Lc Filter for Three Phase Inverter Report

LC FILTER FOR THREE PHASE INVERTER  A Project report submitted by:

MUTHURAJ P

–

13MQ37

ELDHO JACOB

–

13MQ81

Dissertation submitted in partial fulllment of the reuirements reuirements for the de!ree of 

 MASTER OF  MASTER OF ENGINEERING  ENGINEERING  Branch: EEE   Branch:  EEE 

Specialization: POWER ELECTRONICS & DRIVES

of P"# COLLEGE OF

TECHNOLOGY 

MARCH - 2014

ELECTRICAL & ELECTRONICS

PSG COLLEGE OF TECHNOLOGY $Autonomous %nstitution&

'(%M)A*(+, - ./1 00/

LC FILTER FOR THREE PHASE INVERTER  LC FILTER FILTER DESIGN:

A low pass LC filter is required at te output ter!inal of Full "rid#e $S% to reduce reduce ar!oni ar!onics cs #enerat #enerated ed &' te pulsat pulsatin# in# !odula !odulatio tion n wa(efo wa(efor!) r!) *ile *ile desi#nin# LC filter+ te cut,off frequenc' is cosen suc tat !ost of te low order ar!onics is eli!inated) To operate as an ideal (olta#e source+ tat !eans no additi additiona onall (olta# (olta#ee distor distortio tion n e(en e(en tou# tou# under under te load load (ariat (ariation ion or a nonl nonlin inea earr load load++ te te outp output ut i!ped i!pedan ance ce of te te in(e in(ert rter er !ust !ust &e -ept -ept zero) zero) Terefore+ te capacitance (alue sould &e !a.i!ized and te inductance (alue sould &e !ini!ized at te selected cut,off frequenc' of te low,pass filter) Eac (alue of L and C co!ponent is deter!ined to !ini!ize te reacti(e power  in tese co!ponents &ecause te reacti(e power of L and C will decide te cost of LC filter and it is selected to !ini!ize te cost+ ten it is co!!on tat te filter co!ponents are deter!ined at te set of a s!all capacitance and a lar#e inductance and consequentl' te output i!pedance of te in(erter is so i#) *it tese desi#n (alues+ te (olta#e wa(efor! of te in(erter output can &e sinusoidal under te linear load or stead' state condition &ecause te output i!pedance i!pedance is zero) "ut in case of a step can#e of te load or a nonlinear load+ te te outp output ut (olta (olta#e #e wa(e wa(efo for! r! will will &e dist distort orted ed cause cause &' te te slow slow s'ste s'ste! ! response as te output response is non,zero) Fi#ure / sows te power circuit of  te sin#le pase P*0,$S% wit an' linear or nonlinear load) Te load current flows differentl' dependin# on te -ind of loads suc as linear  and nonlinear load) Terefore it is difficult to represent te transfer function of  in(erter output (olta#e to load current)Te plant co!posed of L,C low,pass filter satisfies linear propert'+ so it is possi&le to represent te s'ste! wic as two inputs of in(erter output (olta#e and load current) T1

T3

T5

T4

T6

T2

C 1

n V1 100Vdc R a

C 2

1k

R c 1k

F%G /

n

R b 1k

FLO* CHA2T TO 3ES%GN A PASS%$E4LC5 F%LTE2  STA2T

HA20ON%C ANALYS%S OF P*0 $OLTAGE AN3 NONL%NEA2 C622ENT

SELECT%NG C6T,OFF F2E76ENCY

SELECT%NG 0%N%060 CAPAC%TANCE "ASE3 ON COST

SELECT%NG C6T,OFF F2E76ENCY SELECT%NG CONT2OLLE2 2ESPONSE

%S THE CONT2OL 2ESPONSE 2EAL%9A"LE:

SELECT%NG CONT2OLLE2 GA%NS SAT%SF%NG CONT2OL 2ESPONSE

ANALYS%NG O6TP6T $OLTAGE HA20ON%CS 6N3E2  THE L%NEA2 AN3 NON,L%NEA2 LOA3

 *D 2 4

SELECT%NG 3C L%N8 $OLTAGE AN CALC6LATE %N36CTANCE

F%G 1 STOP

FORMULA USED:

4i5To find inductor+ 1

 L=

8

Vdc∗1

∗

 Δi Lmax

 Fs

∗

*ere+ $dc ; 3C (olta#e of te in(erter   Δi Lmax  ; Current ripple

4ripple current can &e cosen as /<= , />= of rated current5 Fs ; Switcin# frequenc'

4ii5To find capacitor+

C =15

 Prated

∗

3

∗2

2

πf ∗V  rated

*ere+  Prated

 ; 2eacti(e power rated

4reacti(e power is cosen as />= of te rated power5 $rated ; AC rated (olta#e

DESIGN OF INDUCTOR:

FILTER DESIGN: INVERTER LC FILTER  SWITCHING FRREQUENCY = 5KHz OUTPUT CURRENT

= 1A RMS

LINE VOLTAGE

= !"V RMS

LINE FREQUENCY

= 5Hz

CAPACITANCE VALUE CALCUALATED = 1#F$ %V INDUCTANCE VALUE CALCULATED

= '5(H

INDUCTANCE DESIGN PROCEDURE

Se(eral factors need to &e considered wile desi#nin# an inductor+ few of wic are listed &elow 1' F)*+#*,-. /0 O*)2ti/, !' C/)* M2t*)i23 S*3*-ti/, "' E,*)4. H2,3i,4 C226i3it. /0 t7* I,#-t/) 8*t*)(i,*9 t7* 9iz* /0  t7* -/)* ' C23-#32t* N#(6*) /0 T#), 5' S*3*-ti/, /0 C/*) ;i)* %' E9ti(2ti/, /0 L/99*9 2, T*(*)2t#)* Ri9*

%n tis application te %nductor as to andle lar#e ener#' due to te 20S current is /
Te desi#n of te ac inductor requires te calculation of te (olt,a!p 4$A5 capa&ilit') %n tis applications te inductance (alue is specified)

R*32ti/,97i /0$ A)*2 P)/#-t A$ t/ t7* I,#-t/) V/3t
Te (olt,a!p capa&ilit' of a core is related to its area product+ Ap+ &' te equation tat !a' &e stated as Follows)

Fro! te a&o(e+ it can &e seen tat factors suc as flu. densit'+ "ac+ te window utilization factor+ 8u 4wic defines te !a.i!u! space occupied &' te copper in te window5+ and te current densit'+ ?+ all a(e an influence on te inductor area product+ Ap)

F#,2(*,t23 C/,9i*)2ti/,9

Te desi#n of a linear ac inductor depends upon fi(e related factors@ / ) 3esired inductance 1) Applied (olta#e+ 4across inductor5 ) Frequenc' B) Operatin# Flu. densit' wic will not saturate te core >) Te!perature 2ise

Te inductance of an iron,core inductor+ wit an air #ap+ !a' &e e.pressed as@

Final deter!ination of te air #ap requires consideration of te effect of frin#in# flu.+ wic is a function of #ap di!ension+ te sape of te pole faces+ and te sape+ size+ and location of te windin#

Frin#in# flu. decreases te total reluctance of te !a#netic pat+ and terefore increases te inductance &' a factor+ F+ to a (alue #reater tan tat calculated fro! Equation

W7*)* G i9 ;i,i,4 3*,4t7 /0 t7* -/)*

 Now tat te frin#in# flu.+ F+ as &een calculated+ it is necessar' to recalculate te nu!&er of turns usin# te frin#in# flu.+ Factor F

wit te new turns+ N4new5+ and sol(e for "ac

Te losses in an ac inductor are !ade up of tree co!ponents@ /) Copper loss+ Pcu 1) %ron loss+ Pfe ) Gap loss+ P#

Te copper loss+ Pcu+ is %12 and is strai#tforward+ if te s-in effect is !ini!al) Te iron loss+ Pfe+ is calculated fro! core !anufacturers data) Gap loss+ P#+ is independent of core !aterial strip tic-ness and per!ea&ilit')

INDUCTOR DESIGN STEPS

/ 3esi#n Spec

$L

1<

A

%nductance

L

"

Line Current

%L

/< A

C

Line Frequenc'

f

>< Hz

3

Current 3ensit' ?

