yè)生產(chǎn)和日常生活中獲得了廣泛的應(yīng)用。異步電動(dòng)機(jī)的轉(zhuǎn)速根據(jù)負(fù)載的要求，人為的或自動(dòng)的進(jìn)行調(diào)節(jié)，稱為調(diào)速。但出于不同的使用目的，往往對(duì)電動(dòng)機(jī)的速度提出不同的要求，如電動(dòng)車輛，電梯，機(jī)床等要求有良好的速度調(diào)節(jié)性能；調(diào)速也是風(fēng)機(jī)，水泵類負(fù)載節(jié)能運(yùn)行的需要。一般籠型異步電動(dòng)機(jī)的轉(zhuǎn)速略低于同步轉(zhuǎn)速，且在負(fù)載變化時(shí)變化不大，是一種接近于恒速的驅(qū)動(dòng)裝置，其本身的調(diào)速性能不佳。因此電動(dòng)機(jī)的調(diào)速控制一直是電氣專家學(xué)者致力于解決的問(wèn)題。近年來(lái)，直流調(diào)速，交流變頻調(diào)速隨著技術(shù)的進(jìn)步，性能在不斷改善。直流電動(dòng)機(jī)具有優(yōu)良的調(diào)速性能

7、，但它有一個(gè)根本的缺點(diǎn)，就是有機(jī)械式的整流器整流子和電刷，因此它的維護(hù)工作量較大；而且由于機(jī)械式整流器的限制，制造大功率高電壓的直流電機(jī)比較困難。由于這些原因，限制了直流可調(diào)速拖動(dòng)系統(tǒng)的使用范圍。我們知道，交流異步電動(dòng)機(jī)的轉(zhuǎn)速n與定子旋轉(zhuǎn)磁場(chǎng)的速度、轉(zhuǎn)子的轉(zhuǎn)差率s有以下關(guān)系：式中電源效率，hz，p電動(dòng)機(jī)極對(duì)數(shù)；改變電源的頻率，電動(dòng)機(jī)可以調(diào)速。變頻調(diào)速既適用于同步電動(dòng)機(jī)，又適用異步電動(dòng)機(jī)，是一種高效率的調(diào)速方案。2變頻器概述 變頻器是異步電動(dòng)機(jī)調(diào)速系統(tǒng)中的關(guān)鍵設(shè)備。變頻器是利用電力半導(dǎo)體器件的通斷作用將工頻電源變換為另一頻率的電能控制裝置。我們現(xiàn)在使用的變頻器主要采用交直交方式（vvvf變頻或矢

8、量控制變頻），先把工頻交流電源通過(guò)整流器轉(zhuǎn)換成直流電源，然后再把直流電源轉(zhuǎn)換成頻率、電壓均可控制的交流電源以供給電動(dòng)機(jī)。變頻器的電路一般由整流、中間直流環(huán)節(jié)、逆變和控制4個(gè)部分組成。整流部分為三相橋式不可控整流器，逆變部分為igbt三相橋式逆變器，且輸出為pwm波形，中間直流環(huán)節(jié)為濾波、直流儲(chǔ)能和緩沖無(wú)功功率。7變頻器實(shí)際上就是一個(gè)逆變器.它首先是將交流電變?yōu)橹绷麟?然后用電子元件對(duì)直流電進(jìn)行開(kāi)關(guān).變?yōu)榻涣麟?一般功率較大的變頻器用可控硅.并設(shè)一個(gè)可調(diào)頻率的裝置.使頻率在一定范圍內(nèi)可調(diào).用來(lái)控制電機(jī)的轉(zhuǎn)數(shù).使轉(zhuǎn)數(shù)在一定的范圍內(nèi)可調(diào).變頻器廣泛用于交流電機(jī)的調(diào)速中.變頻調(diào)速技術(shù)是現(xiàn)代電力傳動(dòng)技術(shù)

