A Simple And Efficient Implemantation Of Interleaved Boost Converter

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1 A Simpl And Efficint Implmantation Of Intrlavd Boost Convrtr Nasir Coruh Dpartmnt of Elctrical Eninrin Satilmis Urun Civil Aviation Coll Tarik Erfidan Dpartmnt of Elctrical Eninrin Smra Ozturk Dpartmnt of Elctrical Eninrin Abstract Rcntly, DC-DC boost convrtrs ar usually rquird in many applications which has low output volta, such as rnwabl nry sourcs. Th intrlavd boost convrtrs consists of svral idntical boost convrtrs connctd in paralll and controlld by th intrlavd mthod which has th sam switchin frquncy and phas shift. Th advantas of intrlavd boost convrtrs includ incrasd fficincy, rducd siz and improvd rliability. This papr prsnts, simpl dsin and implmntation of a two phas intrlavd boost convrtr. Kywords - Intrlavd Boost Convrtr, cor slction I.INTRODUCTION Rnwabl nry sourcs with low output volta, such as th ful cll stacks and photo-voltaic (PV) nration systm, hav rcivd a rat attntion in rsarch filds bcaus thy appar to b th possibl solutions to th nvironmntal problms [1]-[3]. DC-DC convrtrs ar an important componnt as powr lctronics intrfacs for photovoltaic nrators and othr rnwabl nry sourcs. Most rnwabl powr sourcs, such as photovoltaic powr systms and ful clls, hav quit low-volta output and rquir sris connction or a volta boostr to provid nouh volta output [4]-[7]. Boost convrtrs ar popularly mployd in quipmnts for diffrnt applications, as prrulators or vn intratd with th lattr-sta circuits or rctifirs into sinl-sta circuits [8] [10]. Intrlavd mthod usd to improv powr convrtr prformanc in trms of fficincy, siz, conductd lctromantic mission, and transint rspons. Th bnfits of intrlavin includ hih powr capability, modularity, and improvd rliability. Howvr, an intrlavd topoloy improvs convrtr prformanc at th cost of additional inductors, powr switchin dvics, and output rctifirs [11]. Th powr loss in a mantic componnt dcrass whn th siz of th inductor incrass thouh both th low powr loss and small volum ar rquird. This mans that thr is a trad-off rlationship btwn th powr loss and th mantic componnt siz. Thrfor, th dsin of mantic componnts in convrtrs is on of th important challnin problms. Thr ar svral wll-known stratis for slctin a cor for th dsin of mantic componnts, for xampl, th ara product (Ap) mthod and th cor omtry (K) mthod. Th Ap mthod is widly usd for dsinin th inductors and transformrs for dc-dc powr convrtrs opratin in CCM and DCM. On th othr hand, th concpt of th K approach is to slct a propr cor satisfyin th lctromantic conditions, th rstriction of th cor window ara, and th rstriction of th windin loss, simultanously. This mthod is usful to dsin inductors and transformrs with low cor and ac windin losss[1]. II.INTERLEAVED OPERATION Fiur 1. Two-phas intrlavd boost convrtr Th intrlavd boost convrtrs consists of svral idntical boost convrtrs connctd in paralll and controlld by th intrlavd mthod which has th sam switchin frquncy and phas shift. Rippl cancllation both in th input-output volta and currnt wavforms, rducd currnt pak valu, and hih rippl frquncy ar som of th bnfits of intrlavin opration in convrtrs. Morovr, incrasd fficincy and hih rliability can b achivd. Also, by hih frquncy, th siz and losss of th mantic componnts can b rducd. Ths intrlavd boost convrtrs ar distinuishd similar with convntional convrtrs by critical opration mod, discontinuous conduction mod (DCM), and continuous conduction mod (CCM). In critical opration mod, filtr dsin is mor /11/$6.00 c 011 IEEE 364

