Research on a Novel Soft-Switching Buck Converter

Transcription

1 Rsach Jounal of Appld Scncs, Engnng and Tchnology 5(8): , 0 ISSN: ; -ISSN: Maxwll Scnfc Oganzaon, 0 Submd: Ocob 7, 0 Accpd: Januay 0, 0 Publshd: May 05, 0 Rsach on a Novl Sof-Swchng Buck onv, Yuanbn, Png G and Bn Nu Hangzhou Non-ommssond Offc Acadmy of APF, Hangzhou 00, hna ollg of vl Avaon, Nanjng nvsy of Aonaucs and Asonaucs, Nanjng 006, hna Absac: Basd on classcal zo volag anson buck pwm conv, an dal buck conv wh pwmconolld sof-swchng ccu s poposd. Th poposd auxlay ccu allows h man swch o opa wh zo-volag swchng. Bsds, all of h smconduco dvcs opa und sof-swchng condons. Thus, losss w ducd. I was analyzd n dal o dmonsa h opang pncpl of h novl ccu. Fnally, smulaon suls a gvn analyss and h smulaon suls a povdd o vfy h pfomanc of h poposd buck onv. Kywods: Buck conv, sonanc, sof-swchng, zo volag anson INTROTION Rcn yas, as h ns ncasd by h ndusy n pow convs wh hgh fquncy and small sz, los of novl opologs hav bn poposd n laus (Mans al., 005; n al., 00). Wh h swchng fquncy ncas, hgh pow dnsy can b achvd. Bu und h had swchng condon, h d d and du d s lag dung h communcaon pocss. So sof-swchng chnqu s dvlopd and som was mployd o h pow convs, usually auxlay componns a usd (Wu al., 008; al., 00). In h las yas, sachs pad mo anon o o Volag Tanson (), whch s h volag-mod sof-swchng mhod (Syd al., 008). Th opaon of s smla o PWM convs and s addonal conducons hav low losss (Adb and Fazanhfad, 009; Iannuzzo, 005). Th locaon of auxlay ccu causs hs makabl faus and h auxlay ccu s placd n paalll wh h man pow conv. Bfo h man swch s und on, h auxlay ccu woks, whn h man swch s und off, h auxlay ccu cass (Mans al., 005). In ha way, h addonal conducon losss a mosly ducd. Moov, h opaon chaacscs hav fw nfluncs. Pvously poposd -PWM convs hav a las on of h followng dawbacks (Panda al., 008): Th auxlay swch s und off whl s conducng cun. Tha causs h swchng losss Th man conv swch opas wh a hgh pak cun sss and/o volag sss Th auxlay ccu componns hav hgh volag and/o cun sss Som ccus a complx, dffcul o conol and so on. Ths sudy psns a novl buck conv by usng a sonan auxlay nwok. And h poposd conv achvs zo-volag swchng fo h man swchng and zo-cun swchng fo h auxlay swchng. THE NOVE SOFT-SWITVHING BK ONVERTER cu dscpon and assumpon: Th poposd novl sof-swchng buck conv s show n Fg.. I s h combnaon of h convnonal PWM buck conv and h poposd auxlay snubb ccu. Th auxlay ccu consss of a sonan nduco, sonan capaco,,, h auxlay dods,, and auxlay swchng. Th followng assumpons a mad dung on swchng cycl n od o analyz h sady-sa opaons of h poposd ccu. Inpu volag s consan Oupu volag o s consan o oupu capaco o s lag nough Oupu cun I o s consan o oupu nduco s lag nough Oupu nduco s much lag han sonan ccu nduco Rsonan ccus a dal Smconduco dvcs a dal ospondng Auho: Bn Nu, ollg of vl Avaon, Nanjng nvsy of Aonaucs and Asonaucs, Nanjng 006, hna 450

2 Rs. J. Appl. Sc. Eng. Tchnol., 5(8): , 0 o o Fg. : Th poposd novl sof-swchng buck conv (a) mod ( 0 ~ ) o Fg. : Ky hocal wavfoms of h poposd conv (b) mod ( ~ ) Rvs covy m of all dods s gnod Opaon pncpls and analyss: Basd on h assumpons abov, ccu opaon n on swchng cycl can b dvdd no nn sags. Th ky wavfoms a shown n Fg. and h quvaln ccu of h opaon sags s shown n Fg.. Th dald analyss of vy sag wll b dscussd n h followng paagaphs. Mod ( 0 ~ ): Po o 0, h man dod s conducng, whl h man swchng and h auxlay swchng w off. A h bgnnng of hs sag: o Io 45 (c) mod ( ~ )