9、重要發(fā)展的方向，隨著電力電子技術(shù)的發(fā)展，交流變頻技術(shù)從理論到實(shí)際逐漸走向成熟。變頻器不僅調(diào)速平滑，范圍大，效率高，啟動(dòng)電流小，運(yùn)行平穩(wěn)，而且節(jié)能效果明顯。因此，交流變頻調(diào)速已逐漸取代了過(guò)去的傳統(tǒng)滑差調(diào)速、變極調(diào)速、直流調(diào)速等調(diào)速系統(tǒng)，越來(lái)越廣泛的應(yīng)用于冶金、紡織、印染、煙機(jī)生產(chǎn)線及樓宇、供水空調(diào)等領(lǐng)域。3三相異步電動(dòng)機(jī)變頻調(diào)速原理及其種類三相異步電動(dòng)機(jī)的調(diào)速開(kāi)始于上世紀(jì)50年代末。在電氣傳動(dòng)領(lǐng)域中，原來(lái)只用于恒速傳動(dòng)的交流電動(dòng)機(jī)實(shí)現(xiàn)了調(diào)速控制，以取代制造復(fù)雜，價(jià)格昂貴，維護(hù)麻煩的直流電動(dòng)機(jī)。以后，隨著電力電子技術(shù)和微型計(jì)算機(jī)的發(fā)展，再加上現(xiàn)代控制理論向電氣傳動(dòng)領(lǐng)域的滲透，使得交流調(diào)速技術(shù)得到了

10、迅速發(fā)展，其設(shè)備容量不斷擴(kuò)大，性能指標(biāo)及可靠性不斷提高，高性能交流調(diào)速系統(tǒng)應(yīng)用的比例逐年上升，在各工業(yè)部門(mén)中，使得交流調(diào)速系統(tǒng)逐步取代直流調(diào)速系統(tǒng)，以達(dá)到節(jié)能，縮小體積、降低成本的目的。根據(jù)三相異步電動(dòng)機(jī)的轉(zhuǎn)速公式為 式中為異步電動(dòng)機(jī)的定子電壓供電頻率；為異步電動(dòng)機(jī)的極對(duì)數(shù)；為異步電動(dòng)機(jī)的轉(zhuǎn)差率。所以調(diào)節(jié)三相異步電動(dòng)機(jī)的轉(zhuǎn)速有三種方案。異步電動(dòng)機(jī)的變壓變頻調(diào)速系統(tǒng)一般簡(jiǎn)稱變頻調(diào)速系統(tǒng)，由于調(diào)速時(shí)轉(zhuǎn)差功率不變，在各種異步電動(dòng)機(jī)調(diào)速系統(tǒng)中效率最高，同時(shí)性能最好，是交流調(diào)速系統(tǒng)的主要研究和發(fā)展方向。3.1變頻調(diào)速原理及其機(jī)械特性改變異步電動(dòng)機(jī)定子繞組供電電源的頻率，可以改變同步轉(zhuǎn)速，從而改變轉(zhuǎn)速。如

11、果頻率連續(xù)可調(diào)，則可平滑的調(diào)節(jié)轉(zhuǎn)速，此為變頻調(diào)速原理。三相異步電動(dòng)機(jī)運(yùn)行時(shí)，忽略定子阻抗壓降時(shí)，定子每相電壓為 式中為氣隙磁通在定子每相中的感應(yīng)電動(dòng)勢(shì)；為定子電源頻率；為定子每相繞組匝數(shù)；為基波繞組系數(shù)，為每極氣隙磁通量。如果改變頻率，且保持定子電源電壓不變，則氣隙每極磁通將增大，會(huì)引起電動(dòng)機(jī)鐵芯磁路飽和，從而導(dǎo)致過(guò)大的勵(lì)磁電流，嚴(yán)重時(shí)會(huì)因繞組過(guò)熱而損壞電機(jī)，這是不允許的。因此，降低電源頻率時(shí)，必須同時(shí)降低電源電壓，已達(dá)到控制磁通的目的。對(duì)此，需要考慮基頻（額定頻率）以下的調(diào)速和基頻以上調(diào)速兩種情況。3.2.基頻以下變頻調(diào)速18為了防止磁路的飽和，當(dāng)降低定子電源頻率時(shí)，保持為常數(shù)，使氣每極磁通

12、為常數(shù)，應(yīng)使電壓和頻率按比例的配合調(diào)節(jié)。這時(shí)，電動(dòng)機(jī)的電磁轉(zhuǎn)矩為上式對(duì)求導(dǎo)，即 ，有最大轉(zhuǎn)矩和臨界轉(zhuǎn)差率為由上式可知：當(dāng)常數(shù)時(shí)，在較高時(shí)，即接近額定頻率時(shí)，隨著的降低，減少的不多；當(dāng)較低時(shí)，較小；相對(duì)變大，則隨著的降低，就減小了。顯然，當(dāng)降低時(shí)，最大轉(zhuǎn)矩不等于常數(shù)。保持常數(shù)，降低頻率調(diào)速時(shí)的機(jī)械特征如圖1所示。這相當(dāng)于他勵(lì)直流電機(jī)的降壓調(diào)速。圖1 變頻調(diào)速的機(jī)械特性（a） 基頻以下調(diào)速（常數(shù)）（b）基頻以上調(diào)速（=常數(shù)）3.3.基頻以上變頻調(diào)速在基頻以上變頻調(diào)速時(shí)，也按比例身高電源電壓時(shí)不允許的，只能保持電壓為不變，頻率越高，磁通越低，是一種降低磁通升速的方法，這相當(dāng)于它勵(lì)電動(dòng)機(jī)弱磁調(diào)速。保持

