Analysis, Design and Experimentation of Series-parallel LCC Resonant Converter for Constant Current Source.

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1 This article has bee accepted ad published o J-STAGE i advace of copyeditig. Cotet is fial as preseted. Aalysis, Desig ad Experimetatio of Series-parallel LCC Resoat Coverter for Costat Curret Source. Sahaya Sethamil Lourdusami a), Rajasekara airamai, Electrical ad Electroics Egieerig Departmet PSNA college of Egieerig ad Techology Didigul-646, Tamiladu, Idia a) elsahayam@gmail.com Abstract: This paper presets the topology selectio, desig ad experimetatio of LCC resoat coverter with isolated trasformer for costat curret source. Possible LCC topologies are classified based o the umber of elemets cotribute to the dyamical chage i eergy. Topologies suitable for costat curret source are selected based o the source/sik combiatio. The curret gai trasfer fuctio is obtaied for the selected topologies usig sie-wave approximatio method. The LCC resoat coverter behavig as a costat curret source whe operated at a particular resoat frequecy is selected. The expressios for coverter curret gai, compoet stresses, ad the coditio for optimized coverter desig for miimum size of resoat tak is derived. Experimetal results of the coverter show that Zero-voltage switchig is achieved ad is suitable for costat curret power supply. Keywords: Costat-curret source, Resoat power coversio, Zero-voltage switchig, Sie wave approximatio Method. Classificatio: Electro devices, circuits, ad systems Refereces IEICE 4 DOI:.587/elex..47 Received July 3, 4 Accepted July 3, 4 Publicized August 7, 4 [] Weldig hadbook, volume weldig processes, 8th editio, America weldig society, Miami FL, R. L. O Brie Editor, February 99. [] Weldig ad brazig of carbo steels, Book-, Arc Weldig, America Society of Metals, Metals Park, Editor Charles A. Davis, 976. [3] Metals Hadbook, ol-6., Weldig Brazig ad Solderig, 9th editio,america Society of Matals, Metals Park, 983. [4] D. Novoty, D. Breckiridge ad K. Hartke, Power supplies adapted for diode

2 pumped laser systems, Laser Focus World, April, pp [5] M. K. Koli, S. R. Tiwari ad M. B. Borage, QCW laser diode driver pulsed curret source, Proc. of DAE-BRNS Natioal Laser Symposium (NLS), pp [6] C. Colema ad R. Sherwood, Iductive storage yields efficiet power alterative, Laser Focus World, April 3, pp [7] F. Bordry ad A. Dupaquier, High curret low voltage power coverters for LHC: Preset developmet directios, Proc. of Europea Particle Accelerator Coferece, EPAC 96, Sitges, 996. [8] Costat curret regulator type THO, Augier S.A., Frace, [9] Costat Curret Regulators CCR- ad CCR-5, Hoeywell airfield lightig product catalog, Hoeywell Iteratioal Ic. [] M. Day, LED driver cosideratios, Electroics desig ews Asia, Ja.4, pp [] Larimore, B.; LED Lightig ad DC/DC Coversio Cotrol Itegrated o Oe C Microcotroller, Texas Istrumets Kit Documetatio, Oct. [] C. Simpso, Battery chargig, Natioal Semicoductors. [3] Switch mode, liear ad pulse chargig techiques for Li+ batteries i mobile phoes ad PDAs, Applicatio ote, Maxim Semicoductors, AN 93, Dec.. [4] Portable devices eed high performace battery chargers, Applicatio ote,maxim Semicoductors, AN 7, Dec.. [5] C. G. Kim, D. H. Seo, J. S. You, J. H. Park, ad B. H. Cho, Desig of a cotactless battery charger for cellular phoe, IEEE Tras. Id. Electro.,vol. 48, o. 6, pp , Dec.. [6] Y. Jag ad M. M. Jovaovi, A cotactless electrical eergy trasmissio system for portable-telephoe battery chargers, IEEE Tras. Id.Electro.,vol. 5, o. 3, pp. 5 57, Ju. 3. [7] R. Ayyaar ad N. Moha, A ovel full-bridge DC DC coverter for battery chargig usig secodary-side cotrol combies soft switchig over the full load rage ad low magetic requiremet, IEEE Tras.Idustry Applicatios, ol. 37, No., March/April [8] Y. C. Chuag ad Y. L. Ke, A ovel high-efficiecy battery charger buck zero-voltage-switchig resoat coverter, IEEE Tras. Eergy Covers., vol., o. 4, pp , Dec. 7. [9] S. J. Jeo, G. H. Cho, Zero-voltage ad zero-curret switchig full bridge DC-DC coverter for arc weldig machies, Electroics Letters,vol. 35, o. 3, pp , Jue 999. [] H. Pollock, J. O. Flower, Series-parallel load-resoat coverter for cotrolled-curret arc weldig power supply, IEE Proc.-Electr. Power Appl., vol. 43, o. 3, May 996. [] R. Severs, Topologies for three-elemet resoat coverters, IEEE Tras. Power Electro., vol. 7, o., pp , Ja. 99. [] I. Batarseh, Resoat coverter topologies with three ad four eergy storage elemets, IEEE Tras. Power Electro., vol. 9, o., pp ,Ja [3] R. L. Steigerwald, A compariso of half-bridge resoat coverter topologies, IEEE Tras. Power Electro., vol. 3, o., pp. 74 8, Apr. 988.

3 [4] M. J. Schutte, R. L. Steigarwald, ad M. H. Keraluwala, Characteristics of load resoat coverters i high power factor mode, i Proc.IEEE APEC 9, 99, pp Itroductio Regulated power source with costat curret output idepedet of output voltage are termed as costat-curret sources are applied i residetial, commercial ad idustrial applicatios [-3]. The features of resoat coverters are zero voltage switchig (ZS), zero curret switchig (ZCS), high-frequecy operatio, high efficiecy, small size, ad low electromagetic iterferece (EMI). They have bee successfully applied to costat curret power sources [4-9].The basic resoat coverter topologies are series resoat ad parallel resoat coverters with iductor (L) ad capacitor (C) as reactive elemets. The draw backs of series resoat coverter are poor part load ad o-load regulatio. O the other had, the drawbacks of series resoat coverter are parallel resoat coverter are poor part-load efficiecy ad lack of iheret dc blockig for the isolatio trasformer. Series-parallel resoat coverters overcome the limitatios of series ad parallel resoat coverters. Series-parallel resoat coverters with LCC reactive elemets ad LCL reactive compoets were ivestigated i [] ad []. The series-parallel resoat coverters with LCC reactive compoets are eglected here for the size of the coverter. If the iductive elemets are less the size of the coverter will be miimum. So, series-parallel resoat coverters with LCC reactive compoets are aalyzed ad a suitable LCC resoat coverter is chose for costat curret source. Selectio of Resoat Topologies For itercoectig sources ad loads there are 36 possible classes of resoat ad o-resoat topologies cotaiig oly L ad C are available []. The topology umbers are used idetify the topologies. The block diagram of resoat dc-dc coverter is give i fig.a.the resoat tak ca be eergized from either a voltage (v) or curret (i) source ad ca be used to supply either a voltage (v) or curret (i) load as show i fig.b.thus, two idividual arragemets ca be appropriately combied to give v/v, v/i, i/i ad i/v four possible source/load arragemets. The resoat tak elemet topology trasfer fuctio must have either low pass or bad pass filter characteristics. This ca be aalyzed usig sie-wave approximatio techique used i [3].Here, the topologies with less umber of iductive elemets is preferred ad is show i fig..also, the topology will ot cotribute to dyamical chage i eergy if the curret source is coected i series with the capacitor ad voltage source i shut with the iductor. The selected resoat topologies are give i fig.3. Here the resoat coverter must be a costat curret source. Hece, the resoat coverter for the costat curret source should be of the type v/i type source/load combiatio. 3

4 (a) (b) Fig.. (a) Block diagram of a dc-dc resoat coverter. (b) Simplified block diagram Fig.. All possible topologies with less umber of iductive elemets. Fig.3. Selected LCC topologies for v/i type source/load combiatio. 4

5 Aalysis of Selected LCC Topologies Fig.4. Sie-wave approximatio method block diagram. The resoat coverter cosists of a square-wave iverter fed by a dc voltage source ad the output of the iverter is give to the resoat tak, the output of the resoat tak is rectified ad filtered by a full bridge rectifier ad a LC filter respectively. The output of the filter is give to the load. The selected topologies for v/i type source/load combiatio is aalyzed usig sie-wave approximatio method as show i fig.4.i this method, the output of the square-wave iverter is substituted by its fudametal siusoidal equivalet ad the output rectifier ad filter by the equivalet ac resistace (R ac ). Oly the fudametal compoet of the iput is trasferred to the output ad supply of all the harmoics is eglected. The equivalet ac resistace for the rectifier with filter is R ac 8 R () L The iput rms voltage is, () i rms d The resoat frequecy r (3) LC The ormalized switchig frequecy is defied as s (4) r The characteristic impedace of the resoat etwork is Z L C (5) The loaded quality factor (Q) of the resoat etwork is Q r L Z (6) L L R R The trasformer turs ratio is assumed to be uity ad defied as N N The ratio of capacitors is defied as C C (7) x (8) The voltage gai is defied as M (9) d 5

6 The curret gai is defied as H I MQ () d Z The voltage base value is defied as b d () The curret base value is defied as I b d / Z () The trasfer fuctio for curret gai of selected LCC resoat topologies are derived by usig the equatios ()-() ad is listed i table. Table.Curret Gai Trasfer Fuctios Topology H T 5 T 6 H Curret gai x x j Q. Costat Curret Source Topology Selectio (3) The plot of curret gai vs. ormalized switchig frequecy for x= is obtaied for the selected topologies are show i fig.5.the desired coverter characteristics for costat curret source are good load regulatio ad fixed frequecy operatio for wide load rage. For that, the curret gai should coverge with the chage i Q at a ormalized switchig frequecy. I topology T 5 of fig.5a the curret gai coverges at ω =.4 with the chage i Q. For the case of topology T 6 i fig.5b ad topology T i fig.5c does ot possess the desired curret gai characteristics. Whereas, topology T 6 i fig.5d the curret gai coverges at more tha oe ormalized frequecy is ot a desirable characteristic. So the LCC resoat coverter of topology T 5 is foud to be suitable for costat curret source. Q 8 Q j x x 8 (4) Q H (5) T j 8 3 x T 6 H Q x x j x x 8 (6) Fig.5a.Curret gai plot of topology T 5 Fig.5b.Curret gai plot of topology T 6 6

7 Fig.5c. Curret gai plot of topology T Fig.5d.Curret gai plot of topology T 6. LCC Resoat Tak Optimizatio Resoat coverter size depeds o the size of the reactive compoets. Therefore, optimized miimum size of resoat etwork is preferred for the resoat coverters. The physical size of the resoat etwork ca be foud usig (KA/KW) ratio of resoat etwork. Usig the voltage ad curret stress equatios the (KA/KW) ratig is give by KA ( L IL) ( C IC) ( C IC ) (7) KW H Q For topology T 5 the ormalized curret ad voltage stress of the resoat compoets is defied as Let I A x x j Q 8 I L, rms L Ib A (8) Q j 8 x I (9) C I j 8x C, rms Q C () b I L C I A x j Q () L, rms 8 b A C, rms b Q x j 8 () A C, rms C (3) b A By substitutig the equatios (9) to (4) i equatio (8) KA 8x x j x KW Q Q (4) Q j 8 7

8 Fig.6a.Curret gai plot of topology T 5 for ω =.5 ad x = 9.75 Fig.6b.KA/KW ratio plot for LCC resoat coverter of topology T 5. To esure ZS operatio ω must be close to uity, So x = 9.75 is chose as show i fig.6a. For a particular value of Q the (ka/kw) ratig is miimum termed as Q opt, the optimum value of Q. From the plot of equatio (4) show i fig.6b for x = 9.75 ad ω =.5 It is observed that the value of Q opt =8.3 for topology T 5.The LCC resoat coverter of topology T 5 will be compact i size ad less weight if it is desiged for this optimum value of Q for a costat curret source. 3 Desig Example of LCC Resoat Coverter for Costat Curret Source Fig.7.Schematic diagram of LCC resoat coverter for costat curret source. 8

9 The LCC resoat coverter show i fig.7 is desiged for costat curret source. The desig specificatios are Iput voltage: Output voltage: Switchig frequecy: Capacitor ratio: Output curret: d =4. =. f s =85Khz. x=9.75. I =6.9A. From fig.6b the optimum value of Q Q opt 8.3. From equatio (6) Z Qopt 8.3 (5) R L From equatio (4), sice ω =.5 s f s r (6).5.5 From equatio (9) for x=9.75 ad ω =.5 H I Z 8.3 (7) From (5) ad (7) IR L.3 d d (8) Where R.739 (9) L From equatio (6) I Qopt RL L 35H (3) r Rearragig equatio (3) C.F (3) L r From equatio (8) C Cx.F (3) The outputs filter compoets L ad C are desiged usig the relatioships give i [4] to meet the output ripple requiremets Let I Z L C.843A, d d d A % of d L I ad A % of C L fsid AL H (33) 9

10 C I 8 A 3F (34) d C 3 Experimetal Results The LCC resoat coverter proposed for a costat curret source is fed by a dc source of 4 ad is cotrolled by a costat switchig frequecy with 85 khz.the waveforms are measured usig a digital storage oscilloscope. Fig. 8 plots the waveforms of the drai to source voltage ( ds ) ad drai to source curret (I s ) shows the switch S achievig ZS coditio. Fig. 8. The experimetal DSO waveforms of drai to source voltage ds (Y -axis /div i chael ) ad drai to source curret I s (Y -axis A/div i chael ) of switch S with X-axis.5 s /div with full-iput dc voltage. Fig.9 shows the output voltage ( a ) of the square-wave iverter ad iductor curret (I L ) of the resoat elemet iductor. Fig. 9. The experimetal DSO waveforms of square-wave iverter voltage a (Y -axis /div i chael ) ad resoat iductor curret I s (Y -axis A/div i chael ) with X-axis.5 s /div. Fig. illustrates the resoat tak output ( b ) ad full-bridge rectifier iput curret (I b ) waveforms. Fig.. The experimetal DSO waveforms of resoat tak output voltage b (Y -axis /div i chael ) ad full-bridge rectifier iput curret I b (Y -axis A/div i chael ) with X-axis.5 s /div.

11 Fig. exhibits the voltage ad curret waveforms of the full-bridge rectifier diodes D ad D. Fig.. The experimetal DSO waveforms of full-bridge rectifier diodes D,D voltage d, d (Y -axis /div i chael ) ad full-bridge rectifier diodes D,D curret I d, I d (Y -axis A/div i chael ) with X-axis.5 s /div. Fig. shows the output voltage ad curret waveforms. I this figure, we ca observe that the output is a smooth dc voltage ad curret, which is the perfect for a costat curret source. Fig.. The experimetal DSO waveforms of Output voltage (Y -axis /div i chael ) ad Output curret I (Y -axis 5 A/div i chael ) with X-axis.5 s /div. Fig.3. Output curret of the experimetal coverter with the variatio of Load resistace.

12 Fig.4. Efficiecy of the experimetal coverter with the variatio of output power. Fig. 3 shows the output curret of the coverter with the variatio of load resistace. The load is varied from light-load coditio to full load for the coverter at 4 iput ad the output curret is approximately costat at 6.9 A. The slight sag i the characteristics is due to the icrease i coductio losses i the bridge iverter ad resoat etwork. Fig.4 shows the experimetal coverter efficiecy with the output power variatio for R L =.739 Ω (full load) ad iput dc voltage variatio from 5 to 4. This coverter efficiecy is high over the full coversio rage. The maximum ad miimum efficiecy of the coverter is 88% at 9W (full load) ad 7% at W (light load). 4 Coclusios This paper has preseted the aalysis of all possible LCC resoat coverter topologies ad selectio of a appropriate resoat coverter topology for costat curret source. Aalysis is doe usig siusoidal approximatio method.a LCC resoat coverter topology is foud suitable for costat curret source applicatio with iheret soft switchig capability. The desig of the coverter is doe based o the operatig poit ad optimized loaded quality factor of the LCC resoat coverter. The proposed topology offers the advatages of low switchig loss ad high efficiecy. The experimetal results demostrate the effectiveess of the developed coverter for costat curret source.

R. W. Erickson. Department of Electrical, Computer, and Energy Engineering University of Colorado, Boulder

R. W. Erickson. Department of Electrical, Computer, and Energy Engineering University of Colorado, Boulder R. W. Erickso Departmet of Electrical, Computer, ad Eergy Egieerig Uiversity of Colorado, Boulder 4.2.2. The Power MOSFET Gate Source Gate legths approachig oe micro p - p Cosists of may small ehacemetmode