3 Rs. J. Appl. Sc. Eng. Tchnol., 5(8): , 0 o o (d) mod 4( ~ ) 4 (g) mod 7( ~ ) 6 7 o o (h) mod 8( ~ ) 7 8 () mod 5( ~ ) 4 5 o o () mod 9( 8 ~ ) 9 (f) mod 6( 5 ~ ) 6 Fg. : Th quvaln ccu of h opaon sags 45

4 Rs. J. Appl. Sc. Eng. Tchnol., 5(8): , 0 A 0, h auxlay swchng s und on, whch alzs zo-cun un-on as s n ss wh h sonan nduco. ung hs sag, ss and h cun of h man dod fall smulanously a h sam a lnaly. Ths mod nds a whn achs I o and bcoms zo. Th man dod s und off wh VS bcaus of and bng xsn. In hs sa, () ( ) 0 Io ( 0 ) () Th cun of h sonanc nduco flows hough h dod whch vs paallld and h man swchng uns on wh VS. And h m whn uns on s la han h m uns on. Th dlayd m: π d 0 + Io + (8) In hs nval, sonanc occus wh h nduco and capaco and.ths mod nds wh s chagd up o h npu volag : ω (9) ( ) [ cos ( )] 0 Io () ω (0) ( ) [ cos ( )] Mod ( ~ ): Th dod sas conducng wh VS a h nsan whn h man dod s und off. A, 0, I o 0, I, 0, 0,, In hs nval, sonanc occus wh h nduco and h capaco, ncass on and falls, a h nd of hs mod, h volag of h capaco falls o zo: wh, sn ( ) I + ω ( ) () o ( ) ( ) cos (4) wh, ( ) snω ( ) + + I () o + ω () Whn h bcoms, h dod s und on wh VS. In hs sa: accos ω () w (5) Mod 4( ~ 4 ): A, Io, max,,.whn uns on, nw A, 0 h dod vs paalllld sonanc sas wh and, and s chagd up: s conducng, clamps h volag of h man swchng wh zo. A hs momn: ( ) I max sn ( ) cos ( ) ω + ω (4) Io + (6) ( ) I max snω ( ) snω( ) (5) π (7) wh, Mod ( ~ ): A, 0, I, o Io +, 0, ω (6) 0, 0, 0. 45

5 Ths mod nds whn s chagd up o s maxmum volag. ods and a und off wh S du o h xsnc of. And a h sam m, auxlay swchng uns off wh S. In hs sa: 4 I acan ω max Rs. J. Appl. Sc. Eng. Tchnol., 5(8): , 0 (7) Mod 5 ( ~ 4 5 ): Th s no sonanc n hs mod and h ccu opaon s dncal o ha of a convnonal PWM buck conv: I o (8) Mod 6( 5 ~ 6 ): A 5, I o, 0,,. Th man swchng s und off und VS bcaus h volag of h capaco canno s suddnly. s clampd o zo. Rsonanc occus wh and. Th volag and cun quaons fo hs mod a: ω (9) 5 ( ) sn ( ) ( ) 0 (0) ( ) cosω ( ) () 5 π π 56 ω () wh, ω () Ths mod nds whn h volag acoss bcoms zo. Mod 7( 6 ~ 7 ): A 6, 0, 0, Th dod uns on und VS. Rsonanc sas wh nduco and capaco. And s chagd up. Fo hs sa, h quaons a: ( ) I ( ) ω (4) sn 6 ( ) I ( ) ω (5) cos ω (6) Whn bcoms zo, hs mod coms o an nd. Th m nval fo hs mod s gvn as: 67 π π ω (7) Mod 8 ( ~ ): A Th sod ngy of capaco s now ansfd o load. 8 ~ Mod 9( 9 ): A 8, h man dod s conducng und VS, h load cun wll flow hough h man dod. ung hs mod, h conv opas lk a convnonal PWM buck conv unl h auxlay swchng s und on n h nx swchng cycl. In hs mod: I o (8) ESIGN PROERE Th poposd conv opas wh an npu volag 00V, oupu volag o 80V, load cun of 0A and h swchng fquncy of 0kHz.. Th followng dsgn pocdu s dvlopd consdng pocdu of laus (hang al., 007). Slcon of h sonan nduco. Fom h analyss of mod, h spd of h cun flowng hough ncass fas f h sonan nduco s oo small, hus can' lm h vs cun of h man dod. And fom h analyss of mod, f h sonan nduco s oo small, I wll b vy lag, whch may ncas h un-on losss of h auxlay swchng. In h dsgnaons, s consdd as followngs: T s. In hs cas, fom (): 0.0Ts ( ) Io (9) Slcon of,,. In od o povd VS un-on fo h man swchng, h ngy of should ansfom o, consdng I (0)

