TELKOM
NIKA Indonesia
n
Journal of
Electrical En
gineering
Vol. 14, No. 3, June 20
15, pp. 455 ~ 4
6
9
DOI: 10.115
9
1
/telkomni
ka.
v
14i3.793
8
455
Re
cei
v
ed Fe
brua
ry 10, 20
15; Re
vised
April 28, 201
5; Acce
pted
May 7, 201
5
Design and Implementation of Embedded Processor
Based Brushless Motor Drive using Lead Acid Battery
as Source with Lithium Ion Capacitor
Sat
h
ish kumar Shanmugam*
1
, Meen
akumari Ra
machandr
an
2
1
Jansons Instit
ute of T
e
c
hnol
og
y, Coim
bator
e, India
2
Kongu En
gi
ne
erin
g Col
l
eg
e, Erode, Indi
a
*Corres
p
o
ndi
n
g
author, e-ma
i
l
: sat_meae
2k5
@
rediffmai
l.co
m
A
b
st
r
a
ct
F
o
r the past tw
o decad
es, Brushl
ess DC
motor has b
e
co
me
more effici
ent an
d rob
u
st motor
i
n
ind
u
strial a
p
p
l
i
c
ations d
ue to
their si
mpl
i
cit
y
in
structure, relia
bil
i
ty, good
mech
an
ical
properti
es. T
h
e
abse
n
ce of br
u
s
hes featur
es
t
hes
e
mot
o
r
s
s
i
mi
lar
t
o
A
C
mo
t
o
r
s
w
hereas their sp
ee
d perf
o
rmanc
e is ne
arl
y
equ
al to that of the DC mot
o
r
s
.
T
hus the comb
in
ed adv
ant
ages of AC a
n
d
DC motors mak
e
these
motors
mor
e
effici
ent
i
n
vari
ous
ap
pli
c
ations. T
h
e u
s
e of th
ese machi
nes in different
fi
elds
su
ch
as aer
ospa
ce
,
robotics, el
ectric vehicl
es, etc., requires w
i
de ran
ge of s
pee
d contro
l. T
he Conv
erter
selected for th
e
Brushl
ess DC
Motor is the P
W
M Inverter. The d
e
sig
n
w
a
s
base
d
on t
he
output e
q
u
a
tio
n
si
mil
a
r to tha
t
of
conve
n
tio
nal
d
c
machi
nes. T
h
is g
e
n
e
rates
hig
h
-re
so
lutio
n
PW
M outputs
,
used to
cont
rol the
sw
itchi
n
g
pattern of the BLDC Inverter.
By varying the
PW
M si
gnal p
r
oduc
ed fro
m
the microc
o
n
tro
ller, the spe
ed
of
the
motor ca
n
be var
i
ed. T
h
e
Hall Effect se
n
s
ing
unit
gi
ves
infor
m
ati
on a
b
out the rot
o
r p
o
sitio
n
an
d b
a
s
e
d
on th
is r
o
tor i
n
formati
on, sw
it
chin
g se
qu
enc
e of t
he MO
SF
ET
is d
e
cid
ed.
T
he fir
i
ng
p
u
ls
es to t
he
gate
of
the MOSF
ET
are g
i
ven
by
the Co
ntrol S
i
gna
l
Gen
e
rati
on Mo
dul
e. B
a
sed
on th
e
deve
l
op
ed
mo
del
simulati
on stu
d
i
es are
perfor
m
ed in M
a
tlab/Si
mu
link
envir
on
me
nt and
hard
w
are imple
m
en
tation of BLD
C
M
drive us
ing
Lead acid batter
y
as source
With Lithiu
m
ion capacitor
system
is done and results were
ana
lysed
usin
g
Digital Sc
ope
Oscillosco
pe (
D
SO) and out
p
u
t w
e
re Carrie
d
Out Sucessfully.
Ke
y
w
ords
: se
pic conv
erter, MOSF
ET
, BLDC motor,
p
o
w
e
r conveter, PIC microc
ontro
lle
r
Copy
right
©
201
5 In
stitu
t
e
o
f
Ad
van
ced
En
g
i
n
eerin
g an
d
Scien
ce. All righ
ts reser
ved
.
1. Introduc
tion
In BLDC
Mot
o
r the SEPIC converter i
s
used
to boost
the i
nput vo
lt
age f
r
om
12
volt DC
to 24 volt DC. A SEPIC is simila
r to a traditional
bu
ck-b
oo
st conv
erter, but ha
s advantage
s
o
f
having no
n-i
n
verted o
u
tp
ut (the outpu
t has the sa
me voltage p
o
larity as the
input), usi
n
g
a
seri
es capa
ci
tor to
cou
p
le
ene
rgy from
the in
put to
the o
u
tput (and th
us can
re
spo
nd
mo
re
gra
c
efully to
a sho
r
t-ci
rcui
t output),
an
d bei
ng
ca
pa
ble of t
r
ue
shutdo
wn:
wh
en the
switch is
turned off, its output drops to 0V.In S
EPIC co
nvert
e
r the voltage drop
and
switchi
ng time of
diode i
s
critical to a SEPIC reli
ability and effi
ciency.
Schottky diodes
be used
too rweduce
the
spi
k
e
s
. Then
this DC out
put is given to the vo
ltage
source inve
rter whe
r
e the
DC voltage
is
conve
r
ted int
o
AC voltage.
The g
a
te pul
se
s a
r
e ge
ne
rated from th
e drive
r
unit
and it is
give
n to
inverter switches.
The
inv
e
rter outp
u
t
of AC
su
pply
is u
s
ed
to
drive th
e BL
DC moto
r. T
he
controlle
r ch
ose
n
in this
pape
r is PIC Micro
c
ont
roller. Thi
s
ge
nerate
s
hi
gh-resolution P
W
M
outputs, u
s
e
d
to co
ntrol th
e switchi
ng p
a
ttern of
the
BLDC Inverte
r
. By varying
the PWM
sig
nal
prod
uced fro
m
the micro
c
ontrolle
r, the
spe
ed of
the
motor
can b
e
varied. The
singl
e pha
se
AC
sup
p
ly of 230
V, 50 Hz i
s
the inp
u
t so
urce a
nd it
i
s
gi
ven to the
ste
p
do
wn tran
sforme
r. The
n
t
h
e
step d
o
wn vo
ltage is
given
to voltage re
gulator
wh
ere
it regul
ates t
he voltage
an
d it gives the
5
volt and 1
5
v
o
lt reg
u
lated
DC voltage
s. The
5 vo
lt regulate
d
DC
voltage is giv
en to the
driv
er
unit. Similarly the 15 volt
regul
ated DC voltage is gi
ven to the PIC micro
c
ontroller unit. Th
e
power
whi
c
h
is g
o
t from
the
sola
r m
o
d
u
le i
s
store
d
in the
batteri
es
and
is u
s
ed to
drive t
he
BLDC motor.
