Transcript Slide 1
EE8407
Power Converter Systems
Topic 4
Graduate Course EE8407
Bin Wu
PhD, PEng
Professor
ELCE Department
Ryerson University
Contact Info
Office: ENG328
Tel:
(416) 979-5000 ext: 6484
Email:
[email protected]
http://www.ee.ryerson.ca/~bwu/
Ryerson Campus
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
Topic 4
Multi-pulse SCR Rectifiers
Z
Llk
ia
I d Ld
20
Ls
iA
Llk
ia~
Llk
ia
0
Z
L
O
A
D
vd
20
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Multi-pulse SCR Rectifiers
Topic 4
Lecture Topics
• Six-pulse SCR Rectifier (Building Block)
• 12-, 18- and 24-pulse SCR Rectifiers
• THD and PF
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Multi-pulse SCR Rectifiers
Topic 4
Why Use Multi-pulse SCR Rectifiers?
• To reduce line THD
• To improve input power factor
• To avoid semiconductor devices in series.
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
Six-pulse SCR Rectifier
• Converter Configuration
I d Ld
P
g1
va
GND
vb
vc
a
ia
b
ib
c
ic
g5
g3
S3
S1
S5
L
O
A
D
vd
g4
g6
Id
g2
S4
S6
N
S2
(a)
(b)
• Assumption: 1) Ideal SCRs - no power loss
2) Ld dc current ripple free
• Use constant current source Id as a load
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
Six-pulse SCR Rectifier
• Waveforms
va
v
vb
0
ig 3
ig 4
3 2
t
ig 2
area A1
Vd
/3
1 / 2
vab d (t )
/
6
/3
3
2
ig1
• Average dc voltage
vc
ig 5
I
ig 6
v
6
6
va
II
2
vP
5
6
7
6
vb
9
6
t
11
6
vc
va
vb
t
0
vd
v ab
vN
v ac
vbc
vba
v ca
vcb
v ab
v ac
A1
Vd
t
VLL cos
1.35VLL cos
ia
1
1
Id
0
ib
0
2
S 6 , S1
ON
ia1
t
S1 , S 2
ON
Id
t
ic
0
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
t
6
EE8407
Topic 4
Six-pulse SCR Rectifier
• Fourier Analysis
ia
1
1
1
I d sint 1 sin 5t 1 sin 7t 1 sin11t 1
5
7
11
1
1
1
sin13t 1 sin17t 1 sin19t 1 ....
13
17
19
2 3
• RMS current
1
Ia
2
2
0
1/ 2
ia 2 d ( t )
1/ 2
11
1 56
2
2
I d d ( t ) 76 I d d ( t )
6
2 6
2
I d 0.816 I d
3
• THD
THD
I a2 I a21
I a1
(0.816I d ) 2 (0.78I d ) 2
0.311
0.78I d
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Six-pulse SCR Rectifier
Topic 4
• Power Factor (PF)
• Displacement Power Factor
1 2 1
DPF cos 1 cos
• Overall Power Factor
PF
cos1
0.955 cos
2
1 THD
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
Six-pulse SCR Rectifier
• Waveforms
at Various Firing Angles
45
v
90
va
vb
vc
vP
0
vN
vd
vab
vac
vbc
2
vba
vca
vd v P v N
vab
vac
0
vP
vd
vab
vac
vba
vca
vcb
2
2
vca
vba
vc
vN
va
vP
vcb
vab
vb
vac
vbc
vba
vca
2
t
Vd
2
t
vcb
vd vP v N
0
t
180
vc
vb
vbc
2
(b) 90
135
vN
vbc
2
va
vc
vd
(a) 45
v
vb
vN
vcb
Vd
0
vP
va
2
t
Vd
(c) 135
vd
(d) 180
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
Six-pulse SCR Rectifier
• Effect of Line Inductance Ls
Id
P
va
vb
GND
vc
a ia
Ls
S3
S1
Ld
S5
v Ls
b ib
Ls
c ic
Ls
L
O
A
D
S4
S6
vd
S2
N
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
Six-pulse SCR Rectifier
• Waveform During SCR Commutation
g
vP
Ag
va
0
2
6
1
i
