ZVZCS PWM DC-DC CONVERTER WITH CONTROLLED OUTPUT RECTIFIER

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1 Aca Elecroechnica e Informaica, Vol., o.,, 7 ZVZC PWM DC-DC CVERTER WITH CTRLLED TPT RECTIFIER Jaroslav DDRIK, Vladimír RŠČI Deparmen of Elecrical, Mecharonic and Indusrial Engineering, Faculy of Elecrical Engineering and Informaics, Technical niversiy of Košice, Lená 9, 4 Košice, lovak Republic, el.: , jaroslav.dudrik@uke.sk, vladimir.ruscin@uke.sk ABTRACT A new zero-volage zero-curren swiching (ZVZC) full-bridge phase-shifed PWM converer wih conrolled oupu recifier is presened in his paper. Zero-volage urn-on and zero-curren urn-off for all power swiches of he inverer is achieved for full load range from no-load o shor circui by using new secondary energy recovery clamp and modified PWM conrol sraegy. Moreover by adding secondary energy recovery clamp he zero-curren urn-on and zero-volage urn-off for recifier swich is ensured. The principle of operaion is explained and analysed and simulaion resuls are presened. Keywords: sof swiching, ZVZC converer, swiched-mode power supply. ITRDCTI The sof swiching PWM converers are very suiable for high volage, high power applicaions where IGBTs are predominanly used as power swiches. The convenional phase shifed PWM converers are ofen used in many applicaions because heir opology permis all swiching devices o operae under zerovolage swiching by using circui parasiics such as power ransformer leakage inducance and devices juncion capaciance. However, because of phase-shifed PWM conrol, he converer has a disadvanage ha circulaing curren flows hrough he power ransformer and swiching devices during freewheeling inervals. The circulaing curren is a sum of he refleced oupu curren and ransformer primary magneizing curren. Due o circulaing curren, RM curren sresses of he ransformer and swiching devices are sill high compared wih hose of he convenional hard-swiching PWM fullbridge converer. To achieve sof swiching and decrease he circulaing curren, various snubbers, auxiliary circuis and/or clamps conneced mosly a he secondary side of power ransformer are applied [] [8]. The firs way of decreasing he circulaing curren is achieved by applicaion of he reverse bias for he oupu recifier when he secondary volage of he ransformer in he freewheeling inerval becomes zero. The oupu recifier (D 5, D 6 ) is hen reverse biased and he secondary windings of he ransformer are opened (Fig. ). Consequenly, boh primary and secondary currens of he ransformer become zero. nly a low magneising curren circulaes during freewheeling inerval as shown in Fig.. Thus, he RM curren of he ransformer and swiches are considerably reduced in he freewheeling inerval. Hence, he converer achieves nearly zero-curren swiching for he righ leg (ransisors T, T 3 ) due o minimised circulaing curren during he inerval of righ leg ransiion and achieves zero-volage swiching for he lef leg (ransisors T, ) due o refleced oupu curren (I /n=i P, n= P / ) during he inerval of lef leg ransiion. T T T 3 T D 4 C D T 3 C 4 TR D 5 D 6 C + nubber L C Fig. Principle of he ZVZC converer operaion φ=var. d T=cons. Magneizing curren D 3 D T Fig. peraion waveforms of ZVZC PWM converer The anoher mehod how o reduce he circulaing curren in he converer is using he conrolled oupu recifier (Fig. 3) [], [3]. Turn-off losses are reduced by non dissipaive urn-off snubbers (capaciors C C 4 ). Reducion of urn-on losses is achieved by using he leakage inducance of power ransformer. In he converers menioned above, he inverer swiches operae under zero-volage swiching eiher in one leg (converer in Fig. ) or in boh legs of he converer (converer in Fig. 3). I I FEI TKE

