PPKEE, Pusat Pengajian Kejuruteraan Elektrik & Elektronik

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UNlVERSITI S AH"IS lvlALA YSIA JPeperibaan Senu~ster Pertama Sidang Akf:ldemik ] 995/96 Masa: i[3jam] --_._._-------------_ ... __ ._._-_.-. __ ._---_._ ..... _-.. -----_._-----_ .. _----ARAHAN KEPADA CALON : Sila pastikan lbahawa kertas pep'E:riksaan ini m~'i!llgandungi 12 muka surat bercetak dan ENAM W soalan sebelum amda Illmnulakan peperliksaan ini. Jawab LlMJU',1'-l soalan. Agihan markah biBLgi soalan clibt:,rikan di sut s,~bda.h kanan soalan berkenaan. Jawab semua s(>alan di d;dam Bahasa Malaysia. ...2/-455 - 2·· [EEE 441] 1 . (a> Apakab langlk.ah-langka)lI ~i"llng terlibllt di dalam rekabentuk I~el'alatan elektronik kuasn? What are the step:~ involved ;n d~~.~igning power electronics equipment? (15%) (b) A,pakah ke:s,an,,·kesan sam]piogan dad pernlatan elektronik kuasa? What are the' peripheral effect.!, oJ)')(}Wcr electronics equipment? (15%) (c) ]~entuk glelom bang puHh:a.n TUTUP i(turo off) suatu peranti ditunjukluan olellt Rajab 1~1. .fika Qrr ialah cas pulihan seperti clitunjuk.I[IlDl oleh kawasan IOIl"ekan, IRM ialah arus balikan puncak, trr ialallt masa pulih bali~m dan tl, t2 merupakan bahagiao dati trr• Terbitkan ullgkapan unhll k 1t~"1' dal1l IRM dalam sebutan Qrr dan di/dt untnk polilillln pentas dan pulilaan lembld. The wave/ormsi)r turnof!recovelY ofa device is shown in Figure 1-1. /fQrr is the recovered charge shown J'n the shaded area, IRA! is the peak reverse current, trr;s the n~verse recover), time, and time t 1 and t2 are subdivisions of 1',.1'. Derive' the expressions)i" tn' and IRM in J'I~rm of Qrr and di/dt for abrupt recovery arnd a very soft reCOl'e~.IV, (40%) ... 3/-456 "" 3·" Vn ._._- -..... - .... ----~ .. t .---. _ ... _._-_. '\~''''--''-'-"---_ ... _-Rajab 1-1 FiguY(~ /-1 [EEE 441] (d) Per'anti E:,lT dikend.aRiilk.BIR untuk sua.tu kala dan kehilangan Ilensuisa;lIl1llya dUunjukkllt1l ole:h Rajah 1-2. Nilai r(t) boleh ditentukl~.1Il diari Rajah l<~. niberi: R;re::: O.8°C/'N, Res = O.50 C/W, dan TA = 850 C. Tentukaml: A BfT is (~{JI~rated in a period.ic mtmner with thlE! losses as shown in Figure 1-2. The value o./r(t) .may be detel'mined}'om Figure 1-3, R.Jc = O.8°C/W, Res == O.soC/W, and TA =, 85~)c.. rInd: I( i) NUa.i p\il.m~llk (TJ - T (~ ) thE: pe:ak value of (TJ" 1(::,~, and i(ii) Nil alii RSA supaya Hilaaii plillncak TJ dibadkan kepada 150oC. th~! value ofRsA that limit the peak value ofTJat 15{)oC. .. .4/-457 2. <a) ·,4- [EEE 441] 20 -1 _1_0+---+~ ____ ....:.-_____ -....;._ .... ~ masa 13 (ms) 1 2 3 Rajab 1·2 Figure 1-2 SAMBUTAII nmMAL masa,t' (rn!j) Rajab 1·3 Fl!;'W'e 1-3 Apakab c:ill'i v-i bagi tbi,I'ist(l,r? 10 Apakab lJlode~. dna tranS,lsta:f' bagi thiris1l:or? ZIo/JClll nil p;,)~c ~ R8Je' 1.0· CN/ M,. ~ o CURVES APPl V F OR POW! R -PULSE TRA'N SHOWN RE~O 1.ME Ar 11 (30%) Explain wh.at is the v-i characteristic o/thyristors? Explain what is the two transistors model ofth.'Ir'ristors? (30%) ... 