Commutation Circuit
CHAPTER: 1 INTRODUCTION
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Commutation Circuit
1.1 INTRODUCTION OF PROJECT:Our Project “COMMUTATION CIRCUIT OF CLASS – A, B C ! i" con"i"t o# turn o## c$aracteri"tic o# t$e SCR% Our &roject o&erate" tota''( )a"e* on t$e SCR% T$e main &art o# our &roject i" SCR +P-M .$ic$ i" u"e* in our &roject/% Once SCR "tar" con*ucting, gate 'o""e" contro'% In "&ite o# remo0ing gate "igna', SCR remain to con*ucting "tage% T$e commutation i" t$e &roce"" to turn o## an SCR% To turn1o## an SCR i" ac$ie0e* )( +i/ +i/
Ano* Ano*ee curr curren entt #a' #a''" '" )e'o )e'o. . t$e t$e $o'* $o'*in ing g cur curre rent nt or
+ii/ +ii/
Re0er Re0er"e "e 0o' 0o'ta tage ge a&& a&&'i 'ie* e* to to t$e t$e SCR SCR #or #or "u## "u##ic icie ient nt tim time% e%
T$e SCR ma( )e turn1o## eit$er )( natura''( or )( u"ing e2terna' circuit% In AC circuit", .$en t$e current t$e SCR goe" t$roug$ a natura' 3ero, a re0er"e 0o't 0o'tag agee aut automat omatic ica' a''( '( a&&e a&&ear ar"" acro acro"" "" t$e SCR% SCR% T$i" $i" i" ca'' ca''e* e* nat natura' ura' commutation% In 4C circuit", t$e ano*e current $a" to )e #orce* to 3ero )( an e2terna' circuit to turn1o## t$e SCR% T$i" i" ca''e* a" #orce* commutation%
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Commutation Circuit
1.1 INTRODUCTION OF PROJECT:Our Project “COMMUTATION CIRCUIT OF CLASS – A, B C ! i" con"i"t o# turn o## c$aracteri"tic o# t$e SCR% Our &roject o&erate" tota''( )a"e* on t$e SCR% T$e main &art o# our &roject i" SCR +P-M .$ic$ i" u"e* in our &roject/% Once SCR "tar" con*ucting, gate 'o""e" contro'% In "&ite o# remo0ing gate "igna', SCR remain to con*ucting "tage% T$e commutation i" t$e &roce"" to turn o## an SCR% To turn1o## an SCR i" ac$ie0e* )( +i/ +i/
Ano* Ano*ee curr curren entt #a' #a''" '" )e'o )e'o. . t$e t$e $o'* $o'*in ing g cur curre rent nt or
+ii/ +ii/
Re0er Re0er"e "e 0o' 0o'ta tage ge a&& a&&'i 'ie* e* to to t$e t$e SCR SCR #or #or "u## "u##ic icie ient nt tim time% e%
T$e SCR ma( )e turn1o## eit$er )( natura''( or )( u"ing e2terna' circuit% In AC circuit", .$en t$e current t$e SCR goe" t$roug$ a natura' 3ero, a re0er"e 0o't 0o'tag agee aut automat omatic ica' a''( '( a&&e a&&ear ar"" acro acro"" "" t$e SCR% SCR% T$i" $i" i" ca'' ca''e* e* nat natura' ura' commutation% In 4C circuit", t$e ano*e current $a" to )e #orce* to 3ero )( an e2terna' circuit to turn1o## t$e SCR% T$i" i" ca''e* a" #orce* commutation%
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Commutation Circuit
CHAPTER: 2 A LITERATURE SURVEY
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Commutation Circuit
Literature Reie!:
In t$i" &roject .e are "tu*( t$e c$aracteri"tic o# t$e SCR +t$(ri"tor/% In t$i" &roject .e are u"ing SCR +t$(ri"tor/ P-M% it i" t$e genera' &ur&o"e SCR% T$i" SCR i" u"e common'( #or t$e genera' &ur&o"e% So .e are u"e t$i" SCR in our &roject% For t$i" &roject .e co''ect t$e re#erence" #rom man( &'ea"e"% A" re#erence .e are u"e 5i6i&e*ia #or co''ect t$e in#ormation a)out t$e SCR an* it" c$aracteri"tic",
