Internati
o
nal
Journal of Ele
c
trical
and Computer
Engineering
(IJE
CE)
V
o
l.
6, N
o
. 5
,
O
c
tob
e
r
201
6, p
p
. 2
073
~207
9
I
S
SN
: 208
8-8
7
0
8
,
D
O
I
:
10.115
91
/ij
ece.v6
i
5.1
149
3
2
073
Jo
urn
a
l
h
o
me
pa
ge
: h
ttp
://iaesjo
u
r
na
l.com/
o
n
lin
e/ind
e
x.ph
p
/
IJECE
Improved Performance of DP
FC Using Sliding Mode
Cont
roll
er M
e
thod
D
.
Na
ra
simha
Ra
o
1
,
T.
Surn
e
dra
2
, S
.
Ta
ra K
a
ly
an
i
2
1
Departm
e
nt
of
Ele
c
tri
cal
and
E
l
ectron
i
cs
,
K L
Univers
i
t
y
Gun
t
ur
, Indi
a
2
Department of
Electrical and
El
ectron
i
cs, JNTU H
y
der
a
bad
,
India
Article Info
A
B
STRAC
T
Article histo
r
y:
Received J
u
n
9, 2016
Rev
i
sed
Au
g
19
, 20
16
Accepte
d
Se
p 2, 2016
Modern power sy
stems demand the need
of ac
tiv
e power flow with the help
of P
o
wer Electr
onics
control de
vices
is
need
ed.
In the fam
i
l
y
of F
l
exible A
C
Tra
n
smission d
e
vice
s (FACTS
),
D
y
na
mic PFC (DPFC) offe
rs the same
controlling fun
c
tion as Unified
PFC
(UPFC),
comprising th
e contro
l of
transmission angle, bus voltage
and lin
e impedan
ce. A tec
hnical modification
of UPFC is DPFC in which flu
c
tua
tions
of voltage
at DC link is eliminated
that enab
les
the individu
al oper
a
tion
as
series and paralle
l cont
rollers.
Th
e
concep
t of DFACTS is u
s
ed in design of
the series converter
. Th
e
replacement of
the high
ratin
g
thr
ee
phas
e
s
e
ries
conv
ert
e
r with th
e
m
u
ltiple low rating single ph
ase conver
t
ers res
u
lts in cost red
u
ction an
d
i
n
c
r
ea
se
s re
li
a
b
ili
ty
grea
t
l
y
.
T
h
i
s
DC L
i
nk is
us
e
d
to tr
ans
f
er th
e
real
power
between
two co
nverters
in UP
F
C
s
u
ch as
in DPFC which elim
i
n
ates th
e 3rd
harmonic frequencies at tr
ansmission
lines. D-FACTS converter
s are actin
g
as insulation b
e
tween high
voltage phases
acts
as 1-
ᴓ
float
i
ng wi
th respe
c
t
to
ground. These r
e
sults in lower
cost for the DPFC sy
stem compared to th
e
UPFC. This paper describ
e
s the comparison of PI and Sliding Mode
Controllers which conclude that SMC is
a better control s
t
rat
e
g
y
com
p
ared t
o
PI.
Keyword:
Cu
rren
t con
t
ro
l
DPFC
FACTS
Po
wer flo
w
c
o
ntr
o
l
Sym
m
et
ri
cal
com
pone
nt
Transm
ission
UPFC
Voltage
s
o
urce
conve
rter
Copyright ©
201
6 Institut
e
o
f
Ad
vanced
Engin
eer
ing and S
c
i
e
nce.
All rights re
se
rve
d
.
Co
rresp
ond
i
ng
Autho
r
:
D. Nar
a
sim
h
a
Rao,
Depa
rtem
ent of Electrical a
n
d
El
ect
ro
ni
cs E
n
gi
nee
r
i
n
g,
K L Un
iv
ersity,
Gu
nt
u
r
,
I
ndi
a
Em
a
il: n
a
rasi
mh
arao
@k
lun
i
versity.in
1.