13、=常數(shù),升高頻率時(shí)，電動(dòng)機(jī)的電磁轉(zhuǎn)矩為 上式求，得最大轉(zhuǎn)矩和臨界轉(zhuǎn)差率為 由于較高，、和比大的多，則上式變?yōu)?因此，頻率越高時(shí)，越小，也越小。保持 為常數(shù)，升高頻率調(diào)速時(shí)的機(jī)械特性如圖1（b）所示。二、異步電動(dòng)機(jī)在兩相靜止坐標(biāo)系下的數(shù)學(xué)模型在研究異步電動(dòng)機(jī)的數(shù)學(xué)模型時(shí)，在文中作如下的假設(shè)：(1)忽略空間諧波。設(shè)三相繞組對(duì)稱(在空間上互差120。電角度)，所產(chǎn)生的磁動(dòng)勢(shì)沿氣隙圓周按正弦規(guī)律分布；(2)忽略磁路飽和，各繞組的自感和互感都是恒定的；(3)忽略鐵芯損耗；(4)不考慮頻率和溫度變化對(duì)繞組電阻的影響。異步電動(dòng)機(jī)在靜止坐標(biāo)系、上的數(shù)學(xué)模型為：(1)電壓方程為：(2)磁鏈方程為：(3)轉(zhuǎn)矩方程

14、為：t (3) e=n p(i11-i11) (3)(4)運(yùn)動(dòng)方程為：t e-t l =j*dw/(dt*n p)(4) 式中r 1、r 2、l 1、l 2為定子、轉(zhuǎn)子電阻和自感，l m為定子、轉(zhuǎn)子間互感， 為電機(jī)轉(zhuǎn)子角速度；u1、u1為、軸定子電壓，i1、i1、1、1為、軸定子電流及磁鏈，t e為電磁轉(zhuǎn)矩；t l為負(fù)載轉(zhuǎn)矩；n p為電機(jī)極對(duì)數(shù)；j 為電機(jī)轉(zhuǎn)動(dòng)慣量。把靜止軸系下三相/二相變換公式代入上述表達(dá)式，得到：將(6)式代入(5)式作非奇異變換，得到以定子電流及定子磁鏈為狀態(tài)的異步電機(jī)狀態(tài)方程為：三、 異步電動(dòng)機(jī)的仿真模型基于matlab/simulink的異步電機(jī)系統(tǒng)仿真可以利用sim

15、ulink模塊搭建，但是，并非所有的數(shù)學(xué)模型都能利用模塊輕易地搭建起來(lái)，有的模型更適合于matlab/simulink支持的s一函數(shù)(_)格式，matlab語(yǔ)言或著c等語(yǔ)言格式來(lái)描述，構(gòu)成s一函數(shù)模塊，像標(biāo)淮的simulink模塊直接調(diào)用。上述經(jīng)過(guò)3/2變換的三相異步電機(jī)的數(shù)學(xué)模型仍是一個(gè)高階、非線性、強(qiáng)禍合的多變量系統(tǒng)，用框圖搭建非常煩雜，而且易于出錯(cuò)。本文的方法是利用matlab格式編寫(xiě)異步電機(jī)的s一函數(shù)來(lái)實(shí)現(xiàn)電機(jī)的建模，其模型簡(jiǎn)潔明了、不易出錯(cuò)。在 ma tl ab/simulink軟件平臺(tái)中提供了一個(gè)sfuntmpl. m的模板文件，可以利用這個(gè)模板文件邀行修改，按自己的需要來(lái)構(gòu)建自己