etc%
5e
are
ta6e
more
re#erence"
'i6e
...%e'ectronic"$u)%org7"cr1turn1o##1met$o*"7 #rom t$i" 'in6 +.e)"ite/ .e are "tu*( a)out t$e turn1o## met$o* o# t$e SCR +t$(ri"tor/% t$i" met$o*" are mention in t$i" re&ort% From t$e ...%e'ectrica'-u%com7 .e are "tu*ie* a)out t$e *etai'e* o# t(&e o# t$e commutation met$o* .$ic$ .e are u"e to turn1o## t$e SCR in our &roject +C'a""1A, C'a""1B C'a""1C/% 5e are not ta6e re#erence" #rom on'( internet )ut .e are u"e t$e re#erence )oo6 a'"o% For t$i" .e are ta6e more in#ormation #rom t$e )oo6 o# t$e Po.er 8'ectronic" +Secon* e*ition/ +M 4 Sing$ 9 B 9$anc$an*ani/% 5e a'"o con"i*er B L T$eraja P S Bim)$ra )oo6 a" t$e re#erence, #rom t$i" )oo6 .e #in* t$e *e"ign con"i*eration #or our &roject% From t$i" *e"ign con"i*eration .e cou'* un*er"tan* t$e *ee&ne"" o# our &roject *e"ign% From t$i" .e ca'cu'ate t$e rating" o# t$e com&onent" t$at .e are u"e in our &roject% 4ue to t$e *e"ign con"i*eration .e &re&are t$e circuit *iagram o# our &roject #rom .$ic$ .e &re&are our actua' running circuit% T$e actua' circuit i" mention in t$e re&ort )e'o.% For t$e #orming t$e actua' circuit .e are u"e t$e "tee' )o2 #or t$e enc'o"ure an* t$e )oar* u"e in t$e ".itc$)oar* i" u"e #or t$e to& at .$ic$ t$e com&onent" are mount% For t$e "$o.ing t$e circuit *iagram .e "tic6 t$e &rinte* "tic6er &a&er *ue to at t$e time o# &ractica' .e can ea"i'( un*er"tan* an* e2&'ain to ot$er t$e .or6ing o# our &roject% P a g e | "
Commutation Circuit
In t$i" our &roject .e are actua''( tr( to contro' t$e o&eration o# t$e SCR +t$(ri"tor/% B( t$e $e'&ing o# t$e e2terna' com&onent or u"ing our circuit .e are actua''( contro' t$e time o# turn on an* o##% B( t$e contro' t$e time o# on1o## it can )e u"e#u' at man( &'ace% In our &roject it can )e o)taine*% In our &roject one L84 i" &'ace*, .$ic$ in*icate t$e o&eration o# t$e SCR +t$(ri"tor/% So t$e contro' o# SCR +t$(ri"tor/ on1o## i" "$o.n )( t$e in*ication o# t$e L84
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Commutation Circuit
CHAPTER: 3 THE PROJECT ANALYSIS
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Commutation Circuit
3.1 %&at i' C())utati(*++++...
An SCR can )e turne* ON )( a&&'(ing a&&ro&riate &o"iti0e gate 0o'tage )et.een t$e gate an* cat$o*e termina'", )ut it cannot )e turne* OFF t$roug$ t$e gate termina'% T$e SCR can )e )roug$t )ac6 to t$e #or.ar* )'oc6ing "tate #rom t$e #or.ar* con*uction "tate )( re*ucing t$e ano*e or #or.ar* current )e'o. t$e $o'*ing current 'e0e'% T&e tur* OFF ,r(e'' ( a* SCR i' a//e0 ())utati(*% T$e term commutation mean" t$e tran"#er o# current" #rom one
&at$ to anot$er% So t$e commutation circuit *oe" t$i" jo) )( re*ucing t$e #or.ar* current to 3ero "o a" to turn OFF t$e SCR or T$(ri"tor% To turn OFF t$e con*ucting SCR t$e )e'o. con*ition" mu"t )e "ati"#ie*%
T$e ano*e or #or.ar* current o# SCR mu"t )e re*uce* to 3ero or )e'o.