2 Aca Elecroechnica e Informaica, Vol., o., 3 However, he opimal swiching for IGBTs is zerovolage urn-on and mainly zero-curren urn-off due o eliminaion of he curren ail influence, which has considerably high involvemen in creaion of he IGBT urn-off losses. T D 4 C D T 3 C 4 TR C C 3 D 3 D T The semiconducor swich T in he secondary side is used o rese secondary and consequenly also primary curren. The ransisor T operaes wih double swiching frequency. A urn-off of he swich T he energy sored in leakage inducance is clamped by D C and C C and hen ransferred hrough D and L o he load. By using nondissipaive urn-off snubber o reduce urn-off losses of he ransisor T, he overall efficiency is increased. The addiional energy recovery clamp is very simple, consising of only few componens and so he addiional cos is no high. 3. PERATI PRICIPLE T 5 T 6 Conrolled recifier L C Fig. 3 Principle of he ZV converer operaion dv T/ dz =var Fig. 4 peraion waveforms of ZV PWM converer. PWER CIRCIT F THE PRPED CVERTER I To avoid he problems menioned above, he opology of he following ZVZC converer was proposed. The proposed DC-DC converer shown in Fig. 5 consiss of high-frequency inverer, power ransformer, oupu recifier, oupu secondary swich and oupu filer. The main par of he converer includes high frequency full-bridge inverer consising of four ulrafas IGBT s T - and freewheeling diodes D -D 4. The secondary winding of he high-frequency sep-down power ransformer TR is conneced hrough a fas recovery recifier D 5, D 6 and secondary swich T o oupu filer consising of smoohing choke L and capacior C. The converer is conrolled by modified pulse-widh modulaion (Fig. 6), and consequenly he zero-volage urn-on and zero-curren urn-off all of he ransisors T - in he inverer are reached. The basic operaion of he proposed sof swiching converer has nine operaing modes (inervals) wihin each half cycle. The swiching diagram and operaion waveforms are shown in Fig. 6. I is assumed ha all componens and devices are ideal. The urn-off snubber used for decreasing urn-off losses of he secondary swich was no included ino circui analysis. Inerval ( - ): The ransisors T, T and T are urned on a. The primary curren (only magneizing curren) flows hrough diodes D, D and consequenly he ransisors T and T are urned on wih ZV. The collecor curren of he ransisor T sars o flow in he loop T -C C -D -L -L -C and capacior C C is discharged. o, he rise of he collecor curren is in resonan way wih he resonan frequency ω R differen a no-load and shor circui in a range: C C + ω ( L + L ) C () C ( L LC ) R C + CC Inerval ( - ): The ransformer leakage inducance L LP refleced o he primary side causes ha primary curren is linearly increased wih he slope /L LP while he secondary volage u is zero as a resul of commuaion beween oupu freewheeling diode D and recifier diode D 5. The discharging of he clamp capacior C C causes he curren overshoo a urn-on of he ransisor T, which maximum is limied by he value of he smoohing inducance curren i L. Inerval ( - 3 ): A he commuaion beween diode D 5 and oupu freewheeling diode D is finished. A 3 he clamp capacior curren commuaes o clamp diode D C. Inerval ( 3-4 ): Transisors T and T are conducing and he energy is delivered from he source o he load via power ransformer TR, diode D 5 and smoohing choke L and from inducance L in he loop L -L -C -D C -D. o, he smoohing inducance curren is a sum of he secondary curren and inducance L curren: i = i + i () L Inerval ( 4-5 ): The primary curren increases wih he slope: C C I FEI TKE

3 4 ZVZC PWM DC-DC Converer wih Conrolled upu Recifier di d n L + n L p = + (3) Where LP L m P n = is power ransformer urns raio and L m magneizing inducance of he power ransformer TR. Inerval ( 5-6 ): A 5 he secondary ransisor T urns off. A ha ime he commuaion beween ransisor T and clamp diode D C occurs and charging of he clamp capacior C C sars. This commuaion ime can be negleced, because only parasiic inducance of wires is in he commuaion loop T -D C -C C. Aferwards he commuaion beween D C, D 5 and oupu freewheeling diode D sars. Because in he commuaion pah a relaively large leakage inducance of he ransformer is found, he commuaion is slow. In he menioned commuaion pah he resonance occurs and rise of he curren depends on he resonan frequency