16、的s一函數(shù)。根據(jù) 數(shù) 學(xué) 模型之(5)式，輸人是靜止a,8軸上的定子電壓、,u,以及轉(zhuǎn)子電角速度.，輸出是靜止a,a軸上的定、轉(zhuǎn)子電流i,ii,0。根據(jù)matlab語(yǔ)言設(shè)計(jì)一個(gè)名為acmotor_sfun的s-函數(shù)，模型見(jiàn)圖l。當(dāng)仿真的時(shí)候，sfunction模塊直接調(diào)用simulink 中自己編寫(xiě)的acmotor_sfun.m二文件，即可完成m文件所要求的運(yùn)行功能。m文件的具體程序如下:%兩相靜止坐標(biāo)系下的電機(jī)模型(im) %狀態(tài)變量: x(1)=wr; x(2)=phi_a; x(3)=phi_b; x(4)=i_a; x(5)=i_b; %輸入變量為 u(1)=ua; u(2)=ub;

17、u(3)=uc; 三相輸入電壓; u(4)=t_l 負(fù)載轉(zhuǎn)矩%輸出變量 sys(1)=wr; sys(2)=i_a; sys(3)=i_b; sys(4)=i_c; sys(5)=te function sys,x0,str,ts = motor(t, x, u,flag, rs, rr, ls, lr, lm, j, np) switch flag, case 0, sys, x0, str, ts=mdlinitializesizes; case 1, sys=mdlderivatives(t, x, u, rs, ls, rr, lr, lm, j, np); case 2, 9, sy

18、s= ; case 3, sys=mdloutputs(t,x,rs, ls, rr, lr, lm, j, np); case 4, sys=mdlgettimeofnextvarhit(t,x,u); otherwise error(unhandled flag = ,num2str(flag); end % 初始化 function sys,x0,str,ts=mdlinitializesizes sizes = simsizes; sizes.numcontstates = 5; sizes.numdiscstates = 0; sizes.numoutputs = 5; sizes.

19、numinputs = 3; sizes.dirfeedthrough = 1; sizes.numsampletimes = 1; sys = simsizes(sizes); x0 = 0; str = ; ts = 0 0; % 微分 function sys=mdlderivatives(t,x,u,rs,ls,rr,lr,lm,j,np) delta=1-lm*lm/(ls*lr); %狀態(tài)方程(x(1)=wr,x(2)=phi_a,x(3)=phi_b,x(4)=i_a,x(5)=i_b) dx(1)=(np2*lm/(j*lr)*(x(2)*x(5)-x(3)*x(4)-np*u

20、(3)/j; dx(2)=-(rr/lr)*x(2)-x(1)*x(3)+(rr/lr)*lm*x(4); dx(3)=-(rr/lr)*x(3)+x(1)*x(2)+(rr/lr)*lm*x(5); dx(4)=lm*rr/(delta*ls*lr*lr)*x(2)+lm/(delta*ls*lr)*x(1)*x(3)-(lm*lm*rr+lr*lr*rs)/(delta*ls*lr*lr)*x(4)+u(1)/(delta*ls); dx(5)=lm*rr/(delta*ls*lr*lr)*x(3)-lm/(delta*ls*lr)*x(1)*x(2)-(lm*lm*rr+lr*lr*rs

21、)/(delta*ls*lr*lr)*x(5)+u(2)/(delta*ls); sys=dx;%sys(1)=(np*np*lm/(j*lr)*(sys(2)*sys(5)-sys(3)*sys(4)-u(4)/j; % 微分結(jié)束 % 輸出 function sys=mdloutputs(t,x,rs, ls, rr, lr, lm, j, np)sys(1)=x(1); %wr sys(2)=sqrt(2/3)*x(4); %i_a sys(3)=-sqrt(1/6)*x(4)+sqrt(1/2)*x(5); %i_b sys(4)=-sqrt(1/6)*x(4)-sqrt(1/2)*x(

22、5); %i_csys(5)=np*(lm/lr)*(x(2)*x(5)-x(3)*x(4); %te % 輸出結(jié)束 % 終止 function sys=mdlterminate(t, x, u) sys = ; function sys=mdlgettimeofnextvarhit(t,x,u) sampletime = 200; % example, set the next hit to be one second later. sys = t + sampletime; % end mdlgettimeofnextvarhit 四、s-function程序function a,b,c,

23、d,k,x0 = motor(par,ts,aux)%motor ode file representing the dynamics of a motor.% a,b,c,d,k,x0 = motor(tau,ts,g)% returns the state space matrices of the dc-motor with% time-constant tau (tau = par) and known static gain g. the sample% time is ts.% this file returns continuous-time representation if

