Enerji ve Çevre Dünyası 27. Sayı (Temmuz-Ağustos 2004) / Energy & Cogeneration World - Enerji & Kojenerasyon Dünyası

AC -Li NK CONVERTER a R n e d c e i t n s t l y N , a t t h i e o n U a n l i R t e e d n e S w ta a te b s l e D E e n p e a r r g t y m e L n a t b o of r a E t o n r e y r g h y a s ( D O E ) u 4 8n 0d Ve rAwCr i tpt reont oat yppreo jaedc vt at on cdeeds Ai gCn - Aa nCd pdoewveerl ocpo nav e5 r0tkeWr t , o control wind turbines. The US DOE seeks to use cu edge power conversion technology that has distincttting­ dc oi fnfevreernsci oens taencdh naod lvoagni et asg. eTsh iosv enre p r e v a l e n t p o w e r xt-generation power tuescehsn or el ol igayb l ei s, beaf fsi ce ide not n, caons ta- ed fvfaenc ct i ev ed cc oo nmt rpool nme nettsh oadn dt h a t iimnnporvoavteivmeetnitmsintog tmheetphoowdsertoecreate clean power. These lectronics within the wind tuturrbbiinneesw, iyllieloldwinegr athneiminmitieadl iaanted rliefdetime costs of small wind uction in the cost of energy. SCR-BASED CONTROL Ta dhveadnec es idg na, l gcoarl li et hdmasnf o" Ar Cc o- lni ntkr o" l lci nogn vvearrtieor, i n c o r p o r a t e s us aspects of the electric power, which allows the use of less complex, less ex Thpeeinnsniovveahtiavredwcoanretrotol aal gcohirei tvhem spraelcloiswiont h epower control. use of tt oh ycrri setaotres ,c loera sn i lpi coowne cr . oSn tCr oRl sl e ad r er e uc tni ifqi eure ( Si nCt Rh a) ,t ct hoemypaorneetnht es amvoasiltasbilme.pAles, srugged, and reliable switching device uch, !hey have been the work-horse of the utility industry for many years, and only recently have they begun to be displaced by the more complex but easier to control insulated gate bipolar transistor (IGBT). The main c pre o ro a n v s tr o id o n e l a fo o n v r d e m r a i b t g h i r l e a it yt o i n t r g o ig c tin o re a I l a G t S eB C T c R s le - h b a a a n s e se r b d w e e a c v n ir e c t f u h o i e t r m d in s e c s t r h i e g a a n t s s e I . G d B Ts Hhiogwheervecro,sut,sainngdIGhiBgThserccoommepsleat the cost of lower efficiency, xity. The new AC-link ccoanpvaebri ltiet ire sp roofv imd eosdethrne eI Gq Bu iTv-abl eanstedp odweevricqeusa, l ibt y a n d control ut also incorporates the efficiency and reliability benefits of SCRs. CLEAN POWER Aaltgtohreithhmeaicrt moef tthhoednfeowr tceocnhtnroollogy i s a n advanced l ing the active components, at hdev asnwci et cdh i"nsgo fdt we vaircee" sc, oonf t tr hoel apl loowwesr tchoen vc eo rntveer .r tTe hr i tso use less complex, less expensive SCRs to achieve precision power control, incl uding power waveforms with minimal dainsdtocrutirornenatnodn mbiontihmtahl efiilntepruint ga. nTdhoeudtpevice creates voltage ut with total harmonic distortion at or below 3-5% of the fundamental. The clean power is the resul! of a charge transfer method !hat is fundamentally different from the typical "dou conversion" process of a PWM device, which convebrtlescproewaetersfraomroAC to DC, stores energy on a DC bus, then ugh AC waveform from the DC bus. As the vnaarmiaebliemfprelieqs, the AC-link device transfers power from uency AC directly to constant frequency AC power, el iminating the DC bus. The voltage that is created "Kojenerasyon: Yüksek Verim, Temiz Çevre, Enerjide Yeniden Yapılanma" ARTICLE / MAKALE has a distinctly more sinusoidal quality than PWM waveforms, and thus requires minimal filtering to achieve the very low harmonic distortion levels necessary to export it to the utility grid (Figure 2). NO ISOLATION Sn ei necde t op oi ws oel ra ti en t ei t rfnraolmt ot ht heeAdCe vpioc we ei sr ga rl wi da. yTshAi sCc, otmh eprlee t iesl yn o eliminates the risk of device fail ures which can cause catastrophic DC current injection. EXTREMELY LOW dV/DT üne particularly noteworthy quality of the device's voltage waveform is the extremely low voltage rise. For example, a 5408000VvP/uWseMc,sywshteermeawsiltl hheave a dV/dt on the order of 3000- unfiltered AC-link dV/dt is less than 5 v/usec. This extremely low dV/dt eliminates the need for extra filtering and installation restrictions, and preserves generator insulation and bearing lifetimes. it wil l al so reduce audible noise on the generator. HIGH EFFICIENCY t T h h r e o new converter aims to operate at higher efficiencies ughou switch i n g " t, imtseoapnei nrga tiito nswa l itrcahnegse.wThhi lee dceuvrri ceent i st h"rsooufgt h t h e device is zero, greatly reducing common switching losses. ti nh aand dI Gi tBi oTns, . SOCvRe sr atl lh, et mh es edl ev es isg na raei masmtoo r ien cerfefiacsi een et d e v i c e fficiency a 9 b t y 7 %2 -, 5b upte mr coernet ai gmep op rot iannt tsl y, roepaecrhai nt i gn gp aeta kh i ge fhf i ce ifef incci ei en sc yo fe v e n l ow power throughput. Moreover, it provides greater rset al itaeb- iol i ft -yt haen- da r ti mc omnuvnei tryt etros . gi nr i da da dn iot imo na,l i tehse tchoannv et or dt eary o' sffe r s unique flexibility in terms of power quality and an intelligent ac on nd t reonl ssuyrsi nt eg ms, eaal ml o lwe si nsg i ni tt et og raadt ai opnt wt oi t eh vtohlev i nugt i l irteyggurl ai dt .i o n s , CONCLUSIONS The high cost and poor reliability of power converters has mleedtthooda ffoorcruesdon power converter designs as a primary ucing the cost of wind generated electricity. Cu e s pr er ecni at l ltye cshi nncoel otghi ee ys wa reer eb en iontg i nsi ttri aeltl cy hdeed s pi ganse! dt hf eo irr t lhi me i t s , clean power and rel iability demands that connecting wind turbines to the utility grid requires. Public/private t ep e a n c r a h t b n n l e e o r ls o w h g i i n i p c d s a , l t u s in r u b n c i o n h v e a as t s i t o o t n h c , e o a s D n t- d O e E f ! f h e p is c r t o i n v j e e e w c ly i , t s h e e a c r v v h e e no a s lo p r g u a y r n r e w g d e il l of high valued, distributed power applications primarily targeted at commercial and small industrial businesses. Cu s p erer ednst ltyh, at hnear er eaer ec ovnaos mi ai cr aelal ys voifatbhl ee wfoor rel dl ewc ti trhi c l opwo we rewr i n d generation, and only by reducing the cost of energy by targeting specific areas such as new power electronics designs can the industry make generating wind power at these sites a reality. ENERJİ & KOJENERASYON OÜNYASI I 55

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