Liping Zhang* College of Electronic and Electrical Engineering Shanghai University of Engineering Science Songjiang District, Shanghai , China

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1 Alcaon of Fzzy Slf-Omzng Conrol Basd on Dffrnal Evolon Algorhm for h Rao of Wnd o Coal Adjsmn of Bolr n h Thrmal Powr Plan Tng Ho Shangha Unvrsy of Lng Zhang* Shangha Unvrsy of Ychn Chn Shangha Unvrsy of Absrac Th ys of coal ar mllx n domsc small and mdm szd bolrs, and wh nsabl ngrdns, h mhod of mananng h amon of wnd and coal sly n a fxd rooron of h wnd adjsmn dos no always nsr h bs conomcal bolr combson rocss, h ky of omzng combson s o modfy rasonabl rooron of wnd and coal onln. In hs ar, a knd of fzzy slfomzng conrol basd on dffrnal volon algorhm s roosd, whch ald n h owr lan bolr sysm, h bolr combson ffcncy has bn sgnfcanly mrovd han rvos ndrc conrol. In hs ar, a hrmal owr lan s or rsarch objc, n h cas of drmnng h omm sysm rformanc, h n ffcncy can b ncrasd sgnfcanly sng hs mhod, and h moran sss of nrgy ffcncy of owr lans can b sccssflly solvd. Kywords fzzy slf-omzng conrol; dffrnal volon algorhm; bs rao of wnd o coal; bolr ffcncy I. INTRODUCTION Bolr combson conrol sysm s a nonlnar sysm, and wh h characrscs of m-varyng, nos dsrbng, r hysrss, h xrnc of h oraor can b sd wh h convnonal conrol mhods. B n h rocss of h acal oraon of h bolr, hs xrncs nformaon s moran. Omal conrol of modrn conrol hory s also dffcl o b ald n h modllng of sch sysms. Howvr, fzzy conrol can b js ald o conrol h nknown or changng rocss for hs knd of mahmacal modl [].Usng fzzy hory and fzzy conrol mhod, h xrnc of h oraor can b smmd. Morovr, a knd of fzzy conrol sragy can b achvd sng hs fzzy logc nfrnc mhod. In hs ar, hrmal owr lan s or rsarch objc, h owr lan s small, and has hr MW ns, 3 ss of 50/h coal-frd bolr. Th slf-omzng smlaon s sd o fnd h bs rao of wnd o coal, and combnng dffrnal volon algorhm, h qanzaon facor y wll b omzd, hn fzzy conrol chnology s sd o rgla h sd of blowr sd and coal fdr, fnally 3 bolrs of h hrmal owr lan cognraon combson ffcncy sgnfcanly wll b mrovd han rvos ndrc conrol, whch s agrd wh or abov analyss. II. BOILER FUZZY SELF-OPTIMIZING CONTROL SYSTEM AND DIFFERENTIAL EVOLUTION ALGORITHM A. PID fzzy conrollr sysm Th rror and rror chang ra bwn h amon ransfrrd and h fxd val as n varabls ar always sd n h gnral fzzy conrollr; hrfor, has h smlar ffc wh h convnonal PD conrollr []. A good dynamc qaly can b oband sng sch fzzy conrollr n conrol sysm. Howvr, sady-sa rror of h amon ransfrrd s dffcl o lmna. In ordr o lmna h sady-sa rror of h conrol sysm, PID fzzy conrol sysm can b sd as shown n Fg. In h fgr, and ar rscvly h rror and rror drvav. Convnonal conrol abl form s sd for fzzy conrol. y o - d d K K Fg.. PID fzzy conrollr schmacs K E Fzzy Conrol K E Tabl U Objc O conrol abl nd o b changd o h amon of acal conrol val hrogh an o lnk, and hn cold o h conrolld objc o achv h conrol. Commonly, h wo ways of o lnk sd ar rooronal o and ngral o, h formr has a fas s rsons characrsc, b s rror conrol; h lar can b clos o h no rror conrol, b wh h slow rsons and h y P a g

