current source inverters -.ppt

7/24/2019 current source inverters -.ppt

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Chapter 5 DC to AC Converters

Outline

5.1 Commutation 5.2 Voltage source inverters 5.3 Current source inverters

5.4 Multiple- inverter connections and multi- levelinverters


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5.1 Commutation types

Basic operation principle of inverters

A classification of inverters !"uare- #ave inverters $are discussed in t%is c%apter& '(M inverters $ #ill )e discussed in C%apter *&+%e concept of commutation

load

t

! 1

! 2

! 3

! 4

i o

u o U d

u o

i o

t 1 t 2


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4 types of commutation

1&,evice commutationull/- controlled devices 0+O 0B+ MO! +

2& ine commutation'%ase- controlled rectifier '%ase- controlled AC controller+%/ristor c/cloconverter

3& oad commutation

4& orced commutation


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(1) Load commutation

t

t

t

t

L

C

O

O

O

O

i

i

t 1

)& a&

d

L d

V+ 1

V+ 2

V+ 3

V+ 4 u o

i o

i d

u o u o i o

i o

u V+

i V+ 1 i V+ 4

i V+ 2 i V+ 3

u V+ 1

u V+ 4


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Another c$assification of commutations

Se$f%commutation

&'terna$

commutation

4 types of Commutations

Device commutation

Forced commutation

Line commutation

Load commutation

For fully-controlleddevices

For thyristors


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2 c$asses of inverters

Voltage !ource nverter

$V! &

Current !ource nverter

$C! &

C

d

d

V+ 1

V+ 2

V+ 3

V+ 4 u o

i o

i d V, 1

V, 2

V, 3

V, 4

u o

C i o

V1

V2

V3

V4 d

6

-


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5.2 o$ta e source inverter ( S )Features

,C side is constant voltage lo# impedance $voltage source or )ul7 cap&AC side voltage is s"uare #ave or "uasi- s"uare #ave.

AC side current is determined )/ t%e load.Anti- parallel diodes are necessar/ to provide energ/ feed)ac7 pat%.$free#%eeling diodes feed)ac7 diodes&

V, 1

V, 2

V, 3

V, 4

u o

L C

i o V1

V2

V3

V4

d

6

-


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Sin $e%phase ha$f #rid e S

+%e current conducting pat% is determined )/ t%e polarit/ of load voltage and loadcurrent. $+%is is true for anal/sis of man/ po#er electronics circuits.&

+%e magnitude of output s"uare- #ave voltage is d82.

V, 1

V, 2 u o

L R i o

V1

V2

d 2

d d

2


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Sin $e%phase fu$$ #rid e S

Operation principle

V, 1

V, 2

V, 3

V, 4 u o

L R C i o V1

V2

V3

V4

d

6

-


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Output voltage control )/ p%ase-s%ift

V, 1

V, 2

V, 3

V, 4

u o

L C i o V1

V2

V3

V4

d

6

-

t

t

t

t

t

u o u

o i o i o

o

o

o

o

o

u 01

u 02

u 03

u 04

1 t 2 t 3


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nverter *ith center% tapped transformer+push%pu$$ inverter

load

6

-

i o u o

U d V1 V2

V, 1 V, 2


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!hree%phase S

(

V1

V4

V

V, 4

d

V* V2

V3 V5

>

V, * V, 2

V, 1 V, 3 V, 5 2

>

6

-

d 2

1?= conduction

,ead time $)lan7ing time& to

avoid @s%oot t%roug%

t

t

t

t

t

t

t

t

o

o

o

o

o

o

o

o

a

b

c

d

e

h

uUN

uVN

uWN

uUV

u NN

uUN

iU

id

d 2

d

d

2 d

*

3 3d


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Basic e"uations to o)tain voltage

