TELKOM
NIKA Indonesia
n
Journal of
Electrical En
gineering
Vol.12, No.7, July 201
4, pp
. 5129 ~ 51
3
6
DOI: 10.115
9
1
/telkomni
ka.
v
12i7.577
2
5129
Re
cei
v
ed Fe
brua
ry 1, 201
4; Revi
se
d March 21, 201
4
;
Accepte
d
April 3, 2014
Investig
ating the Effect of Different PWM Modes on
Ripple Reduction in Five-Phase BLDC Motor with Ne
w
Method
Se
y
e
d Mohsen Mirbaghe
ri*
1
, Se
y
e
d S
a
jjad Salehi GHalehsefid
2
,
Se
y
e
d Mohammad Hoss
ein Mousav
i
3
1,2
Department of Electrical En
gin
eeri
ng, Masj
ed-so
leim
an Br
anch, Islamic A
z
ad Un
iversit
y
,
Masje
d
-sol
eim
an, Iran
3
Departme
n
t of Electrical En
gi
neer
ing, Ma
hshahr Bra
n
ch, Islamic Aza
d
Uni
v
ersit
y
, Mahs
h
ahr, Iran
*Correspo
n
d
in
g auth
o
r, e-mail: m89.mirb
agh
eri@
gmai
l.com
1
, s.salehi1
983
@gma
il.co
m
2
,
mohamm
adh
o
s
ein
64@
gmai
l.com
3
A
b
st
r
a
ct
Torque
r
i
pp
le i
s
one of
the main draw
backs of
brus
h
l
ess D
C
motors. In the cas
e
of thre
e ph
a
s
e
motors, PW
M mo
des h
a
ve a
signific
ant effe
ct on t
he gen
e
r
ated torqu
e
ri
ppl
e. So, like three p
has
e BL
DC
motors, w
e
inv
e
stigate the eff
e
ct
of different PW
M modes o
n
torque ri
ppl
e
of five-phase
BLDC
motor th
at
has l
e
ss torq
u
e
rip
p
le
in
hig
h
spee
d. In this
investi
gatio
n w
e
w
ill sh
ow
tha
t
freew
heeli
ng
current i
n
in
act
i
ve
phas
e is i
m
port
ant factor in torque ri
ppl
e. Also
simul
a
tion i
n
matl
ab/Si
muli
n
k
prove this ev
ent.
Ke
y
w
ords
: five-ph
a
se BL
DC
motor, PW
M control, ne
utral
poi
nt
Copy
right
©
2014 In
stitu
t
e o
f
Ad
van
ced
En
g
i
n
eerin
g and
Scien
ce. All
rig
h
t
s reser
ve
d
.
1. Introduc
tion
BLDC m
o
tors with trape
zoi
dal indu
ce
d e
m
f waveform
have sig
n
ifica
n
t advantage
s such
as high effici
ency, good
power de
nsit
y, operati
on in high sp
ee
ds and requi
reme
nt to less
prote
c
tion. S
o
, these
mot
o
rs are
widel
y used
in in
dustri
e
s like
comp
uter, h
o
m
e ap
plian
c
es,
indu
strial aut
omation, etc [1].
However,
the
m
a
in
dra
w
ba
ck of th
e
s
e
motors i
s
the existe
nce
of
high
rippl
e i
n
outp
u
t torq
ue. The
maj
o
r
cau
s
e
of
the ge
nerate
d
rip
p
le i
s
d
ue to tu
rn
-o
n of
freewheeli
ng
diode
s conn
e
c
ted to ina
c
tive phase an
d cu
rre
nt flow in this ph
a
s
e. Two fact
ors
lead to turn
-on of diod
es conne
cte
d
to t
he inactive pha
se
. First one is the indu
ctive
cha
r
a
c
teri
stic of motor winding
s whi
c
h
prevent
s fro
m
being zero of inactive phase cu
rre
nt
immediately
after switch-off. So it tak
e
s time for
the
c
u
rrent to bec
o
me ze
ro
and this
leads to
curre
n
t flow
in ina
c
tive p
hase. Thi
s
p
r
ocedu
re
an
d its effe
ct on torque
ri
pple h
a
s
be
en
investigate
d
compl
e
tely in
[2]. Secon
d
factor
is th
e
existen
c
e
of indu
ced
emf
and
switchi
n
g
method
whi
c
h, in certain
con
d
ition
s
ca
use th
e
fo
rward
bia
s
of d
i
ode
s conn
ected to ina
c
tive
pha
se a
nd le
ad to current
flow in in
activ
e
pha
se
and
make
s to
rqu
e
ripple
[3]. The se
co
nd fa
ctor
has
wide
r ran
ge and
effect
. As mention
ed in the
ab
stract, pha
se i
n
crea
sing i
s
one of the ri
p
p
le
redu
ction
me
thods in
high
sp
eed
s [4, 5
]. Also,
switching
method
is effe
ctive in
torq
ue
rippl
e
of
motors with i
n
crea
sed
pha
se. In this
pa
per,
we inten
d
to investig
a
t
e the differe
n
t
PWM mod
e
s
of
five-pha
se
m
o
tor
and
its
effect on
torq
ue
ripple
a
s
i
t
has be
en
a
l
ready
don
e f
o
r th
ree
ph
a
s
e
motors
in [6-8].