2 ovrshoo s rlavly larg. Th combnaon of boh ways s sd n h sysm, whch hav advanags of a small ovrshoo and shor m ransn. Mahmacal xrsson of PD-y fzzy conrollr can b drvd by algbrac rodc-addon-focs fzzy nfrnc mhod: In formla (), A D P A P D (),j,j j j j j, j j Ths n-o rlaonsh of h n and o PID fzzy conrollr can oband as shown n Fgr : K U K K K K P Ud (A PK DK )d K A K A (K K P K K D) K (A PK DK ) d K K D Th abov mnond fzzy conrollr hav for adjsabl aramrs: qanfy facors K K, scal facor and ngral coffcn K, ncrasng K K, h rsolon of h rror can b mrovd, hn h conrol accracy s also mrovd. B f K K ar oo bg, wll brng nsabl for h sysm [3]. Incrasng or K, rsons sd wll ncras, b whch wll lad o osclla. Basd on acal adjsd xrnc, h dsrabl val as,. Whn and ar oo largr, and shold b dcrasd, and whn h samlng rod s longr, hn and can b chosn largr. B. Fzzy slf-omzng conrollr n h rao of wnd o coal In h bolr conrol, d o h amon of lvrzd coal canno b accraly masrd onln, so h xcss ar coffcn α s sd o sbs β whch rrsns h rao of wnd o coal volm, so rao of wnd o coal and α ar qvaln. Th rao of acal ar volm (V) and h horcal ar amon ( o ) s h xcss ar facor α. Accordng o "Safy Dconary", xhas of h bolr s qalfd whn h xcss ar coffcn α s whn h rang of.5 o.5 of h hrmal owr lan [4], n addon, h hrmal ffcncy s hghs a hs m. If xcss ar coffcn α s oo larg, xcss ar fl gas wll ak oo mch ha, ncrasng xhas gas mrar wll lad o ha loss ncrasng, a h sam m, wll rodc a larg amon of x and x ollon; on h conrary, f α s oo small, coml combson of fl canno b garand. Slcng () h arora α s an moran mans o rdc bolr ha loss and mrov hrmal ffcncy. In hs sysm, α s h skng omzaon ndx, f: α [.5,.5] (3) Sar fzzy slf-omzng sarch, whn α s whn h rang of.5 o.5, ndcas ha h omm workng rang has bn fond, and hn omzaon can b sod. Slf-omzng fzzy conrollr works as follows: combson coal as an ndx sd o fnd h bs rao of wnd o coal [5] wh fzzy slf-omzng conrollr. Incrmn of coal consmon y wll b masrd a ach samlng rod, accord o y and h omzaon s of rvos cycl o drmna h omzaon s. Y and X ar coal consmon and fzzy lngsc varabls of h ss. y s qanzaon facor of y, whch convrs h fzzy lngsc varabls of coal consmon ncrmn Y o h acal val, x s scal facor, whch convr h X o acal val of h s. K y Y Y X X Fzzy slfomzng conrollr Incrmnal coal consmon y X s So lnk K x Wnd α Coal Frnac Fg.. Fzzy slf-omzng conrollor basd on dffrnal volon algorhm for h rao of wnd o coal In raccal alcaons, n ordr o nsr h sably of slf-omzng rocss, a so lnk [6] s addd. If h mrar of h frnac has a bg flcaon d o nvronmn dsrbon, h sarch shold b sod o avod malfncon. Slcng Y, X rscvly as 8 and 6 lngsc varabls of fzzy sbss s conand as follows: Y { B, M,,, P, P, PM, PB} X { B, M,, P, PM, PB} NB, NM, NS, NO, PO, PS, PM, PB rscvly dno ngav bg, ngav mdm, ngav small, ngav zro, osv zro, osv small, osv mdm and osv bg. Th fzzy doman of Y and X ar dfnd as 4 and grads: 3 P a g

3 Y α {-6,-5,-4,-,-,-,-0, 0,,,, 4,5,6} X α {-6,-5,-4,-,-,-,,,, 4, 5,6} Slf-omzng sarch rocss conrol rls showd as n Tabl I. X - s h omzaon s of rvos cycl, X s h omzaon s. Tabl II shows h rl abl abo fzzy slf-omzng conrol n h rao of wnd o coal. TABLE I. RULE TABLE ABOUT FUZZY SELF-OPTIMIZING CONTROL IN THE RATIO OF WIND TO COAL Y NB NM NS PS PM PB NB PB PB PB NB NB NB NM PM PB PB NB NB NM NS PS PM PM NM NM NS NO PS PS PS NS NS NS PO PS PS PS NS NS NS PS NS NM NM PM PM PS PM NM NB NB PB PB PM PB NB NB NB PB PB PB Conrol sragy of h conrollr can b smmarzd as follows: IF X - =NB AND Y=NB THEN X =PB IF X - =NB AND Y=NM THEN X =PM Aly synhss rls of fzzy nfrnc, and cold wh manal corrcon, h lma slf-omzng conrol abl can b oband as shown n Tabl II. TABLE II. X