E

Efficienc' #oal

F

<) H

<< ADc!1

ef

< = %ron Powder 

0aterial 0a#netic

G

 per!ia&ilit'

u!

/1<<

H

Flu. 3ensit'

"ac

/)B Tesla

%

*indow 6tilisation

8u

<)B

?

Te!p 2ise Goal Tr

< C

Calculate Apparent 1  power Pt Pt  $A  $L%L

1<< A

 Calculate Area Product AP

AP  $A/
/)JJ// K c!B

B

Select Core %ron Powder Core E%11J core 0aterial

0a#netic Pat Len#t

0PL

B) c! 1JBB #

0ean Len#t Turn

0LT

%ron Area

Ac

/)<1J c!1

*indow Area

*a

1B)B c!1

Area product

Ap

K<)<B c!B

Coef

8#

1JJ) c!>

Surface Area

At

/
0aterial P

P

*indin# Len#t

G

La!ination E

1)K c!

J)>K >)K/>

Calculate Nu!&er of > Turns

N

 %nductance 2equired

L

Calculate required K air#ap

l#

l#  4<)BpiN1Ac/<, BDL5 , 40PLDu!5

1)J8G  windin# wei#

l#

1J)><1>>  turns

<) H

<)BB
B)B
Calculate Frin#in# flu. J F

F

Calculate New nu!&er  of turns

N/

 N/sqrt4l#LD<)BpiAC F/<,J5

/)<<K >/

1<1)K< 1K turns

/< Calculate flu. densit' "ac  $L/
"ac

/)B>//>< K Tesla

Calculate "are wire // area Awl

<)<  c!1

Awl%LD?

Select wire fro! *ire /1 ta&le A* G /B

Calculate *indin# 2esistance

Aw

<)<1 c!1

uO!Dc !

uO!Dc J1)J !

1<

/ 20LTN/uOH!/ <,

2

<)>B>BB>   1 O!s

/B Calculate Copper Loss PL  %L1  2L

PL

>B)>BB>1 > *

wD-

/)>BB>>    O!

Pfe

<)1
P#

>>)1BKBJ BJ *

PL

///)><11B 11 *

Calculate *atts per /> -ilo#ra! *D8  <)<<<>>KfI/)J"I/) J

/ Calculate Core Loss Pfe wD- *tfe

/K Calculate Gap Loss P#  8iEl#f"1

/J Calculate Total Loss su! of losses

Calculate surface area watt / densit'  psi  PLDAt

psi

<)/<BB 1 watts per c!1

Tr  

)K> >

Calculate te 1< Te!perature rise Tr  B><psiI<)J1

Calculate *indow 1/ utilisation <)/>K/B/  watt

8u  N/AwD*a

%N36CTO2 *%N3%NG 3ETA%LS

3

510 2

50

I 1

0

I

Inductor Termination

Winding Arrangement

*%N3%NG 3ETA%LS  N o)

*indin# no)

Ter!inals

No *ire %nsulation of #au#e  &etween turn S*G windin# La'ers s

/

%

/M1

1<<

/B

Nil 4$arnisin# 2eqd5

1

%

Tappin# 

C/)* D*t2i39 : EI !!5

1/<

2e!ar-s

CORE DIMENSIONAL DETAILS

WIRE TALE

S%06LAT%ON C%2C6%T@

S%06LAT%ON 2ES6LTS@ *itout Filter@

*it Filter@

2EFE2ENCES@ [1] 0iss) San#ita 2 Nandur-ar + 0rs) 0ini 2aee( +3esi#n and Si!ulation of tree  pase %n(erter for #rid connected Poto(oltic s'ste!s+  Proceedings of Third Biennial National Conference, NCNTE !"#!, Fe$ !%!&