A New Macro-Model for Power Diodes Reverse Recovery

Transcription

1 Proceeings o he 7h WSEAS Inernaional Conerence on Power Sysems, Beijing, China, Sepember 15-17, 7 48 A New Macro-Moel or Power Dioes Reverse Recovery ALI DASTFAN Depaen o Elecrical & Roboic Engineering Shahroo Universiy o Technology Shahroo, Iran asan@ieee.org Absrac: - The power ioe is one o he mos imporan elemens o he power elecronics circuis, because o is role in ieren converers. The objecive o his paper is o in a moel or power ioe reverse recovery, which can be use in circui simulaion. A simple macro-moel or reverse recovery in power ioe, ha is he mos imporan ynamic eec or power circui, is evelope. Then in orer o veriy he accuracy o he moel, PSPICE simulaion an benchmark es resuls o a power ioe in a DC/DC boos converer are given. The simulaion an experimenal resuls emonsraes he accuracy o he propose power ioe moels. Finally, calculaion o he ioe power losses ue o he ioe reverse recovery is given an is compare wih simulaion an experimenal resuls. Key-Wors: -Macro moel, power ioe moel, power losses, PSPICE simulaion, es resul 1 Inroucion The power ioe is one o he mos imporan, because o is role in power elecronics circuis, an in he some ways he leas unersoo power evice. Till oay, various power ioe moels have been propose [1-9], however, ue o he ieren requiremens an simulaors, here is no unique moel or he power ioes. Tha means a power ioe moel may work on one paricular simulaor bu suer rom some iiculy on oher simulaor. In general he power ioe moels can be classiie as eiher macro-moels [1]-[4] or eaile physical moels [6], [8], [9]. The macro-moels are compose o elecrical equivalen circuis which are no irecly relae o inernal physical processes in he evice. Physical moels inclue equaions or ri an iusion o elecrons an holes. They usually conain many mahemaical equaions an parameers, an are complicae o incorporae ino circui simulaors. In he irs secion o his paper a simple macromoel or reverse recovery in power ioe is evelope o simulae he behaviour o he power ioes uring reverse recovery ransien. Then in orer o veriy he ioe moel, operaion o power ioe in he boos converer is invesigae by PSPICE simulaion an experimen. The calculaion o he ioe power losses ue o he ioe reverse recovery is also presene. The preice value o he losses or ieren swiching requencies is compare wih he power losses oun by experimens. Dioe Moel or Reverse Recovery Transien The reverse recovery phenomenon in ioe occurs when a orwar biase ioe is urne o rapily. The excess charges sore in is juncion uring orwar conucion, akes some ime o be remove. During his ime, he ioe remains conucing an a reverse cuen lows hrough i. Aer mos o he sore charge has been remove, epliion layer in ioe begins o accumulae a reverse volage an he ioe cuen evenually alls o almos zero. Figure 1 shows ioe cuen an volage waveos uring urn-o an einiions relae o ha. Where: = Reverse recovery ime I = Maximum reverse cuen I I I / 1 Q V r.1i Figure 1: Dioe reverse recovery cuen an volage waveos