INTRODUCTION
The increa
sing usage of electricity causes
m
o
re
dem
a
nd i
n
usi
n
g t
h
e r
e
newa
bl
e ene
r
gy
sou
r
ces
m
a
ke i
t
com
pul
sory
t
o
co
nt
r
o
l
a h
uge
p
o
w
e
r
t
h
at
e
n
a
b
l
e
s t
h
e
po
we
r sy
st
em
for a
qui
c
k
swi
t
c
h
bet
w
ee
n t
h
e
ren
e
wab
l
e en
erg
y
so
urces and
th
e
stand
-
b
y
p
o
wer g
e
n
e
ra
tio
n [1
]. Th
is d
e
man
d
s
th
e av
ai
lab
ility o
f
stand
-
b
y
po
we
r wh
ene
v
er rene
wa
bl
e ener
gy
i
s
una
bl
e t
o
sup
p
l
y
the load. T
h
ere
f
ore the
n
eed t
o
control the powe
r
m
e
t
hods i
s
i
n
c
r
eased
[2]
.
T
h
e param
e
t
e
rs used t
o
c
ont
r
o
l
vol
t
a
ge val
u
e
,
t
r
ansm
i
ssi
on
angl
e,
l
i
n
e
i
m
pedance
are adjusted in
order t
o
enha
nce th
e p
o
we
r fl
ow
. The
Po
we
r
Fl
ow C
ont
rol
l
i
ng
Devi
ce (
P
F
C
D) i
s
a de
vi
c
e
t
h
at
tries to
ch
ange syste
m
p
a
ra
m
e
ters to
en
h
a
n
ce
th
e pow
er
f
l
o
w
p
e
rf
or
m
a
n
ce. The com
b
ined FACTS
com
pone
nt
s ar
e t
h
e ap
pr
o
p
ri
at
e devi
ces t
o
enha
nce act
i
v
e
po
wer
fl
o
w
[
2
]
,
[
3
]
.
The
UP
FC
i
s
t
h
e p
o
w
e
rf
ul
PFCD, able t
o
adjust line i
n
ternal
a
ngl
e
of
t
h
e m
achi
n
e,
bus
v
o
l
t
a
ge,
a
nd t
h
e
param
e
t
e
rs o
f
t
r
a
n
sm
issi
on
syste
m
. Th
e maj
o
r
o
p
e
ration
o
f
the UPFC is ex
ecu
ted with
series co
nv
erter b
y
inj
ectin
g
t
h
e vo
ltag
e
, to
cont
rol
p
h
ase
angl
e, m
a
gni
t
u
de, o
f
t
h
e t
r
a
n
sm
i
ssi
on l
i
n
e [3]
,
[4]
.
D
PFC
em
ul
at
es UPFC
i
n
i
nde
pen
d
ent
l
y
ad
ju
sting
th
e lin
e i
m
p
e
d
a
n
c
e, co
n
t
ro
l cap
abilit
y, in
tern
al an
g
l
e b
e
t
w
een
t
h
e bu
s vo
ltag
e
an
d
ind
u
c
ed
EMF
[5
].
In
DPFC t
h
ere is absen
c
e of DC
lin
k which
m
a
k
e
s
to
interact con
v
e
rters
b
ack to
b
a
ck in
UPFC
[6
].
Figure 1 s
h
ows the configura
tion
of the DPFC in whic
h each conver
ter
within the
DPFC is operat
e
d
in
d
e
p
e
nd
en
tly d
u
e
to
on
e
DC cap
acito
r wh
ich
prov
id
es
th
e requ
ired
DC vo
ltag
e
.
Oth
e
r th
an
series and
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
JECE
Vo
l. 6
,
N
o
. 5
,
O
c
tob
e
r
20
16
:
207
3
–
20
79
2
074
p
a
rallel co
nv
erters,
DPFC
n
e
ed
s a filter t
o
byp
ass
h
i
gh
freq
u
e
n
c
y co
m
p
on
en
ts conn
ected
i
n
p
a
rallel to th
e
Y-
∆
tran
sfo
r
m
e
r an
d serv
ice tran
sm
issio
n
lin
e. Th
e n
e
ed
o
f
these extra
com
p
one
nts is e
x
plained later. T
h
e
r
e are
two m
a
jor a
d
vantages
of
DPFC com
p
ared to
UPFC:
1.
