TELKOM
NIKA
, Vol.11, No
.3, Septembe
r 2013, pp. 4
33~440
ISSN: 1693-6
930,
accredited
A
by DIKTI, De
cree No: 58/DIK
T
I/Kep/2013
DOI
:
10.12928/TELKOMNIKA.v11i3.1079
433
Re
cei
v
ed Ma
rch 2
0
, 2013;
Re
vised June
19, 2013; Accepte
d
Jul
y
5
,
2013
Resear
ch of Driving Circuit in Coaxial Induction
Coilgun
Yadong Zha
ng, Jiangjun
Ruan, Yuan
chao Hu
*
, Ruohan Gong, Weijie Zhang, Kaipei Liu
Schoo
l of Elect
r
ical En
gin
eeri
ng, W
uhan U
n
i
v
ersit
y
Luo-
jia-s
han W
u
cha
ng, W
uha
n, Hube
i Provi
n
ce, P.R.Chin
a
*Corres
p
o
ndi
n
g
author, e-ma
i
l
: hu
yua
n
ch
ao3
211
@12
6
.com
A
b
st
r
a
ct
Catu d
a
ya
mer
upak
an p
e
ra
lat
an p
entin
g d
a
l
a
m
pel
unc
ur kumpar
an i
nduk
si koaksi
al. Ko
nfigur
as
i
rangk
aia
n
pe
nge
mudi
me
mp
en
garu
h
i s
e
cara l
a
n
g
sun
g
efisie
nsi p
e
lu
ncur ku
mp
aran. Maka
la
h in
i
me
mberik
an
a
nalis
is ri
nci te
n
t
ang sif
a
t kons
truksi ra
n
g
ka
ia
n pe
ng
e
m
ud
i b
e
rbas
is su
mbe
r
kapas
itor. T
i
g
a
topologi dari rangk
aian
pengem
ud
i dibandingkan,
m
e
liputi
rangk
ai
an osilas
i
,
crow
bar dan setengah
gel
o
m
ba
ng. H
a
l in
i
me
mbuktik
an b
ahw
a r
ang
kaia
n ya
ng
me
mi
liki efisi
ensi
yang le
bih
ba
ik
terga
n
tung
pa
da
para
m
eter ri
nci
perco
ba
an, te
rutama res
i
sta
n
si crow
bar.
R
e
sistor crow
ba
r tidak
hany
a me
ng
atur
efis
i
ensi
sistem, t
e
tapi
j
uga
ke
naik
a
n
suhu
ku
mp
ara
n
. Day
a
electr
omag
netik
(EM
F
)
ditera
pkan
pad
a armatur aka
n
prob
le
m l
a
i
n
y
ang
me
mp
eng
aruh
i ko
ndis
i
l
a
yan
an s
i
rkuit
pen
ge
mudi.
Ran
g
kai
an
osi
l
asi
dan
crow
ba
r
sehar
usnya
dit
e
rapk
an p
a
d
a
pel
uncur k
u
mp
aran i
n
d
u
ksi
si
nkron d
an tak-
sinkro
n. Ran
g
kaia
n seten
g
a
h
gel
o
m
ba
ng ka
dan
gkal
a di
gu
naka
n
dal
a
m
p
e
rcob
aan. Me
s
k
ipu
n
efisie
nsi
rangk
aia
n
sete
nga
h gel
o
m
b
a
n
g
sang
at tingg
i, kecepat
an a
r
matur
n
ya re
n
dah.
Se
bua
h
rangk
aia
n
set
eng
ah g
e
lo
mb
ang i
n
d
epe
nd
en
seder
han
a
diu
s
ulka
n p
ada
makal
ah
ini. S
e
c
a
ra u
m
u
m
, sifa
t kompreh
ens
if rangk
ai
an cr
o
w
bar ad
ala
h
y
ang
pali
ng
praktis
pad
a tig
a
ra
ng
kain k
has ters
ebut. Si
mp
ul
an
nya,
maka
la
h i
n
i d
a
p
a
t me
mberik
an p
e
d
o
m
an
praktis untuk r
angk
aia
n
pe
ng
emud
i .
Ke
y
w
ords
: EML, coil la
unch
e
r, pow
er supp
ly, efficiency, crow
bar, circuit
A
b
st
r
a
ct
Pow
e
r supply i
s
crucial eq
uip
m
e
n
t in coaxi
a
l induc
ti
on co
il lau
n
cher. Co
nfi
gurati
on of the
drivin
g
circuit directly
influ
ences
the
efficiency
of th
e coi
l
l
aunc
her
.T
his pap
er g
i
ves a
detai
le
d
ana
lysis
of th
e
prop
erties
of th
e dr
ivin
g c
i
rcuit
constructi
on
b
a
sed
o
n
th
e ca
pacitor
so
urce.
