Converter Topologies

Transcription

1 High Sepup Raio DCDC Converer Topologies Par I Speaker: G. Spiazzi P. Teni,, L. Rosseo,, G. Spiazzi,, S. Buso,, P. Maavelli, L. Corradini Dep. of Informaion Engineering DEI Universiy of Padova

2 Seminar Ouline Why we need high sepup raio converers? Applicaion fields Low power high sepup raio opologies Coupled inducors High power high sepup raio opologies Non isolaed Isolaed 2

3 Why? High Sepup Raio Topologies Lowvolage highcurren energy sources Fuelcells (some kw) Paralleled phoovolaic modules in domesic applicaions (some kw) Microinverer, i.e. connecion of a single phoovolaic module o he grid (some hundred was) Sepdown inverers require an inpu volage higher han he maximum line volage peak 3

4 Example of Microinverer Uiliy grid Microinverer srucure W single pv panel High SepUp Microinverer for single panel DCDC Modulariy Reducion of parial shading effecs Dedicaed Maximum Power Poin Tracker (MPPT) 4

5 Simple Boos Topology Boos scheme including some parasiic elemens: Diode model U i I L r L L U D r S r D S Swich model D C I o R o U o Volage conversion raio (neglecing inducor curren ripple): M = 1 1 d 1 r D ( 1 d) rs R ( 1 d) o 1 d 2 r L U U D o = 1 F d,u 1 d (,R ) o o 5

6 Simple Boos Topology Volage conversion raio M including conducion losses: M ideal 8 M max R o Duycycle 6

7 Simple Boos Topology Converer efficiency: P η = P ou in = UoI UI i o i = UoI UI i D L = ( d) = F( d,u, R ) M 1 o o 1 η R o Duycycle 7

8 Low Power Applicaions Example: inegraed BoosFlyback converer L m S 1:n 21 D 2 D 1 C 1 U 2 U 1 Uo I can be seen as a flyback converer wih a non dissipaive snubber: D 1 and C 1 deliver o he oupu he energy sored in he ransformer leakage inducance 8

9 Inegraed BoosFlyback Converer Ideal waveforms: CCM operaion of flyback secion DCM operaion of boos secion L m 1:n 21 i D2 D 2 U 2 Uo S i D1 D 1 C 1 U 1 i D1 i D =T s 0 Advanages: ZCS urn on Sof diode urn off Reduced swich volage sress 9

10 Inegraed BoosFlyback Converer Problems: Parasiic oscillaions a D 2 urn off caused by is capaciance C r resonaing wih ransformer leakage inducances and L s u r L m 1:n 21 i s L s C r D 2 U 2 Uo High volage sress across D 2 S D 1 C 1 U 1 Dissipaive RCD snubber is needed 10

11 Modified IBF Converer L m S 1:n 21 i s L s D 3 x C r u r D 2 D 1 C 1 U 2 Uo U 1 Clamping diode D 3 added o he original opology Advanages: Clean diode volage waveforms wihou parasiic oscillaions Energy ransfer oward he oupu also during swich urn on inerval Sligh volage gain increase due o resonances beween parasiic componens 11

12 Modified IBF Converer Inerval T 01 = 1 0 i D1 i D2 i D2 L m L s D 2 U 2 Uo i D =T s 0 S C 1 U 1 12

13 Modified IBF Converer Inerval T 12 = 2 1 u r i D1 C r i D2 L m L s U 2 Uo i D =T s 0 S C 1 U 1 13

14 Modified IBF Converer Inerval T 23 = 3 2 i D1 i D2 L m L s D 3 i D3 U 2 Uo i D =T s 0 S C 1 U 1 Noe: acual i D3 slope can be eiher posiive or negaive 14

15 Modified IBF Converer Inerval T 34 = 4 3 i D1 i D2 L m L s D 3 i D3 U 2 Uo i D =T s 0 S i D1 D 1 C 1 U 1 15

16 Modified IBF Converer Inerval T 45 = 5 4 u r i D1 C r i D2 L m L s U 2 Uo i D =T s 0 i D1 D 1 C 1 U 1 16

17 Modified IBF Converer Inerval T 56 = 6 5 i D1 i D2 i D2 L m L s D 2 U 2 Uo i D =T s 0 i D1 D 1 C 1 U 1 17

18 Modified IBF Converer Inerval T 67 = 7 6 i D1 i D2 i D2 L m L s D 2 U 2 Uo i D =T s 0 C 1 U 1 18

19 Converer Parameers Inpu volage: Oupu volage: Nominal oupu power: Swiching frequency: = 2535 V U o = 400 V P o = 300 W f s = 100 khz Magneizing inducance: L m = 20 µh Primary leakage inducance: = 0.4 µh Secondary leakage inducance: L s = 2 µh 19