Is
ol
at
i
on
o
f
l
o
w
v
o
l
t
a
ge a
n
d
t
h
e se
ri
es c
o
n
v
ert
e
r
’
s l
o
w
co
m
ponent
rat
i
n
g
causes
l
o
w c
o
st
2
.
Th
e in
ab
ility
of th
e series co
nv
erter in th
e
syste
m
cau
ses
h
i
gh
ly reliab
l
e
Fi
gu
re 1.
C
o
m
p
l
e
t
e
Li
ne Di
a
g
ram
of DP
FC
Sy
st
em
2.
PRI
NCI
PLE OF DPF
C
In
t
h
e Un
ified Co
n
t
ro
llers, t
h
ere is co
mmo
n
con
n
ecti
o
n betwee
n the
AC term
inals
of se
ries a
nd
paral
l
e
l
co
nt
r
o
l
l
e
rs d
u
ri
ng
ex
chan
ge
o
f
real
p
o
we
r.
N
o
n s
i
nus
oi
dal
c
o
m
p
o
n
e
n
t
s
we
re
ex
pl
ai
ne
d
by
po
we
r
t
h
eo
ry
. In F
o
u
r
i
e
r a
n
al
y
s
i
s
, t
h
e n
on si
n
u
soi
d
al
cu
rre
n
t
and v
o
l
t
a
ge
i
s
expres
sed
by
i
n
cl
udi
ng
several
si
nus
oi
dal
si
g
n
al
s of
di
ffe
re
nt
fre
que
nci
e
s
and am
pl
i
t
udes [7]
.
The
re
al
powe
r
t
h
at
resul
t
s
d
u
e t
o
n
o
n
si
nus
oi
dal
c
u
rr
ent
s
a
n
d
v
o
l
t
a
g
e
s. T
h
e
real
p
o
w
er
can
be
des
c
ri
be
d i
n
eq
uat
i
on
(
1
)
∑
cos
∅
(
1
)
whe
r
e
Ii
=curr
e
nt ,
V
i
=
vo
ltag
e
,
i
th
= h
a
rm
oni
c f
r
eq
ue
ncy
,
∅
= phase
angle
betwee
n the
ha
rm
onic curre
n
ts and
voltages.
From
t
h
e ab
o
v
e eq
uat
i
o
n i
t
i
s
obse
r
ved
at
di
ffe
rent
ha
rm
oni
c fre
que
nci
e
s o
f
act
i
v
e po
we
r ar
e
insulated from
each
othe
r a
n
d the
real
power at
other
ha
rm
onic freque
ncy is not a
f
fec
t
ed by t
h
e
volt
a
ge
or
current.
The
re
al power is independ
en
t at d
i
fferen
t frequ
en
cies; th
is c
o
n
t
roller with
ou
t AC su
pp
ly g
e
n
e
ratin
g
real power
at
o
n
e
h
a
rm
o
n
i
c
freq
u
e
n
c
y to
utilise th
e sa
m
e
po
wer t
h
at o
t
h
e
r co
m
p
on
en
t
frequ
en
cy
[7
],[8
].
Fo
llowing
th
e
sam
e
ap
p
r
o
a
ch in
DPFC, activ
e
p
o
wer can
be ab
so
rb
ed
b
y
th
e
p
a
ralle
l converter from
source at
sup
p
l
y
fre
que
n
c
y
and i
n
sert
e
d
i
n
t
o
t
h
e sy
st
em
at ot
her fre
que
ncy
com
p
o
n
ent
.
T
h
i
s
har
m
oni
c co
m
pon
ent
of
cu
rren
t
flows t
h
rou
g
h
t
h
e
p
o
wer lin
e. Based
o
n
th
e
qu
an
ti
ty o
f
real power
u
tilised
b
y
t
h
e syste
m
at th
e sup
p
l
y
fre
que
ncy
,
t
h
e
vol
t
a
ge
i
s
ge
ne
rat
e
d
by
t
h
e
D
PFC
seri
es c
o
n
v
ert
e
r
s
at
t
h
e
h
a
rm
oni
c fre
q
u
e
n
cy
t
h
us a
b
so
r
b
i
n
g
t
h
e po
wer
fr
o
m
t
h
e li
ne send by
t
h
e ot
he
r
con
v
ert
e
r .