The 1
2
vol
t
battery is
use
d
for
hardwa
r
e im
ple
m
entation p
u
rpo
s
e. In thi
s
R
e
s
e
ar
ch
, the
b
a
tter
y
b
ank
is
d
e
s
i
g
n
ed b
y
c
o
nn
ec
tin
g
tw
o 6 vo
lt
b
a
tte
r
i
es
in
se
r
i
es
to g
e
t
12
volt. Single-ended primary-inductor
converter (SEPIC) is a type
of DC-DC converter allowing
the
ele
c
tri
c
al potential
(vol
tage) at
its o
u
t
put to be
gre
a
ter tha
n
, le
ss tha
n
, or
eq
ual to that
at its
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ISSN: 23
02-4
046
TELKOM
NI
KA
Vol. 14, No. 3, June 20
15 : 455 – 46
9
456
input; the out
put of the SEPIC is
controlled by the
duty c
y
c
l
e of the control trans
i
s
t
or. A SEPIC
is simil
a
r to
a tradition
al
buck-boo
st
conve
r
ter, b
u
t
has a
d
vant
age
s of havi
ng no
n-inve
rt
ed
output
(the
o
u
tput ha
s th
e
same
voltage
pola
r
ity a
s
th
e inp
u
t), u
s
in
g a
se
rie
s
ca
pacito
r
to
cou
p
le
energy from
the input to t
he outp
u
t (a
nd thu
s
c
an
respon
d mo
re gra
c
efully t
o
a short
-
ci
rcuit
output), and being
c
a
p
able of true shut
down: when the switc
h
is
t
u
rned off, its
output drops
to
0V.In SEPIC
converter the volt
age drop and
swit
ching time of diode i
s
criti
c
al to a SEPIC
reliability and
efficiency. T
he diod
e's
switchi
ng ti
me
need
s to be
extremely fast in ord
e
r to
not
gene
rate hig
h
voltage spi
k
e
s
acro
ss th
e inducto
rs, whi
c
h co
uld cause dama
g
e
to compone
nts.
Fast conventi
onal dio
d
e
s
or Sch
o
ttky diode
s ma
y
be used. The
function of
an inverte
r
is to
cha
nge a
DC input voltage
to AC output
voltage of
de
sire
d freq
uen
cy and ma
gni
tude. In ca
se
of
3-ph
ase inve
rter, the inverter ci
rcuit chang
es
DC i
nput voltage
to a symmetrical AC out
put
voltage of desired mag
n
i
t
ude and fre
quen
cy. An
opt
o-i
s
olato
r
,
also call
ed an opto co
u
p
ler,
photo cou
p
le
r,
or optical
i
s
olato
r
,
is a comp
one
nt
that tran
sfers
electri
c
al
sig
nals
between
two
isolate
d
ci
rcui
ts (he
r
e PIC
microc
ontroll
er unit a
nd d
r
iver unit) by u
s
ing lig
ht. In this p
r
oje
c
t op
to
isolato
r
i
s
al
so u
s
ed to
blo
c
k over volta
ges,
so
t
hat surge
a
one
p
a
rt of
system
will n
o
t de
stroy
the other p
a
rt of the system.P
IC microco
n
trolle
rs ( Programma
ble Interfa
c
e
Controlle
rs), are
electroni
c circuits
that can
be
p
r
og
ramm
ed
to ca
rry o
u
t a vast
ran
g
e of tasks. Th
e PIC 1
6
F87
7
A
issued to
con
t
rol the voltage so
urce inv
e
rter
swit
che
s
to co
ntrol t
he sp
eed of t
he BLDC mo
tor.
Brushle
s
s DC el
ectri
c
motor
(BL
D
C moto
rs,
BL
mo
tor
s
)
a
l
s
o
kn
ow
n a
s
e
l
ec
tr
onic
a
lly
comm
utated
motors are synchrono
us
motor that
a
r
e po
wered b
y
a DC
elect
r
ic
sou
r
ce via
an
integrate
d
inv
e
rter , which
prod
uces an
AC ele
c
tr
i
c
si
gnal [1,
2] to
drive the
mot
o
r. Fo
r
hardware
impleme
n
tation 24 volt rating motor i
s
u
s
ed.
2. Rese
arch
Metho
d
The Fig
u
re 1
sho
w
s the
b
l
ock dia
g
ram
of the Embe
dded
syste
m
ba
sed B
L
DC moto
r
drive for com
m
ercial appli
c
ation
s
. For
hard
w
a
r
e im
p
l
ementation a
12 volt battery is use
d
. This
12 volt DC is
given to the SEPIC c
onvert
e
r.
Figure 1. Block di
agram of
Embedde
d system ba
sed
BLDCM drive
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TELKOM
NIKA
ISSN:
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046
De
sign a
nd Im
plem
entation of Em
bedded Pro
c
e
s
sor Based…
(Sa
t
hish kum
a
r Shanm
ugam
)
457
Brushle
ss
m
o
tors con
s
ist
of a statio
nary part,
the
stator a
nd a
ro
tating pa
rt, the roto
r.