2 Proceeings o he 7h WSEAS Inernaional Conerence on Power Sysems, Beijing, China, Sepember 15-17, 7 49 Q = Reverse recovery charge I /= Slope o he ioe orwar cuen This ransien can be ivie ino wo secions. The irs secion, < <, sars when cuen is ecreasing rom i. Prior o his ime (a = - ), he ioe sore charge can be represene by: Q() = = i (1) Where is he orwar minoriy caier lieime. The ioe cuen uring irs secion can be oun by using he ollowing equaion: Q() Q() i () = + () A he en o secion one (a = 1 ), he ioe reverse cuen reach is maximum value, I. This ime can be oun by assuming ha he oal sore charge uring secion ( 1 < < ) is irecly proporional o he reverse cuen [7]. Q() = I (3) 1 = r Where r is he reverse biase minoriy caier lieime. During secion he ioe cuen alls exponenially an can be represene as: ( ) i () = I e (4) When is he ime consan o he circui. Figure is a propose simple macro-moel or power ioe reverse recovery an consiss o an ieal ioe, wo resisances, an inucance, an a volage conrolle cuen source. In his circui, aer ioe urne o, or << he ieal ioe conucs an he series inucance o he exernal circui eeines he ioe cuen an is slope(i /). As ioe cuen linearly ecreases, ( << 1 ), he consan volage across inucance ( I L F ) commans a consan reverse cuen hrough he conrolle cuen source unil cuen reaches I. The ieal ioe hen becomes blocke since is cuen has ecrease o zero an i can be regare as an open swich. The parallele RL a 1 <<, imposes an exponenial cuen wih a ime consan equal o L/R as given in (4) where =L/R. Thereore, his moel only epens on wo parameers: L/R an K (he coeicien o he volage conrolle cuen source). Some power ioe manuacurers may provie one or wo ioe parameers, such as I,, an Q, or speciie I an I / coniions. The oher parameers can be oun as explaine by Fliners e al []. Q an I / have been use in his simulaion, an L/R an K can be relae o hese parameers. From Equaion (4) ime consan L/R can be oun as ollow: R C V L Ieal Dioe A R L = i() = = i() =.1 Thereore, by solving Equaion (4), ime consan is equal o: L 1 = ( ) (5) R ln1 / For power ioes wih so recovery, Equaion (5) can be simpliie, because he Reverse Snap-o Facor (RSF) in hese ioes is close o one [], [7]. Tha means: RSF = Q = 1 Q1 Thereore, I an can be relae o Q an I / as ollow: = Q (6) Q = / Thereore in ha case ime consan is equal o: Q L 1 Q 1 Q = ( ) = (7) R ln1 / / ln1 / A egree o reeom exiss beween L an R, so he inucance se o a small value ha makes V L negligible compare o orwar volage across ioe (e.g., 1pH). Thereore, or K>>1, his inucance acs as a probe measuring I / or he conrolle cuen source. R can be calculae rom L an ime consan, ha has been calculae rom (7), as ollow: L 11 / R = = 1 ln1 (8) Q i K*V L Figure : Propose Moel or he ioe reverse recovery

3 Proceeings o he 7h WSEAS Inernaional Conerence on Power Sysems, Beijing, China, Sepember 15-17, 7 5 LS Dioe Vc S Lσ C R L Cuen (A) Volage (V) I1 V1 Figure 3: DC boos converer A = 1 volage across L is LI /, hereore K can be oun a his ime which reverse cuen has maximum value: KL = (9) 1 Q 11 Q K = = = 1 LI / L I / I / 3 Simulaion an Experimen Resuls To valiae he propose moel, simulaion an experimenal es have been caie ou. Figure 3 shows he circui use o suy ioe reverse recovery. The power ioe is BYX5, which is 1 V, A wih maximum orwar volage o 1.8 V. The reverse recovery ime,, an Q are given by he manuacurer. Compuer Simulaion or he DC/DC boos converer circui was conuce or he swiching requency o 1 khz using PSPICE. Circui componen values ha have been use are: L s = 8.mH, C= 1mF, R L = 5Ω, L σ =1μH Figure 4 shows he simulaion resuls o he cuen an volage waveos o he power ioe D 1 uring he reverse recovery ransien. Figure 5 shows he experimenal resul when he orwar cuen is aroun 3 A. From his graph i can be seen ha oal reverse recovery charge is approximaely 38 μc, I is abou 5 A, I / is abou 3 A/μs when i is abou.5 A. Comparison o he simulaion an experimenal waveos (Figures 4 & 5) shows ha he general characerisics are very similar. The only ierence is beween volage waveos. In simulaion resuls he volage across he ioe alls o a value which is even greaer han he blocking volage an hen graually seles o is inal value, bu experimenally he ioe volage alls o value less han he blocking volage an recovers back o i. This migh be ue o no having a realisic IGBT moel in he simulaion. The cuen an volage waveos o he IGBT oun by experimen uring urn-on process an when he cuen is.5 A is shown in Figures 6. I will be shown in he nex subsecion ha his Time (μsec.) Figure 4: Simulaion resul: Dioe cuen an volage waveos Figure 5: Experimenal resul: ioe cuen an volage waveos uring ioe urn-o ransien (5 A/iv 1 V/iv & 5 μsec/iv) ierence has lile eec on he calculaion o power losses. 4 Dioe Power Losses One o he objecives o his paper is o in power losses ue o ioe reverse recovery in he circui wih ieren swiching requencies. Using he basic einiion o average power in Figure 1 an or one cycle is: Figure 6: Experimenal resul: IGBT cuen an volage waveos uring swich urn-on ransien (.5 A/iv 1 V/iv &.5 μsec/iv)