20 Volage Conversion Raio M Comparison beween calculaions and spice simulaions M M = U U o g M = 1 U U This unmached poin corresponds o a differen opological sequence 1 g Duycycle 20

21 Volage Conversion Raio Effec of resonan inervals on he overall volage gain M Wih parasiic componens Duycycle No parasiic componens M = U U o g 21

22 Experimenal Resuls = 35 V, U o = 400 V, P o = 300 W u x [100V/div] u DS [50V/div [2.5A/div] Peaking due o a small dip in he converer inpu volage due o fas curren rise ime 22

23 Experimenal Resuls = 35 V, U o = 400 V, P o = 300 W u x u x u DS u DS I mpk i D i D2 i D =T s 0 23

24 Experimenal Resuls = 25 V, U o = 400 V, P o = 300 W u x [100V/div] u DS [50V/div L m L s D 3 i D3 U 2 Uo S C 1 U 1 [5A/div] D 3 urns off during he swich on inerval 24

25 Measured Efficiency η 0.95 P o = 200 W f s = 100kHz η 0.94 f s = 100kHz P o = 300 W f s = 200kHz 0.92 f s = 200kHz [V] [V] 25

26 Measured Efficiency f s = 100 khz η = 35V = 25V P o [W]

27 IBF Converer wih Volage Muliplier Volage muliplier cell D 2 U 2 D 3 C 3 U 3 U o L m D 1 S C U

28 IBF Converer wih Volage Muliplier IBF converer wih volage muliplier cell versus modified IBF D 2 D 3 X U 2 C 3 U 3 U o L m 1:n 21 i s L s D 3 x C r u r D 2 U 2 Uo L m D 1 S C U 1 1 S D 1 C 1 U 1 Similar behavior wih a higher degree of freedom in conrolling he swich volage sress 28

29 Converer Waveforms BOOST secion in DCM and FLYBACK secion in CCM N p u r C r x D 2 i s L D s 3 N s C 3 U 2 U 3 I mvl I mpk I gpk I mpk I m1 I m2 im U o i D1 L m D 1 C 1 S U 1 i s ( 5 ) i D2 I m1 /n 21 I m2/n 21 i s ( 2 ) i D3 i D3 ( 3 ) =T s 0 29

30 Experimenal Prooype Design example: Inpu volage: = 25 35V Oupu volage: U o = 400V Nominal oupu power: P o = 300W Swiching frequency: f s = 100kHz Boos oupu: U 1 = 75V Magneizing inducance: L m = 20µH Primary leakage inducance: = 0.4µH Secondary leakage inducance: L s = 2µH 150V raed mosfe Based on desired curren ripple and DCM CCM mode a nominal power From he design consrains: M= U o / =400/35=11.42 M 1 = U 1 / =75/35=2.143 Numerically solving: d = 0.519, n 21 = M 2 = U 2 / = M 3 = MM 1 M 2 = U 3 / = M calculaed volage M 1 gains (coninuous 5 curves) and simulaion resuls (doed) Duycycle

31 Experimenal resuls u x u DS Measured main waveforms in a swiching period = 35V, V o = 400V, P o = 300W u x : 100V/div; u DS : 20V/div; : 5A/div u r C r x D 2 i s N s U 2 N p L D s 3 C 3 U 3 im U o u DS u x u x u DS L m D 1 S C U 1 1 zero curren urn on layou sray inducances resonance Deails of urn on and urn off inervals

32 Converer efficiency The converer efficiency was measured as a funcion of inpu volage, a P o =300W,Fig.1, and a =[25V,35V] and variable oupu power, Fig. 2 η Efficiency η Efficiency = 35V = 25V [V] Fig Fig P o [W]

33 Isolaed IBF Converer N p u r im C r x D 2 i s L D s 3 N s C 3 U 2 U 3 U o For isolaion,, he loss less snubber D 1 C 1 is subsiued by an acive clamp L m D 1 C 1 S U 1 i d i o U AC C AC S AC Lm S D 2 N p D 1 C r u r U 2 L s i s N s C 1 U 1 U o R o 33

34 Isolaed IBF Converer Advanages: ZVS urn on Sof diode urn off Reduces swich volage sress Clean diode volage waveforms wihou parasiic oscillaions Energy ransfer oward he oupu also during swich urn on inerval Reduced acive clamp circulaing curren 34

