Tema 4: Conversores con aislamiento galvánico · Tema 4: Conversores con aislamiento galvánico 1....

Tema 4: Conversores con aislamiento galvánico

1. Modelo del transformador

1.1. Transformador ideal

1.2. Inductancia magnetizante

1.3. Inductancias de fugas y pérdidas

2. Conversores con aislamiento galvánico

2.1. Conversor Flyback

2.2. Conversor Forward

2.3. Conversor Push Pull

2.4. Conversor Half Bridge

2.5. Conversor Full Bridge

1

1.1. Modelo del transformador. Transformador ideal

Ley de Ampère:Ley de Ampère:

02211 ininE f d id l 0

Ley de Faraday:

En un transformador ideal 0

Fundamentals of Power Electronics, second edition”. R. W: dtd

nv

nv

2

2

1

1

Erickson, D. Maksimovic. Springer (Kluwer Academic Press), 2001.

dtnn 21

Otras relaciones:lAl

Reluctancia:

Inductancia: )linealrelacióno(suponiend; LindndL

Para cada bobinado:

Inductancia: )linealrelación o(suponiend ; Lindi

ndi

L

n ni

2nL

2

En un transformador ideal, la L asociada a cada bobinado es infinita


3


4

1.2. Modelo del transformador. Inductancia magnetizante

5


6


7

1.3. Modelo del transformador. Inductancias de fugas y pérdidas

8


9


10

Switching DC Power Supply: Multiple Outputs2. Conversores con aislamiento galvánico

• In most applications, several dc voltages are required, possibly electrically isolated from each other

11

Flyback Converter2.1. Conversor Flyback

• Derived from buck‐boost

12


• Switch on and off states (assuming incomplete core demagnetization)

13


• Switching waveforms (assuming incomplete core demagnetization)

14


15


40V

Vv 22 iVNv t

0V

1 inVv 1

2 inVN

v

oVv 2oVNNv

2

11

ton

toff

6.0AV(L1:1)- V(L1:2) V(L2:1)- V(L2:2) V(R1:1)- V(R1:2)

-40V

inM

s

MM V

LDTdttv

Li )(1

1

I(L1)+2* I(L2)5.0A

5.5A

SEL>>

MM LL

012

1 osM

inM

s VTDNL

NVLDT

4.0A

8.0A

ton

t

1iiM 02 i

0i 2 iNi

Time

50.00ms 50.01ms 50.02ms 50.03ms 50.04msI(L1) I(L2)

0A

toff 01 i 21

iN

iM

dttvL

i )(12

22

Time

(verde) 1v (rojo) 2v (azul) oVArriba:

En medio: (azul) Mi

2

MLNNL 2

1

22

2

Abajo: (verde) 1i (rojo) 2i

16

Forward Converter2.2. Conversor Forward (idealizado)

• Derived from Buck; idealized to assume that the transformer is ideal (not possible in practice)( p p )

17

2.2. Conversor Forward (idealizado)

L2L1 R1Vin

D1

Dideal

L3

200u

{LM*N2N1*N2N1}{LM} 1020 C1500u

00

D2Dideal

K K1

COUPLING = 1K_Linear

L1 = L1V1V1 = 0

PARAMETERS:N2N1 = 2f s = 50k

0

M1Rof f{Rof f } L1 = L1

L2 = L2

V1

TD = 0

TF = {1/(1000*f s)}PW = {Duty /f s}PER = {1/f s}

V1 = 0

TR = {1/(1000*f s)}

V2 = 10 Duty = 0.4LM = 1mRof f = 1meg

0 0

Mbreakn{Rof f }

PER = {1/f s}

18

1 inVv 1

22 inV

NNv ton

2.2. Conversor Forward (idealizado)

toff

oinL VVNNv

1

2

oL Vv

ton Lii 2

oL

21

21 i

NNii M

toff 021 ii

inM

s

MM V

LDTdttv

Li )(1

1MM

(azul) Lv (rojo) oVArriba:

En medio: (azul) 1i (rojo) 2i (verde) Li

Abajo: (azul) Mi

19

Forward Converter: in 2.2. Conversor Forward (en la práctica)

Practice

• Switching waveforms (assuming complete core demagnetization)

20

2.2. Conversor Forward (en la práctica)

L4

L2

D1

DidealL1Vin R1

L3 {LM*N3N1*N3N1}L4

10uH

{LM*N2N1*N2N1}D2Dideal

{LM}201

C1500u

0 D3

K K1


PARAMETERS:N2N1 = 0.5f s = 100k

M1

0D3Dideal

0R2

L1 = L1L2 = L2L3 = L3

f s 100kDuty = 0.5LM = 3.2mRof f = 1megN3N1 = 0.2

V1

TD = 0

TF = {1/(1000*f s)}PW = {Duty /f s}

V1 = 0

TR = {1/(1000*f s)}

V2 = 10 Mbreakn

00

{Rof f }

PW {Duty /f s}PER = {1/f s} 00

21

2.2. Conversor Forward (en la práctica)

ODCL Ii ,

ton Lii 2 21

21 i

NNii M

OC,

03 i

inM

s

MMMMAX V

LDTdttv

Lii )(1

1

3

MM LL

toff 021 ii 31

3 iNNiM

MMAXMAX iNNi

3

13

1

DNN

Tt

S

M

1

3

(azul) LiArriba:

Abajo: (azul) Mi

(verde) 1i (rojo) 2i

(rojo) 3i

22

PWM to Regulate Output2.3. Conversor Push-Pull

• Basic principle is the same as discussed in Chapter 8

23

Push‐Pull Inverter2.3. Conversor Push-Pull

k i d b bl• Leakage inductances become a problem24

3.3. Conversor Push-Pull

L5D1 DidealR2

C1

L1{LM}

10uH

R1

1

L2{LM*N2N1*N2N1}

D1

1e10

I

500u 1

L3 L4{ * * }

VinI

I

M1

{LM} {LM*N2N1*N2N1}

D2

Dideal VinM2

R3

1e10I

I

MbreaknPARAMETERS:N2N1 = 0.5f s = 100kDuty = 0.3

K K1


L1 = L1

Vin120

Mbreakn

Vc1 Vc2I

LM = 3.2mRof f = 1megN3N1 = 0.2

L2 = L2L3 = L3L4 = L4

00 0

V1

TD = 0

V1 = 0

TR = {1/(1000*f s)}

V2 = 10V2

TD = {0.5/f s}

V1 = 0

TR = {1/(1000*f s)}

V2 = 10

Vc1 Vc2

TF = {1/(1000*f s)}PW = {Duty /f s}PER = {1/f s} 0

TF = {1/(1000*f s)}PW = {Duty /f s}PER = {1/f s} 0

25

2.3. Conversor Push-Pull

26

Half‐Bridge Converter2.4. Conversor Half Bridge

i d f k• Derived from Buck27

Full‐Bridge Converter2.5. Conversor Full Bridge

• Used at higher power levels (> 0.5 kW )

28

Core Utilization in Various Converter Topologies

• At high switching frequencies, core losses limit excursion of flux density

29

Implementing Electrical Isolation in the Feedback

Loop

• Two ways are shown• Two ways are shown

30

Tema 4: Conversores con aislamiento galvánico · Tema 4: Conversores con aislamiento galvánico 1....

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