SHANTILAL SHAH ENGINEERING COLLEGE BHAVNAGAR
DEPARMENT OF ELECTRICAL ENGINEERING
ACADEMIC YEAR 2015-16
POWER ELECTRONICS-II
3-Phase Inverter 180 degree conduction mode
S.NO NAME ENROLLMENT 1 SUDHIR SINGH 130430109052 2 BHAVIN PATEL 130430109039 3 SAMIR DABHI 130430109011
Faculty: PROF.J.K.CHAVDA
dc
LOAD
3-Phase Inverter Circuit
180 degree conduction mode This is a controlling scheme for 3-phase inverter. Each switch conduct for period of 180 degree. Switches are triggered in sequence of their numbers with an interval of 60 .⁰ At a time, three switches(one from each leg) conduct. Two switches of same leg are prevented from conducting. Switch pair in each leg, i.e. S1 , S4,S3 , S6 and S5 , S2. One complete cycle is divide into 6 modes.
Table for gatting scheme
S.NO INTERVAL DEVICE CONDUCTING INCOMING DEVICE OUTGOING DEVICE
1 I 5, 6, 1 1 4
2 II 6, 1, 2 2 5
3 III 1, 2, 3 3 64 IV 2, 3, 4 4 1
5 V 3, 4, 5 5 2
6 VI 4, 5, 6 6 3
Waveform of gating signals
wt
wt
wt
wt
wt
wt
0
0
0
0
0
0
g1
g2
g3
g4
g5
g6
π 2
/ 3
2 / 3
Analysis of 180 degree conduction for 3-phase inverter
The waveform of 3-phase inverter for 180 degree conduction divided into six interval of 60 degree for complete 360 degree interval.
Interval 1 Operation0
3t
1
1
1
32 223
2 323
eq
s s
eq
san cn
sbn
R RR R
V Vi
R R
Vi Rv v
Vv i R
SV
R
R
R
NC
AI 1
Interval 2 Operation 23 3
t
2
2
2
32 223
23
2 3
eq
s s
eq
san
sbn cn
R RR R
V Vi
R R
Vv i R
Vi Rv v
Interval 3 Operation 23
t
3
3
3
32 223
223
eq
s s
eq
an bn
scn
R RR R
V ViR R
iv v
Vv i R
Output phase voltage for star connected load
INTERVAL I II III IV V VI
Waveform for phase voltage
wt
wt
wt
2 3
2
3
32
0
0
0
3sv
3sv
3sv
3sv
23sv
23sv
Van
Vbn
Vcn
Fourier Series for Line-to-Line Voltages
1
5 56 6
56 6
1,3,5,...
( cos( ) sin( ))2
1 ( ) ( )
4 sin( )sin( )2 3
4sin sin ( )
3 6
oab n n
n
n s s
sn
sab
n
av a n t b n t
b V d t V d t
V n nbn
V nv n tn
1,3,5,...
1,3,5,...
4 sin sin ( )3 2
4 7sin sin ( )3 6
sbc
n
sca
n
V nv n tnV nv n tn
12 23
2
0
2 ( )2
2 0.81653
L s
L s s
V V d t
V V V
Line to line rms voltage
RMS value of the nth Component
1
4 sin32
14 sin 60 0.7797
2
sLn
sL s
V nVn
nVV V
THANK YOU
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