6 Rs. J. Appl. Sc. Eng. Tchnol., 5(8): , 0 I () Th capaco wll ansfom h ngy o a las h m pod f dung h un off of h man swchng, accodng o fomula (): π π 56 ω f () f s h fall m of h man swchng. Wh h ngy balanc dfnd as: + I () omax Th capaco can b calculad. SIMATION RESTS Fg. 5: Th dv wavfoms of man and auxlay swchng a 0.8 duy cycl of h man swchng Th conv s smulad usng smulaon sofwa Oad, vson 0.5. Th majo paams a gvn as follows: uh 0. nf 80nF nf 00V o 80V I o 0A f s 0kHz Fgu 4 dpcs h dv wavfoms of man and auxlay swchng whn h man swchng s duy cycls s 0.4 and Fg. 5 dpcs h dv wavfoms of man and auxlay swchng wh 0.8 duy cycls of h man swchng. Th wavfoms of cun and volag on man swchng wh 0.4 duy cycls of h man swchng s shown n Fg. 6, whn h volag of man swchng falls o zo, h cun hn ncass. And bfo h volag ncass, h cun falls o zo. So h pow loss s naly o zo, h man swchng achvs zo-volag swchng. Fgu 7 dscbs h wavfoms of cun and volag on auxlay Fg. 6: Th wavfoms of cun and volag of man swchng a 0.4 duy cycl Fg. 4: Th dv wavfoms of man and auxlay swchng a 0.4 duy cycl of h man swchng 455 Fg. 7: Th wavfoms of cun and volag of auxlay swchng a 0.4 duy cycl

7 Rs. J. Appl. Sc. Eng. Tchnol., 5(8): , 0 Fg. 8: Th wavfoms of cun and volag of man dod a 0.4 duy cycl Fg. 0: Th wavfoms of cun and volag of auxlay swchng a 0.8 duy cycl Fg. 9: Th wavfoms of cun and volag of man swchng a 0.8 duy cycl Fg. : Th wavfoms of cun and volag of man dod a 0.8 duy cycl swchng wh 0.4 duy cycls of h man swchng, bfo h cun of auxlay swchng ncass, h volag has dcasd o zo and h volag ncass af h cun has dcasd o zo. Thus h cun of auxlay achvs zo-cun swchng and h pow loss s ducd. Bu whn h cun dcass o zo, h s a flucuaon of volag. Fgu 8 psns h man dod uns on and off und sofswchng condons wh 0.4 duy cycls of h man swchng. Fgu 9 dpcs h wavfoms of cun and volag on man swchng wh 0.8 duy cycl of man swchng. Fgu 0 dscbs h wavfoms of cun and volag on auxlay swchng wh 0.8 duy cycl of man swchng. And Fg. psns h wavfoms of cun and volag on man dod wh duy cycl of man swchng. As h fgus shown, whn h duy cycl of man swchng ncass, h s a small flucuaon of volag, bu has ll nflunc n h ccu. ONSION As h smulaon suls shown, h man swchng uns on and off wh VS. And h auxlay swchng S uns on and uns off. All h dods opa und sof-swchng condons. Swchng losss a ducd. And h addonal volag and cun ssss on h man dvcs do no ak plac. Th poposd ccu can also b usd n h vhcl volag conv, whch h auho wll dvlop fuh sach nx sp.

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