t$e 'e0e' o# $o'*ing current an* t$en% A "u##icient re0er"e 0o'tage mu"t )e a&&'ie* acro"" t$e SCR to regain it" #or.ar* )'oc6ing "tate% 5$en t$e SCR i" turne* OFF )( re*ucing #or.ar* current to 3ero% T$ere
e2i"t e2ce"" c$arge carrier" in *i##erent 'a(er"% To regain t$e #or.ar* )'oc6ing "tate o# an SCR, t$e"e e2ce"" carrier" mu"t )e recom)ine*% T$ere#ore, t$i" recom)ination &roce"" i" acce'erate* )( a&&'(ing a re0er"e 0o'tage acro"" t$e SCR %
3.2 Detai/' ( ())utati(* )et&(0' T$e re0er"e 0o'tage .$ic$ cau"e" to commutate t$e SCR i" ca''e* commutation 0o'tage% 4e&en*ing on t$e commutation 0o'tage 'ocate*, t$e commutation met$o*" are c'a""i#ie* into t.o major t(&e"% T$o"e are #orce* commutation an* natura' commutation% Let u" *i"cu"" in )rie# a)out t$e"e met$o*"% P a g e |
Commutation Circuit
3.2.1 Natura/ C())utati(*:
In natura' commutation, t$e "ource o# commutation 0o'tage i" t$e "u&&'( "ource it"e'#% I# t$e SCR i" connecte* to an AC "u&&'(, at e0er( en* o# t$e &o"iti0e $a'# c(c'e t$e ano*e current goe" t$roug$ t$e natura' current 3ero an* a'"o imme*iate'( a re0er"e 0o'tage i" a&&'ie* acro"" t$e SCR% T$e"e are t$e con*ition" to turn OFF t$e SCR% T$ere#ore, t$e SCR i" turne* OFF commutate* natura''( or automatica''( .it$out an( e2terna' circuit an* $ence ca''e* a" natura' commutation% T$i" met$o* o# commutation i" a'"o ca''e* a" "ource commutation, or 'ine commutation, or c'a"" F commutation% T$i" commutation i" &o""i)'e .it$ 'ine commutate* in0erter", contro''e* recti#ier", c(c'e con0erter" an* AC 0o'tage regu'ator" )ecau"e t$e "u&&'( i" t$e AC "ource in a'' t$e"e con0erter"%
3.2.2 F(re0 C())utati(*:
P a g e |
Commutation Circuit
In ca"e o# 4C circuit", t$ere i" no natura' current 3ero to turn OFF t$e SCR% In "uc$ circuit", #or.ar* current mu"t )e #orce* to 3ero .it$ an e2terna' circuit to commutate t$e SCR $ence name* a" #orce* commutation% T$i" commutating circuit con"i"t" o# com&onent" 'i6e in*uctor" an* ca&acitor" ca''e* a" commutating com&onent"% T$e"e commutating com&onent" cau"e to a&&'( a re0er"e 0o'tage acro"" t$e SCR t$at imme*iate'( )ring t$e current in t$e SCR to 3ero% Ba"e* on t$e manner in .$ic$ t$e 3ero current ac$ie0e* an* arrangement o# t$e commutating com&onent", #orce* commutation i" c'a""i#ie* into *i##erent t(&e" "uc$ a" c'a"" A, B, C, 4, an* 8% T$i" commutation i" main'( u"e* in c$o&&er an* in0erter circuit"%
T$ere are #o''o.ing #orce* commutation met$o*" to turn1o## t$e SCR:1 i%
C'a"" A 1 "e'# commutation )( re"onating t$e 'oa*%
ii%
C'a"" B 1 "e'# commutation )( LC circuit%
iii%