ω R : C C C ω R = ( L + LL ) for R = (4) C + CC ω = ( L + L ) C for R = (5) R L C During he commuaion he energy sored in he leakage inducance is ransferred o he clamp capacior C C and consequenly an over-volage Δ appears on ransformer secondary volage. Is value can be calculaed from equaion (he oupu curren ripple is negleced): L L I = CC CC (6) where L L is he ransformer leakage inducance refleced o he secondary side and CC is maximum clamp capacior volage. Then Δ = CC (7) P Inerval ( 6-7 ): nly small magneizing curren i m flows hrough primary winding of TR. The oupu curren flows rough oupu freewheeling diode D. Inerval ( 7-8 ): In his inerval he ransisors T and T are urned off wih ZC. nly small magneizing curren i m is swiched off by ransisors T and T. The magneizing curren charges or discharges he inernal oupu capaciances C C 4 of he IGBT ransisors T respecively. The minimum dead ime d for he ransisors in he leg is given by:, (8) d min recom where recom is minoriy carrier recombinaion ime of IGBTs due o sored charges ha could no be removed a urn-off process. When we ake ino accoun also charging and discharging of he capaciances C C 4 by magneizing curren, hen minimum dead d for achieving of zero volage urn-on mus be: d,min 4C (9) I m,max o, in he end of he inerval he siuaion from firs inerval is repeaed for he ransisors T 3 and, which urn-on a zero-volage during conducion of he freewheeling diodes D 3, D 4 (a 9 ). T D D 3 T 3 TR D 4 D 5 D 6 D T _ L L D C R D D C C C T T urn-off snubber Fig. 5 cheme of he proposed ZVZC PWM DC-DC converer I FEI TKE

4 Aca Elecroechnica e Informaica, Vol., o., 5 T, T d T 3, T T T, T T 344V 3V 6.A.A C -C 4 V 8.A T, T u Δ D 3,D 4 V 4.A. / P V A i D i D i D5 i D i D6 i D i D5-7V >> -.6A 69.us 7.us 7.us 74.us 76.us 78.us 8.us V(P) IC(Z4)- I(D4) i T Fig. 7 wich (ransisor + diode D 4 ) volage u CE4 and swich curren i C4 +i D4 i DC 4V A i CC V A Fig. 6 peraion waveforms of he converer Inerval ( 8-9 ): A 8 he freewheeling diodes D 3, D 4 sars o lead primary curren and hus condiions for he zero-volage urn-on for he ransisors T 3 and are se up. 4. IMLATI RELT V -V 383V V V -V A >> -A V(P) IC(Z4)- I(D4) 9A A A -A EL>> 7.us 7.us 74.us 76.us 78.us 8.us 8.us 84.us 86.us V(P)- V(P) I(La) A simulaion model in programme rcad was creaed o verify he properies of he proposed converer. The simulaions were made a inpu volage = 3V. Parameers: Transformer TR parameers: Turns raio n = 6.5, Magneizing inducance L m = 8 μh, Leakage inducance L LP = 5 μh. Clamp circui parameers: Clamp capacior C C = nf, Clamp inducance L = μh. The following waveforms were obained a resisive load. Fig. 7 shows swich volage u CE4 and swich curren i C4 +i D4 during urn-on and urn-off of he ransisor in he converer. The swich (ransisor including diode D 4 ) is urned-on under zero-volage because a urn-on of he ransisor is freewheeling diode D 4 is in on-sae. Moreover he rae of rise of he collecor curren is limied by he leakage inducance L LP of he ransformer. The ransisor urn-off losses are negligible because ransisor urns-off only small magneizing curren (abou Amp in his case) as can be seen in Fig. 7. Fig. 8 wich volage u CE4 and swich curren i C4 +i D4.(upper waveforms), Power ransformer TR primary volage up and primary curren, (boom waveforms) Fig. 8 shows primary volage and curren of he power ransformer TR a oupu load curren above I = A (boom waveforms) in comparison wih swich volage u CE4 and swich curren i C4 of he ransisor (upper waveforms). I is eviden ha no circulaing curren flows hrough primary winding of he power ransformer. Afer urn-off of he ransisor only a small magneizing curren is conducing hrough primary winding of he power ransformer. Maximum magneizing curren I m,max is approximaely Amp. Depending on he dead ime d i should be high enough for charging or discharging oupu capaciances C C 4 of he IGBT swiches and hus o achieve zero-volage urn-on. Collecor volage u D and collecor curren i D of he secondary ransisor T (boom waveforms) is shown in Fig. 9. The secondary swich (ransisor T ) is urned-on under zero-curren due o influence of he leakage inducance of he ransformer L L refleced o he secondary side and clamp inducance L. The urn-off loss is reduced by clamp capacior C C acing as he non-dissipaive snubber as i is eviden in Fig. 9. I FEI TKE