H
e
r
e a lossless conve
r
ter is
assum
e
d, so that active
po
we
r ge
nerat
e
d at
fu
n
d
am
ent
a
l
com
pone
n
t
freq
u
e
n
cy
an
d t
h
e p
o
w
er a
b
sor
b
e
d
f
r
om
t
h
e harm
oni
c fre
que
ncy
are ass
u
m
e
d as equal. T
h
e
hi
gh-pass
filter of the
DP
FC
allows
the
passa
ge of th
e funda
m
ental
com
ponents
,
bl
oc
ki
n
g
t
h
e h
a
rm
oni
c freq
u
e
ncy
com
pone
nt
s, by
t
h
at
sh
owi
ng t
h
e
har
m
oni
c co
m
pon
ent
s
t
o
ha
ve a
ret
u
r
n
p
a
th
. Th
e h
a
rm
o
n
i
c cu
rren
t
is circu
l
ated
th
ro
ugh
h
i
g
h
-p
ass
filters, series and
p
a
rall
el co
nv
erters
an
d
t
h
e
gr
o
u
n
d
.
F
o
r
t
h
e e
x
c
h
an
ge
of
t
h
e
real
p
o
w
er
i
n
t
h
e
D
PFC
t
h
e
t
h
i
r
d
ha
rm
oni
c f
r
e
que
ncy
c
o
m
p
o
n
ent
i
s
id
en
tified
d
u
e
to
its u
n
i
qu
e ch
aracter of the
fre
quency
3
rd
harm
oni
c
com
pone
nt
s. In a 3
-
ᴓ
system
,
the
f
und
am
en
tal a
n
d 3
rd
m
u
ltiple com
pone
nt com
b
ined i
n
ject curre
nt i
n
to t
h
e
grid.”
The ze
ro-se
que
nce
harm
oni
cs i
s
n
o
t
al
l
o
we
d
by
Y–
t
r
a
n
sf
orm
e
rs,
w
h
i
c
h a
r
e
u
s
eful
t
o
m
i
ti
gat
e
re
duce
v
o
l
t
a
ge l
e
vel
de
fi
ci
ency
i
n
p
o
wer system
.
Th
erefo
r
e, t
h
ere is
n
o
requ
irem
en
t o
f
ex
cess filter t
o
rest o
f
th
e
n
e
t
w
o
r
k
for m
itig
at
in
g
t
h
e
harm
onic leaka
g
e.
2.
1.
Contr
o
l princi
ple ofDPF
C
Fig
u
re
2
sho
w
s th
e three types of co
n
t
ro
llers th
at
con
t
ro
l
th
e m
u
ltip
le co
nv
erters; th
ey are m
a
in
co
n
t
ro
l, series co
n
t
ro
l and
sh
un
t con
t
ro
l. Th
e p
a
ram
e
ter
s
o
f
series an
d p
a
rallel co
n
t
ro
l are m
a
in
tain
ed
b
y
them
selves, they are also called as local cont
rollers
.
At th
e syste
m
lev
e
l th
e cen
tral co
n
t
ro
l con
t
ro
l
s
th
e
DPFC
f
unct
i
o
n
s
. T
h
e
fu
nct
i
o
n
o
f
t
h
ese
t
h
ree
cont
rol
l
e
rs
i
s
g
i
ven
he
re.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
ECE
I
S
SN
:
208
8-8
7
0
8
Im
pr
oved
Perf
orm
a
nce
of
DP
FC
Usi
n
g
Sl
i
d
i
n
g
M
ode
C
o
nt
r
o
l
l
e
r Met
h
o
d
(
D
. N
a
r
a
si
m
h
a
Ra
o)
2
075
Fi
gu
re 2.
B
l
oc
k Di
ag
ram
of DPFC
wi
t
h
C
o
nt
r
o
l
l
e
r
2.
1.
1.