T
h
ree
top
o
lo
gi
es of t
he
drivi
n
g
circuit are co
mpare
d
incl
ud
ing
oscill
ation, cro
w
bar and
h
a
lf-
w
ave circuits. It is proved that
w
h
ich circuit h
a
s
the b
e
tter effi
ciency
de
pen
d
s
on th
e d
e
ta
iled
p
a
ra
meter
s
of the
expe
riment, esp
e
ci
ally th
e crow
b
a
r
resistanc
e. Crowbar resistor
regulates not
only efficiency of the syst
em
, but also tem
perature rise of the
coil. El
ectro
m
a
gnetic forc
e (
E
MF) appl
ied
on the
ar
ma
tu
re w
ill b
e
a
n
o
t
her pro
b
l
e
m
w
h
ich infl
ue
nc
es
service c
ond
iti
on of th
e driv
i
ng circ
uits. Oscillati
on
an
d cr
ow
bar circu
i
ts shou
ld
be a
p
p
l
ied to
both
of the
synchro
nous
a
nd asy
n
chro
no
us in
ductio
n
co
il la
unc
hers, re
spective
ly. Half
-w
ave circuit is
seld
o
m
use
d
i
n
the exp
e
ri
me
nt. Althoug
h effic
i
ency of the
hal
f-w
a
ve circui
t is very hig
h
, the
speed
of the a
r
matur
e
is low
.
A
simple
i
nde
pe
n
dent
ha
lf-w
ave circuit
is
pro
p
o
sed
in
th
is
p
a
per. In
ge
ner
al
, the c
o
mpre
he
nsive
pro
perty
of
crow
bar circu
i
t is the
most pr
actical
in th
e t
h
ree ty
pica
l cir
c
uits. Conc
lus
i
ons of th
e
pap
er cou
l
d
provi
d
e
gui
del
ines for p
r
actice.
Ke
y
w
ords
: EML, coil la
unch
e
r, pow
er supp
ly, efficiency, crow
bar, circuit
1.
Introduc
tion
A coaxial
ind
u
ction
coil la
uncher u
s
e t
he L
o
re
ntz
(
J
×
B
) fo
rce to
accele
rate
a
proje
c
til
e
with a con
d
u
c
ting armatu
re
. Compa
r
ed
with conv
e
n
tional we
apo
n, coil laun
che
r
has advanta
ges
of high effici
ency, low
co
st, perfe
ct control
p
r
op
erty and wide
applicability [1]. At present,
impulse
capa
citor i
s
widely
use
d
a
s
storage p
o
wer
e
quipme
n
t wh
ose
ene
rgy d
ensity, si
ze
a
nd
weig
ht determine wh
ether coil laun
che
r
could be
u
s
ed or not. Dri
v
ing circuit configuration can
also influ
e
n
c
e the laun
ch
efficiency, tempe
r
at
ure rise an
d su
st
ained
repetiti
on rate di
re
ctly.
Ho
wever,
pe
ople
do
not p
a
y eno
ugh
at
tention to th
e
re
sea
r
ch of driving ci
rcuit
than
fi
re co
n
t
rol
and
optimiza
t
ions [2]. So
me a
r
ticle
s
reach the
op
posite
con
c
lu
sion
s
whi
c
h
puzzle
d
a
lot
of
peopl
e [3-5]. This pape
r gives a detailed analy
s
i
s
of the pro
pertie
s
of the driving ci
rcuit
con
s
tru
c
tion
based on the
cap
a
cito
r so
u
r
ce.
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
930
TELKOM
NIKA
Vol. 11, No. 3, September 20
13: 43
3 – 440
434
Gene
rally
sp
eaki
ng, the
r
e
are three ty
pical
dr
ivin
g
circuits that
have a
pplied
to coil
laun
che
r
sy
stem, inclu
d
ing
oscill
ation ci
rcuit, cro
w
ba
r circuit a
nd
half-wave ci
rcuit, whi
c
h a
r
e
sho
w
n in Fig
u
re 1, wh
ere,
L
is the self indu
ctan
ce of the coil;
R
S
,
R
C
,
R
D
are re
sista
n
ces of the
system, the coil, the cro
w
b
a
r re
si
stor respectively.