5/-456 - 5 ,. [EEE 441] (b) Apakah IUledah-kaedah U!ltu){ menghidupkan thiristor? Apakah tU,juan ka.walan dildt dan dv/dt? What are t."e means of turning -on .thyristors? What are tJu! pwpose of di/dt and dv/dt protections? (40%) (c) Litar mud:ah llntuk mengilidupkan thiristor ditunjukkan oleh Rajah 2-1. Bentuk gelomballg arlllS dan vol1an untuk proses tersebut ditunjukkan oleh Rajah 2:-2. Diberi: E:= 100 V, R = 10 0 ,C = 4JA.F dan tq = 30JA.s. Adakah thiristolr tersebut berada dalam keadaan Jllincang balikau y~lIIlg mencuklllpi supaya berlaku 'turn-off' . A. simple circuit to tum off thyristor is shown in Figure 2-1. The current and voltage wavejormjor the proces.'i is shown in FIgure 2-2. In Figure 2-1, E = 100 voltj,; R = 10 Q , C = 4pF and required tq = 30/JS. Is the thyristor reverse biased long enoughfo,~ tum-offto occur? Describe why? R 1+ E 1"C ~ S Rajab 2-1 Figure 2-1 .. ,6/· 45~} -~---.--.---------- IL VAK E ; .t ------Vak /.....,--Rll,iiab 2-2 Figure 2-2 . 3. (a) Terangk.IUlt operasi bagi lienaiilLOnverter sntu fasa? [EEE441] (30%) Terbitkalll pel'samaan UB1tuk voltan keJuaran purata dan rms bagi semikoDl'erter 58tu fa,s a .• Explain the operation of a single phase semiconverter? Derive the expressions for the ave'rage and nns output voltages of a single phase semiconverter. (40%) ... 7/-- 7,· [EBE 441] (b) Konverter penuh tiga fua di dalam Rajah 3 dikendalikan dari punca 3 fasa sambungalU Y 208V, 60Hz dan rinta.ngan beban lalah R ;:: 100. Jika vollan keluaran purata yang diperlukan ialah 60% darl vol,tan keluarall m~lksimum, kiJoakan: A three phase full converter in Figure 3 is operated from a three phase Y connected 208J;~ 60Hz supply and the load resistance is R = 10Q. If it is required to obtain an average output yoltage of 60% of the maximum possible output. voltage, calculate. ( i) sudat len gab a the' delay angle a, (ii) arU!1 keluaran rms thi.~ 117IS output current (iii) arull keluaran purllta" dan thi.~ average output cun-er.ll, and (iv) kecekapan penukaran thi.~ rectification ejficien(ry. 5 ;,.T 6 L---"l. __ ,_,...;...._  ___ --" Rajalil 3 Figure 3 46.i Load (60%) ... 8/-·8· .. [EEE 441] 4. (a> Apakah I.arameter-paraml~tel" k,eupayaan bagi pemenggal? What are the perfonnance panmeters of a chopper? (20%) (b) Uagi pemenggal Buck sepl1~rd ditunjukkan oleh Rajah 4 terbitkan: For the Buck Chopper shown in FIgure 4 derive: (i) hllbungan voltan keluaran, dan the output voltage relation, and (ii) hubungan al'us anaksimum Imax dan arus minimum Imin. circuit current relation, lmax and Imin. (40%) (c) Pemenggal Buck, seperti dH:unjukkan oleh Rajah 4, dikendalikan I)ada 10'o.Hz, membekalk~m lOOW pada 12V ke beban dari punca 20V. Tentukan: A Buck Chopper as shown in Figure 4, operating at 10kHz, supplies 100Wat J 2V to a loadfrom a 20V SOUlrce. Find: ( i) nilai induktans untuk :a.rus induktor yang berterusan tm' inductance for comimtOus inductor current (ii) ImalH; - Imio9 dan /tnllX -: Imi'l, and (iii) nUai kapasitans ya"llg diperlukan supaya AV t - O. tV . tht~ value of capacitance needed.for AV I~ - 0.1 V. . .. 