Ma
in Co
ntro
l
The f
o
rem
o
st
fu
nct
i
o
n o
f
t
h
e
m
a
i
n
cont
r
o
l
com
m
onl
y
know
n as ce
nt
ral
cont
r
o
l
l
e
r i
s
t
o
ge
nerat
e
refe
rence si
gn
als for c
o
ntr
o
lled co
n
v
erter
s
of th
e DP
FC.
These a
r
e ge
nerated at the s
y
ste
m
freque
ncy. The
central control gives re
fere
nc
e signal
of current and
voltages for both th
e
controllers in
accorda
n
ce wit
h
the
sy
st
em
requi
re
m
e
nt
[5]
.
At
t
h
e sy
st
em
l
e
vel
,
t
h
e cent
r
al
c
ont
rol
i
s
de
pe
n
d
ent
on t
h
e f
u
nct
i
onal
op
erat
i
on
of
th
e DPFC; th
ey are d
a
m
p
o
u
t p
o
wer
o
s
cillatio
n
s
at
low frequ
e
n
c
y, power-flow con
t
rol an
d
asymm
e
t
r
ical
com
pone
nt
sbal
anci
n
g
.
2.
1.
2.
Series Control
Series co
n
t
ro
l
is presen
t i
n
all th
e sing
le ph
as
e co
nv
erter circu
its. Th
e co
n
t
ro
ller i
s
to
fix
t
h
e
cap
acito
r v
o
ltag
e
o
f
co
nv
erter with
h
e
lp
of
3
rd
ha
rm
oni
c
vol
t
a
ge
or
cu
r
r
ent
s
.
It
i
n
ject
s v
o
l
t
a
ge
at
s
u
p
p
l
y
fre
que
ncy
ap
pr
ove
d by
t
h
e m
a
i
n
cont
rol
[
6
]
.
In D
PFC
seri
e
s
con
v
ert
e
r co
nt
r
o
l
,
t
h
e m
a
jor co
nt
rol
l
o
o
p
i
s
t
h
e
t
h
i
r
d
ha
rm
oni
c fre
q
u
ency
c
o
n
t
rol
.
Fo
r
DC
v
o
l
t
a
ge c
ont
rol
pha
so
r c
ont
rol
pri
n
ci
pl
e i
s
a
p
pl
i
e
d.
2.
1.
3.
Shun
t Contr
o
l
It
i
n
ject
s a fi
x
e
d p
o
we
r w
h
i
c
h com
b
i
n
at
i
o
n
of f
u
ndam
e
nt
al
and t
h
i
r
d ha
rm
oni
c com
ponent
c
u
r
r
en
t
in
to
tran
sm
issi
o
n
lin
e i
n
o
r
d
e
r to
tran
sm
it
th
e real po
we
r fo
r series conv
erters is th
e m
a
i
n
obj
ectiv
e
o
f
sh
un
t
cont
rol.
At the
fundam
ental freque
n
cy of t
h
e 3
rd
ha
rm
oni
c cur
r
ent
a
n
d
b
u
s
vol
t
a
ge a
r
e
locke
d
. T
h
e motto of
p
a
rallel conv
erter is to
ex
ch
ang
e
requ
ired
Q
v
a
rs to
grid
and
also
m
a
in
tain
in
g
fix
e
d
DC cap
acito
r vo
ltage.
3.
CONTROLLER DE
SIGN
3.
1.
Contr
o
ller des
i
gn usin
g
PI
Th
e tran
sfer fun
c
tio
n of t
h
e PI co
n
t
ro
ller is describ
e
d
as:
(
) =
+
2
Pro
p
o
rt
i
o
nal
g
a
i
n
i
s
deri
ve
d usi
n
g KP = 2.
ξ
.
ω
n
.
C wh
ich
calcu
lates th
e p
e
rform
a
n
ce o
f
th
e DC lin
k
v
o
ltage
co
n
t
ro
l.
Simila
rly, th
e in
tegral g
a
in
is d
e
riv
e
d
u
s
ing
KI
=C
ω
n
2
t
h
at determin
es its settlin
g
ti
m
e
. T
h
e PI
co
n
t
ro
ller is to set th
e DC-lin
k
vo
ltag
e
as am
p
l
itu
d
e
o
f
the d axis curre
nt of the AP
F in
v
e
rter to
co
n
t
ro
l the
DC
-l
i
n
k v
o
l
t
a
g
e
for co
ve
ri
n
g
t
h
e i
nvert
e
r
l
o
s
s
es based
on i
t
s
refere
nce val
u
e [9]
.