5 6 ZVZC PWM DC-DC Converer wih Conrolled upu Recifier 3V V V V 3A A A >> -4A V(P) IC(Z4)- I(D4) 5 5 During commuaion beween secondary diode, oupu freewheeling diode, and secondary swich he secondary volage and accordingly recified secondary volage is zero. A urn-off of he secondary swich he secondary and also recified volage rises as a resul of energy sored in leakage inducance. The over-volage can be decreased o accepable value by proper design of he clamp capacior and clamp inducance. For compleeness Fig. shows also he clamp capacior curren and clamp inducance curren (boom waveforms). EL>> -8 69us 7us 7us 74us 76us 78us 8us 8us V(M:d) I(Rcollecor) Fig. 9 wich volage u CE4 and swich curren i C4 +i D4 (upper waveforms),collecor volage u D and collecor curren i D of he ransisor T, (boom waveforms) The clamp diode curren is displayed in Fig. ogeher wih recified secondary volage. um of he collecor curren and clamp diode curren equals he value of he smoohing inducance curren EL>> V(M:d) I(Rcollecor) 8.us 8.us 8.us 83.us 84.us 85.us 85.9us I(Dc:A) V(D) Fig. Collecor volage u D and collecor curren i D of he secondary ransisor T (upper waveforms) Recified secondary volage ud of he power ransformer TR and clamp diode curren i DC (boom waveforms) 5 5. CCLI of swiching and reducion of circulaing currens in he proposed converer are achieved for full load range using secondary side energy recovery clamp in combinaion wih modified PWM. By proper design i is possible o uilize he magneizing curren of power ransformer for charging or discharging oupu capaciances of he IGBT swiches and hus zero-volage urn-on of he IGBTs o achieve. If he magneizing curren is no high enough for charging or discharging oupu capaciances of he IGBT swiches, during chosen dead ime, hen a leas zerocurren urn-on is reached as a resul of leakage inducance of he power ransformer. The IGBT ransisors are urned-off almos under zero curren. nly small magneizing curren of he power ransformer is urned-off by IGBT ransisors. The main ask of he proposed secondary energy recovery clamp is ransfer of he leakage inducance energy o he load a urn-off of he secondary swich. Moreover i ensures zero curren urn-on and zero volage urn-off of he secondary swich. Because his funcion of clamp is no fully effecive when clamp inducance curren is coninuous, an addiional urn-off snubber is employed o improve urnoff process of he secondary swich. IGBTs in he full bridge inverer operae a almos ideal swiching condiions ZV urn-on and ZC urn-off, which is he main advanage of he proposed converer. of swiching of he secondary swich and leakage energy ransfer o he load is ensured by energy recovery clamp conaining only non-dissipaive componens. 5 ACKWLEDGMET 5 EL>> -6 V(M:d) I(Rcollecor) 8.us 8.us 8.us 83.us 84.us 85.us 85.9us I(Cc) I(Ls) Fig. Collecor volage u D and collecor curren i D of he secondary ransisor T (upper waveforms) Clamp capacior curren i CC and snubber inducance curren i L (boom waveforms) This work was suppored by lovak Research and Developmen Agency under projec APVV-95-7 and by cienific Gran Agency of he Minisry of Educaion of lovak Republic under he conrac VEGA o. /99/9. The auhors also wish o hank for he suppor o he R&D operaional program Cenre of excellence of power elecronics sysems and maerials for heir componens. The projec is funded by European Communiy, ERDF European regional developmen fund. I FEI TKE