The
sp
ace
be
tween
the
sta
t
or a
nd th
e ro
tor i
s
called
t
he ai
r
gap. T
he
stator carri
e
s th
e
windi
n
g
s
and the
rotor
carrie
s the
m
agnet
s. Bru
s
hless m
o
tors
can
have i
n
si
de rotors
call
ed“In
run
n
e
r
” or
outsid
e
rotors called
“O
ut run
ner”. In
either
ca
se t
he stato
r
win
d
ing
s
a
r
e
sta
t
ionary, allo
wing
dire
ct windi
n
g
acce
ss
without bru
s
h
e
s or slip ri
ng
s.In addition, the ratio of torque d
e
livere
d
to
the size of the motor is hi
gher, ma
kin
g
it usef
ul in appli
c
ation
s
whe
r
e spa
c
e
and wei
ght are
critical facto
r
s. Even though conv
e
n
tion
al DC m
o
tors
are hi
ghly efficient, it had some drawba
cks
due
to com
m
utator and brushes
whi
c
h need proper m
a
intenance. But in B
RUS
HLESS
DC
MOTO
R wh
e
n
the functio
n
s of com
m
u
tator and
b
r
ush
e
s were
impleme
n
ted by
solid- state
swit
che
s
, mai
n
tenan
ce fre
e
motors we
re reali
z
ed. In
stead of com
m
utating the
armatu
re current
by using b
r
ush
e
s, he
re
electro
n
ic
comm
utat
ion is used. This elim
in
ate
s
the pro
b
le
ms
asso
ciated
with the brush
and the co
mmutato
r a
r
rangem
ent, thereby, ma
kin
g
a BLDC m
o
re
rugg
ed a
s
co
mpared to a
DC m
o
tor.Brushl
ess
DC
Motor i
s
a ro
tating ele
c
tric machi
ne
wh
ere
the stato
r
is
a
cla
ssi
c th
ree
pha
se
stator l
i
ke t
hat of a
n
indu
ction mot
o
r
an
d the
rot
o
r ha
s
su
rface
mounted
pe
rmanent
mag
nets. T
he BL
DCM
is d
r
ive
n
by recta
n
g
u
lar
strokes
cou
p
led
with
the
given rotor po
sition. Th
e g
e
nerate
d
stato
r
flux inte
rac
t
s
with the rot
o
r flux, which
is
generated
by
a roto
r m
agn
et that defin
e
s
the
torq
ue
and th
e
spee
d of the
moto
r. The
voltag
e strokes mu
st b
e
prop
erly
appli
ed the
two
p
hases of thre
e ph
ase
wind
ing
system,
so that the
an
gle b
e
twe
en t
he
stator flux an
d rotor flux i
s
kept
clo
s
e
to
90
deg
ree
.
BLDC moto
rs a
r
e
a type
of syn
c
h
r
ono
us
motor. Thi
s
mean
s the
m
agneti
c
field
gene
rated
by
the
stator
an
d the m
agn
etic field
gen
erated
by the rotor rotate at the same freq
u
ency. BL
DC motors do n
o
t experien
c
e the slip that is
norm
a
lly see
n
in Inductio
n
motors.
Figure 2. Cro
ss Se
ctional
View of BLDC Motor
BLDC
motors are
come i
n
singl
e pha
se,
2-ph
ase an
d
3-ph
ase conf
iguratio
ns
are
sho
w
n
in Figure 2.
Corre
s
p
ondin
g
to its type, the st
ator has the sa
me
number of
windi
ng
s. Out of
these,
3-p
h
a
s
e m
o
tors
are the m
o
st
popul
ar
and
widely
used.
Three-pha
se moto
rs ha
ve a
numbe
r of sl
ots (a
nd teet
h) that
are ev
enly divisible
by three. A p
hase is a
n
in
dividual g
r
ou
p of
windi
ng
s with
a sin
g
le te
rminal a
c
cessi
b
le from
outside the m
o
tor. Most b
r
u
s
hl
ess moto
rs
a
r
e
three
-
ph
ase. Each individ
u
a
l loop of wire makin
g
up
a pha
se wi
ndi
ng is called a
turn.
The stato
r
of
a BLDC moto
r co
nsi
s
ts
of stac
k
e
d
s
t
ee
ls
la
mina
tio
n
s w
i
th
w
i
nd
in
gs
p
l
ac
e
d
in sl
ots th
at a
r
e axially
cut
along
the in
n
e
r p
e
ri
phe
ry. Traditio
nally,
the stato
r
re
semble
s that
of
an
Ind
u
ctio
n motor. Ho
we
ver,
the win
d
i
ngs
are
distributed i
n
a
di
fferent ma
nn
er. Mo
st BL
DC
motors have
three stato
r
windi
ng
s conne
cted in
star fashio
n.Each of the win
d
ing
s
are
con
s
tru
c
ted
with nume
r
o
u
s
coil
s interco
nne
cted to form a windin
g
. One or m
o
re
coil
s are pl
aced
in the
slot
s
and th
ey are
intercon
ne
cted to
ma
ke
a wi
ndin
g
. Each
of the
s
e
win
d
ing
s
are
distrib
u
ted ov
er the
stator
perip
he
ry to form
an
even
numbe
r of po
les. The
r
e a
r
e two types
of
stator windin
g
s
varia
n
ts:
a) Trap
ezoidal
motors
b)
Sinusoi
dal motors
This
different
iation is
mad
e
on the
ba
sis of the i
n
te
rco
nne
ction
of coil
s in th
e stato
r
windi
ng
s to g
i
ve the differe
nt types of b
a
ck El
ect
r
om
otive Force (EMF). The T
r
ape
zoid
al mo
tor
gives a b
a
ck EMF in trape
zoid
al fashio
n and th
e sinu
soi
dal
motor give
s a back EM
F in
sinu
soi
dal a
s
sho
w
n in the
below
Figu
re
3 & 4.
In addition to the
back EMF, th
e pha
se
current
also
ha
s t
r
ap
ezoi
dal
and
sinusoidal
vari
ations in
th
e resp
ective
typ
e
s of
moto
r. Dep
endin
g
u
pon
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ISSN: 23
02-4
046
TELKOM
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KA
Vol. 14, No. 3, June 20
15 : 455 – 46
9
458
the cont
rol po
wer
su
pply capability, the motor with
th
e co
rre
ct voltage rating of the stator
can
be
cho
s
e
n
.48 V,
or le
ss than
that voltage
rated m
o
tors
are
u
s
ed
in
a
u
tomotive, ro
botics, small
arm
movement
s etc. Motors
with 100 V
or hig
her th
an that ratin
g
s a
r
e u
s
ed
in applian
c
es,
automation
a
nd in in
du
stri
al appli
c
atio
n
s
.The
st
ator
of the PMBL
DC
motor i
s
made
up of
stee
l
st
ampin
g
s
wi
t
h
slot
s in it
s
int
e
rior
su
rf
a
c
e.
The
s
e
sl
ots acco
mmo
date eithe
r
a
closed o
r
op
en
distrib
u
ted
armature
wi
ndi
ngs.
Tra
d
itio
nally, the
st
a
t
or resembl
e
s that
of a
n
indu
ction
mot
o
r;
however. Th
e win
d
ing
s
a
r
e di
strib
u
ted
in a di
fferen
t
manne
r. M
o
st BL
DC
m
o
tors have th
ree
stator
windin
g
s conn
ecte
d
in star
fashi
o
n. Each of these
windi
ngs
is co
nstructe
d with nume
r
ous
coil
s interco
n
necte
d to form a win
d
ing.
One o
r
mo
re coil
s a
r
e pl
ace
d
in the
slots an
d they are
interconn
ecte
d to make a windin
g
. Each of t
hese
winding
s is distribut
e
d
over the sta
t
or
perip
he
ry to form an eve
n
numbe
r of pol
es.