T
h
e di
f
f
ere
n
ce of r
e
fe
rence
value
of the
APF c
u
rrent a
n
d
measur
ed val
u
e m
easured loa
d
c
u
rrent
3.
2.
Sliding Mo
de con
t
roller
(
S
MC
) of
D
C
v
o
l
ta
ge
SM
C
st
rat
e
gy
has bee
n
c
o
m
m
onl
y
appl
i
e
d f
o
r
p
o
we
r
con
v
e
r
t
e
rs
pr
o
b
l
e
m
s
, due t
o
i
t
s
operat
i
o
n
ch
aracteristics
su
ch
as stab
ilit
y, respo
n
s
e
fast an
d
robu
stn
e
ss d
u
ring
h
i
gh
v
a
riation
in
load
[10
]
. Th
e co
n
t
ro
l
actio
n
SMC
u
tilizes SM th
eory as a
j
u
m
p
fun
c
tio
n wh
ich is g
i
v
e
n
b
y
th
e eq
u
a
tion
(3
)
s
(
y
) =
k
.
sign
(y
)
(3
)
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
J
ECE
Vo
l. 6
,
N
o
. 5
,
O
c
tob
e
r
20
16
:
207
3
–
20
79
2
076
Th
e Lyapu
nov f
u
n
c
tion
m
u
st b
e
b
r
oug
h
t
to
zer
o
;
and
to
ach
iev
e
th
is, it
is su
f
f
i
cien
t th
at its
d
e
ri
v
a
tiv
e is no
t po
sitiv
e [10]. To
m
i
n
i
miz
e
th
e ch
atteri
ng
ph
en
o
m
en
on d
u
e
to
th
e d
i
sco
n
tinuo
us n
a
t
u
re
o
f
t
h
e co
nt
r
o
l
l
e
r,
i
t
i
s
necessar
y
t
o
defi
ne a
di
ffe
re
nt
fu
nct
i
on i
n
nei
g
h
b
o
r
h
oo
d
of t
h
e
sl
i
d
i
ng s
u
rfac
e
wi
t
h
m
a
xim
u
m
and
m
i
nim
u
m
l
i
mi
t
val
u
e. I
f
a poi
nt
of t
h
e
state traj
ecto
r
y falls with
in
th
is in
terv
al, a sm
o
o
t
h
function ca
n re
place the
disc
ontinuous
part
of th
e
control. T
hus
, t
h
e c
ontroller bec
o
m
e
s [11].
= {
/
.(
y)
|
(y
)| <
≠
0
.(
(y
))
|
(y)
|
>
(4
)
Wh
ere,
k
c
represen
ts th
e op
timal g
a
in
v
a
lu
e. In
ord
e
r to
con
t
ro
l th
e DC li
n
k
v
o
ltag
e
Vdc an
d
to
rem
o
ve th
e
chat
t
e
ri
n
g
by
usi
n
g
t
h
i
s
SM
C
,
t
h
e bl
oc
k d
i
agram
of
t
h
e SM
C
st
rat
e
gy
i
s
gi
ve
n by
Fi
gu
re 3. Acc
o
r
d
i
n
g
t
o
Figure
3, the sl
iding
surface
ds(y)/dy = 0 is
use
d
to synt
he
sis a comma
nd current
I*[12]
,[13]. In this c
a
se I*
i
s
gi
ve
n
by
I*
=
.
(
) (
5
)
Fi
gu
re
3.
B
l
oc
k
di
ag
ram
of S
M
C
C
ont
r
o
l
l
e
r
f
o
r
v
o
l
t
a
ge
reg
u
l
a
t
i
o
n
4.
SIMULATION RESULTS
To
sim
u
late
th
e SMC o
r
PI co
n
t
ro
lled
DPFC, a
m
o
d
e
l in
Matlab
/
Si
m
u
li
n
k
is d
e
v
e
lop
e
d
.