This paper
i
s
organized
as follows.
Five pha
se
BLDC motor will
be
i
n
troduced in
section
II. In section
III, different
PWM modes will be
anal
y
z
ed. T
he
sim
u
lation of Torque in
differen
t
PWM mod
e
s
and con
c
lu
sio
n
are p
r
e
s
ent
ed in se
ction
IV and V, respectively.
2. Introduc
tion of Fiv
e
Phase BLDC
Motor
A five phase motor alo
ng
with its drive
are sho
w
n in
Figure 1.
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 23
02-4
046
TELKOM
NI
KA
Vol. 12, No. 7, July 201
4: 5129 – 51
36
5130
Figure 1. Equivalent Circuit
of Five-pha
se BLDC M
o
to
r
Perman
ent m
agnet i
s
pla
c
ed o
n
the
rotor
and
the
waveform
of th
e ind
u
ced
em
f will b
e
trape
zoid
al. T
h
is m
o
tor is supplie
d by
a rectan
gula
r
cu
rre
nt, so
the
output to
rque
is th
eo
retical
l
y
con
s
tant a
nd
without
ripple
.
But actually
it is
not true a
nd the
r
e
will
be ri
pple i
n
th
e output to
rq
ue
due to the co
ndu
ction of freewheelin
g d
i
ode
s and cu
rre
nt flow in inactive ph
ase [3]. In normal
operation, fo
ur ph
ases of
the five phase motor a
r
e
a
c
tive and on
e
is inactive. T
w
o of four a
c
t
i
ve
pha
se
s have
positive
cu
rrent flow
and
two othe
r p
h
a
se
s h
a
ve n
egative curre
n
t flow. Figu
re 2
sho
w
s the ind
u
ce
d emf wa
veform and th
e pha
se curre
n
t of five phase BLDC mot
o
r
.
a
a
i
e
,
b
b
i
e
,
c
c
i
e
,
d
d
i
e
,
e
e
i
e
,
5
5
2
5
3
5
4
5
6
5
7
5
8
5
9
2
Figure 2. The
Waveform of
Induce
d
emf and t
he Pha
s
e Curre
n
t of Five Phase B
L
DC Motor
3. Analy
s
is o
f
Differe
n
t P
W
M Mode
s
There are f
our PWM
mode
s in three p
h
a
s
e
motors: O
N
_PWM, PWM_
ON,
H_O
N
_
L_PWM and
H_P
W
M_L_O
N [6,
7]. In this se
cti
on, we inve
stigate the effe
ct of these fo
ur
mode
s on torque rip
p
le of five phase mo
tor.
3.1. ON_P
WM Mode
The ind
u
ced
emf wavefo
rm and th
e switchi
ng
sche
me of five ph
ase B
L
DC m
o
tor d
r
ive
are
shown in Figure 3.
We as
sume that the motor
operates in
A&B region.
The equations of
motor termi
n
al voltages a
r
e
expresse
d
as (1
) where U
dc
is the
dc lin
k voltage and S is
the
swit
chin
g fun
c
tion of e
a
ch
pha
se. When
S=1, the
up
p
e
r switch is
o
n
and the l
o
wer switch is
o
f
f,
and when S=0, the lower
switch i
s
on and the upper switch i
s
off.