2 difficult bcaus critical point vary by load. In th DCM, althouh th disadvantas rlatd to th rvrs rcovry ffcts(rres) of boost diods ar improvd, thr ar advantas such as hih input pak currnt and conduction losss. Howvr, DCM nrally undsirabl for hihpowr applications. Intrlavd boost convrtrs opratin in CCM hav bttr utilization of powr dvics, lowr conduction losss, and lowr input pak currnt. Hihpowr applications ar asily achivd with CCM[13]. Two-phas intrlavd boost topoloy is ivn at Fiur 1. Aftr, S 1 turns-on, i L1 currnt incras linarly. In this intrval nry stord in L 1. Whn S 1 turns-off, D 1 conducts th stord nry in L 1 to th load and output capacitor. Currnt in L 1 ramps down with a slop dpndnt on th diffrnc btwn th input and output volta. Aftr a half priod of S 1 switchin cycl, S also turns-on, compltin th sam cycl of vnts. Sinc both powr channls ar combind at th output capacitor, th ffctiv rippl frquncy is twic that of a sinl-phas boost convrtr. At Fiur, it can b sn that th input currnt, i, for two-phas intrlavd boost convrtr is th sum of ach channls inductor currnts. Bcaus sinals ar 180 phasshiftd, th input currnt rippl producd is th smallst. A. Cor Slction Inductors ar dsind for a ivn rulation,, E α = K K dsird to b %1. In (1), E is nry handlin capability of mantic cor and calculatd by, 1 E L I pk (1) = () K is lctrical conditions cofficint and dpnd on output powr, P o and opratin flux dnsity B m K = P B (3) o m (10 ) In (1), th othr constant that nry and rulation rlatd is cor omtry cofficint, K, K W A K MLT a c u = (4) K, is rlatd with, window ara of cor, W a, iron ara of cor, A c, window utilization factor, K u, and man lnth turn, MLT. Ths paramtrs ar dpnd on cor shaps and typs. From (1), K is, K = E α K (5) Fiur. Idal wavforms of th currnts in th inductors L 1 and L for intrlavd boost convrtr opratin at CCM. III.INDUCTOR DESIGN Th dsin of mantic componnts in convrtrs is on of th important problms. To dsin an inductor for a DC- DC convrtr, dsird inductanc, L, th dc currnt flows throuh inductanc, I dc, currnt rippl on inductanc, I L, and powr loss paramtrs should b ivn. Opratin frquncy is ssntial paramtr whn slctin th matrial of mantic cor. Cor omtry(k ) and Ara Product(A p ) approachs ar two mthods for slctin cor. Ths mthods ar primarily usd in th dsin of inductors for switchin-mod powr supplis (SMPS). In this papr, cor omtry approach usd to slct mantic cor. For intrlavd opration two idntical boost convrtr parall connctd and opratd with 180 phas shiftd. Dsind inductor will usd for both phass. Aftr calculatin cor omtry cofficint, suitabl inductor cors shap and typ ar dfind from th standard dsin data tabls of mantic B. Wir Slction Bfor wir ara calculation, currnt dnsity, J, should dfind. It should b notd that, at Ara Product approach currnt dnsity is stimatd, but in Cor Gomtry approach currnt dnsity is calculatd. 4 E 10 J = B A K m p u In (6), A p is ara product and wir ara, A w is ivn by (7) A I J (6) rms W = (7) With th calculatd A w, wir is slctd from wir standards th IEEE Confrnc on Industrial Elctronics and Applications 365

3 C. Air Gap Lnth Th inductanc valu is adjustd by th air-ap lnth. TABLE 1. Paramtr Dsin Paramtrs Valu l π. N Ac 10 MPL = ( ) (8) L μ MPL is mantic path lnth and μ μ is prmability of cor matrial. In (8), N is numbr of turns. But to dfin actual numbr of turns, frinin flux at th air ap should b known. So possibl numbr of turns is usd to calculat airap lnth and ivn by ffctiv window ara, W a(ff), N W S aff ( ) F p = (9) Aw Effctiv window ara is th product of window ara and ffctiv window factor. Effctiv window factor dfins how much of th availabl window spac may actually b usd for th windin and nrally 0.75 is a ood valu for dsin. S F, is fill factor. D. Numbr of turns: Frinin flux can rduc th ovrall fficincy of th convrtr, by nratin ddy currnts that caus localizd hatin in th windins. Whn dsinin inductors, frinin flux must to b takn into considration. Frinin flux factor is, l G F = 1+ ln( ) (10) A l G is windin lnth. With considrin th ffct of frinin factor, ral numbr of turns is, N = c l L π Ac F (10 ) μ (11) V : 60-80V i V i(min) V out I o : 60V : 10V : 1A Δ I L : 0.5 P o : 10W D max : 0.5 f s L : 100kHz : 1.5mH α : 1% V.RESULTS Fiur 3. Wavforms of inductor currnts for CCM opration; a) Sinlphas boost convrtr,(500ma/div,5μs/div) b) Two-phas intrlavd boost convrtr,(00ma/div,5μs/div) Fiur 3 shows th wavforms of inductor currnts for sinl phas and two phas intrlavd boost convrtr. It is obvious that, in intrlavd opration man inductor currnts rducd by half. As a rsult, total loss of inductors sinificantly rducd. IV. INTERLEAVED BOOST CONVERTER DESIGN FOR CCM OPERATION In this study, IRFP450, 500V-13A MOSFET and IXYS DESI30-1a, 100V-30A diods ar slctd in powr convrtr circuit. Firin sinals ar nratd by MICROCHIPs dspic40f3011 microcontrollr which is 16 bit and runnin up to 10MHz. Whn opratin abov 100kHz, thn th only matrial is frrit. Frrit matrials hav a nativ tmpratur cofficint rardin flux dnsity. Accordin to K (5), ETD-39 3C90 frrit cor is slctd. By usin (7) AWG-19 typ wir slctd and from (8), l for th cor is 0.4cm. Finally, (11) ivs 106 turns for inductor windin. Th ivn paramtrs listd in Tabl 1. Fiur 4. Wavforms of input currnt rippls for CCM opration; a) Sinl-phas boost convrtr,(50ma/div,5μs/div) b) Two-phas intrlavd boost convrtr,(50ma/div,5μs/div) Fiur 4 shows that, ffctiv rippl frquncy incrasd twic and pak to pak valu of input currnt rippl rducd with intrlavd opration. Thus, input filtr siz will b dcrasd. In this papr, RM-4 frrit cor is usd at input filtr dsin of intrlavd boost convrtr and RM-6 frrit cor is usd in input filtr convntional boost convrtr. As a rsult, volum of input filtr rducd by thr tims in intrlavd boost convrtr th IEEE Confrnc on Industrial Elctronics and Applications