24、input argument ts% is zero. if ts0, a discrete-time representation is returned. to make% the idgrey model that uses this file aware of this flexibility, set the% value of structure.fcntype property to cd. this flexibility is useful% for conversion between continuous and discrete domains required for

25、% estimation and simulation.% see also idgrey, iddemo7. % l. ljung% copyright 1986-2011 the mathworks, inc.% $revision: .2.1 $ $date: 2011/12/27 15:42:57 $ t = par(1);g = aux(1); a = 0 1;0 -1/t;b = 0;g/t;c = eye(2);d = 0;0;k = zeros(2);x0 = 0;0;if ts0 % sample the model with sample time ts s

26、 = expm(a b*ts; zeros(1,3); a = s(1:2,1:2); b = s(1:2,3);end五、電機(jī)系統(tǒng)模型六、仿真過(guò)程及其結(jié)果（1）20hz電流20hz電流整體20hz電壓設(shè)置20hz轉(zhuǎn)速（2）50hz電流50hz電流整體50hz轉(zhuǎn)速50hz電壓設(shè)置六、總結(jié)本文討論了基于兩相靜止坐標(biāo)系下的三相異步交流電機(jī)在matlab/simulink環(huán)境下的仿真，介紹了s一function建模的方法，其特點(diǎn)是編程容易，模型直觀，沒(méi)有煩瑣的框圖。然后以轉(zhuǎn)動(dòng)慣量的大小變化對(duì)電機(jī)啟動(dòng)時(shí)的影響為例，進(jìn)行電機(jī)模型的仿真，從仿真結(jié)果可以看出所建模型符含實(shí)際異步電機(jī)的運(yùn)行特性，驗(yàn)證了設(shè)計(jì)模型

27、的正確性，為進(jìn)一步基于dsp的矢量控制變頻調(diào)速系統(tǒng)的研究奠定基礎(chǔ)。參考文獻(xiàn)1陳建業(yè)，電力電子電路的計(jì)算機(jī)仿真，北京：清華大學(xué)出版社，20052陳剛，軟開(kāi)關(guān)雙向dc/dc變換器的研究，浙江大學(xué)博士學(xué)位論文，20013張國(guó)安，朱忠尼，新型推挽式移相式軟開(kāi)關(guān)拓?fù)溲芯?，電工技術(shù)雜志，1998（1）4伊林林，軟開(kāi)關(guān)pwm 雙向d c / d c 變換器的研5百度g an employment tribunal claimemployment tribunals sort out disagreements between employers and employees.you may need to m

28、ake a claim to an employment tribunal if: you dont agree with the disciplinary action your employer has taken against you your employer dismisses you and you think that you have been dismissed unfairly.for more information about dismissal and unfair dismissal, seedismissal.you can make a claim to an

29、 employment tribunal, even if you haventappealedagainst the disciplinary action your employer has taken against you. however, if you win your case, the tribunal may reduce any compensation awarded to you as a result of your failure to appeal.remember that in most cases you must make an application t

30、o an employment tribunal within three months of the date when the event you are complaining about happened. if your application is received after this time limit, the tribunal will not usually accept it.if you are worried about how the time limits apply to you, take advice from one of the organisati

31、ons listed underfurther help.employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation.most people find making a claim to an employment tribunal challenging. if you are thinking about making a claim to

32、 an employment tribunal, you should get help straight away from one of the organisations listed underfurther help.if you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your compensation if you win the case. this is known as

33、adamages-based agreement. in england and wales, your solicitor cant charge you more than 35% of your compensation if you win the case.if you are thinking about signing up for a damages-based agreement, you should make sure youre clear about the terms of the agreement. it might be best to get advice

34、from an experienced adviser, for example, at a citizens advice bureau. to find your nearest cab, including those that give advice by e-mail, click onnearest cab.for more information about making a claim to an employment tribunal, seeemployment tribunals.the (lack of) air up there watch mcayman islan

35、ds-based webb, the head of fifas anti-racism taskforce, is in london for the football associations 150th anniversary celebrations and will attend citys premier league match at chelsea on sunday.i am going to be at the match tomorrow and i have asked to meet yaya toure, he told bbc sport.for me its a

36、bout how he felt and i would like to speak to him first to find out what his experience was.uefa hasopened disciplinary proceedings against cskafor the racist behaviour of their fans duringcitys 2-1 win.michel platini, president of european footballs governing body, has also ordered an immediate inv