Figure 3. Tra
pezoidal Ba
ck EMF
Figure 4. Sinusoi
dal Back
EMF
LDC motor
‟
s rotor i
s
mad
e
of perm
ane
nt magnet an
d can va
ry from two to ei
ght pole
pairs with
alternate
No
rth
(N) an
d Sout
h (S) p
o
le
s. Base
d on the
required
ma
gn
etic field de
n
s
ity
in the roto
r, the prope
r ma
gnetic m
a
teri
al is ch
o
s
en t
o
make the rotor.The
roto
r shaft ca
rri
es a
rotor po
sition sen
s
o
r
.
The positio
n
sen
s
or
p
r
ovide
s
in
formation
ab
out the po
siti
on of the
sha
ft at
any instant to
the controller which se
nd
s sign
al to the electroni
c co
mmutator.
2.1. Conv
entional Workin
g Block Dia
g
ram of BL
DC Moto
r
The Brushle
s
s DC M
o
tor i
s
a
com
b
inat
ion of a P
e
rmanent M
a
g
net AC M
o
to
r an
d an
Elec
tronic
Commutator. I
n
BLDC motor inve
rte
r
has to
repl
ace th
e co
mmutator of
a
conve
n
tional
DC moto
r a
s
sho
w
n in Fig
u
re 5.
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
De
sign a
nd Im
plem
entation of Em
bedded Pro
c
e
s
sor Based…
(Sa
t
hish kum
a
r Shanm
ugam
)
459
Figure 5. Fun
c
tional Blo
ck
Diag
ram of BLDC Motor
Brushle
ss d
c
motor =P
erm
anent mag
net
ac motor
+ Electro
n
ic
com
m
utator
The co
mmut
a
tor act
s
like
a three pha
se freq
uen
cy
converte
r. T
he com
m
utat
ion of a
bru
s
hle
s
s DC motor d
epen
ds u
pon the
positio
n of th
e roto
r. The
angle
betwe
e
n
the mag
net
o -
motive force
of stator and
magneto –
motive forc
e
of rotor is fixed to 90 deg
ree
s
(el
e
ctri
cal).
There a
r
e
se
veral m
e
thod
s to
convert
DC to A
C
.
T
hey differ ma
inly in thei
r
a
pproxim
ation
to a
perfe
ct sin
u
soidal
signal.
As one
wo
uld
expect the
b
e
st ap
proxim
ation yield
s
the be
st tra
n
sf
er of
power to a d
e
vice that ex
pect
s
a si
nu
soidal si
gnal.T
he appli
ed DC voltage i
s
sup
p
lied to t
he
inverter
blo
c
k, thereby it
converts DC t
o
AC. Th
e
in
verter i
s
a
six
-
step
current
inverter i
n
wh
ich
one of the
p
hases i
s
con
ducte
d event
ually for
1
20
degree of th
e
cycle. It is
conne
cted to t
he
stator
win
d
in
g of the BL
DC moto
r.Roto
r Po
sition Se
nso
r
i
s
u
s
ed
to se
nse
the
po
sition of t
he
rotor
of the
BLDC
motor.
Hall Effect
sensor i
s
a
transdu
cer th
a
t
varies it
s o
u
tput voltage
in
respon
se to
a magn
etic fi
eld. Hall Effe
ct se
nsor
s a
r
e used for
proximity switching, po
sition
ing,
spe
ed dete
c
tion, and cu
rre
n
t sen
s
ing in BLDC mo
to
r drive.Hall
sen
s
ors are com
m
only use
d
to
time the spe
ed of wheel
s and
shafts,
su
ch a
s
fo
r
internal
co
mb
ustion
engi
ne
ignition timin
g
,
tachom
eters
and
anti-l
o
ck bra
k
in
g
syst
ems. T
hey a
r
e u
s
ed
in
brushl
ess
DC e
l
ectri
c
m
o
tors to
detect th
e p
o
s
ition
of the
p
e
rma
nent
ma
gnet. Hall
se
nso
r
s
can
be
used to
o
perate a
s
a
swit
ch.
Its cost is le
ss tha
n
other mecha
n
ical swit
che
s
. It is also used in the bru
s
hle
ss
DC moto
r to
sen
s
e the p
o
s
ition of the rotor and to
switch
the tran
sisto
r
in the ri
ght seq
uen
ce
.
2.2. Commercial Applications
BLDC motors fulfill many f
unctions ori
g
i
nally
perform
ed by
brushed
DC m
o
tors,
but
cost
and control complexity pre
v
ents BLDC
motors from
repla
c
ing b
r
u
s
hed moto
rs
completely in the
lowe
st-co
s
t a
r
ea
s. Neve
rt
hele
ss, BL
DC moto
rs
ha
ve come to
dominate
ma
ny appli
c
atio
ns,
particula
rly device
s
such
a
s
compute
r
a
nd ha
rd d
r
ive
s
an
d CD/DV
D
playe
r
s. S
m
all co
oling f
ans
in ele
c
tro
n
ic equip
m
ent
are
po
wered
exclu
s
ively
by BLDC m
o
tors.
They
can
be fo
un
d in
cordle
ss po
wer tool
s
wh
ere the in
crea
sed effici
en
cy of the moto
r l
ead
s to lo
nge
r pe
riod
s
of u
s
e
before th
e ba
ttery need
s to be cha
r
g
ed. Low
spe
ed, low po
we
r BL
DC m
o
tors are use
d
in dire
ct-
drive turnta
bl
es for g
r
amo
phon
e re
co
rd
s.
High p
o
wer
BLDC m
o
tors are found i
n
electri
c
ve
hicle
s
an
d h
y
brid vehicl
e
s
. The
s
e
motors are e
s
sentially AC synch
r
o
nou
s motors
wit
h
perm
ane
nt magnet roto
rs. The Se
g
w
ay
Scoote
r
and
Vectrix Maxi-Scoote
r
u
s
e
BLDC te
c
h
n
o
logy. A number of el
ectric bi
cycle
s
use
BLDC moto
rs that a
r
e
so
m
e
times built i
n
to the
wh
ee
l hub
itself,
with the
stator
fixed soli
dly to
the axle and the magnet
s attache
d
to and rotating
wi
th the wheel.
T
here is a tre
nd in the HVAC
and
refrig
eration ind
u
st
ries to use BL
DC moto
rs
in
stead of vari
o
u
s type
s of
AC moto
rs .