C'a"" C 1 com&'ementar( commutation%
i0%
C'a"" 4 1 au2i'iar( commutation% Au2i'iar( SCR ".itc$ing C or LC%
0% 0i%
C'a"" 8 1 e2terna' &u'"e commutation% C'a"" F 1 AC 'ine commutation%
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Commutation Circuit
CHAPTER: " THE OUTLINE OF THE PROJECT
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Commutation Circuit
".1 5LOC6 DIA7RA8
".2 5LOC6 DIA7RA8 DESCRIPTION
T$e )'oc6 *iagram o# t$e commutation circuit i" a" "$o.n in t$e #igure% In t$i" #ir"t )'oc6 i" "$o.n #or t$e &o.er "u&&'(% T$i" "u&&'( ma( )e AC or 4C% T$i" "u&&'( i" gi0en to t$e SCR% T$i" i" "$o.n in t$e "econ* )'oc6% 5it$ t$e )'oc6 o# t$e SCR t$e )'oc6 o# commutation circuit i" "$o.n% T$i" commutation circuit i" connecte* .it$ t$e SCR, *ue to t$i" t$e turn1o## o# t$e SCR can )e *one% At 'a"t )'oc6 i" "$o.n o# t$e 'oa*% T$i" 'oa* i" connecte* .it$ t$e SCR%
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Commutation Circuit
".3 CIRCUIT DIA7RA8
".3.1 C/a'' A C())utati(* 9'e/-())utati(*:
T$i" i" a'"o 6no.n a" re"onant commutation% T$i" t(&e o# commutation circuit u"ing L1C com&onent" in "erie" .it$ t$e 'oa* are "$o.n in Fig % In Fig, 'oa* R L i" in "erie" .it$ t$e L1C circuit% In t$i" &roce"" o# commutation t$e #or.ar* current &a""ing t$roug$ t$e *e0ice i" re*uce* to 'e"" t$an t$e 'e0e' o# $o'*ing current o# t$e *e0ice% ;ence, t$i" met$o* i" a'"o 6no.n a" t$e current commutation met$o*% T$i" .a0e#orm o# t$e t$(ri"tor 0o'tage, current an* ca&acitor 0o'tage are "$o.n in Fig%
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Commutation Circuit
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Commutation Circuit
T$e 'oa* re"i"tance RL an* t$e commutating com&onent" are "o "e'ecte* t$at t$eir com)ination #orm" an un*er*am&e* re"onant circuit% 5$en "uc$ a circuit i" e2cite* )( a 4%C% "ource, a current o# t$e nature "$o.n in #ig +/ .i'' )e o)taine* acro"" t$e *e0ice% T$i" current, a" e0i*ent #rom it" "$a&e, $a" 3ero 0a'ue at t$e &oint 9 .$ere t$e *e0ice automatica''( turne* OFF% Be(on* &oint 9, t$e current i" re0er"e* in nature .$ic$ a""ure" *e#inite commutation o# t$e *e0ice% T$e t$(ri"tor .$en ON carrie" on'( t$e c$arging current o# ca&acitor C .$ic$ .i'' "oon *eca( to a 0a'ue'e"" t$an t$e $o'*ing current o# t$e *e0ice, .$en ca&acitor C i" c$arge* u& to t$e "u&&'( 0o'tage 8*c% T$i" "imu'taneou"'( ".itc$e" o## t$e t$(ri"tor% T$e time #or ".itc$ing o## t$e *e0ice i" *etermine* )( t$e re"onant #re>> ;3, )ecau"e o# t$e nee* #or an L?C re"onant circuit .$ic$ carrie" t$e #u'' 'oa* current% T$i" commutation circuit i" u"e* in "erie" in0erter%