(a)
O
scillation
cir
c
uit; (
b
) Cr
ow
ba
r
cir
c
uit; (
c
)
Half-wave cir
c
uit
Figure 1. Three typical driv
ing circuit
s
Oscillation
ci
rcuit i
s
a si
mple RL
C
ci
rcuit
who
s
e
coil an
d ca
p
a
citor
suffers damped
oscillation
cu
rrent (altern
a
ting current).
Cap
a
cito
rs
keep
s chargin
g
and
disch
a
rging u
n
til ene
rgy
exhausting which will
influ
ence the
service lifetime
of
capacitor. Al
ternating field in the bore
will
indu
ce the
alt
e
rnatin
g e
ddy
cu
rrent in th
e armature
a
nd p
r
op
el the
arm
a
ture
out
of the b
a
rrel.
In
Figure 1(b
)
, capa
citor is sh
orted by cro
w
ba
r di
ode
when it relea
s
es the ene
rg
y completely and
voltage falls t
o
ze
ro. And t
hen, drivin
g coil and the
crowb
a
r di
ode
make
up a
RL circuit. Thu
s
, in
the cro
w
b
a
r
circuit, the cu
rre
nt and flux in the co
il wi
ll not chan
ge
directio
n. When coils of the
barrel a
r
e fed
in seq
uen
ce
by a set of ca
pacito
r
drive
n
circuits, the
coil lau
n
che
r
can
be seen
as
the cylin
der reco
nne
ction
gun.
Cro
w
b
a
r circuit
co
ul
d
increa
se
the
se
rvice
life
of the
cap
a
ci
tor
and
control th
e flow of
current by
crowb
a
r resi
stor
wh
ich i
s
wi
dely
use
d
not o
n
ly in coil l
aun
cher
but also i
n
ra
il launche
r. If the RL
C ci
rcuit con
nec
t
s
a diode i
n
se
ries, the
oscil
l
ation ci
rcuit will
turn to be
half-wave ci
rcuit as shown in Figu
re
1(c).
T
he capacitor will suff
er
hi
gh reverse
voltage after
discha
rge. T
h
e ene
rgy d
e
livered to th
e
armatu
re i
s
v
e
ry limited
which
re
sult in
less
use
in p
r
a
c
ti
ce. But h
a
lf-wave
circuit
is very
us
efu
l
in some
sp
ecial
situatio
n, su
ch
a
s
the
resea
r
ch of sustain
ed re
pe
tition launch.
2. Comparison of Oscillation Circuit and Cro
w
bar Circuit
2.1. Simulation Models
With
reg
a
rd
to o
scill
ation
circuit
and
cro
w
ba
r
circuit,
referen
c
e
[3] t
houg
ht that o
scill
ation
circuit gai
n hi
gher
efficien
cy of energy transfo
rmat
io
n and mu
zzle velocity. In con
t
rast, refe
ren
c
e
[4] arg
ued
th
at, unde
r th
e
sa
me
co
ndit
i
ons,
high
er
efficien
cy ca
n be
a
c
hi
eved
from
cro
w
bar
circuit
rathe
r
t
han
oscillatio
n
ci
rcuit. In o
r
der to ve
rify
whi
c
h
circuit
is b
e
tter, a
si
mple
singl
e
st
age
coil laun
ch
er is con
s
tru
c
t
ed as Fig
u
re
2. To
fit
the actual op
erational enviro
n
ment, the solid
aluminu
m
cyli
nder
arm
a
ture is a
ssig
ned
to an or
igin
a
l
velocity of 50m/s. The
co
pper
stra
nd
coil
is po
wered b
y
different external
circuit
s
whi
c
h
are sh
own in Fi
gure
1(a) a
nd Fig
u
re 1
(
b). All the
driving
circuit
s
have the
sa
me ca
pa
citan
c
e (1.2 mF
)
and initial voltage (6
kV
).