T
he
mos
t
s
i
gnific
ant reason to
switc
h
to
a BLDC moto
r i
s
t
he d
r
am
atic redu
ction i
n
p
o
we
r
req
u
ire
d
to
operate them
versu
s
a typical AC m
o
tor.While
sha
ded-pole a
n
d
perma
nent
split ca
pa
cito
rs
motors on
ce
dominate
d
as the fan motor of choi
ce, m
any fans are now run u
s
in
g a BLDC m
o
tor.
Some fan
s
u
s
e BL
DC m
o
tors
also in o
r
der to in
crea
se overall
syst
em efficien
cy
.The appli
c
ati
o
n
of
bru
s
hle
ss DC (BLDC) motors
within
indust
r
ia
l en
ginee
ring p
r
i
m
arily focu
se
s on ma
nufa
c
turing
engin
eeri
ng
o
r
ind
u
st
rial
au
tomation d
e
si
gn. In m
anuf
acturi
ng, BL
DC m
o
tors a
r
e
prim
arily u
s
e
d
for motion
control, po
siti
oning o
r
a
c
t
uation
sy
ste
m
s. BLDC
motors are i
deally suite
d
fo
r
manufa
c
turi
n
g
appli
c
atio
ns be
ca
use
of
their high po
wer
den
sity, good spe
ed-to
rque
cha
r
a
c
teri
stics, high efficie
n
cy and
wide
spe
ed ra
nge
s and low mai
n
tenan
ce.
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 23
02-4
046
TELKOM
NI
KA
Vol. 14, No. 3, June 20
15 : 455 – 46
9
460
2.3. Modeling of BL
DC M
o
tor Driv
e
Comp
uter
simulation play
s a gre
a
t rol
e
in
research to analyze
the behavio
r of new
circuits, which leads to i
m
prove
d
und
ersta
ndin
g
of the circuit. In indust
r
y, they are u
s
e
d
to
sho
r
ten th
e o
v
erall d
e
si
gn
pro
c
e
s
s [6,
7], sin
c
e it i
s
usually e
a
si
er to
stu
d
y the influ
e
n
c
e
the
para
m
eter o
n
the
syste
m
beh
avi
our in sim
u
latio
n
, as
co
mpa
r
ed to
acco
mplishi
ng it i
n
the
laboratory
on
the h
a
rd
wa
re bread
boa
rd
.The
simulati
on i
s
u
s
e
d
to
cal
c
ulate
the
circuit
wavefo
rm,
the
dynami
c
and steady state
pe
rf
orm
a
nce of
the system,
voltage
and
cu
rre
nt rating of vari
o
u
s
comp
one
nts.
Simulink is
a
n
interactive t
ool for mod
e
li
ng, sim
u
latin
g
an
d p
r
ototyping
analo
g
a
nd
mixed sign
al
system usi
n
g t
he block sets rathe
r
than the line
of code. MATLAB/Simulink
platform i
s
be
ing u
s
e
d
in
in
dustri
e
s al
so
to simu
l
a
te
al
gorithm
s and
evaluat
e alternatives early
i
n
the desi
gn p
r
oce
s
s and
convenie
n
t tool for moni
to
ring
simulatio
n
re
sults.
Wh
en DC suppl
y is
swit
che
d
on t
o
the moto
r t
he a
r
matu
re
windi
ng d
r
a
w
s a
cu
rre
nt. The
curre
n
t d
i
stributio
n wit
h
in
the stato
r
armature
wi
ndi
ng d
epe
nd
s
upon
rotor
po
sition
and
the
device i
s
tu
rned
on. An
E
M
F
perp
endi
cul
a
r to perma
nen
t magnet field
is set up. T
h
en the armat
u
re
con
d
u
c
to
rs exp
e
rie
n
ce
a
force. Th
e re
active force d
e
velop
s
a torque in t
he rot
o
r. If this torque is mo
re th
an the opp
osi
ng
frictional
an
d
load
torq
ue,
the m
o
tor
st
arts. It i
s
a
self
starting
motor.As the
motor pi
cks up
spe
ed, the
r
e
exists a
rel
a
tive ang
ular veloci
ty b
e
twee
n the
pe
rman
ent ma
g
net field
and
the
armatu
re
co
n
ducto
rs. A
s
p
e
r F
a
ra
days l
a
w of
el
e
c
tro
m
agneti
c
in
d
u
ction, a
n
E
M
F is
dynami
c
ally
indu
ced in a
r
mature cond
uctors.Thi
s b
a
ck EMF as per Le
n’s l
a
w, opp
oses the cau
s
e (i.e)
armatu
re
cu
rrent an
d i
s
red
u
ce
d. As
a
re
sult
the
devel
oped
torq
ue
redu
ce
s. Final
ly the roto
r
wi
ll
attain a stead
y speed
whe
n
the develop
ed torqu
e
is e
x
actly equal to the oppo
sin
g
frictional lo
ad
toque. Th
us the moto
r
attains
a
steady state con
d
itio
n.Whe
n
the
l
oad-to
rq
ue i
s
increa
se
d, the
rotor spee
d t
end
s to fall.
As a
re
sult th
e ba
ck EMF
gene
rated
in
the armature
windi
ng ten
d
s
to
get red
u
ced.
Then the
cu
rrent dr
a
w
n f
r
o
m
the main
s i
s
in
cre
a
sed a
s
the
sup
p
ly voltage re
mai
n
s
constant.More torque is developed by the moto
r and it will attain a new dynamic equilibri
um
positio
n when
the develo
p
e
d
torq
ue i
s
eq
ual to
the
ne
w loa
d
torque
. Then the
po
wer drawn fro
m
the mains V*I
is equal to th
e mech
ani
cal
powe
r
delive
r
ed.
2.4.
General BLDC
Mo
tor Equation
2.4.1. Voltage Equation
The voltage e
quation i
s
given as
V dc= 2[
Rs I a+ (L
-M
) d I a / d t] + e1- e
2
= Ra I a + La d I a /d t +
e1-e
2
(1)
Whe
r
e:
V dc= Voltag
e of the DC supply, V.
Rs= Stator wi
nding resi
sta
n
ce,
Ω
/ph.
I a=
Armature
c
u
rrent, A.
L=Self Indu
ct
ance of stat
or wi
ndin
g
p
e
r ph
ase, H.
M=Mutu
al Indu
ctan
ce
betwe
en two
stator ph
ase
s
, H. e1=B
a
ck
EMF of the first cu
rren
t-ca
rrying
pha
se wi
ndin
g
, V.
e2=Ba
ck EMF of the seco
nd cu
rrent-ca
rrying p
h
a
s
e
windi
ng, V.