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
Inve
stigating
the Effect of
Different PW
M Mode
s on
Rippl
e… (Se
y
ed Mo
hsen
Mirba
ghe
ri)
5131
)
(
d
b
n
n
n
n
n
e
d
c
b
e
d
c
b
e
d
c
b
dc
d
dc
dc
b
S
S
V
V
V
V
V
e
e
e
e
i
i
i
i
dt
d
L
L
L
L
i
i
i
i
R
R
R
R
U
S
U
U
S
1
4
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(1)
In Equation
(1), i
b
, i
c
, i
d
, i
e
are th
e ph
ase
cu
rre
nts, e
a
, e
b
, e
c
, e
d
, e
e
are th
e ind
u
ced ph
ase
voltages, V
n
is neutral voltage with refe
ren
c
e to gro
und, R is the windin
g
re
sista
n
ce of each
pha
se a
nd L
is the in
du
cta
n
ce
of pha
se
. Also i
b
=i
c
=-
i
d
=-i
e
an
d e
b
=e
c
=-
e
d
=-
e
e
. Accordi
ng to t
he
different valu
es of S
b
, S
d
, the neutral voltage will have
different values a
s
in (2
).
1
4
3
0
1
1
0
2
1
0
4
1
d
b
dc
d
b
b
dc
d
b
dc
S
S
U
S
S
Sd
S
U
S
S
U
Vn
,
,
(2)
a
a
i
e
,
b
b
i
e
,
c
c
i
e
,
d
d
i
e
,
e
e
i
e
,
5
5
2
5
3
5
4
5
6
5
7
5
8
5
9
2
Figure 3. The
Induce
d
Voltage Waveform and Sw
itch
ing Sche
me o
f
Five Phase BLDC M
o
tor
Drive in ON-PWM Mode
The in
du
ced
voltage i
s
p
o
s
itive in
regi
o
n
A.
It ca
n b
e
prove
d
that
the in
du
ced
voltage i
n
five phase
m
o
tor is
alway
s
le
ss tha
n
0.5U
dc
[3]. From Equation
(2), the te
rminal voltage
of
inactive ph
ase a is expre
s
sed a
s
:
dc
a
dc
dc
a
dc
dc
a
dc
dc
a
dc
n
dc
n
a
a
n
dc
a
U
U
U
U
U
U
U
U
U
U
U
U
V
U
V
e
U
V
U
e
4
5
4
1
4
5
4
3
2
1
4
3
4
1
2
1
2
1
0
(3)
Acco
rdi
ng to
(3),
sin
c
e t
he termi
nal
voltage exce
eds
U
dc
, the
n
diod
e
D
1
is
fo
rw
ar
d
biased an
d causes
curre
n
t flow in inacti
ve phase
a. No
w we a
s
su
me to be in operatin
g re
gio
n
B.
Then the terminal voltage
of phase a i
s
expresse
d a
s
:
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 23
02-4
046
TELKOM
NI
KA
Vol. 12, No. 7, July 201
4: 5129 – 51
36
5132
dc
a
dc
dc
a
dc
dc
a
dc
a
dc
n
n
a
a
dc
n
a
dc
U
U
U
U
U
U
U
U
U
U
U
V
V
e
U
U
V
e
U
4
3
4
1
4
3
4
1
2
1
0
4
1
4
1
2
1
0
2
1
(4)
From
Equati
on (4),
sin
c
e
the terminal
voltage
be
comes ne
gati
v
e then
diod
e D
2
is
forwa
r
d
bia
s
ed an
d cau
s
es
curre
n
t flow in i
n
a
c
tive pha
se
a. Therefore i
n
ON_P
WM m
ode,
c
u
rrent flows
in both region A&B.