Sim
u
latio
n
works are ca
rri
ed out to a
n
alyze the
DPFC perform
a
nce in
a transm
ission
syste
m
. A two
bus
powe
r syst
e
m
is
con
s
i
d
ere
d
f
o
r
sim
u
l
a
t
i
on. Act
i
v
e Po
we
r
fl
ows
bet
w
ee
n t
h
e t
w
o
bus
sy
st
em
s are obt
ai
ne
d by
al
l
o
wi
n
g
di
ffe
re
nt
p
h
as
e bet
w
ee
n t
h
e
t
w
o
sy
st
em
.
DPFC
c
o
nsi
s
t
s
of
6
-
si
ngl
e
pha
se seri
es
c
o
n
v
e
r
t
e
rs a
n
d
shu
n
t
co
n
t
ro
ller. Th
e p
a
rallel co
nv
erter is a
1-
ᴓ
co
nt
r
o
l
l
e
r pl
ace
d
bet
w
ee
n
neut
ra
l
poi
nt
o
f
-Y
t
r
ansf
o
r
m
e
r and
sol
i
d
gr
o
u
n
d
, a
n
d o
n
t
h
e
ot
he
r si
d
e
of i
t
i
s
ene
r
g
i
sed by
c
onst
a
nt
DC
s
o
u
r
ce.
Here a t
r
a
n
sm
issi
on sy
st
em
wi
t
h
a
v
o
ltag
e
of
38
0V
an
d 50H
z is
co
nsid
er
ed
.
Table
1.
System
Param
e
ters in Sim
u
link
Table 2.
Meas
ure
d
Values
of conve
r
ter
Para
m
e
ter Abbreviation
Value
Vs
Sending end volta
ge
220 V
Vr
Receiving end volt
a
ge
210 V
L
I
nductance co
m
p
o
n
ent
in line
6 m
H
θ
Angle between two end
bus voltages
1
o
Sy
m
bol Descr
i
ption
Value
Vsh,max
M
a
xim
u
m
shunt voltage by
shunt con
v
er
ter
50 V
Ish
,
m
a
x
M
a
xim
u
m
shunt cur
r
e
nt by
shunt con
v
er
ter
9 A
Ish,ref
,
Shunt conver
t
er
r
e
fer
e
nce
thir
d harm
onic curr
ent
3A
Vsh,dc
dc sour
ce supply
20V
Vs
e,
m
a
x
3
Ser
e
isconver
t
eMaxim
u
m
ac
voltage at line side of
7 V
fsw
Ser
e
is Conver
t
er Switching
fr
equency
for
shun
t and
6 kHz
Ise,
m
a
x
Ser
e
is Conver
t
er peak ac
current at line
ter
m
inal of
15 A
Fi
gu
re
4.
Seri
e
s
i
n
ject
ed
V
o
l
t
a
ge
Fi
g
u
re
5
.
f
u
nd
am
ent
a
l
com
ponent
o
f
i
n
ject
e
d
vol
t
a
ge
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
ECE
I
S
SN
:
208
8-8
7
0
8
Im
pr
oved
Perf
orm
a
nce
of
DP
FC
Usi
n
g
Sl
i
d
i
n
g
M
ode
C
o
nt
r
o
l
l
e
r Met
h
o
d
(
D
. N
a
r
a
si
m
h
a
Ra
o)
2
077
Fig
u
re
6
Fund
amen
tal Lin
e
C
u
rren
t
Figu
re 7.
Activ
e an
d Reactive Power
Fi
g
u
r
e
8.
V a
n
d
I
Del
t
a
Si
de
Fi
gu
re
9.
TH
D
A
n
al
y
s
i
s
at
cu
rre
nt
at
rece
vi
n
g
e
n
d
Si
de
Fi
gure
10. T
H
D Analysis of
voltage
at rec
e
iving end
Figure
11. THD a
n
alysis of
Current at recei
ving e
n
d
Figure
12. T
H
D
analysis-Voltage
Figure
13.
T
H
D
analysis-
Cur
r
ent
0
0.
05
0.
1
0.
15
0.
2
0.
25
0.
3
0.
3
5
0.
4
0.
45
0.