The
re
sultant
EMF a
c
ross the two p
h
a
s
e
win
d
ing
s
i
s
p
r
op
ortio
n
a
l
to the
moto
r
spee
d.
Hen
c
e the a
b
o
ve voltage e
quation
can b
e
written a
s
:
V dc=
Ra I a+ La d i a/ d t+
Kb
ω
(
2
)
2.4.2. Gener
a
l Torque Eq
uation
The ele
c
trom
agneti
c
torqu
e
is pro
p
o
r
tio
nal to stator
current and i
s
given by:
T
e
=
K
b
I
a
(
3
)
The load to
rq
ue whi
c
h vari
es with moto
r spee
d is give
n by:
TL=K T
ω
(
4
)
The me
cha
n
i
c
al eq
uation
of the rotor is:
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
De
sign a
nd Im
plem
entation of Em
bedded Pro
c
e
s
sor Based…
(Sa
t
hish kum
a
r Shanm
ugam
)
461
Te- TL
=J d
ω
/d t+
B
ω
(
5
)
Substituting
Equation (3)
and (4
) into Equation (5)
we get:
Kb I a- K T
ω
=J d
ω
/d t +
B
ω
(
6
)
Whe
r
e,
Kb=EMF con
s
tant of the motor, Vs/ rad (Nm/A).
ω
= Mechani
cal spe
ed of the rotor, rad /s.
Te=Ele
ctro
m
agneti
c
torqu
e
develop
ed
by the motor, Nm.
TL=L
oad T
o
rque, Nm.
KT=Lo
ad To
rque con
s
tant, N ms /rad.
The equ
ation
s
discu
s
sed h
e
re are used to dev
elop the param
eter
blocks. To trigger the
swit
che
s
of th
e inverters, P
W
M si
gnal
s a
r
e u
s
ed. To
o
b
tain the po
si
tion of therot
or of the BL
DC
for getting th
e app
ro
priate
swit
chin
g
se
quen
ce, the
rotor p
o
sitio
n
sen
s
o
r
s, i.e.
hall sen
s
ors
are
mounted o
n
the shaft of the rotor.Th
e
hall
signal
s generated
by these se
nso
r
s
will be
in
corre
s
p
ond
en
ce with that o
f
the rotor po
sition.
A swit
ching sequ
en
ce is gen
erate
d
usin
g the h
a
ll
sign
als a
nd the PWM si
gn
als are used to trigge
r the correpo
nding
switch
es of the
inverter.
2.5. Simulation Model of
BLDC Mo
tor
The BL
DC m
o
tor
has to
b
e
eq
uipp
ed
with a p
o
sitio
n
sen
s
o
r
whi
c
h
inform
s th
e
controlle
r
what th
e po
sition of the
rotor m
agneti
c
p
o
le i
s
,
wit
h
re
sp
ect to
the pa
rticul
ar
stator pha
se
windi
ng. This is done in o
r
der to switch
the motor O
N
and OFF [7]. The positio
n
sen
s
ors u
s
e
d
that are usually optical and Hall sensor. The en
coder
will act as a posi
tion sensor, in the
experim
ent carri
ed out in t
h
is
Re
sea
r
ch
. The mathe
m
atical m
ode
l of BLDC m
o
tor is
sh
own
in
this se
ction.
The stato
r
of a BLDC m
o
tor is
sim
ilar t
o
that of a poly phase AC i
ndu
ction mot
o
r.
The fun
c
tion
of the mag
net in the
ro
tor is to
idea
lly fix the air gap flux d
e
nsity. The
stato
r
windi
ng
s are
distrib
u
ted in
nature. Sin
c
e
BLDC moto
r drive is a sp
ecial ma
chi
n
e, an inverter is
requi
re
d for i
t
s ope
ration.
A typical BL
DC
drive
con
s
ist
s
of a Vo
ltage source
inverter, BL
DC
motor a
nd rotor po
sition
se
nso
r
s fo
r findi
ng the rotor p
o
sition afte
r e
v
ery swit
chin
g se
quen
ce
o
f
the inverte
r
. The ind
u
ced
voltages a
nd
curre
n
ts in a
BLDC
motor
drive a
r
e tra
p
e
zoi
dal in n
a
ture.
The Fig
u
re
6 sho
w
s the si
mulation mo
d
e
l of BLDC
M
o
tor d
r
ive an
d the mathe
m
atical e
quat
ions
that are mo
d
e
led a
r
e in
co
rporate
d
in the
SIMULI
NK bl
ock diag
ram
and the
cha
r
a
c
teri
stics of th
e
motor a
r
e
stu
d
ied from the
output
wavef
o
rm
s of
si
mul
a
tion. The
si
mulation
of the BLDC d
r
ive
is
discussed in this model.
Figure 6. Simulation Mod
e
l
of BLDC Mot
o
r
The BL
DC m
o
tor fe
d fro
m
a DC
so
urce
throug
h a
sta
ndard th
ree
p
hase inve
rter
bridg
e
.
Two
switche
s
sho
u
ld
be
con
d
u
c
ting fo
r eve
r
y patte
rn, o
ne from
lower leg
a
nd a
nothe
r from
uppe
r le
g
re
sulting in
alternate ex
citatio
n
of
two
pha
se
s at
a time
out of
thre
e
pha
se
s
whi
c
h
facilitates
con
t
inuou
s rotati
on of the roto
r. In
BLDC m
o
tors, the fiel
d is gene
rate
d by perman
ent
magnet
s mo
u
n
ted on
the
rotor, an
d the
rotating fiel
d i
s
ge
ne
rated
by mean
s of
stator
win
d
in
gs.
While n
o
po
wer is requi
red
for field excitati
on, lead
s to elimination
of rotor lo
sse
s
.
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KA
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15 : 455 – 46
9
462
2.6. Propose
d
Gener
a
l Circuit Diag
ra
m of BLDC
Motor
Figure 7 sh
o
w
s the bl
ock
diagram for a
3-pha
se BL
DC d
r
ives,
which
con
s
i
s
ts of a 3-
pha
se invert
er and a BL
DC moto
r. T
he 3-p
h
a
s
e i
n
verter u
s
e
s
a signal g
e
nerate
d
by the
microcontroll
er to trigge
r the po
wer d
e
vice to pr
o
d
u
c
e necessa
ry curre
n
t in the motor wi
ndin
g
for
rotor s
haft
rot
a
tion.