α Y α X α- TABLE ABOUT FUZZY SELF-OPTIMIZING CONTROL IN THE RATIO OF WIND TO COAL Th sarch sd can b mrovd by ncrasng x and y, h val of x can also affc h loss of sarch, so y can b chosn basd on h sarch sd rqrmns, x can b chosn accordng o h rqrmns of h loss of sarch. Th dffrnal volon algorhm s addd n h sysm o omz h val of h qanzaon facor y, makng h fzzy val of ncrmnal coal consmon can b convrsd mor rcs o h acal val afr ach omzaon, bolr ffcncy rao s mrovd sgnfcanly, and scally a low load. C. Dffrnal volon algorhm Th basc da of dffrnal volon algorhm s: h ndvdals of crrn olaon followd hrogh maon and crossovr oraon and rodc sd ndvdal, hn, basd on h grdy hoghs, h omm ndvdal s slcd; hrby h nw olaons ar gnrad. Whn n h rocss of ms raon, h -h olaon of ndvdals x (x,x,,x d ),,, s a d-dmnsonal candda solon vcor, h ndvdal wh bs fnss val (x bs,x bs of all ndvdals ar dnod x bs,,x bs ),hn hr-ss oraon as maon, crossovr, slcon ar rformd n h rocss of h -h raons [7]. ) Maon Maon oraon s achvd by DE algorhm wh h dffrnal mhod. Thr ar a vary of dffrnal srags, common dffrnal sragy s o slc randomly wo dffrn ndvdals n h -h gnraon of h olaon, afr mllyng h vcor dffrnc of h wo ndvdal wh varably facor, and a synhc nw ndvdals wh comng ndvdal varaon, s calld varaon vcor. DE/rand/ varaon formla as follows: d x F (x x )(j,, d) (4) rj rj Thr, j s j-dmnsonal comonns of varaon vcor, F s varably facor, sd o adjs h dffrnal scalng of mll, sally slcd as h val bwn (0, ], hr random nmbrs r r r ar dffrn from ach ohr and no qal o, x r s calld a arn bass vcors, x r -x r s a arn dffrnc vcor, hn crossovr o x and varaon vcor ar mlmnd. ) Crossovr I-h ndvdal x and varaon vcor gnrad by maon work as h followng crossovr: y j r3j j, f rand CR (j,,, d) (5) xj, ohrws Thr, y j s h ndvdal of x j-dmnsonal comonns corrsondng o h s ndvdal y, rand s random nmbrs dsrbd nformly bwn [0, ], s cross-facor, sally h val s r-s whn h rang [0, ], cross facor drmns h rooron of ach comonn of varaon vcor n h sd ndvdals y.whn, sd ndvdal s qal o h varaon ndvdal. 3) Slcon Comarng rodcd sd ndvdal y wh h ndvdal x, h omm ndvdal of boh ndvdal s slcd as h nx gnraon. Thrfor, comarng h fnss of sd ndvdal and ndvdal x, whn h fnss of sd ndvdaly s br han h fnss of ndvdals x, y wll rlac ndvdal x and bcom h nx gnraon of 4 P a g

4 ndvdals x, ohrws, x wll b rand and bcom ndvdal x of gnraon. y, f fnss(y ) fnss(x ) x (6) x, ohrws, Whn h fnss of x s br han h fnss of x bs da x bs, mak x bs x, and sav h bs fnss val fnss bs. In hs way, crossovr, maon and slcon oraons shold b rad, nl h olaon omal adaaon m h r-s hrshold val or rach h maxmm nmbr of raons. A hs on h bs fnss val corrsondng o h ndvdal s h omal solon sarchd by DE algorhm for omzng hs roblm. Th sysm ss dffrnal volon algorhm o omz qanav facor y o mrov h ffcncy of h bolr sysm, scally n low-load oraon. III. EFFECT OF THIS SYSTEM AFTER APPLIED TO THE THERMAL POWER PLANT A. Imrovmn of bolr ffcncy Bolr ffcncy s h avrag n a cran sascal cycl, h avrag ffcncy of a rfrnc rod s calclad as follows: DN η 943 % (7) B In formla (7), rrsns h sandard sam rodcon drng h rfrnc rod; B rrsns h sandard coal consmon drng h rfrnc rod. Fzzy slf-omzng conrollr n h rao of wnd o coal s sd n n, h coal amon s fd back o n val, chang h wnd volm o chang h rao of wnd o coal o achv h hgh ffcncy of h bolr, h smlaon rsls shown n Fgr 3. Fg. 3. Conras crv of bolr ffcncy In fgr 3, crv s h bolr ffcncy whn manally adjsng h rao of h wnd o coal of h sysm, crv s N bolr ffcncy afr addng slf-omzng fzzy conrol, and crv 3 s bolr ffcncy afr sng dffrnal volon algorhm o omz qanav facors y. As sn from fgr 3, whn rnnng wh fll caacy, bolr ffcncy s mrovd as aroxmaly 0.9% afr sng fzzy slfomzng conrollr n h rao of wnd o coal han manal conrol, and ncororang h dffrnal volon algorhm no h bolr sysm, s ffcncy can ncrasd by aroxmaly 0.