5
-8
-6
-4
-2
0
2
4
6
Ti
m
e
i
n
S
e
c
Li
ne c
u
r
r
ent
i
n
A
m
ps
f
undam
ent
al
c
o
m
ponent
of
l
i
ne
c
u
rr
ent
0
0.
05
0.
1
0.
15
0.
2
0.
25
0.
3
0.
35
0.
4
0.
45
0.
5
-3
-2
-1
0
1
2
3
Ti
m
e
i
n
S
e
c
v
o
l
t
age and C
u
r
r
ent
V
o
l
t
a
ge a
nd
C
u
r
r
ent
at
D
e
l
t
a S
i
de
0
0.
05
0.
1
0.
15
0.
2
0.
25
0.
3
0.
35
0.
4
0.
45
0.
5
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
Ti
m
e
i
n
S
e
c
P
o
w
e
r i
n
W
a
tt
A
c
t
i
v
e
and R
eac
t
i
v
e
P
o
w
e
r
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
J
ECE
Vo
l. 6
,
N
o
. 5
,
O
c
tob
e
r
20
16
:
207
3
–
20
79
2
078
Fig
u
r
e
14
. THD
an
alysis-
I
Tabl
e
3. C
ont
a
i
ns Pe
rf
orm
a
nce Di
f
f
ere
n
ces
i
n
Num
e
rical with PI and
SMC Method
PI
SMC
Ser
i
es inject voltage (
1
st and 3r
d)
co
m
ponent
78.
9%
75%
Pundam
e
ntal injected
voltage
14%
13.
2%
L
i
ne cur
r
e
nt
12.
96%
10.
9%
Cur
r
e
nt r
e
ceving end
7.
68%
6.
9%
5.
CO
NCL
USI
O
N
Tw
o di
f
f
ere
n
t
cont
r
o
l
st
rat
e
gi
es f
o
r
DPF
C
are prese
n
t
e
d i
n
t
h
i
s
pa
per
.
The
fi
rst
i
s
based
on
pr
o
p
o
r
t
i
onal
-
i
n
t
e
gral
co
nt
r
o
l
l
e
r (P
I) a
n
d t
h
e s
econ
d
uses a sl
i
d
i
ng m
ode c
o
nt
r
o
l
(SM
C
).
T
h
ese c
ont
r
o
l
l
e
r
s
are
use
d
i
n
or
der
t
o
re
gul
at
e t
h
e
vol
t
a
ge o
f
t
h
e seri
es co
nt
r
o
l
l
e
rt
o im
pro
v
e
dy
nam
i
cal
perf
orm
a
nces. S
e
veral
co
nd
itio
ns
h
a
ve b
e
en
p
e
rformed
in ord
e
r t
o
p
r
ov
e th
e T
HD of series inj
e
cted
vo
ltag
e
. The sim
u
lat
i
o
n
is do
ne
usi
n
g M
A
TL
A
B
/
S
IM
UL
IN
K.
The
re
sul
t
s
o
b
t
ai
ned
by
si
m
u
latio
n
sh
ow that th
e SMC
con
t
ro
ller
o
f
fers
b
e
tter
perform
a
nces than the
PI. Ta
ble is give
n a
bove.
REFERE
NC
ES
[1]
Y. H. Song and A. Johns, “Flexibl
e ac
Transmission Sy
stems (FACTS),”
IEE Power and Energy Series
, vol. 30
.
London, U
.
K, In
stitution
of
Elect
r
ical Eng
i
neers,
1999.
[2]
N. G. Hingor
ani and
L. G
y
ug
y
i
,
“Unde
rstanding
FACTS: Concep
ts and
Techno
lo
g
y
of
Flex
ible AC Transmission
S
y
stems,” New
York, IEEE Pres
s, 2000.
[3]
L. G
y
ug
yi
,
et al.
, “The unified p
o
wer flow controller: A ne
w approach to power transmission control,”
IE
EE T
r
ans.
Power Del
.
, vol/issue: 10(2), pp.
1085–1097, 199
5.
[4]
A. A. Ed
ris, “Proposed term
s an
d defin
itions
for
flexibl
e
ac trans
m
ission
sy
st
em
(facts),”
I
EEE
T
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