37、estigation into the referees actions.cska said they were surprised and disappointed by toures complaint. in a statement the russian side added: we found no racist insults from fans of cska.age has reached the end of the beginning of a word. may be guilty in his seems to passing a lot of different li

38、fe became the appearance of the same day; may be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. always feel oneself should go to do something, or write something. twenty years of life trajectory deeply shallow,

39、suddenly feel something, do it.一字開(kāi)頭的年齡已經(jīng)到了尾聲?；蛟S是愧疚于自己似乎把轉(zhuǎn)瞬即逝的很多個(gè)不同的日子過(guò)成了同一天的樣子；或許是追溯過(guò)去，對(duì)自己那些近乎偏執(zhí)的怪異信念的醒悟，這些天以來(lái)，思緒一直很凌亂，在腦海中不斷糾纏。總覺(jué)得自己自己似乎應(yīng)該去做點(diǎn)什么，或者寫(xiě)點(diǎn)什么。二十年的人生軌跡深深淺淺，突然就感覺(jué)到有些事情，非做不可了。the end of our life, and can meet many things really do?而窮盡我們的一生，又能遇到多少事情是真正地非做不可？during my childhood, think lucky mon

40、ey and new clothes are necessary for new year, but as the advance of the age, will be more and more found that those things are optional; junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly foun

41、d that isnt really grow up, it seems is not so important; then in high school, think dont want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has

42、 sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already cant remember his appearance.童年時(shí)，覺(jué)得壓歲錢和新衣服是過(guò)年必備，但是隨著年齡的推進(jìn)，會(huì)越來(lái)越發(fā)現(xiàn)，那些東西根本就可有可無(wú)；初中時(shí)，以為要有一場(chǎng)暗戀才意味著真正的成長(zhǎng)，但三年過(guò)去后，自己心平氣和的寫(xiě)同學(xué)錄的時(shí)候，突然就發(fā)現(xiàn)是不是真正的成長(zhǎng)了，好像并沒(méi)有那么重要了；然后到了高中，覺(jué)得非要吐露出自己的心聲才能為高中生涯里的懵懂情愫劃上一個(gè)句點(diǎn)，但畢業(yè)晚會(huì)的時(shí)候最終還是被梗塞在了咽喉，

43、后來(lái)再次站在他曾經(jīng)揮汗如雨的球場(chǎng)，看著他投過(guò)籃球的球框時(shí)，突然間發(fā)現(xiàn)自己已經(jīng)想不起他的容顏。originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time.原來(lái)，這個(gè)世界上，對(duì)某個(gè)事件能產(chǎn)生化學(xué)反應(yīng)的，除了非做不可的堅(jiān)決，還有，時(shí)間。a persons time, your ideas are always special to clear. want, want, line is clear, as if nothing c

44、ould shake his. also once seemed to be determined to do something, but more often is he backed out at last. dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. those who do, just green years oneself give oneself an arm inje

45、ction, or is a self-righteous spiritual.一個(gè)人的時(shí)候，自己的想法總是特別地清晰。想要的，不想要的，界限明確，好像沒(méi)有什么可以撼動(dòng)自己。也曾經(jīng)好像已經(jīng)下定了決心去做某件事，但更多的時(shí)候是最后又打起了退堂鼓。嫌惡過(guò)自己的怯懦，最終卻發(fā)現(xiàn)有很多緣分，有很多錯(cuò)過(guò)，好像冥冥之中真的已經(jīng)注定。那些曾經(jīng)所謂的非做不可，只是青蔥年華里自己給自己注射的一支強(qiáng)心劑，或者說(shuō)，是自以為是的精神寄托罷了。at the moment, the sky is dark, the air is fresh factor after just rained. suddenly thoug

46、ht of blue plaid shirt; those were broken into various shapes of stationery; from the corner at the beginning of deep friendship; have declared the end of the encounter that havent start planning. those years, those days of do, finally, like youth, will end in our life.此刻，天空是陰暗的，空氣里有著剛下過(guò)雨之后的清新因子。突然想

47、到那件藍(lán)格子襯衫；那些被折成各種各樣形狀的信紙；那段從街角深巷伊始的友誼；還有那場(chǎng)還沒(méi)有開(kāi)始就宣告了終結(jié)的邂逅計(jì)劃那些年那些天的非做不可，終于和青春一樣，都將在我們的人生中謝幕。baumgartner the disappointing news: mission aborted. r plays an important role in this mission. starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity

48、and limited cloud cover. the balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers)