Soft Switching Techniques for High Voltage Gain in Asymmetrical Full Bridge Converter

Transcription

1 Proceeg of National Conference on Technological Avanceent Power an Energy 6 Soft Switchg Technique for High Voltage Ga Ayetrical Full Brige Converter Nayana G. Nair an T.S. Angel Abtract Thi paper explore the technique of Ayetrical full brige converter with high voltage ga. t achieve zero voltage witchg of all power witche, zero current witchg of output ioe. Prototype of the converter i evelope, experiente an valiate ug the ayetrical pule with oulation technique. The propoe converter achieve a ga of with zero witchg loe, no conuction loe an a fixe witchg frequency. Keywor Ayetrical full brige converter, oft witchg, zero voltage witchg (ZVS, zero current witchg (ZCS. T. NTROUCTON HE full brige ayetrical zero voltage witchg i the popular topology for C C converter with a fixe witchg frequency, zero witchg an high ga. The ajor fiel of application of thee type converter lie electric vehicle, UPS, fuel cell, photovoltaic yte etc []. t i ue a an terize yte between the low voltage ource an loa which require high voltage conventional boot converter, which were ue thee application have certa rawback like it require extree uty cycle to obta high voltage ga an it voltage ga i liite ue to it paraitic coponent. Another rawback of the conventional boot converter i the revere recovery proble of the output ioe which egrae the yte perforance uch a efficiency an electric agnetic noie. High tep up C C converter ug couple uctor were trouce to overcoe the rawback of conventional boot converter. But ue to the leakage uctance of the couple uctor there were paraitic ocillation acro the witche an ioe. Galvanic iolation between the put an output tage of thee power converter are a ajor concern about the afety apect. Thee high tep up C C converter are eigne a current fe converter. ue to thi the voltage tree of the witche are evere an hence active nubber are ue to clap the voltage acro the witche an to provie zero voltage witchg (ZVS []. But the preence of thee active nubber require aitional witche an hence caue aitional conuction loe an thu a ecreae the yte frequency. Voltage-fe converter uch a phae-hift full-brige (PSFB converter [3], are the olution to overcoe the rawback of current fe converter. The proble of high voltage tre acro the witche an ioe are eliate Nayana G. Nair, epartent of Electrical an Electronic Engeerg, Arita Vihwa Viyapeetha, Kolla, nia, E- ail:nayan999gn@gail.co T.S. Angel, epartent of Electrical an Electronic Engeerg, Arita Vihwa Viyapeetha, Kolla, nia, E-ail:angelt@a.arita.eu here an hence zero voltage witchg i achieve. But here alo exit rawback like large conuction lo ue to circulatg current, uty cycle lo an voltage pike acro output rectifier. Even though auxiliary nubber circuit can be ue to overcoe the proble of large voltage pike of the output rectifier, the coplexity an the overall cot are creae an yte efficiency ecreae ue to aitional circuit. Overall yte efficiency can be creae by ug Ayetrical Pule With Moulation (APWM technique [4]. Here the avantage are zero witchg lo, no conuction lo penalty an fixe witchg frequency. But aga rawback exit like the axiu uty cycle i liite to 0.5 an it require large turn ratio of tranforer. ater APWM control chee for the ayetrical full-brige converter wa trouce without conierg the tranforer turn ratio. Thee were alo calle buck type converter but they are not uitable for tep up application. A a olution to the entire proble ayetrical full brige converter i propoe. Thi ayetrical pule with oulation technique have avantage like high voltage ga with fixe witchg frequency, oft witchg operation of all power witche an ioe an clape voltage power witche an output ioe. There i no revere recovery proble of the output ioe an liitation of axiu uty cycle iappear.. CRCUT ESCRPTON The block iagra repreentation of the propoe converter i hown Fig.. Fig.. Block iagra repreentation of the propoe converter t conit of 4 block naely i put.c upply which a 48 volt upply i given ii verter circuit which convert.c to A.C iii tranforer i ue here to tep up the voltage along with the voltage oubler circuit iv voltage oubler circuit an v pule generation part. SBN

2 Proceeg of National Conference on Technological Avanceent Power an Energy 7 Fig.. Circuit iagra The circuit iagra o f the propoe converter with highvoltage ga i hown Fig.. The converter conit of four witche S through S 4. The voltage acro the witche S an S the firt brige are confe to the put voltage V. The clapg capacitor C c can clap the voltage acro the witche S 3 an S 4 the econ brige. The output tage conit of a voltage oubler tructure that conit of the econary wg N of the tranforer T, the erial uctor, the output capacitor C o an C o, an the output ioe o an o. Accorg to the voltage oubler tructure, the voltage ga creae an the voltage tree of the output ioe are confe to the output voltage V o without any auxiliary circuit. The tranforer T i oele a the agnetizg uctance an the ieal tranforer that ha a turn ratio of :n (n=n /N. t leakage uctance i clue the erial uctor. The voltage acro the capacitance C o the econary ie i V o an the voltage acro the capacitance C o i V o.the output voltage i the u of V o an V o. The a avantage of the propoe converter clue the eliation of witchg loe an it ata low conuction lo an iprove the efficiency. t provie high voltage ga at fixe witchg frequency. t allow the oft witchg operation [5]-[6] of all power witche an ioe thu revere recovery proble i alleviate ue to an aitional uctor the econary ie of the tranforer. Moe [t 0, t ]: Fig. 3. Theoretical wavefor. MOA ANAYSS The operation of the propoe converter urg witchg perio T are ivie to four oe an that can be explae with the help of Fig. 3. Fig. 4. Moe operation Moe operation of the propoe converter i hown Fig. 4. The voltage acro the paraitic capacitance C through C 4 are V S, V S, V S3 an V S4. At t 0, the witche S an S 3 are turne OFF. Then, the energy tore the agnetic coponent tart to charge/icharge the paraitic capacitance C through C 4. Therefore, the voltage acro C an C 3 tart to rie fro zero an the voltage V S4 tart to fall fro (V +V c an the voltage v S tart to fall fro V. When the voltage v S an v S4 arrive at zero, their boy ioe an 4 are turne ON. Then, the gate ignal are applie to the witche S an S 4. Sce the current have alreay flown through an 4 an the voltage V S an V S4 are clape a zero before the witche S an S 4 are turne ON, zero- SBN

3 Proceeg of National Conference on Technological Avanceent Power an Energy 8 voltage turn-on of S an S 4 i achieve. With the turn-on of S an S 4, the priary voltage v p acro i V. Then, the agnetizg current creae learly fro it iu value a follow: ( t ( t t0 ( Sce the voltage V acro i nv +V o, the econary current i creae fro it iu value o a follow: Moe [t, t ]: n Vo i ( t io ( t t0 ( Moe operation i hown Fig. 5. At t, the current i an i 0 arrive at zero an the ioe o i turne OFF. Then, the output ioe o turne ON an it current creae learly. Sce the current changg rate of o i controlle by the erial uctor, it revere-recovery proble i ignificantly alleviate. Sce the voltage V i (nv V o thi oe, the current i are given by boy ioe an 3 are turne ON an the gate ignal are applie to the witche S an S 3. Sce the current have alreay flown through an 3 an the voltage v S an v S3 are clape a zero, zero-voltage turn ON of S an S 3 i achieve. With the turn-on of S an S 3, the voltage v p acro i -(V +V c. Then, the current i ecreae learly fro it axiu value a follow i ( t ( t t0 (4 Sce the voltage v acro i -(n (V + V c +V o, the current i ecreae fro it axiu value o a follow: n( Vo i ( t o ( t t (5 Moe 4 [t 3, t 4 ]: Moe 4 operation of the propoe converter i hown Fig. 7. n Vo i ( t ( t t (3 Moe 3 [t, t 3 ]: Fig. 5. Moe operation Fig. 7. Moe 4 operation Siilar to oe, the current i ani o arrive at zero an the ioe o i turne OFF at t 3. Then, the output ioe o i turne ON an it current creae learly. Sce the current changg rate of o i controlle by, it revererecovery proble i ignificantly alleviate. Sce the voltage V i (n(v +V c V o, the current i i given by n( Vo i ( t ( t t3 (6 At the en of thi oe, the current i an i arrive at an o, repectively. V. ESGN PARAMETERS Fig. 6. Moe 3 operation Moe 3 operation i hown Fig. 6. Siilar to oe, the witche S an S 4 are turne OFF at t. The paraitic capacitor C an C 4 tart to be charge fro zero an the capacitor C an C 3 tart to be icharge fro V an (V +V c repectively. When C an C 4 are fully charge an icharge, the voltage V S an V S3 becoe zero an the A. Clapg Capacitor Voltage (V c Referrg to the voltage wave for V p Fig. 3, the voltecon balance law give V T V V ( T 0 (7 ( c B. Voltage Ga The ioe current o can be written a nv V o 0 T (8 SBN