9/-5. (a) -9- [EEE441] Rajah 4 Figure 4 R Huraikan kawalan BUKA-TUTUP dalam kawalan ac. Explain the ON-OFF control in QiC controller. (40%) (20%) (b) Pengawall voltan ac 58tu fasa separuh gelombang di dalam Rajah 5-1 mempuillyai beban p.~rintang R = 200 dan voltan masukan V. == 208V(rms), 60Hz. Jika kuasa keluaran Po = 2kW diperlukan. The Single-phase half wave GI::: voltage controlJ.~r in Figure 5-J has a resistive load of R ,,= 20Q and the input voltage is Vs = 208V(rms). 60Hz. If the desired output power is Po = 2kW. (Ii) Te:rbitkan persamann ~Iudut len gab dalam sebutan a Derive the equation jbr delay angle in term of a (ii) Kira faktor kuasa masukan PF (Jika ex: - .y) Find the input power Jutor P F (if ex: - ;). (40%) ... 10/-- 10-')' 1 I>I~ 0-[ J_. -,'!<J--0---'][' 1 Rajab 5-1 Figul'f~ 5-1 [EEE 441] R (c) Litar di dalam Rajah ~~-2 dikawal oleb penukar tap sinkronis. Voltan uta,ma ialah 240V (rms), 60 Hz. Voltan sekunder ialab Vl == 120V d~lD Vl = 100V. Jika beban perintang R = 250, voltan beban rms ialab 200V dal;11 Ct = 950, tentokan. The circuit in .Flgure 5-2 is confrolled as a synchronous tap changer. The primary voltage is 240V (rm:O, 60Hz. The secondary voltages are Vj = J 20V and V2 = JOOv. £fthe load resi.~tance is R = l5D, the rms load voltage is 200V, and Ct = 95°, determim: ( i) BrIll!; rms thiristor r 1 dan T 2, the' lms (;"urrent of no,ristor TJ and T2, . (ii) arm; rms thiristor T3 dan T4 the' mls current of Thyristor 13 and T4. and (iii) raldor kuasa maSlIJlkan, PF. thE~ input power factor Pli: 48,; (40%) ... 111-6. (a) f1' 1J -11-RaJah 5-2 Figure 5-2 Ap,akah IU'iJrasil.' operasi ih 11llglislIIatu inver1ter? [EEE 441] _o-f L Apakab fUlclgsi dliod suaplbaHlI{ di dalam Htal' inverter? Descl'ibt~ is the prinClfple of opEration (~{ an invert,~r? What are t'f-4E~ PUlp()SeS ofjieedl,ackdiodes in inverter? (30%) (b) Aplilkah Jlc:ne~cbi,b umtuk lII'wnlgll:u15ilkan volC:an keluaran tiga fasa dari smlto litsllr iimlclr:ter? Ter'lIlDg:~Jt,n ulltuk p'engaliran 1800. lWhat are lhl-: an'(ll'lgiements/bl" obtaining three phase output voltages? Explain J~)r J 80 degree conduction. (40%) ... 12/-4 fn~) [EEE 441] (c) Apakah Jluu!~dab-k.aedah untuk mengawal voltan di dalam inverter satu fasa., Terangkan dUll (\Inri kaedah-kaedah yang digunakan. What are the methods for vol.trzge control within the inverters? Explain two of the techniques used. (30%) "0000000-46C 

EEE 441 - ELEKTRONIK KUASA OKT-NOV 1996

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EEE 441 - ELEKTRONIK KUASA OKT-NOV 1996

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