4 (a) (b) Fiur 5. Wavforms of MOSFETs V DS, I D and switchin powr dissipation for a) sinl phas boost convrtr.(v/div:50, A/div:, W/div:100), b) two phas intrlavd boost convrtr.(v/div:50, A/div:1, W/div:100) Fiur 5 shows, switchin powr losss of MOSFETs for boost convrtr and two phas intrlavd boost convrtr. In Fiur 5(a), pak valu of MOSFETs powr dissipation wavform is approximatly 130W. In Fiur 5(b), by th rducd inductor currnt, pak valu of MOSFETs powr dissipation for intrlavd boost convrtr is narly 90W. (a) (b) Fiur 6. Output volta, output currnt and output powr wavforms; a) sinl phas boost convrtr, (V/div:0, A/div:500mA, W/div:5), b) two phas intrlavd boost convrtr, (V/div:10, A/div:500mA, W/div:5) Output volta, currnt and powr dissipation wavforms ar ivn at Fiur 6 for boost convrtr and two phas intrlavd boost convrtr. From Fiur 7,it is sn that ovrall fficincy of Intrlavd Boost Convrtr rachs a valu ovr 96% at full output powr of 10W at a switchin frquncy of 100kHz. Bcaus of low inductor rsistanc, inductor losss can b inord and all powr losss ar dissipatd by powr switchin componnts. Powr rat of convntional boost convrtr is limitd bcaus total powr loss occur on a sinl powr switch. Fi.7 Efficincy comparison of Intrlavd Boost Convrtr(IBC) and Convntional Boost Convrtr(CBC). IV. CONCLUSION This papr prsnts dsin and implmntation of intrlavd boost convrtr undr CCM opration. Mantic componnt slction is studid and diffrncs btwn boost convrtr and two phas intrlavd boost convrtr is ivn. Fiur 3 shows that, in intrlavd opration man inductor currnts rducd by half. As a rsult, total loss of inductors sinificantly rducd. It can b sn from Fiur 4 that, ffctiv rippl frquncy incrasd twic and pak to pak valu of input currnt rippl rducd with intrlavd opration. Thus, input filtr siz will b dcrasd. As shown in Fiur 5, switchin powr losss rducd intrlavd tchniqu. This papr prsnts that, intrlavd tchniqu on boost convrtrs incras systm fficincy and powr dnsity REFERENCES [1] Cacciato M., Consoli A., Attanasio R., and Gnnaro F A multi-sta convrtr for domstic nration systms basd on ful clls. In Proc. IEEE Ind. Appl. Soc. Conf., vol. 1, pp [] Vrachary M., Snjyu T., and Uzato K Nural-ntworkbasd maximum-powr-point trackin of coupld-inductor intrlavd-boost convrtr- supplid PV systm usin fuzzy controllr. In IEEE Trans. Ind. Elctron., vol. 50, no. 4, pp [3] Wan D., H X., and Zhao R ZVT Intrlavd Boost Convrtrs with Built-In Volta Doublr and Currnt Auto-Balanc Charactristic. In IEEE Trans. Powr Elctron.,vol. 3, no. 6, pp [4] Kobayashi K., Matsuo H., and Skin Y., 006. Novl solar-cll powr supply systm usin a multipl-input DC DC convrtr. In IEEE Trans. Ind. Elctron., vol. 53, no. 1, pp [5] Mazumdr S. K., Burra R. K., and Acharya K., 007. A ripplmitiatin and nry-fficint ful cll powr-conditionin systm. In IEEE Trans. Powr Elctron., vol., no. 4, pp [6] Hsih Y., Hsuh T., and Yn H An Intrlavd Boost Convrtr With Zro-Volta Transition. In IEEE Trans. Powr Elctron., vol. 4, no. 4., pp [7] Wan C.M A nw sinl-phas ZCS-PWM boost rctifir with hih powr factor and low conduction losss. In IEEE Trans. Ind. Elctron., vol. 53, no., pp [8] Jan Y., Dillman D. L., and Jovanovic M. M A nw softswitchd PFC boost rctifir with intratd flyback convrtr for stand-by powr. In IEEE Trans. Powr Elctron., vol. 1, no. 1, pp th IEEE Confrnc on Industrial Elctronics and Applications 367

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