3.2. PWM_O
N
Mode
The ind
u
ced
emf wavefo
rm and the
switchi
ng sch
e
m
e of the mo
tor drive a
r
e
sho
w
n in
Figure 4. With a dedu
ction
similar to (1
),
the neutral voltage is a
s
:
)
(
e
c
n
S
S
V
1
4
1
(5)
Acco
rdi
ng to the different value
s
of S
c
and S
e,
the neu
tral voltage wi
ll have differe
nt values a
s
:
1
4
3
0
1
1
0
2
1
0
4
1
e
c
dc
e
c
e
c
dc
e
c
dc
S
S
U
S
S
S
S
U
S
S
U
Vn
,
,
(6)
With a
pro
c
e
dure
simil
a
r t
o
wh
at we u
s
ed for
(3
) a
n
d
(4
), it is
co
nclu
ded th
at
whe
n
the
motor i
s
in th
e ope
ratin
g
region A, the
current of
in
act
i
ve pha
se
a is in the n
egati
v
e dire
ction
a
n
d
whe
n
it is in the operatin
g regio
n
B, the cu
rre
nt of inactive ph
ase a flo
w
s
in the positiv
e
dire
ction. So
the current
flows in
both
region
s
A a
nd B in
PW
M_O
N
mo
de
and
ca
us
es
torq
u
e
ripple.
a
a
i
e
,
b
b
i
e
,
c
c
i
e
,
d
d
i
e
,
e
e
i
e
,
5
5
2
5
3
5
4
5
6
5
7
5
8
5
9
2
Figure 4. The
Induce
d
Voltage Waveform and Sw
itch
ing Sche
me o
f
the Five Ph
ase BL
DC
Motor Drive in PWM_ON
Mode
3.3- H_
ON_L
_PWM mode
The indu
ce
d voltage wave
form and swit
chin
g schem
e of five phase BLDC mot
o
r drive
are sho
w
n in
Figure 5. The
equation
s
of motor term
i
n
al voltages in
regio
n
A,B are expre
s
sed
as:
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
Inve
stigating
the Effect of
Different PW
M Mode
s on
Rippl
e… (Se
y
ed Mo
hsen
Mirba
ghe
ri)
5133
)
(
e
d
n
n
n
n
n
e
d
c
b
e
d
c
b
e
d
c
b
dc
e
dc
d
dc
dc
S
S
V
V
V
V
V
e
e
e
e
i
i
i
i
dt
d
L
L
L
L
i
i
i
i
R
R
R
R
U
S
U
S
U
U
2
4
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(7)
Acco
rdi
ng to
the differe
nt value
s
of S
d
, S
e
, the neutral voltage
will
have differen
t
values
as in (8
). It is assume
d that t
he motor is i
n
operating region A.
1
0
1
1
0
4
3
0
2
1
e
d
dc
e
d
e
d
dc
e
d
dc
S
S
U
S
S
S
S
U
S
S
U
Vn
,
,
(8)
The in
du
ced
voltage is po
sitive in this
re
gion.
With
a
pro
c
ed
ure si
milar to th
at p
r
eviou
s
ly
mentione
d, the voltage terminal of the inactive ph
ase a is as
(9).
dc
a
dc
dc
a
dc
dc
a
dc
dc
a
dc
n
dc
n
a
a
n
dc
a
U
U
U
U
U
U
U
U
U
U
U
U
V
U
V
e
U
V
U
e
2
3
2
1
2
3
4
5
4
3
2
1
2
1
2
1
0
(9)
a
a
i
e
,
b
b
i
e
,
c
c
i
e
,
d
d
i
e
,
e
e
i
e
,
5
5
2
5
3
5
4
5
6
5
7
5
8
5
9
2
Figure 5. The
Induce
d
Voltage Waveform and Swit
ch
ing Sche
me o
f
Five Phase BLDC M
o
tor i
n
H_O
N
_
L_PWM Mode
Since the
terminal voltage
of pha
se a
e
x
ceed
s
U
dc
then dio
de
D
1
is forwa
r
d bi
a
s
ed
and
c
a
us
es
c
u
rrent
flow. Now it
is
ass
u
med
that
th
e
mot
o
r
ope
rate
s i
n
region
B.
With a
de
du
ction
simila
r to
(9
), Equation
(1
0) i
s
obtaine
d. Fro
m
(10
)
we
con
c
lud
e
that the
dio
de i
s
n
o
t forward
biased in
re
g
i
on B an
d
cu
rre
nt doe
s
no
t flow in in
act
i
ve pha
se
a. So the
curre
n
t only flows
in
regio
n
A in H_ON_L_P
WM mode, i.e. the torqu
e
rip
p
le is lo
wer.