==

=

>B(>B(

(>BV>BV(

V>B>BV

uuu

uuu

uuu.or line voltage .or p%ase voltage of t%e load

==

=

B >>(>B(>

>>BV>BV>

>>B>B>

uuu

uuu

uuu

&$31

&$31

(>V>>(>BV>B>B >>B uuuuuuu ++++=

&$31

(>V>> >> uuuu ++=

uUN uVN uWN + + =0


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9uantitative anal/sis

ourier series e:tension of output line- to- line voltage

Magnitude of output voltage $line- to- line& fundamental component

ffective value of output voltage $line- to- line& fundamental component

1* = k n+=

++=

n

k t nn

t U

t t t t t U

u

sin&1$1

sin32

13sin

13

111sin

11

1;sin

;

15sin

5

1sin

32

d

dV

5-?

5-1= ddV1m 1.132 U U U ==

5-11 ddV1m

V1 ;?.=*

2U U

U U ===


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5., Current source inverter (CS )

Features

,C side is constant current %ig%impedance $current source or

large inductor&AC side current is "uasis-"uare#ave. AC side voltage isdetermined )/ t%e load.

>o anti-parallel diodes are needed.sometimes series diodes areneeded to )loc7 reverse voltagefor ot%er po#er semiconductordevices.

V+ 1

V+ 2

V+ 3

V+ 4 u o

i o d

d

i d

C


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Sin $e%phase #rid e CS

'arallel esonant nverter

V+ 1

V+ 2

V+ 3

V+ 4

u o L R i

L d

I d C

L 1

L 2 L 3 L !

!#itc%ing fre"uenc/ is a little %ig%er

%an t%e resonant fre"uenc/ so t%at t%e

oad )ecomes capacitive and load

current is leading voltage to realiDe

oad commutation.

O

t O O

O

O

O

O

O

u 0 1 4

u 0 2 3 i +

i o

I d

t 1 t 2t 3

t 4t 5

t *t ;t

u o

t

u AB

t t

I d

i V+ 1 4 i V+ 2 3

u V+ 2 3

u V+1 4

t

t

t

t

t

t

t


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!hree% phase se$f%commutated CS

V+ 2

U U d

id

V W

V+ 1 V+ 3

V+ 4

V+ 5

V+ *

iU

iV

iW

uUV

t

t

t

t o

o

o

o


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!hree% phase force% commutated CS

V, 1

L

C 1

,

V+1

U d

6

-

d

C " C 3

C !

C 2

C #

V+3 V+5

V+4 V+* V+2

V, 3 V, 5

V, 4 V, * V, 2

UVW

V+1 V+3

d

6 - C 13

V, 1 V, 3

V, 2

V+2

U V

W


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!hree% phase $oad%commutated CS

O

O

O

O

O

O t

u u u V u (

i V

i (

i

u dM

V+2 u V+1

t

t

t

t

t

V+* V+5

V+1 V+3

V+4

$u%&e ' i&t(ibuto (

U d U d)

V+1

V+3

V+5

V+4

V+*

V+2

U V W

, 3-


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5.4 -u$tip$e% inverter connections and mu$ti%$eve$ inverters!eries connection of 2 single- p%ase V! s

12=

*=

1?= t O

t O

t O

3rd Earmonicsu 1

u 2

u o

3rd Earmonics

U d

1

2

u 1

u 2


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Series connection of 2 ,% phase S s

. /

! 1 1

! 2

B 1

21

C 1

B 21

22

C 21

B 22 C 22

u .0

u .2

u .1 U d

)

))

t O

t O

t O

t O

t O

31

31 &

$16 &

U 1

U A21

.U B22

U 2

U >

$U A1 & U d

U d

32 U d

31 U d

32 U d

$16 U d

31 U d


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-u$ti%$eve$ nverters 3- level inverter

6

-

6

V

6 (

U d

V, 1 V 11

OB

V 12

V, 11

V, 12

V, 4 V 41

V 42

V, 41

V, 42

i L s R s

current source inverters -.ppt

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