4 Proceeings o he 7h WSEAS Inernaional Conerence on Power Sysems, Beijing, China, Sepember 15-17, 7 51 T 1 p losse = v()i() = s v()i() (1) T Where i () is given in (1), an v () is equal o: ( ) i v () = Vr Lσ = (Vr e ) (11) So power losses are equal o: ( ) plosse = s (Vr + L e )I σ ( 1) e = (. 1 1) = 9. ( 1) e = 1 1 (. ). ( ) e (1) Aer solving his inegraion, 1 plosse = s (1.1Vr I I ) (13) I F = sq ( Vr ) ln1 By using ioe parameers an is cuen, he ioe power losses ue o reverse recovery can be esimae. 4.1 Esimaion o Dioe Power Losses The esimae ioe power losses ue o reverse recovery in circui shown in Figure 3 or ieren swiching requencies by using Equaion (13) are given in Table 1. The power losses have also been esimae by simulaion or ieren swiching requencies, which are given in Table 1. This has been calculae by muliplying ioes cuens by heir volages o obain he insananeous power, an hen ining is average or uraion o one power cycle. The measuremen o ioe power losses by experimen has been one by measuremen o cuens an volages in one swiching cycle an hen calculaing he losses as one in he simulaion. Unlike esimaion by equaion (13) an by simulaion, which jus inclue power ioe losses ue o reverse recovery phenomena, he power losses Losses(W) oun by experimen inclue all power losses in he power ioe shown in Figure 3. The oal power losses oun by experimens or swiching requencies up o 5 khz or his circui are also given in Table 1. Figure 7 shows hese power losses or ieren swiching requencies. The simulaion resuls are less han he esimae resuls an his may be ue o no using a goo moel or he IGBTs in he simulaion. 5 Conclusion In his paper, a simple moel o power ioe or reverse recovery ransien has been presene an implemene in PSPICE simulaor. A major eaure o his moel is is simpliciy an simulaion spee compares o oher subcircui moels. The moel has been veriie by comparing experimenal an simulaion resuls or power ioe use in DC boos converer. Power losses have been preice or ieren swiching requencies an compare wih simulaion an experimenal resuls. The power ioe moel propose here provies goo peroance in accuracy an simulaion spee. Reerences Esimae Simulaion Experimenal Swiching Frequency (khz) Figure 7: Dioe power losses [1] Liang Y. C. an Gosbell V. J., "Dioe Forwar an Reverse Recovery Moel or Power Elecronics SPICE Simulaion," IEEE, Transacions on Power Elecronics, Vol. 4, No. 3, PP , 199 [] Fliners F. M., Wols P. J., Kwong K., "The Preicion o Dioe Reverse Recovery Behaviour From Limie Daa," Ausralasian Table 1: Dioe power losses or ieren swiching requencies Dioe power losses (W) Swiching Frequency (khz) Esimae by (13) Simulaions resuls Experimenal resuls

5 Proceeings o he 7h WSEAS Inernaional Conerence on Power Sysems, Beijing, China, Sepember 15-17, 7 5 Universiies Power Engineering Conerence (AUPEC'9), Queenslan, PP , 199 [3] Baar G., Smih D. M., Zelaya H., an Gooman C. J., "New High Power Dioe Moel wih boh Forwar an Reverse Recovery," IEE Power Elecronics an Variable Spee Drives, pp , 1994 [4] Tseng K. J., Yang J., an Foo C. F., "Peroance o power Dioe Moel or Circui Simulaion," IEEE Proceeing o 1995 Inernaional Conerence on Power Elecronics an Drive Sysems, Singapore, PP , 1993 [5] Goebel H. an Homann K., "power Dioe Hybri Moel wih Forwar an Reverse Recovery or use in Circui Simulaors," IEEE, APEC'9, Boson, pp , 199 [6] Laurizen P. O. an Ma C. L., "A simple Dioe Moel wih Reverse Recovery," IEEE Transacion on Power Elecronics, Vol. 6, No., pp , 1991 [7] Ghanhi S. K., "Semiconucor Power Device," John Wiley & Sons, 1997 [8] Ma C. L., Laurizen P. O., an Sigg J., "Moeling o Power Dioes wih he Lumpe- Charge Moeling Technique", IEEE Transacion on Power Elecronics, VOL. 1, NO. 3, 1997 [9] Bryan A. T.,. Kang X., Sani E., Palmer P. R., an Hugins J. L., "Two-Sep Parameer Exracion Proceure Wih Foal Opimizaion or Physics-Base Circui Simulaor IGBT an p-i-n Dioe Moels", IEEE Transacion on Power Elecronics, VOL. 1, NO., 6