%, scally n low-load oraon, ffcncy s mor sgnfcan. B. Savng coal and msson rdcon of h owr Rsrcd by dcon chnology and ndrc conrol, mror wnd sly ofn cass a sbsanal loss of ha or ncoml combson of fl. Th bs conrol sysm basd on h crrn hrmal owr lans can only garan h nrgy convrson ffcncy s gnrally abo 35% [8], s alrady a vry hgh convrson ffcncy of brnng calors, h avrag hrmal ffcncy of hrmal owr lans s abo 3.5%, sysm ffcncy can b ncrasd by.% whn rnnng wh fll caacy, so n hs way w can g consdrabl nrgy savngs. No: Th sandard coal calorfc val calclad sng 7000 Kcal / kg. Th avrag hang rao of hrmal owr lan s abo 84.58%. TABLE III. O owr /kwh ENERGY CONSUMPTION OF THE MW UNIT 4h 30d 365d Ha n /Kcal Coal consmon of n / TABLE IV. O owr /kwh Savng nrgy /Kcal Savng sandard coal consmon / ENERGY SAVINGS OF THE MW UNIT 4h 30d 365d I can b sn from Tabl III and Tabl IV, h nrgysavng ffc s obvos afr sng h conrol mhod n hs arcl. Combnng wh fzzy slf-omzng conrol mhod basd on dffrnal volon algorhm n hs arcl, h bolr combson conrol chnology s achvd, ald n h hr MW ns n h hrmal owr lan, s ffcncy s ncrasd by.%, a bolr can sav 957 ons of sandard coal on yar, so hr ns can sav abo,87 ons of sandard coal n a yar. Ths has a sgnfcan ffc on nrgysavng,nvronmnal rocon, and rdcng amoshrc ds ollon for h lan. 5 P a g

5 IV. CONCLUSION Fzzy slf-omzng conrollr n h rao of wnd o coal s sd n h n wh arora modfcaon, h coal amon s fd back o h forward n val, and so ha vnlaon can radly changng wh h amon of fl changs, and h rao of wnd o coal can b conrolld whn an arora rang. Dffrnal volon algorhm combnd wh fzzy slfomzng conrol sysm nabls h bolr oraon ffcncy sgnfcanly mrovs scally n h saon of low load. In h cas of drmnng h omal rformanc of h sysm, fzzy conrol chnology sd o mak h wnd volm can qckly sarch for h bs val, mrov h hrmal ffcncy of h bolr, achv h ffc of conomzr and ffcncy, and h conomcs of h hrmal owr lan s mrovd graly. ACKNOWLEDGMENT Th rojc has bn sord by h Innovaon Program of Shangha Mncal Edcaon Commsson "Vhcl Collson Avodanc Sysm basd on Vhcl Wrlss Commncaon" (No.YZ5). REFERENCES [] J Chang-an al. Imag rocssng and ransformaon of owr lan alcaon of fzzy conrol[j]. Hgh Volag,007(33- ). [] Mao P.Rsarch Mnhang Powr Plan 5MW n of nrgy-savng chnology o rn[d]. Shangha Jaoong Unvrsy,004. [3] Ba Rxang, Ta Xnmng, L Hn. Fzzy Slf-omzng Conrol on Combson Sysm of Indsral Bolr [J]. Insrmn Tchnq and Snsor, 009, 6 (98-00). [4] C Kqng.Safy Dconary [M].Bjng: Chmcal Indsry Prss, 995(34-350). [5] A Hong.Dynamc Fzzy Exrnal Conrol of h Effcncy of Bolr Combson[J]. Tchnqs of Aomaon & Alcaons,00,(5-8). [6] L Shyong. Fzzy conrol [M].Harbn: Harbn ns of chnology rss. 0(7-77). [7] W Langhong, Wang Yaonan,Yan Xaofang,Zhang Jan.Rsarch on Dffrnal Evolon Algorhm for MOPs[J]. Jomal of Hnan Unvrsy(Naral s),009,36,(53-57). [8] Lng Wng.Th s of fzzy conrol chnology of wnd and coal rao o h dsgn of owr lan [J]. Norhas Elcrc Powr Tchnology,0,7(43-45). 6 P a g