4 Proceeg of National Conference on Technological Avanceent Power an Energy 9 The voltage V o i obtae by V ( o nv Maxiu ioe current o can be written a follow: nv V o o ( T (0 Voltage V o can be obtae by V ( o nv (9 ( The average value of the ioe current io an i o are equal to the output current o an the followg relation can be obtae by ( o ( o Fro (8 an (, an i obtae by, =k (3 =k(- (4 8 0 k ( (5 nv T V0 M (6 V C. Maxiu an Miu Value of the Magnetizg Current (i n oe 3 an 4, the witch current i S3 i flowg through the clapg capacitor C c. Sce the average capacitor current ut be zero uner a teay-tate conition, the average value of i S3 i zero. The axiu value an the iu value are given by T T. ZVS Conition for the Switche S through S4 (7 (8 Fro Fig. 3, there i no current cancellation between i p (=ni an i at t. Therefore, for ZVS of S an S 3, the total energy tore an houl be larger than the energy tore C through C 4. The followg conition houl be atifie: 0 (9 ( C C V ( C3 C4( On the other han, there i current cancellation between i p (=ni an i at t 0. Therefore, for ZVS of S an S 4, the energy ifference between the energie tore an houl be larger than the energy tore C through C 4 a follow: o ( C C V ( C3 C4 ( Thi conition can be ue to etere. (0 E. Voltage Stree of Power Switche an Output ioe The voltage tree of S 3 an S 4 are the u of the put voltage V an the clapg capacitor voltage V c. Sce the clapg capacitor voltage epen on the uty cycle, the voltage tree of S 3 an S 4 can be change accorg to loa. Maxiu value of V S3 an V S4 the econ brige i given by V V V V ( 3,ax 4,ax c When the uty cycle i below 0.5, the axiu value of V S3 an V S4 are lower than the put voltage V. ue to the voltage oubler tructure, the axiu value of the voltage acro the output ioe are confe to the output voltage V o. V. HARWARE MPEMENTATON n orer to verify the valiity of the propoe topology, converter prototype i ipleente. TABE. nput Voltage (V Switchg Frequency (f PARAMETERS USE V 0 khz Maxiu uty Cycle ( ax 0.7 Serial nuctor ( 570 µh Maxiu output power 50W Clapg Capacitance (C c µf Value of C o an C o 0 µf MOSFET RF830 Harware part of the propoe converter i hown Fig. 8 an the paraeter ue for ipleentation i given Table. SBN

5 Proceeg of National Conference on Technological Avanceent Power an Energy 30 Voltage acro the witche are hown Fig. 0. Thu the voltage acro the firt wavefor i.4 an that of econ one i 8.4 with the fluence of clapg capacitor. Fig. 8. Harware part Fig.. (a Here AT89C5 i ue an it conit of aly 4 port P0, P, P an P3 with 8 p. Two p of port are taken for the PWM generation. Controller part i given to the river circuit an here FAN739 i ue. Fig.. (b Fig. 9. Pule urg the ON tie Pule urg the ON tie are hown Fig. 9. Fig.. (c Fig. 0. Voltage acro the witche SBN

6 Proceeg of National Conference on Technological Avanceent Power an Energy 3 [3] Alfre Fieler an Grottollen, nvetigation of Ayetrical Phae Shifte Full Brige, ntitute of Power Electronic an Elecrical rive, pp , 995. [4] Xyu Xu, Ahw M Khabakone an Raeh Oruganti, Analyi an eign of an Optiize Ayetrical Half Brige C-C Converter, EEE Tran.on power electronic, vol. 3, no., pp. 0-5,Jul [5] izhi Zhu, A novel oft coutatg iolate boot full brige ZVS PWM C- C converter for biirectional high power application, EEE Tran.on power electronic, vol., no., pp ,Mar [6] izhi Zhu, Kunrong Wang, Fre C. ee an Jih Sheng ai, New tart up chee for iolate full brige boot converter, EEE Tran.on power electronic, vol. 8, no. 4, pp , Jul Fig.. ( Pule acro each witche i hown the Fig.. (a, (b, (c an (. Fig. 3. Output voltage The output voltage i hown Fig.3 with 45V a output voltage an put a V. Hence the voltage ga of the yte i calculate a hence the ga i very high. V. CONCUSON Ayetrical full-brige converter with high voltage ga i propoe thi paper. The ZVS of all power witche an ZCS of the output ioe are achieve. The propoe converter i able to provie high-voltage ga with relatively low tranforer turn ratio. Alo, without any auxiliary circuit, the voltage acro the witche an the output ioe are effectively clape. Therefore, the propoe converter i uitable for high-voltage application. The voltage ga i with a tranforer turn ratio of 4.5. REFERENCES [] Hyun-ark o, Ayetrical Full-brige Converter with High- Voltage Ga, EEE Tran. on power electronic, vol. 7, no., pp , Feb. 0. [] P. berton an N. Mohan, Ayetrical uty Cycle Perit Zero Switchg o PWM Circuit with No Conuction o Penalty, EEE Tran. n. Applicat., vol. 9, no., pp. -5, 993. SBN