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 23
02-4
046
TELKOM
NI
KA
Vol. 12, No. 7, July 201
4: 5129 – 51
36
5134
dc
a
dc
a
dc
dc
a
dc
dc
a
n
n
a
a
dc
n
a
dc
U
U
U
U
U
U
U
U
U
U
V
V
e
U
U
V
e
U
0
2
1
4
3
4
1
2
1
0
2
1
0
2
1
(10)
3.4. H_PWM
_
L_O
N
Mode
The ind
u
ced
voltage wave
form and
switchin
g sche
m
e
of five phase d
r
ive are sho
w
n in
Figure 6. The
terminal voltage
s of active
pha
se
s in region A, B are expre
s
sed
as:
)
(
c
b
n
n
n
n
n
e
d
c
b
e
d
c
b
e
d
c
b
dc
c
dc
b
S
S
V
V
V
V
V
e
e
e
e
i
i
i
i
dt
d
L
L
L
L
i
i
i
i
R
R
R
R
U
S
U
S
4
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(11)
a
a
i
e
,
b
b
i
e
,
c
c
i
e
,
d
d
i
e
,
e
e
i
e
,
5
5
2
5
3
5
4
5
6
5
7
5
8
5
9
2
Figure 6. The
Induce
d
Voltage Waveform and Swit
ch
ing Sche
me o
f
Five Phase BLDC M
o
tor i
n
H_PW
M_L
_
O
N Mo
de
Acco
rdi
ng to the different value
s
of S
b
, S
c
, the neutra
l voltage is ob
tained a
s
follows:
1
2
1
0
1
1
0
4
1
0
0
c
b
dc
c
b
c
b
dc
c
b
S
S
U
S
S
S
S
U
S
S
Vn
,
,
(12)
It is assum
e
d
that the motor is in op
era
t
ing
regio
n
A. The terminal
voltage of phase a i
s
obtaine
d with
a similar d
e
d
u
ction:
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TELKOM
NIKA
ISSN:
2302-4
046
Inve
stigating
the Effect of
Different PW
M Mode
s on
Rippl
e… (Se
y
ed Mo
hsen
Mirba
ghe
ri)
5135
dc
a
dc
a
U
U
U
e
0
2
1
0
(13)
Acco
rdi
ng to
(13
)
it is con
c
luded that th
e cu
rrent doe
s not flow i
n
region A. In re
gion B,
a simila
r ded
uction le
ad
s to Equation (1
4)
dc
a
dc
a
dc
U
U
U
e
U
2
1
2
1
0
2
1
(14)
So from (14
)
it is seen that
the current fl
ows in inactiv
e
phase a in operating re
g
i
on B.
So the curren
t only flows in
region B in H_PWM_
L_O
N mode, i.e. the torqu
e
rip
p
le is lo
wer.
According
to
a
nal
ysis
pre
s
e
n
te
d
in
se
ction
3,
Table
1
shows
th
e
ob
tained
re
sult
s.
Simulation
s in se
ction 4 prove Table 1 result
s.
Table 1. Obta
ined Results from Se
ction 3
Existence of free
w
h
eeling current
Torque
ripple
ON_P
W
M
Both A&B region
s
high
PWM_O
N
Both A&B region
s
high
H_ON
_L_PWM
Region A onl
y
low
e
r
H_PWM_L_ON
Region B onl
y
low
e
r
4. Simulation
From
the
an
alyse
s
p
r
e
s
e
n
ted in
secti
on 3
we
con
c
lud
e
that i
n
H_
ON_L_P
WM
and
H_PWM_L
_
O
N m
ode
s, t
he current i
n
inactive p
h
a
s
e 'a'
only flows in
one
of th
e two
regi
on
s
A,
B, i.e. the cause
of gen
erating torque
ripple em
erge
s less,
so the torque ripple will be l
o
w.
This
scena
rio is
si
mulated in m
a
tlab/Simulin
k for a moto
r with cha
r
a
c
t
e
risti
cs
pre
s
e
n
ted in Tabl
e
.
2
.
Simulation m
e
thod h
a
s
be
en ad
apted from [3]. In this pape
r si
mula
tions for th
re
e
-
pha
se
motor is
done
and
we
have d
e
velo
ped the
mod
e
l for five p
h
a
se
motor. Al
so g
ene
ral
d
e
scriptio
n of
the
five-phas
e
motor is
done in [5].