Th
e re
sist
a
n
c
e
of
the ci
rcuit in
clud
es th
ree
parts a
s
follo
ws:
system
resi
stan
ce
R
S
of 10 m
Ω
(i
nclu
de
s internal
resi
st
an
ce
of
t
he ca
pa
cit
o
r
)
,
coil re
si
st
an
ce
R
C
of 10
m
Ω
an
d cro
w
bar
re
sista
n
ce
R
D
(jus
t relative
to cro
w
b
a
r
ci
rcuit
)
. No
rmal
ly
,
R
S
and
R
C
are the
sam
e
and
R
D
is t
he majo
r differen
c
e
betwe
en
the two
circui
ts whi
c
h i
n
flu
ence the d
o
wntrend
of
the
cu
rre
nt. To rese
arch the i
n
fluen
ce of t
he
c
r
ow
ba
r
br
anc
h
c
i
rc
u
i
t,
R
D
is cha
nge
d
from 0 to
100 m
Ω
eve
r
y 25 m
Ω
. Th
e
mo
de
ls
ar
e
cal
c
ulate
d
un
der tra
n
si
ent
solver i
n
Ansoft Maxwell which h
a
s b
e
e
n
widely u
s
ed
in coil lau
n
cher
s
t
udies
[6-8].
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
1693-6
930
Re
sea
r
ch of Dri
v
ing
Circui
t in Coaxi
a
l Inductio
n
Coilg
un (Yad
ong Z
hang
)
435
40
mm
30
mm
46
mm
50
mm
Axis of symmetry
A
rmature
Coi
l
Figure 2. Geo
m
etry para
m
eters of
the
si
ngle sta
ge co
il launcher
2.2. Simulati
on Results
Simulation re
sults of
the current
in
th
e co
il a
nd
spe
ed of the
armature
are shown in
Figure 3 an
d Figure 4. It is sho
w
n that i
n
a cr
owba
r circuit, current
and spee
d wi
ll decrea
s
e
wi
th
the increa
se
of the crowb
a
r re
si
stan
ce.
The greater
the re
sista
n
ce
is, the le
ss the redu
ctio
n of
the spee
d a
n
d
current
will
be. Fi
gure 4
sh
ows th
at i
f
crowb
a
r re
sistan
ce i
s
sm
all en
ough,
the
muzzle
spe
e
d
and effici
en
cy of the cro
w
ba
r ci
rcui
t will high
er th
an that of the
oscillation
circuit.
When there is no resi
stor in the crowbar br
anch,
the crowbar circuit will
gain the highest
effic
i
enc
y
.
Acco
rdi
ng to
the above
an
alysis
re
sult,
referen
c
e [3]
is mo
re li
kel
y
to cho
o
se
a large
cro
w
b
a
r
re
si
stan
ce in the
experime
n
t who
s
e
cu
rre
nt dampe
d q
u
ickly and a
r
mature
suffered
great
breaki
ng force. The efficien
cy of
the crowbar circuit i
s
less
than that of the oscillati
on
circuit. In referen
c
e
[4], the cro
w
b
a
r
resi
stan
ce i
s
0 whi
c
h
is
o
ne of the
re
aso
n
s
why t
he
efficien
cy of the crowbar
ci
rcuit is hig
h
e
r
. A
nother important rea
s
o
n
is
t
hat
coil resist
a
n
c
e
R
C
is 0
in the simulati
on, whi
c
h mig
h
t be unre
a
so
nable in p
r
a
c
tice.
Thus, which circuit ha
s the better effici
ency dep
end
s on the deta
iled paramete
r
s of the
experim
ent, espe
cially the
cro
w
b
a
r resi
stance.
0.
00
0.
25
0.
50
0.
75
1.
00
1.
25
1.
50
1.
75
2.
00
Ti
m
e
(
m
s
)
-
20.
00
-
10.
00
0.
00
10.
00
20.
00
30.
00
C
u
rre
n
t
(
k
A
)
Cu
r
v
e
I
n
f
o
o
s
c
illa
t
i
o
n
c
r
o
w
b
ar
0
m
oh
m
cro
w
b
a
r
2
5
m
o
h
m
cro
w
b
a
r
5
0
m
o
h
m
cro
w
b
a
r
7
5
m
o
h
m
c
r
o
w
b
ar
1
0
0
m
oh
m
Figure 3. Current cu
rve
s
of t
he different driving ci
rcuit
s
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
930
TELKOM
NIKA
Vol. 11, No. 3, September 20
13: 43
3 – 440
436
Figure 4. Speed cu
rves of t
he
different d
r
iving ci
rcuits
3. Temperature Ri
se an
d Electroma
gnetic For
ce
of the Cir
c
uit
Beside
s efficiency,
othe
r importa
nt
propertie
s
sh
o
u
ld
al
so be con
s
id
ere
d
, su
ch
a
s
temperature
rise an
d ele
c
tromagn
etic force.
3.1. Tempera
t
ure Ri
se
Different topological structure
will influence t
he temperature ri
se
of the coil
greatl
y
[6, 9].
Energy
store
d
in th
e
cap
a
c
itor (
E
C
)
will
tran
slate i
n
to mu
zzl
e
kin
e
tic e
nergy (
E
K
) the a
r
ma
ture
gaine
d and
heat en
ergy
(
E
R
) expended on the
resi
stor. Assuming the
oscillation ci
rcuit and
c
r
ow
ba
r
c
i
rc
uit h
a
s
th
e
s
a
me
E
C
and
E
K
, and efficienci
e
s of the
two model
s are eq
ual. T
he
energy dissip
ated in the form of heat
E
h
of the armatu
re in ea
ch se
ction is give
n by Equation 1
.
1
av
hK
av
S
EE
S
(1)
Whe
r
e
S
av
= (
S
0
+
S
1
)/2 is the averag
e sli
p
in each se
ction [10] .
Since the transit time of the projectile thr
ough the barrel i
s
only
a few
milliseconds, the
heat tran
sfer into the surroundi
ng sp
ace is negligi
b
l
e
. Therefo
r
e,
the tempera
t
ure ri
se of the
armatu
re in a
sectio
n co
uld
be written a
s
Equation 2.
1
h
E
cG
(2)
Whe
r
e,
c
an
d
G
are the sp
ecific h
eat an
d weig
ht of the armatu
re.
Due to the launcher
ha
s the ability to
provide
magnetic
pressure to proj
ectil
e
s
whi
c
h
results in nea
r con
s
tant a
c
cele
ration. An
d
S
av
in every sectio
n is al
most the sam
e
. Then,
θ
E
h
E
K
. In
this case, the resi
dual en
ergy i
s
co
nsum
e
d
by the resi
st
ance of
the driving
circuit
.
Tempe
r
atu
r
e
rise
of th
e
coi
l
is
determine
d by th
e
pe
rcentage
of the
coil
re
si
stan
ce i
n
the
who
l
e
damping resi
stance. In the oscillation
circuit, the
ratio of the energy loss
on the coil
will
not
cha
nge
whi
c
h
could b
e
writ
ten as Equati
on 3.
C
osc
i
llation
CS
R
R
R
(3)
0.
0
0
0.
25
0.
50
0.
75
1.
00
1
.
25
1.
50
1
.
75
2.
00
Ti
m
e
(
m
s
)
50.
00
52.
50
55.
00
57.
50
60.
00
62.
50
65.
00
67.
50
S
p
eed
(
m
/
s
)
Cu
r
v
e
I
n
f
o
o
s
c
i
ll
a
t
io
n
cr
o
w
b
a
r
0
m
o
h
m
cr
o
w
b
a
r
2
5
m
o
h
m
cr
o
w
b
a
r
5
0
m
o
h
m
cr
o
w
b
a
r
7
5
m
o
h
m
c
r
o
w
b
a
r
10
0m
o
h
m
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
1693-6
930
Re
sea
r
ch of Dri
v
ing
Circui
t in Coaxi
a
l Inductio
n
Coilg
un (Yad
ong Z
hang
)
437
However, crowbar circuit
has no dist
incti
on to
oscillation
circuit until the capacitor
voltage de
cre
a
se
to zero (at 0.38m
s in t
h
is m
odel
). T
hen,
cro
w
b
a
r
resi
stan
ce
R
D
will
replace the
sy
st
em
re
si
st
anc
e
R
S
a
nd dampin
g
re
si
stan
ce will
ch
ange
d
from (
R
S
+
R
C
) to
(
R
D
+
R
C
). T
he
ratio
of energy lo
ss on the coil could be
writte
n as Equatio
n
4.
C
c
r
obar
CD
R
R
R
(4)
If
R
D
=
R
S
, coils in the two driving
circuits
w
ill have the same re
si
stance l
o
ss and
temperature rise.
And
η
oscillation
=
η
cro
w
bar
.
If
R
D
<
R
S
,
η
os
cillation
<
η
c
r
ow
ba
r
, and vice versa.
Thus,
cro
w
ba
r resi
stor re
g
u
lates
not o
n
l
y effici
ency
of the sy
ste
m
, but tempe
r
ature of the
coil
will rise in the same time.
By the same
rea
s
on,
whe
n
R
C
,
R
S
and
E
C
of the two
system
s a
r
e
equal, if
R
D
=
R
S
, s
o
doe
s efficien
cy of the two model
s. In Fig.4, if
R
D
=
R
S
= 10 m
Ω
, the spee
d of the cro
w
b
a
r ci
rcuit
should
be equal to that
of
the
oscillation ci
rcuit. In t
h
is
model, 10 m
Ω
could
be see
n
as
the
watershed of
the crowbar resi
stor that
the effi
ciency is almost the sam
e
wit
h
the oscillation
c
i
rc
uit.
3.2. Electro
magnetic Fo
rce
Electrom
agnetic force
(E
MF) applied
on t
he
armat
u
re will
be another questi
on
which
influen
ce service co
nditio
n
of the driving ci
rcui
ts. Just as
sh
own
in Figure
5, EMF in crowba
r
circuit will not oscillate which
is benefi
c
ial for adjusting the in
teri
or balli
stics performance.
If
power
excitat
i
on of e
a
ch
st
age i
s
synchronized
with t
he po
sition
of
proj
ectile, m
agneti
c
filed
will
be linked alo
ng the barrel
which is wel
l
kno
w
n
a
s
synchrono
us i
ndu
ction coil gun (o
r cylin
der
reconn
ectio
n
gun
). In co
n
t
rast, o
scill
ation ci
rcuit
will
results i
n
oscill
at
ing axial EMF whi
c
h is
difficult to form a smooth
a
c
celerating fo
rce
with
th
e synchrono
us
method
as
de
scribe
d ab
ove. It
is bad for me
cha
n
ical prop
erties of the armatu
re. But it does not alway
s
do so
. Based on th
e
operation p
r
i
n
cipl
e of the
straig
ht line
motor, re
searche
r
s ma
ke
several o
s
cillat
i
ng current
s
with
adjusting firi
ng time to be
a multiphase (usua
lly three multiphase) circ
uit
whi
c
h will produce a
contin
uou
s traveling
wave
magn
etic fie
l
d with
ce
rtai
n velo
city. Magneti
c
trave
ling
wave
ca
n
prop
el the a
r
mature
smo
o
thly in the barrel whi
c
h i
s
ca
lled asyn
ch
ro
nou
s indu
ctio
n coil la
un
ch
er.
Due
to
cu
rre
n
t attenuatio
n, efficien
cy
of the
asyn
chron
o
u
s
in
du
ction
coil
lau
n
ch
er is not
very
high except repla
c
e the ca
pacito
r
to pul
sed alte
rnato
r
[11].
Figure 5. Force curve
s
of t
he different d
r
iving ci
rcuits
0.
0
0
0.
50
1.
0
0
1
.
50
2.
00
2.
50
3.
0
0
Ti
m
e
(
ms
)
-
10.
00
10
.
0
0
30
.
0
0
50
.
0
0
70
.
0
0
90
.
0
0
F
o
r
ce(
k
N
)
Cu
r
v
e
I
n
f
o
os
c
i
l
l
a
t
i
on
cro
w
b
a
r
1
0
m
o
h
m
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
930
TELKOM
NIKA
Vol. 11, No. 3, September 20
13: 43
3 – 440
438
4. Half-
w
av
e Circuit
4.1. Half-
w
a
v
e
Circuit
As
sho
w
n i
n
Figure 1
(
c), t
he di
ode
ma
ke
s the
ci
rcui
t to be
a h
a
lf wave
re
ctifie
r which
works ju
st d
u
ring
the first half-pe
riod
of the
o
scill
a
t
ion ci
rcuit. The
curre
n
t flows
only in
a
dire
ction until
zero. Great resi
dual e
nergy will be stored in the
ca
pacito
r
with n
egative voltage.
Only part of energy of the capa
citor i
s
transfe
rr
ed to
the coil. Althoug
h efficie
n
cy of the half-
wave
ci
rcuit i
s
ve
ry hig
h
,
speed
of th
e a
r
mature i
s
ve
ry low. It
coul
d
also
be
se
en
in Fi
gu
re
6
a
n
d
Figure 7. Sp
e
ed of th
e h
a
lf-wave
ci
rcuit
is the
lo
we
st
in the fo
ur
ci
rcuits.
Thu
s
, h
a
lf-wave
ci
rcuit
is sel
dom u
s
e
d
in the experiment.
Figure. 6. Current cu
rve
s
of
the different driving ci
rcuit
s
Figure 7. Speed cu
rves of t
he
different d
r
iving ci
rcuits
0.
0
0
0
.
25
0.
50
0.
7
5
1
.
00
1.
2
5
1.
5
0
1
.
75
2
.
00
Ti
m
e
(
m
s
)
-2
0
.
0
0
-1
0
.
0
0
0.
0
0
10
.
0
0
20
.
0
0
30
.
0
0
C
u
rr
ent
(
kA
)
Cu
r
v
e
I
n
f
o
ha
l
f-w
a
v
e
o
s
c
illa
t
i
o
n
cro
w
b
a
r
1
0
m
o
h
m
c
r
o
w
b
a
r
10
0m
o
h
m
0.
0
0
0.
25
0
.
50
0
.
75
1
.
00
1.
2
5
1.
50
1
.
75
2
.
00
Ti
m
e
(
m
s
)
50
.
0
0
52
.
0
0
54
.
0
0
56
.
0
0
58
.
0
0
60
.
0
0
62
.
0
0
64
.
0
0
66
.
0
0
Sp
e
e
d(
m
/
s
)
Cu
r
v
e
I
n
f
o
ha
l
f-w
a
v
e
os
c
i
l
l
a
t
i
o
n
cro
w
b
a
r
1
0
m
o
h
m
c
r
o
w
b
a
r
10
0m
o
h
m
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
1693-6
930
Re
sea
r
ch of Dri
v
ing
Circui
t in Coaxi
a
l Inductio
n
Coilg
un (Yad
ong Z
hang
)
439
4.2. Sustaine
d Firing Mission
Ho
wever, i
n
recent yea
r
s,
su
staine
d firi
ng mi
ssi
on h
a
s b
een
paid
attention to i
n
EML
field which requires the
capa
citor to
rech
arg
e
afte
r ea
ch l
aun
ch
[12]. It gives the
half-wa
ve
circuit much
space to play. In oscillation circui
t and crowbar
ci
rcuit, capacitors have to be
recha
r
ge
d fro
m
ze
ro.
Whil
e the h
a
lf-wa
v
e circuit
will
be
recha
r
ge
d from
a
cert
ain hig
h
volta
ge
whi
c
h will imp
r
ove the su
st
ained firin
g
ra
te greatly.
Referen
c
e [1
0] su
gge
sted
a novel
po
we
r condi
tio
ner equivalent ci
rcuit who
s
e ca
pacito
r
s
interconn
ect from bree
ch to muzzle in o
ne
pha
se. It
coul
d not onl
y enhance the utilization ratio
of the energy
, but also pro
v
ide the current to
the stages with g
r
a
dually narro
wed pulse widt
h.
But disadva
n
tage of this spe
c
ial
circuit is ve
ry clea
r. First, it is only applica
b
le for the
asyn
chrono
u
s
in
du
ction
coil laun
ch
er.
Topolo
g
y st
ru
cture
of the
ci
rcuit i
s
to
o
co
mplex to
cont
rol
in cha
r
g
e
an
d discha
rg
e pro
c
e
ss. Se
cond, utilizat
io
n rate of the
cap
a
cito
rs
wil
l
decrea
s
e from
the first
stag
e to the l
a
st
stage
in o
n
e
pha
se
wh
i
c
h re
sult
s in
the different
service
life of
the
cap
a
cito
rs.
T
he late
r, the
long
er. T
h
ird, all the
ca
pacito
r
s hav
e to b
e
u
s
e
d
in
a la
un
ch.
Malfunctio
n
of any capa
citor will cau
s
e the
wh
ol
e system st
oppin
g
se
rvice. Last, all
the
cap
a
cito
rs
co
uld not be ch
arge
d until the last st
ag
e is disch
a
rg
ed.
Sustained firing rate will b
e
low.
This pa
per p
r
opo
se
s a
si
m
p
le in
dep
end
ent half
-
wave
ci
rcuit which
can
be
ap
plie
d in th
e
su
staine
d firi
ng syn
c
h
r
on
o
u
s ind
u
ctio
n
coil gu
n. Two
thyristors (
T
1
and
T
2
) a
r
e
use
d
to co
ntrol
the discha
rge
of the capa
ci
tor as
sho
w
n
in Figure 8.
Figure 8. Force curve
s
of t
he different d
r
iving ci
rcuits
The thyri
s
tors ope
rate o
ne
after an
other
matchin
g
with the differen
t
discha
rge
el
ectro
de
of the cap
a
c
itor. Thi
s
circuit h
a
s th
e followi
n
g
advantag
es:
All the driving circuit
s
are
indep
ende
nt. Capa
citor a
n
d
coil of ea
ch stage
coul
d
be adju
s
ted
as ne
ede
d which i
s
goo
d for
modula
r
de
si
gn. Cha
r
ge
a
nd di
scha
rge
of e
a
ch
ca
p
a
citor i
s
n
o
t i
n
fluen
ced
by
other capa
cit
o
rs
whi
c
h co
uld improve
the su
staine
d
firi
ng
ra
te. Residual ene
rgy
will be reu
s
ed
to
i
m
prove
efficien
cy. Moreove
r
, se
rvice life of each
cap
a
ci
to
r will
be the sa
me. Thus, thi
s
ind
epen
dent half
-
wave ci
rcuit is sugge
sted i
n
the su
stain
ed firing
syst
em. It is wort
h mentioni
ng
that if crowb
a
r
resi
stan
ce
is
cho
s
e
n
p
r
op
erly, laun
chi
n
g prope
rt
ie
s
of the h
a
lf-wave ci
rcuit co
uld b
e
a
c
hiev
ed
throug
h the
cro
w
b
a
r
circuit as
sho
w
n
in Figu
re 7.
Thu
s
, the comprehe
nsiv
e prope
rties
of
cro
w
b
a
r
circu
i
t is the most excelle
nt in the three typica
l circuit.
5.
Conclusio
n
This pap
er gi
ves a
detail
e
d an
alysi
s
of
the
p
r
ope
rtie
s
of
the drivi
ng circuit co
n
s
tru
c
tion
based o
n
the
cap
a
cito
r
so
urce. Driving
circuit
conf
ig
uration
could
influen
ce the
efficien
cy of the
coil la
un
che
r
dire
ctly. Th
ree to
polo
g
ie
s of th
e d
r
iving
circuit a
r
e
com
p
a
r
ed. I
t
is p
r
oved
that
whi
c
h
circuit
has th
e bette
r efficien
cy d
epen
ds
on th
e detaile
d pa
ramete
rs of the expe
rime
nt,
esp
e
ci
ally the cro
w
ba
r re
si
stan
ce
. Crowbar re
si
stor regulate
s
not
only efficiency of
the syste
m
,
but also tem
peratu
r
e ri
se
of the
coil.
If
crow
ba
r re
s
i
st
an
ce is
eq
ual to the system re
si
stan
ce,
resi
stance loss
and temperature ri
se of
t
he crowbar
circuit
and the osc
illation ci
rcuit
will be the
same. Ele
c
tromagn
etic fo
rce
(EMF
) a
pplied o
n
the
armatu
re
wil
l
be anoth
e
r que
stion wh
ich
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
930
TELKOM
NIKA
Vol. 11, No. 3, September 20
13: 43
3 – 440
440
influen
ce se
rvice conditio
n
of
the drivi
ng circui
ts. O
scill
ation circuit
and cro
w
bar ci
rcuit
sh
ould
apply to the
asyn
chrono
u
s
ind
u
ctio
n coil laun
ch
er
and
synchro
nou
s ind
u
ctio
n coil l
aun
ch
er,
respe
c
tively. Half-wave
circuit is
seld
om
use
d
in the
experim
ent. Although efficiency of the h
a
lf-
wave
circuit i
s
very hi
gh, speed
of the a
r
mature
i
s
ve
ry low. Su
stai
ned firin
g
mi
ssion
gives th
e
half-wave ci
rcuit much
spa
c
e to play. A simple in
dep
ende
nt half-wave circuit is
sug
g
e
s
ted in
this
pape
r. Ge
ne
rally spea
kin
g
, the comp
rehe
nsive
propertie
s
of cro
w
b
a
r
ci
rcuit is the
m
o
st
excelle
nt in t
he th
ree
typical ci
rcuits.
Re
sea
r
che
r
s ca
n choo
se
the
prope
r
circui
t based
on
th
eir
purp
o
se
and experim
ental con
d
ition
s
.
Referen
ces
[1]
W
Ying, RA Marsha
ll, C Shuk
ang. Ph
ysics of
Elec
tric Lau
nc
h. Beiji
ng, Chi
n
a: Science Pre
ss, 2004.
[2]
RJ Ka
ye.
Op
eratio
nal
re
qu
irements
an
d
i
ssu
es for
c
o
ilg
un
e
l
ectro
m
agn
etic l
a
u
n
c
hers.
IEEE
T
r
ansactio
n
s o
n
Magn
etics
. 2005: 41(
1): 194
–19
9.
[3]
Shun-S
h
o
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