35 Converer Operaion Hp: negligible capacior volage ripples Inerval T 01 = 1 0 ( 0 ) i d I mpk I mvl i d i o i d ( 0 ) i SAC Lm S D 2 N p L s i s N s C 1 U 2 U 1 U o R o i D2 i D =T s 0 Sof D 2 urn off 35

36 Converer Operaion Hp: negligible capacior volage ripples Inerval T 12 = 2 1 ( 0 ) i d I mpk I mvl i d i o i d ( 0 ) i SAC Lm S N p C r u r U 2 L s i s N s C 1 U 1 U o R o i D2 i D =T s 0 36

37 Converer Operaion Hp: negligible capacior volage ripples Inerval T 23 = 3 2 ( 0 ) i d I mpk I mvl i d i o i d ( 0 ) i SAC Lm S N p D 1 L s i s N s C 1 U 2 U 1 U o R o i D2 i D =T s 0 Noe: acual i D1 slope can be eiher posiive or negaive 37

38 Converer Operaion Hp: negligible capacior volage ripples Inerval T 34 = 4 3 ( 0 ) i d I mpk I mvl i d i o i d ( 0 ) i SAC U AC C AC S AC Lm N p D 1 L s i s N s C 1 U 2 U 1 U o R o i D2 i D =T s 0 Sof D 1 urn off 38

39 Converer Operaion Hp: negligible capacior volage ripples Inerval T 45 = 5 4 ( 0 ) i d I mpk I mvl i d i o i d ( 0 ) U AC C AC Lm C r u r U 2 N p S i AC s U o L s i SAC N s C 1 U 1 R o i D2 i D =T s 0 Reduced acive clamp circulaing curren 39

40 Converer Operaion Hp: negligible capacior volage ripples ( 0 ) i d I mpk Inerval T 56 = 6 5 i d ( 0 ) I mvl i d i o i SAC U AC C AC S AC Lm D 2 N p L s i s N s C 1 U 2 U o R o i U D =T s 0 i D2 40

41 Converer Parameers Inpu volage: Oupu volage: Nominal oupu power: Swiching frequency: = 2535 V U o = 400 V P o = 300 W f s = 100 khz Magneizing inducance: L m = 20 µh Primary leakage inducance: = 0.4 µh Secondary leakage inducance:l s = 2 µh 41

42 Experimenal Resuls = 35 V, U o = 400 V, P o = 300 W (2µs/div) u D1 [100V/div] u DS [20V/div] i d [5A/div] Peaking due o a small dip in he converer inpu volage due o he fas curren rise ime 42

43 Experimenal Resuls = 35 V, U o = 400 V, P o = 300 W (2µs/div) u D1 [100V/div] u DS [20V/div] } i d [5A/div] The resonan phase reduces he acive clamp circulaing curren 43

44 Experimenal Resuls = 35 V, U o = 400 V, P o = 300 W (2µs/div) U AC C AC S AC Lm S D 2 D 1 C r u r L s C 1 U o R o 390 pf exernal capacior added } i d [5A/div] The resonan phase reduces he acive clamp circulaing curren 44

45 Deail of Main Swich Turn On = 35 V, U o = 400 V, P o = 300 W Time scale: 500ns/div ( 0 ) i d I mpk u D1 [100V/div] i d ( 0 ) I mvl u DS [20V/div] i SAC i D2 i d [5A/div] i D =T s 0 6 =

46 Deail of Main Swich Turn Off = 35 V, U o = 400 V, P o = 300 W Time scale: 500ns/div ( 0 ) i d I mpk u D1 [100V/div] i d ( 0 ) I mvl u DS [20V/div] i SAC i D2 i d [5A/div] i D =T s

47 Zero Volage Swiching Deail of he main swich urn on (nominal oupu power) u GS [5V/div] u DS [20V/div] u D1 [100V/div] i d [5A/div] [200ns/div] 47

48 Differen Operaing Mode = 25 V, U o = 400 V, P o = 100 W i d i o u DS [20V/div] u D1 [100V/div] Lm D 2 D 1 C 1 U 2 U 1 U o R o i d [2A/div] D 1 urns off during he swich on inerval 48

49 Measured Efficiency Power sage only P o = 300 W η η 0.95 = 35V = 25V P o [W] [V] 49

50 Commens There are differen opologies presened in lieraure whose behavior is very similar o he Inegraed BoosFlyback converer. These opologies have a drawback of a disconinuous inpu curren waveform, ha make he use of such converers for higher power levels a leas problemaic. For high power applicaions, a coninuous inpu curren represens a very nice feaure 50