Figure 7. BLDC Moto
r Ci
rcuit
The i
n
verte
r
i
s
cont
rolle
d
by PWM
swit
chin
g
schem
es to
d
r
ive t
he BL
DC m
o
tor. Th
e
gating
sign
al
s of M
O
SFE
T
are
shifted
by 60º
by
each g
a
te to
obtain
a 3
-
pha
se
balan
ced
fundamental voltage
with 120º
phase shift.
The se
t
t
ing of the conducti
on
period i
s
done
by
prog
ram
m
ing
the d
e
si
red
on time
of th
e MOSFET
o
n
to the
micro
c
ontrolle
r. Th
ere
are
several
ways to m
o
d
u
late the mot
o
r d
r
ivers. We co
uld switch the high
an
d low
side
dri
v
ers tog
e
the
r
, or
just the high or low d
r
iver
while leavin
g
the ot
her dri
v
er on. Some high sid
e
MOSFET dri
v
ers
use a
capa
cit
o
r ch
arge pu
mp to boost the gate
drive
above the drain vo
ltage. Even though
this
appli
c
ation d
oes n
o
t use t
he ch
arg
e
pu
mp type dr
ivers,
we will
modulate the
high sid
e
dri
v
er
while leavin
g
the low side
driver on. Th
ere a
r
e
thre
e
high side d
r
i
v
ers, any on
e of which
co
uld
be active dep
endin
g
on the
position of the rotor.
PWM
is one of the swit
chin
g techniqu
es wi
del
y
use
d
in
controlling th
e o
u
tput of the
inv
e
rter e
s
pe
cial
ly in overco
m
i
ng the
ha
rm
onics
pro
b
le
m. It
is
kno
w
n
th
at PWM
met
hod
ca
n mo
ved the
un
wanted f
r
equ
e
n
cy
comp
on
ent to a
hig
her
freque
ncy re
gion. Co
nven
tional metho
d
of gene
rati
ng PWM
sig
nal is by u
s
i
ng a hig
h
rat
i
o of
carrie
r freq
u
ency si
gnal
and funda
me
ntal freque
ncy signal gen
erated via a
nalog
ue ci
rcuit.
Advance
m
ent
in the digital
techn
o
logy e
nable
s
PWM
swit
chin
g sch
e
mes to
be g
enerated u
s
in
g
digital co
ntrol
l
er (i.e. micro cont
rolle
r).
Throu
gh thi
s
tech
niqu
e, the harm
oni
cs co
ntent of the
output voltag
e can
be mi
nimize
d a
nd
redu
ce
d
signi
ficantly by
si
mply adju
s
tin
g
the
switchi
n
g
angle
s
of the
pulses
usi
n
g
the program
ming lan
gua
g
e
. Beside
s, g
enerating P
W
M u
s
ing
di
gital
controlle
r en
sures the
si
gnal re
main
s digital all the way from
the pro
c
e
s
so
r to the cont
ro
l
system. The
Pulse Wi
dth Modulatio
n (PWM)
swit
ch
ing schem
es has be
com
e
the essen
c
e
of
adju
s
ting
spe
ed in m
o
tor
drives sy
ste
m
. These
swi
t
ching
sche
m
e
s
can va
ry the ma
gnitud
e
of
the voltage across the terminals
of the
loads and
speed of
the
rot
o
r shaft. It is also
known t
hat,
the unwa
n
ted
frequen
cy compon
ent ca
n be moved
to a higher freque
ncy re
gi
on by means of
several P
W
M switchi
ng
scheme
s
.Ge
nerally, the
r
e
are
two
types
of PWM
mode
s o
p
e
r
a
t
ion
namely PWM
voltage mode and PWM curre
n
t mode
. PWM volta
ge mode de
rives its control
sign
al from th
e output voltage of the switchin
g
co
nvert
e
r. Mean
whil
e PWM curre
n
t mode utilizes
both the o
u
tput voltage i
n
formatio
n a
s
well as
cu
rre
nt inform
a
t
ion from the
indu
ctor in
the
swit
chin
g con
v
erter to d
e
te
rmine th
e de
sire
d duty cy
cle a
pplied to
the switchin
g tran
sisto
r
.
The
impleme
n
tation for PWM
current mo
de is quite
difficult com
pare
d
with the PWM voltage
mode.Th
e id
eal P
W
M
swi
t
ching
st
rate
gy for
po
wer ele
c
troni
cs
conve
r
ter is the o
ne th
at
ca
n
achi
eve the maximum po
ssi
ble voltage
or cu
rrent tr
a
n
sfer
ratio for a given co
nverter, ge
ne
rat
i
ng
minimum lo
w-order
harmo
nic a
nd cre
a
ting minimu
m
swit
ching l
o
sses. Th
e switching
sche
mes
are
used fo
r t
he g
a
ting
sig
nal of th
e Vol
t
age Sou
r
ce I
n
verter (VSI)
whi
c
h i
s
com
m
only u
s
ed
to
drive the BLDC motor. Usin
g the PWM switchi
ng sche
me, several p
a
ram
e
ter can
be adjuste
d to
gene
rate the
desi
r
ed volta
ge and fre
q
u
ency to the lo
ad.
2.7. PI Contr
o
ller Design
In
v
o
lv
ed
in
Proposed
Resear
ch Mod
e
l
PI is a feedb
ack controll
er
whi
c
h d
r
ives the plant to
be controll
ed
with a weight
ed sum
of the erro
r a
nd the integ
r
al of that value. PI
controll
ers
are
widel
y used inin
du
strial a
pplication,
due to their
simpli
city, low co
st and
robu
stne
ss.
T
hese co
ntroll
ers
can
also
be impleme
n
ted
easily th
roug
h anal
og
co
mpone
nts. T
he ge
neral o
peratio
n of P
I
can
be rep
r
esented
by
the
followin
g
equ
ation.
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TELKOM
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ISSN:
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046
De
sign a
nd Im
plem
entation of Em
bedded Pro
c
e
s
sor Based…
(Sa
t
hish kum
a
r Shanm
ugam
)
463
M(t)=
K
p e(t)
+
Ki e(t) dt
Whe
r
e,
e (t) is the sp
eed erro
r
M(t) is the o
u
tput of the con
t
roller
Kp is the pro
portion
al co
n
s
tant
Ki is the integral co
nsta
nt
H
e
re
th
e
c
o
n
t
r
o
ller
pr
o
v
id
es
an
ap
pr
o
p
r
i
a
t
e
feed
ba
ck
to the
system
ba
sed
on
th
e e
rro
r
sign
al. This feedb
ack ta
ke
s a
c
count of t
he mag
n
it
ude
as
well a
s
its rate of
cha
n
ge an
d integ
r
al
effec
t.
