pwm 3 phase rectifier

1. Power Quality Improvement Technique
Multipulse Converters II & Three Phase PWM Rectifier
Dr. Avik Bhattacharya
Assistant Professor
Room No. 227, Department of Electrical Engineering
Indian Institute of Technology Roorkee
Phone: 01332285375
Email: bavikfee@iitr.ac.in
1

2. 18-pulse Series-type Diode Rectifier
2
¥
A
i
s
L
Z
°
-
= 20
d
°
= 0
d
Z
°
= 20
d
d
C
a
i
a
i~
a
i
d
i
a
a
a i
i
i
iA
¢
+
¢
+
¢
= ~
lk
L
lk
L
lk
L
d
V
Phase-Shifting
(Zigzag) Transformer
 Converter Topology

3. 18-pulse Series-type Diode Rectifier (Cont…)
3
0
a
i¢ a
i¢
(b)
0.30
0
-0.30
-0.60
1.50
0.75
-0.75
-1.50
(a)
3
/
~
~ a
a i
i =
¢
a
a
a
A i
i
i
i ¢
+
¢
+
¢
= ~
 
2 
3 
4
THD = 23.7%
THD = 3.06%
0
0.60
(pu)
Simulated Waveforms
•No 5th, 7th, 11th, or 13th
harmonics in the line
current.
• Lowest harmonic: 17th
• Line current THD: 3.06%

4. 18-pulse Series-type Diode Rectifier (Cont…)
4
a
i
a
i~
A
i
5ms/div
pu/div,
2
200Hz/div
pu/div,
5
/
2
(a) Currents:
(b) Spectrum:
a
i
Measured Waveforms

5. 18-pulse Series-type Diode Rectifier (Cont…)
5
2
4
6
8
10
THD(%)
(a) THD
A: Ls = 0.00
B: Ls = 0.05
C: Ls = 0.10
(Llk = 0.05)
A
B
C
A: Ls = 0.00
B: Ls = 0.05
C: Ls = 0.10
(Llk = 0.05)
1.00
PF
0.92
0.96
0.94
0.98
(b) PF
A
B
C
0.2 0.4 0.6 0.8 1
A
I
0 (pu)
0.2 0.4 0.6 0.8 1
A
I
0 (pu)
THD and PF Comparison with 12-pulse:
Improved THD

6. 24-pulse Series-type Diode Rectifier
6
A
i
s
L
Z
°
-
= 15
d
°
= 0
d
Z
°
=15
d
°
= 30
d
a
a
a
a i
i
i
i
iA
)
¢
+
¢
+
¢
+
¢
= ~
a
i
a
i~
a
i
a
i)
lk
L
lk
L
lk
L
lk
L
¥
d
C
d
i
d
V
0.30
-0.30
-0.60
0.60
0.30
-0.30
-0.60
1.50
0.75
-0.75
-1.50
0
(a)
(b)
(c)
a
a
a
a
A i
i
i
i
i )
¢
+
¢
+
¢
+
¢
= ~
a
i¢ a
i)
¢
4
/
~
~ a
a i
i =
¢
a
i¢
 
2 
3 
4
 
3
THD = 24.0%
THD = 24.0%
THD = 1.49%
0
0
0
(pu)
0.60
Typical Waveforms
•Lowest line current harmonic: 23th
• THD: 1.49%

7. 24-pulse Series-type Diode Rectifier
7
THD and PF
0
2
4
6
8
THD(%)
(a) THD
A
B
C
1.00
PF
0.92
0.96
0.94
0.98
(b) PF
A
B
C
A: Ls = 0.00
B: Ls = 0.05
C: Ls = 0.10
(Llk = 0.05)
A: Ls = 0.00
B: Ls = 0.05
C: Ls = 0.10
(Llk = 0.05)
0.2 0.4 0.6 0.8 1
A
I
0 (pu) 0.2 0.4 0.6 0.8 1
A
I
0 (pu)

8. 12-pulse Separate-type Diode Rectifier
8
d
C
s
L
a
i
°
= 0
d
°
= 30
d
d
C
d
i
L
O
A
D
L
O
A
D
a
i~
a
a i
i
iA ~
¢
+
¢
= lk
L
lk
L
d
i~
d
V
d
V~
A
i
 Topology is Separate Type
 Each six-pulse rectifier feeds a separate dc load.

9. 12-pulse Separate-type Diode Rectifier (Cont…)
9
°
= 0
d
°
= 0
d
°
= 0
d
M
°
= 30
d
°
= 30
d
°
= 30
d
Application Example
Phase Shifting
Transformer
Multilevel Cascade
H-bridge Inverter Fed Drive
Comparison with series-type:
 DC current ripple: higher
 Line current THD: close

10. 18-pulse Separate-type Diode Rectifier
10
A
i
s
L
Z
°
-
= 20
d
°
= 0
d
Z
°
= 20
d
d
C
a
i
d
C
L
O
A
D
L
O
A
D
a
i~
d
C
L
O
A
D
a
i
d
i
a
a
a i
i
i
iA
¢
+
¢
+
¢
= ~
lk
L
lk
L
lk
L
d
i~
d
i
d
V
d
V~
d
V
•Line Current THD and Input PF
0.2 0.4 0.6 0.8
0
IA1 (pu)
THD(%)
2
4
6
8
10
A
B
C
0.2 0.4 0.6 0.8
0
0.92
0.94
0.96
0.98
1.00
PF
A
B
C
A: Ls = 0
B: Ls = 0.05pu
C: Ls = 0.10pu
( Llk= 0.05pu )
A: Ls = 0
B: Ls = 0.05pu
C: Ls = 0.10pu
( Llk= 0.05pu )
IA1 (pu)
Continuous
Current Mode

11. 6 Pulse SCR Rectifiers with Inductive Load
11

12. 6 Pulse SCR
Rectifiers with
Inductive Load
(Cont…)
12
 Obviously, the bigger the
α, the lower the line-to-
line voltage will be.
 the range o f the delay
angle α is varied from 0 to
180 radians.

13. 12 Pulse SCR Rectifiers
with Inductive Load
13

14. 12 Pulse SCR Rectifiers with Inductive Load (Cont…)
14
THD and PF

15. 18 Pulse SCR Rectifiers
with Inductive Load
15

16. 24 Pulse SCR Rectifiers
with Inductive Load
16

17. Three Phase Rectifier
• Introduction
• Rectifier functions:
1. The AC to DC conversion.
2. Improve the power factor.
3. Reduce the THDi
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34. Experimental Result
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35. Thank you
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