Table 2. Para
meters of the Five Phase M
o
tor
R
L
speed
0.33(ohm
)
0.67(mH
)
800(rpm
)
K
e
K
t
J
0.066(V/r
p
m)
1.25(N.m/A
)
.0005(Kg.m
^2)
T
load
V
dc
Z
p
28(N.m)
180(V)
8
Figure 7 to Figure 1
0
sh
ow the torque wave
form
s for four different control mo
de
s.
Figure 7. The
Torqu
e
of H_
ON_
L_PWM Mode
Figure 8. The
Torqu
e
of H_
PWM_L
_
O
N
Mode
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ISSN: 23
02-4
046
TELKOM
NI
KA
Vol. 12, No. 7, July 201
4: 5129 – 51
36
5136
Figure 9. The
Torqu
e
of PWM_
ON Mo
d
e
Figure 10. Th
e Torq
ue of ON_P
WM M
ode
Acco
rdi
ng to Table 1, it is see
n
in the Fi
gure 7
-
10 tha
t
torque rippl
e
in case
s 3.3 and 3.4
is le
ss th
an
case
s 3.1
and
3.2. becau
se
in ca
se
s 3.3
and 3.4 free
whe
e
ling
cu
rrent flows in o
ne
regio
n
whil
e in ca
se
s 3.1 a
nd 3.2 free
wh
eeling
current
flows in two
region
s A and
B.
5. Conclusio
n
In this paper,
four different
control mo
de
s
for five phase BLDC mot
o
r wa
s prese
n
ted as
it was alre
ad
y done for three pha
se BL
DC moto
rs. T
he most impo
rtant factor in
making torq
ue
ripple
was
cu
rre
nt flow i
n
i
nactive p
h
a
s
e. The
anal
y
s
is of this issue
sho
w
ed
that in m
ode
s in
whi
c
h the co
ntrol of uppe
r and lower
swit
che
s
is d
one se
pa
rate
ly, have lower torqu
e
rippl
e.
Simulaion
s
in
matlab/Simulink proved thi
s
re
sult.
Ackn
o
w
l
e
dg
ements
The autho
rs would like
to thank Khuze
s
tan
Regi
onal Ele
c
tri
c
Com
p
a
n
y for its
coo
peration.
Referen
ces
[1]
Krishn
an
Ram
u
. Perma
nent
magn
et s
y
nchr
ono
us a
nd bru
s
hless dc
mot
o
r
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a
ylor
&
francis. 200
9: 115-
117.
[2]
R Carlso
n, M
Laj
oie-M
a
zenc,
J F
agundes. Anal
ys
is
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p
l
e
due
to phase com
m
utation i
n
brush
l
ess dc m
a
chi
nes.
IEEE Transactio
n
on
Industrial Ap
pl
icatio
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2– 6
3
8
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[3]
W
Kun, Hu C
h
eng, Z
Ch
ao.
A nove
l
PW
M scheme to
el
iminate th
e d
i
od
e
free
w
h
eel
in
g i
n
the i
nactiv
e
phas
e in BL
DC
motor.
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e society for el
ectrical e
ngi
ne
erin
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4-19
8.
[4]
T
Goplarath
n
a
m
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a
ikar.
Devel
o
p
m
ent
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cost mu
lti-ph
ase
br
ush
l
ess dc
motors
w
i
th unipo
la
r
current excitati
ons.
IEEE Indu
strial App
licati
o
ns
Confer
enc
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[5]
X
Xi, W Yufei,
C Jiany
u
n
. Per
f
ormance
an
al
ysis
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lti-ph
as
e PM
brush
l
ess dc m
o
tor d
r
ive s
y
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.
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03; 1:
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[6]
Z
Xian
gj
un, C Boshi. Influe
nc
e of PW
M mode on
the curre
n
t
generate
d
b
y
bemf of s
w
itc
h
-off phase i
n
control s
y
stem
of BLDC motor
.
IEEE Electrical Machines and System
s Conference
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20
01; 579-
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[7]
L Mingj
i, G Hanjin, S Meih
on
g. Rippl
e T
o
rque Ana
l
ysis an
d Simulati
on of
BLDC Motor w
i
t
h
Differen
t
PW
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ao, HS L
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mmutati
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ue rip
p
l
e
red
u
c
t
ion i
n
BLD
C
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ng PW
M_ON_PW
M
mo
de.
Electric
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n
d
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o
n
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erence
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