6 Aca Elecroechnica e Informaica, Vol., o., 7 REFERECE [] CHE, W. RA, X. ZHAG, R.: A ovel Zero-Volage wiching PWM Full Bridge Converer, IEEE Trans on Power Elecronics, Vol. 3, o., March 8, pp [] XI, H. XIE,.: A ZV Bidirecional DC-DC Converer wih Phase-hif Plus PWM Conrol cheme., IEEE Trans on Power Elecronics, Vol. 3, o., March 8, pp [3] JAG, Y. JVAVIČ, M. CHAG, Y. M.: A new ZV-PWM Full Bridge Converer, IEEE Trans on Power Elecronics, Vol. 8, o. 5, ep. 3, pp. 9. [4] XIKE W XIAGA XIE CHE ZHA; ZHAMIG QIA RGXIAG ZHA: Low Volage and Curren ress ZVZC Full Bridge DC- DC Converer sing Cener Tapped Recifier Rese, IEEE Transacions on Indusrial Elecronics, Volume 55, Issue 3, 8, pp [5] CHLEBIŠ, P.: of wiching Converers, Monograph, VŠB-T srava, srava, Czech Republic, 4, (in Czech). [6] TRIP,. D.: A ew Acive nubber for DC-DC Boos Converers, 8h Inernaional Conference on Engineering of Modern Elecric ysem, ecion Elecronics, radea, Romania, May 5, pp [7] LEE,.-. RHEE,.-W. M, G.- W.: Coupled Inducor Incorporaed Boos Half- Bridge Converer Wih Wide ZV peraion Range, IEEE Trans. on Indusrial Elecronics, Vol. 56, o. 7, July 9, pp [8] HYG CHA LIHA CHE RGJ DIG QIGG TAG FAG ZHEG PEG: An Alernaive Energy Recovery Clamp Circui for Full-Bridge PWM Converers Wih Wide Ranges of Inpu Volage, IEEE Transacions on Power Elecronics, Volume 3, Issue 6, 8, pp [9] XIKE W XIAGA XIE JMIG ZHAG RGXIAG ZHA ZHAMIG QIA: of wiched Full Bridge DC-DC Converer Wih Reduced Circulaing Loss and Filer Requiremen, IEEE Transacions on Power Elecronics, Volume, Issue 5, ep. 7, pp [] DDRIK, J. ŠPÁIK, P. TRIP,. D.: Zero Volage and Zero Curren wiching Full-Bridge DC-DC Converer wih Auxiliary Transformer, IEEE Trans. on Power Elecronics, Vol., o. 5, 6, pp [] BJI, R. GRIVA, G. KVACEVIC, G. TECI, A.: ZV-ZC full-bridge DC-DC converer for volage sep-up in fuel cell disribued generaion sysems, in Record, European Conference on Power Elecronics and Applicaions, 5 ep. 7, pp. 8. [] DDRIK, J.: High Frequency of wiching DC- DC Power Converers, Monograph, Elfa, Košice, lovakia, 7 (in lovak). [3] MAAKAZ, M.: A novel quasi-resonan DC-DC converer using phase-shif modulaion in secondary side of high-frequency ransformer, IEEE PEC record, 996, pp [4] LECHTER, J. BAER, P.: Analysis of Losses in he Power Indirec Converers, Circuis Theory ymposium, IB , Brno, 5, pp. 7, (in Czech). [5] TEREŇ, A. FEŇ, I. ŠPÁIK, P.: DC/DC Converers wih of (ZV) wiching, ELEKTR, secion - Elecrical Engineering. Žilina, lovakia, pp [6] PETRV,.: Expecaions of Resonan Converers ilizaion as Welding Power ources, chemaics o. 7, July 6, pp (in Russian). [7] MILLY, D. MAXIM, V.: imulaion and Analysis of Power Converer Inpu Currens. Inernaional Compuer cience Conference, MicroCAD'98, February 5 6, Miskolc, Hungary, 998, pp [8] HAMAR, J. AGY, I.: Bi-direcional Resonan Buck & Boos Converer, ELECTRMTI, Romania, c. Dec., Vol. 8, o. 4, pp Received January 6, 9, acceped February 4, BIGRAPHIE Jaroslav Dudrik received he M.. and Ph.D. degrees in elecrical engineering from he Technical niversiy of Košice, lovakia, in 976 and 987, respecively. He is currenly full professor of Elecrical Engineering a he Deparmen of Elecrical, Mecharonic and Indusrial Engineering, Technical niversiy of Košice, where he is engaged in eaching and research. His primary ineres is power elecronics. His curren field of research includes dc-o-dc converers, high power sof swiching converers, converers for renewable energy sources and auomoive echnique. Vladimír Ruščin received he M.. degree in elecrical engineering from he Technical niversiy of Košice, lovakia, in 6. In he same year, he joined he Deparmen of Elecrical, Mecharonic and Indusrial Engineering, Technical niversiy of Košice as a Ph.D. suden. His primary ineres is power elecronics. His field of research includes high frequency DC/DC converers, microconrollers, and sof swiching echnique in he power converers. I FEI TKE

Design and Development of Zero Voltage Switched Full Bridge 5 kw DC Power Supply

Design and Development of Zero Voltage Switched Full Bridge 5 kw DC Power Supply Inernaional Journal of Engineering Research & Technology (IJERT) Design and Developmen of Zero Volage Swiched Full Bridge 5 kw DC Power Supply ISSN: 2278-181 Vol. 3 Issue 5, May - 214 S. K. Agrawal, S.