De'i;* C(*'i0erati(*':
9a Loa* in &ara''e' .it$ ca&acitor C Let u" con"i*er t$e re"onant circuit o# Fig%+/% Let 8 *c )e t$e a&&'ie* 4%C% 0o'tage, @ )e t$e 'oa* 0o'tage, an* I )e t$e 'oa* current% T$e circuit e
8*c
I
C
di
+ V
dt
dV dt
+
an*
V R
B( u"ing La&'ace tran"#orm, .e can .rite E dc ( s ) −V ( s ) =S . L I ( s )
+=%=/
P a g e | 1"
Commutation Circuit
V ( s ) I+"/ R +¿ S%C%@+"/
An*
+=%/
From e
+=%/
Edc
But
8*c
S
+=%-/ Su)"titute e
I+"/
I ( s ) +S R
I+"/ SL 1+
I+"/
SL R
+S
¿
Edc
R
2
¿=
Edc 1 + RCS
I+"/
S
[
Edc
I+"/
R
RLCS
Edc S
[ 1+
S
2
+
s
RCS R
]
+ LS + RCLS 2 ]
1 + RCS
[
R . S
EdcSC
Edc 1 [ + SC ] S R
CLD
R + LS + RC L
I+"/ E
CLI+"/
+
1 RC
S+
1
]
LC
+=%/ Ta6ing in0er"e La&'ace tran"#orm o# e
W n − 1/ RC 1+ sin (ωt + ϕ) e √ 1− ℇ2 ε
1
I+t/
Edc R
.$ere
ε=
1 2 R
√
¿
D
L C
*am&ing ratio
P a g e | 1#
Commutation Circuit
1
5n
√ LC
ω =ω
or,
ω=
√
n 1− ε
1
√ LC
√
1−
√
L 1 1 = − 2 2 2 LC 4 R C 4 R C
−1 2 RCω
= tan
∅
2
−ε
−1
− tan
√ 1 −ε 2 = tan−1 2 RCω −ε
i ( t )=0 at t =0
=−sin−1
∅
i ( t )=
Edc R
1 A
−t / 2 RC
⌊ 1 + A e
(
sin
ωt −sin
−1 1
A
)
⌋
+=%G/
No., 'oa* 0o'tage #rom e
V ( s )=
(
2
LC S
+
1 RC
S+
1 LC
)
+=%/ Ta6ing in0er"e La&'ace tran"#orm o# e
W n
√ 1− ε
−t / 2 RC
2
e
sin ωt + Edc
+=%J/
In t$i" ca"e, t$e triggering #re
W n
, "o
t$at t$(e con*uction c(c'e i" com&'ete*%
9<
Loa* in "erie" .it$ ca&acitor C Let u" con"i*er t$e "erie" re"onant circuit
o# Fig % Let t$e t$(ri"tor )e turne* ON at t> .it$ t$e initia' ca&acitor 0o'tage 3ero% T$e circuit e
di
1
dt
C
+
∫ i dt
+=%K/ P a g e | 1$
Commutation Circuit
On *i##erentiating an* *i0i*ing )( L, .e get 2
1 d d t R di i E dc + + = 2 L dt LC L dt dt
+=%=>/
T$e corre"&on*ing $omogeneou" e
d i R di 1 + + i =0 2 dt L dt LC
+=%==/
T$e "o'ution o# t$i" .e''16no.n "econ* or*er e
−εt
[ A
ω0 =
]
cos ωt + A 2 sin ωt
ε=
5$ere
An*
1
+=%=/
R
2l
+=%=/
1
√ LC
+=%=-/
ω =ω 0 √ 1− ε = 2
√
1
−
LC
R
2
4 L
2
+=%=/
0 +¿
¿ 5$en 0 −¿ ¿ i¿ E dc
A=>, A −
i ( t )=e
T$i" gi0e"
L
( ) E R
2 L
t
[
dc
ωL
]
sin ωt
+=%=G/
T$i" e
t =
Or
π
√
1
−
LC
R
2
4 L
2
+=%=/ P a g e | 1
Commutation Circuit
di
No.,
dt
πR
=−e
2 ωL
( ) E dc
+=%=J/
I
T$ere#ore t$e ca&acitor 0o'tage at en* o# con*uction, V L = L
5$ere
[
di dt
−πR
V C = E dc 1 + e
V C = E dc – V L
2 ωL
]
+=%=K/
No., i# V 0 i" t$e initia'1"tate 0o'tage o# t$e ca&acitor t$en e
i ( t )=e
An* For
V c = E dc ω > 0,
∴
Or
( ) R
2 L
[
E dc −V 0 ωL
( ) E +e −
]
sin ωt
+=%>/
πR
2 ωt
(
dc
−V 0 )
+=%=/
.e no. ca'cu'ate t$e con*ition #or un*er*am&e*% 1
−
LC
R<
t
√
4 L
C
R
2
4 L
2
>0 i. e .,
1
>
LC
R
2
4 L
2
+=%/
".3.2 C/a'' 5 C())utati(* 9'e/-())utati(*:
In t$i" met$o*, t$e LC re"onating circuit i" acro"" t$e SCR an* not in "erie" .it$ t$e 'oa*% T$e commutating circuit i" "$o.n in Fig% an* t$e a""ociate* .a0e#orm" are "$o.n in Fig%
P a g e | 1
Commutation Circuit
Initia''(, a" "oon a" t$e "u&&'( 0o'tage 8 4C i" a&&'ie*, t$e ca&acitor C "tart" getting c$arge* .it$ it" u&&er &'ate &o"iti0e an* t$e 'o.er &'ate negati0e, an* it c$arge" u& to t$e 0o'tage 8 4C% 5$en t$(ri"tor T i" triggere*, t$e circuit current #'o." in t.o *irection": +=/ T$e 'oa* current IL #'o." t$roug$ t$e &at$ 8 4C T RL 84C1, an* +/ Commutating current Ic% T$e moment t$(ri"tor T i" turne* ON, ca&acitor C "tart" *i"c$arging t$roug$ t$e &at$ C ?L ? T? C1% 5$en t$e ca&acitor C )ecome" com&'ete'( *i"c$arge*, it "tart" getting c$arge* .it$ re0er"e &o'arit(% 4ue to t$e re0er"e 0o'tage, a commutating current I C "tart" #'o.ing .$ic$ o&&o"e" t$e 'oa* current IL% 5$en t$e commutating current I C i" greater t$an t$e 'oa* current I L, t$(ri"tor T )ecome" turne* OFF% 5$en t$e t$(ri"tor T i" turne* OFF, ca&acitor C again "tart" getting c$arge* to it" origina' &o'arit( t$roug$ L an* t$e 'oa*% T$u", .$en it i" #u''( c$arge*, t$e t$(ri"tor .i'' )e ON again%
P a g e | 1
Commutation Circuit
;ence, #rom t$e a)o0e *i"cu""ion it )ecome" c'ear t$at t$e t$(ri"tor a#ter getting ON #or "ometime automatica''( get" OFF an* a#ter remaining in OFF "tate #or "ometime, it again get" turne* ON% T$i" &roce"" o# ".itc$ing ON an* OFF i" a continuou" &roce""% T$e *e"ire* #re
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Commutation Circuit
De'i;* (*'i0erati(*:
T$e circuit e
di 1 + ∫ i dt =0 dt C 2
L
∴
d t 2
dt
+%=/
1
+ i (t )= 0 C
Ta6ing La&'ace tran"#orm o# t$e a)o0e e
∴
√
2
S L+
1 C
) ( )= I s
0
C L
ω0 =
5$ere
(
sin ω0 t
+%/
√
+%/
1 LC
T$ere#ore, t$e &ea6 communication current i" I C (
√
= E dc
peak )
C L
+%-/
For t$i" c'a"" B commutation met$o*, t$e &ea6 *i"c$arge current o# t$e ca&acitor i" a""ume* to )e t.ice t$e 'oa* current I L, an* t$e time #or .$ic$ t$e SCR i" re0er"e )ia"e* i" a&&ro2imate'( e
= 2 I L = Edc
peak )
√
C L
π t off = √ LC
An*
2
+%/
+%G/
".3.3 C/a'' C C())utati(* 9(),/e)e*tar= ())utati(*:
% P a g e | 21
Commutation Circuit
T$e c'a"" C commutation circuit i" "$o.n in Fig% In t$i" met$o*, t$e main t$(ri"tor +SCR T=/ t$at i" to )e commutate* i" connecte* in "erie" .it$ t$e 'oa*% An a**itiona' t$(ri"tor +SCR T / ca''e* t$e com&'ementar( t$(ri"tor i" connecte* in &ara''e' .it$ t$e main t$(ri"tor%
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Commutation Circuit
Ciruit O,erati(*
8(0e 4: >I*itia/-'tate ( iruit?
Initia''(, )ot$ t$e t$(ri"tor" are OFF% T$ere#ore, t$e "tate" o# t$e *e0ice" are T= OFF,T OFF,
∴ E C
1
8(0e /: 5$en a triggering &u'"e i" a&&'ie* to t$e gate o# T =, t$e t$(ri"tor T= i"
triggere*% T$ere#ore, t.o circuit current, name'(, 'oa* current IL an* c$arging current IC "tart #'o.ing% T$eir &at$" are: Loa* current ILH 8*c R = T= 8*c C$arging current ICH 8*c R C C1 T= 8*c P a g e | 23
Commutation Circuit
Ca&acitor C .i'' get c$arge* )( t$e "u&&'( 0o'tage 8 *c .it$ t$e &o'arit( "$o.n in Fig% T$e "tate" o# circuit com&onent" )ecome" T= ON,
T OFF,
8C= 84C
8(0e 2: 5$en a triggering &u'"e i" a&&'ie* to t$e gate o# T , T .i'' )e turne*
on% A" "oon a" T i" ON, t$e negati0e &o'arit( o# t$e ca&acitor C i" a&&'ie* to t$e ano*e o# T= an* "imu'taneou"'(, t$e &o"iti0e &o'arit( o# ca&acitor C i" a&&'ie* to t$e cat$o*e% T$i" cau"e" t$e re0er"e 0o'tage acro"" t$e main t$(ri"tor T= an* imme*iate'( turn" it o##% C$arging o# ca&acitor C no. ta6e" &'ace t$roug$ t$e 'oa* an* it" &o'arit( )ecome" re0er"e% T$ere#ore, c$arging &at$ o# ca&acitor C )ecome" 84C R C C1 T+a16/ 84C1 ;ence, at t$e en* o# Mo*e , t$e "tate" o# t$e *e0ice" are T= OFF,
T ON,
8C= 184C
8(0e 3: No., .$en t$(ri"tor T= i" triggere*, t$e *i"c$arging current o#
ca&acitor turn" t$e com&'ementar( t$(ri"tor T OFF% T$e "tate o# t$e circuit at t$e en* o# t$i" Mo*e )ecome" T= ON,
T OFF,
8C= 84C
T$ere#ore, t$i" Mo*e o&eration i" e
".3." 7ATE TRI77ERIN7:
For triggering o# t$e gate o# t$e SCR +Si'icon Contro''e* Recti#ier/ gate &u'"e i" gi0en )( t$e &re""ing t$e &u"$ )utton ".itc$% B( &re""ing t$e ".itc$ t$e SCR )ecome in ON "tate % For t$i" PCB i" u"e*%
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Commutation Circuit
".3.# Atua/ Ciruit :
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Commutation Circuit
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Commutation Circuit
"." LIST OF CO8PONENTS USED IN PROJECT
T$ere are #o''o.ing com&onent" are u"e* #or t$e &roject:
SCR +Si'icon Contro''e* Recti#ier/ Re"i"tance In*uctor" Ca&acitor" L84 +Lig$t 8mitte* 4io*e/ Pu"$ )utton ".itc$ Tran"#ormer
".# CO8PONENTS DESCRIPTION @ FI7URES
".#.1 SCR 9Si/i(* C(*tr(//e0 Retiier:
It i" t$e main com&onent o# t$i" &roject .$ic$ $a" to turn OFF )( &ro0i*ing t$e e2terna' circuit% It $a" t$ree termina' ano*e, cat$o*e gate% 5$en .e &ro0i*e t$e "u&&'( at t$e gate termina' t$e SCR )ecome ON eit$er it i" in t$e OFF &o"ition% Rating" : P-M ->>@, Am&% uantit( : -
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Commutation Circuit
".#.2 Re'i'ta*e:
Re"i"tance i" o&&o"ing t$e #'o. o# e'ectron"% It i" u"e to 'imit t$e current in t$e circuit% A'"o 0o'tage *ro& i" occur" in t$i" re"i"tance% It i" mea"ure in o$m% Rating" : =9 uantit( : J
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Commutation Circuit
".#.3 I*0ut(r:
An in*uctor can )e *e#ine* a" an energ( "torage *e0ice .$ic$ "tore" energ( in #orm o# magnetic #ie'*% T$e in*uctance o# an in*uctor i" mea"ure* in ;enner( ;% Rating" : - m; uantit( :
".#." Ca,ait(r:
A a,ait(r +origina''( 6no.n a" a con*en"er/ i" a &a""i0e t.o1termina' e'ectrica' com&onent u"e* to "tore e'ectrica' energ( tem&orari'( in an e'ectric #ie'*% It i" mea"ure in Fara*a( F% P a g e | 2
Commutation Circuit
Rating": %QF uantit( :
".#.# LED 9Li;&t E)itte0 Di(0e:
It i" u"e to 0eri#( t$at t$e current i" #'o.ing to t$at &at$% uantit(: -
".#.$ Tra*'(r)er :
Tran"#ormer i" u"e* to "te& *o.n t$e 0o'tage #rom >@ to =@ Rating" : >@ 7 =1>1= uantit( : =
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Commutation Circuit
".#. Pu'& 5utt(* S!it& :
It i" u"e* to &ro0i*e t$e gate "igna' to t$e SCR% uantit( : -
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Commutation Circuit
CHAPTER: # ADVANTA7ES LI8ITATIONS APPLICATIONS CONCLUSION @ REFERENCEB
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Commutation Circuit
#.1 A0a*ta;e':
5i*e range o# out&ut 0o'tage" an* #re
5a0e#orm i" a&&ro2imate "inu"oi*a' an* )e ea"i'( #i'tere*% P5M $a" 'o. ".itc$ing 'o"" com&are to "ome ot$er met$o*"% 8a"( an* com&act contro''ing circuit in "i3e% T$e out&ut 0o'tage can )e contro''e* e2ce&t )( contro''ing in&ut 4C "ource 0o'tage%
Fe.er com&onent" are u"e* "o co"t i" a'"o 'e""% @aria)'e #re
#.2 LI8ITATION:
#.2.1 F(r t&e C/a'' A C())utati(*
C'a"" – A commutation circuit re
#.2.2 F(r t&e C/a'' 5 C())utati(*
C'a"" – B commutation circuit re
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Commutation Circuit
#.2.3 F(r t&e C/a'' C C())utati(*
In t$i" circuit t.o SCR" are u"e* "o t$e co"t o# circuit i" more com&are* to C'a"" – A C'a"" – B%
C'a"" – C commutation circuit re
#.3 A,,/iati(*:
#.3.1 F(r t&e C/a'' A C())utati(*
It i" u"e #or $ig$ #re>> ;3/ a&&'ication )ecau"e at 'o. #re
#.3.2 F(r t&e C/a'' 5 C())utati(*
T$e &roce"" o# C'a""1B commutation i" u"e* main'( 4%C% Time c$o&&er circuit in .$ic$ t$e c$o&&er i" ON #or "&eci#ic &erio* an* t$en to remain in OFF "tate #or "&eci#ic time &erio*%
#.3.3 F(r t&e C/a'' C C())utati(*
T$i" i" u"e* in t$e &ara''e' in0erter o# t$e =>>>;3% T$i" commutation i" re'ia)'e%
#." : Future S(,e:
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