This document discusses 180 degree conduction mode for a 3-phase inverter. It contains the following information: 1) In 180 degree conduction mode, each switch conducts for a period of 180 degrees with switches triggered in a sequence with an interval of 60 degrees. At any time, three switches (one from each leg) conduct. 2) The complete cycle is divided into six modes with the switching sequence and conducting devices specified for each interval. 3) Equations are provided for the operation and output voltages of each interval along with waveform diagrams showing the phase voltages and line-to-line voltages. 4) Fourier analysis is used to derive expressions for the fundamental and higher order harmonic components of

1. SHANTILAL SHAH ENGINEERING COLLEGE
BHAVNAGAR
DEPARMENT OF ELECTRICAL ENGINEERING
ACADEMIC YEAR 2015-16
POWER ELECTRONICS-II

2. 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

3. dc
LOAD
3-Phase Inverter Circuit



4. 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 60⁰.
 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.

5. 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 6
4 IV 2, 3, 4 4 1
5 V 3, 4, 5 5 2
6 VI 4, 5, 6 6 3

6. 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

7. 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 Operation
0
3
t

 
1
1
1
3
2 2
2
3
2 3
2
3
eq
s s
eq
s
an cn
s
bn
R R
R R
V V
i
R R
Vi R
v v
V
v i R
  
 
  

  


SV
R
R
R
NC
A
I 1

8. Interval 2 Operation2
3 3
t
 
 
2
2
2
3
2 2
2
3
2
3
2 3
eq
s s
eq
s
an
s
bn cn
R R
R R
V V
i
R R
V
v i R
Vi R
v v
  
 
 

  

9. Interval 3 Operation 2
3
t

  
3
3
3
3
2 2
2
3
2
2
3
eq
s s
eq
an bn
s
cn
R R
R R
V V
i
R R
i
v v
V
v i R
  
 
 

 

10. Output phase voltage for star connected load
INTERVAL I II III IV V VI
𝑉𝐴𝑁
𝑉𝑠
3
2𝑉𝑠
3
𝑉𝑠
3
−𝑉𝑠
3
−2𝑉𝑠
3
−𝑉𝑠
3
𝑉𝐵𝑁 −2
𝑉𝑠
3
− 𝑉𝑠
3
𝑉𝑠
3
2 𝑉𝑠
3
𝑉𝑠
3
− 𝑉𝑠
3
𝑉𝐶𝑁
𝑉𝑠
3
− 𝑉𝑠
3
−2𝑉𝑠
3
−𝑉𝑠
3
𝑉𝑠
3
2𝑉𝑠
3

11. Waveform for phase voltage
wt
wt
wt

2 3

2
3
3
2

0
0
0
3
sv
3
sv
3
sv

3
sv
2
3
sv

2
3
sv
Van
Vbn
Vcn

12. Fourier Series for Line-to-Line Voltages
1
5 5
6 6
5
6 6
1,3,5,...
( cos( ) sin( ))
2
1
( ) ( )
4
sin( )sin( )
2 3
4
sin sin ( )
3 6
o
ab n n
n
n s s
s
n
s
ab
n
a
v a n t b n t
b V d t V d t
V n n
b
n
V n
v n t
n
 
 
 
 

 

 







  
 
 
   
  

 

 


13. 1,3,5,...
1,3,5,...
4
sin sin ( )
3 2
4 7
sin sin ( )
3 6
s
bc
n
s
ca
n
V n
v n t
n
V n
v n t
n
 


 






 
 


1
2 2
3
2
0
2
( )
2
2
0.8165
3
L s
L s s
V V d t
V V V



 
 
  
  
 
 Line to line rms voltage

14. RMS value of the nth Component
1
4
sin
32
1
4 sin 60
0.7797
2
s
Ln
s
L s
V n
V
n
n
V
V V






 

15. THANK YOU