3. Results a
nd Analy
s
is
This Expe
rim
ental Re
sult
s
deal
s with h
a
r
dw
are imple
m
entation for Brushl
ess
DC moto
r
drive u
s
in
g PI
C Mi
crocontroller. T
he
se
q
uen
ce
of
tasks in
ha
rd
ware
implem
entati
on i
s
explai
n
e
d
as follo
ws. Fi
rst the h
a
ll sensor o
u
tput
s are det
e
c
te
d from the h
a
ll sen
s
o
r
s. The next ste
p
is
desi
gning
the
PIC
controlle
r
circuit in
PCB. T
he PIC coding
is programmed
next t
o
ge
nerate th
e
gate p
u
lses for firi
ng th
e i
n
verter ci
rcuit
.
The
se
que
n
c
e of step
s
in
clud
es
the de
velopment
an
d
testing of po
wer
sup
p
ly board. Fo
r im
plementin
g
the swit
chin
g p
a
ttern thre
e pha
se inverte
r
is
use
d
. The inverter is dev
elope
d and tested, test
e
d
circuits are cou
p
led. The
speed
control of
BLDC
motor is expe
rim
ented. Now in this
ch
apter
we h
a
ve explain
e
d
the ha
rd
ware
requi
rem
ents,
the respectiv
e
con
n
e
c
tion
diagram
s of different circuit
s
.
3.1. Hard
w
a
r
e
Requir
e
me
nts
The BLDC dri
v
e system co
nsi
s
ts of follo
wing different
module
s
.The
y are,
1)
Powe
r su
pply
module
2)
Control sig
nal
generation m
odule
3)
Inverter mod
u
le
4)
Powe
r MOSF
ET driver mo
dule
3.2. Po
w
e
r S
upply
Unit
Figure 8. LEAD ACID batte
ry powe
r
su
p
p
ly
circ
uit for PIC micr
oco
n
t
roller u
n
it
The PIC
Microco
n
trolle
r i
s
sup
p
lied
with
5 vo
lt. 7805
IC is
used fo
r PIC micro
c
o
n
trolle
r
unit power su
pply circuit an
d
Figure 9. Power
sup
p
ly circuit for drive
r
unit
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ISSN: 23
02-4
046
TELKOM
NI
KA
Vol. 14, No. 3, June 20
15 : 455 – 46
9
464
The
drive
r
u
n
i
t is
sup
p
lied
with 1
5
volt
DC. 78
15 I
C
i
s
used fo
r
driv
er
unit p
o
wer su
pply
c
i
rc
uit.
3.3. Driv
er U
n
it
Drive
r
unit is use
d
to gene
rate the gate
pulse for Se
pic co
nverte
r and Voltage
Source
Inverter
swit
ches. Th
e Fig
u
re 1
0
shows driver
u
n
it for BLDC moto
r drive
syste
m
. For isolati
ng
the low volta
ge ope
rate
d
control ci
rcuit
from the hig
h
po
wer
circu
i
t called o
p
to-cou
pler
or o
p
t
o-
isolato
r
s a
r
e
use
d
.
Figure 10. Dri
v
er Circuit for propo
se
d BL
DCM
system
So the opto isolato
r
s a
r
e
use
d
in between the
pic microcontroll
er
ci
rcuit and
the driver
circuit. The P
I
C micro
c
ont
roller pi
ns f
r
o
m
s1 to
s6
are used to
co
ntrol the M
O
SFET gate d
r
iver.
And the MOSFET gate driv
er ca
n be ge
n
e
rated t
he g
a
t
e pulse
s to e
a
ch
swit
ch of VSI and DC to
DC conv
e
r
ter
.
3.4. Optoco
u
p
ler
The opti
c
ally
cou
p
led i
s
ol
ator o
r
opto
cou
p
ler
wa
s
the device which
co
ntain
s
at least
one
emitter
whi
c
h i
s
o
p
tically
coupl
ed
to a p
hoto
detecto
r th
ro
ugh
som
e
sort of an i
s
olat
ing
medium. Thi
s
arran
geme
n
t permits th
e passa
ge
of
information
from one
whi
c
h contain
s
the
emitter to th
e
other ci
rcuit
passe
d
o
p
tically acro
ss a
n
in
sulatin
g
g
ap; the t
r
an
sf
er i
s
o
ne
way
that
is the
dete
c
t
o
r
can
not
affect the
inp
u
t ci
rcuit. This is i
m
po
rtant
be
cau
s
e
the
emitter
may
be
driven by a low voltage circuit utilizing logic gate
s
whi
c
h the output of the photo detecto
r may be
part of a high voltage dc or ac. Opto
isolator
typi
cally com
e
s
in a small 6-pin or 8-pin
IC
packa
ge, but is esse
ntially a comb
i
natio
n of two disti
n
ct devices:
an optical tra
n
smitter, typically
a gallium
arsenide
LED
(li
ght-emitting
d
i
ode) and
an
optical re
ceiv
er su
ch
a
s
a
phototra
nsi
s
t
o
r
or light-tri
gg
ered di
ac. T
he two are sep
a
rate
d
by a transp
a
re
nt barri
er which blo
cks any
electri
c
al
cu
rrent flow bet
ween
the two, but doe
s allo
w the pa
ssag
e of light. The basi
c
id
ea i
s
sho
w
n, alo
n
g
with the usu
a
l circuit sym
bol for
an opt
o isolato
r
.The
6N13
5 opto i
s
olato
r
co
nsi
s
ts
of a light-emi
tting diode a
nd an inte
gra
t
ed photon
d
e
tector
co
mp
ose
d
of a ph
otodiod
e and
an
open
-colle
cto
r
output tran
sistor. Sepa
rat
e
con
n
e
c
tion
s are p
r
ovid
e
d
for the phot
odiod
e bias a
n
d
the tran
sisto
r
-colle
ctor o
u
tp
ut.
3.5. PIC 16F877
A Microc
ontroller
The PIC 16F
877A Micro
c
o
n
trolle
r [3] is the prim
e co
ntrolle
r of this p
r
oje
c
t. It controls the
operation of
Sepic co
nver
ter an
d Volta
ge Sou
r
ce In
verter a
s
so
ci
ated in thi
s
p
r
oje
c
t. The P
I
C
16F87
7A mi
crocontroller
gi
ves control si
gnal to th
e
M
O
SFET drive
circuit. Th
e variou
s feat
ures
pre
s
ent i
n
th
is PIC1
6F87
7A help
s
to
achi
eve
an
effective con
t
rol over BL
DC
Motor drive.
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