( v a vc ) / 2
9 / 6
5 / 6
g 2
1
vP
vc
t
va
ia1
6
ic
ia
Id
ib
t
0
g
Id
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Six-pulse SCR Rectifier
Topic 4
• DC Voltage Reduction (caused by commutation)
• S1 and S5 on (during commutation)
vP va Ls
from which
vP
dia
di
vc Ls c
dt
dt
va vc Ls dia dic
2
2 dt dt
• Since ia + ic = Id, and id is constant
dia
di
c 0
dt
dt
from which
vP
va vc
2
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Six-pulse SCR Rectifier
Topic 4
• DC Voltage Reduction
• Shaded Area Aγ
Ag
6
6
g
va vP d (t )
• Since va v p Ls dia / dt
Ag
Id
0
Ls dia Ls I d
• Average dc voltage loss
Ag
3Ls
V
Id
/3
• Average dc output voltage
Vd 1.35VLL cos
3Ls
Id
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Six-pulse SCR Rectifier
Topic 4
• Commutation Interval
• Aγ can be rearranged as
g v
VLL
6
ac
cos cos ( g )
Ag
d (t )
2
2
6
v
2
V
sin(
t
) d (t )
where ac
LL
6
• Substitute Ls I d into the above equation
VLL
cos cos ( g )
Ls I d
2
from which
g cos1 cos
2 Ls
I d
VLL
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Six-pulse SCR Rectifier
Topic 4
• Line Current Waveforms
2.00
ia
ib
1.00
ia1
1.41pu
0.00
-1.00
-2.00
(a) = 0°, Ia1 = 1 pu
2.00
ib
ia
Ls = 0.05pu
1.00
0.00
-1.00
-2.00
2
0
Harmonics n
I an / I a1 (%)
0
I an / I a1 (%)
30
(b) = 30°, Ia1 = 1 pu
3 2
2
11
13
17
19
23
25
THD
%
18.6 12.4
6.32
4.58
2.40
1.73
1.02
0.87
23.9
19.7 14.1
8.58
7.27
5.16
4.62
3.43
3.16
28.3
5
7
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
15
EE8407
Topic 4
Six-pulse SCR Rectifier
• Line Current THD
32
THD (%)
32
THD (%)
A
A: L s= 0
B: Ls= 0.05pu
C: Ls= 0.10pu
29
B
26
= 0
C
29
B
A
°
26
C
23
A: = 20 °
B: = 40 °
C: = 60 °
23
Ls = 0.05pu
20
0
0.2
0.4
0.6
(a)
0.8
20
IA1 (pu)
0
0.2
0.4
0.6
0.8
(b)
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
IA1 (pu)
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EE8407
Six-pulse SCR Rectifier
Topic 4
• Power Factor
1.0
PF
A
B
0.8
C
0.6
A: = 0°
B: = 20 °
C: = 40 °
0.4
L s= 0.05pu
0.2
0
0.2
0.4
0.6
0.8
IA1 (pu)
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
12-pulse SCR Rectifier
• Topology
I d Ld
Llk
i A ia ia~
Ls
iA
ia
0
L
O
A
D
Llk
vd
ia~
30
• Main Benefits
- Low line current THD
- No SCRs in series
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
18
EE8407
Topic 4
12-pulse SCR Rectifier
• Application Example
Ld
0
M
Cf
30
• Used for current source inverter (CSI) fed drive
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
12-pulse SCR Rectifier
Topic 4
• Waveforms of Idealized Rectifier (Ls = Llk = 0)
ia
Id
0
/6
2
5 / 6
t
ia~
Id
t
0
ia
Id 2
0
t
ia~
0
iA
1
3
Id
1
2 3
t
Id
1
1
Id
2
0
2 3
1
2 3
Id
t
Id
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
12-pulse SCR Rectifier
Topic 4
• Fourier Analysis
• Secondary currents
1
1
1
1
I d sin t sin 5t sin 7t sin 11t sin 13t
5
7
11
13
1
1
sin 17t sin 19t ....
17
19
ia
2 3
ia~
2 3
1
1
1
I d sin(t 30) sin 5(t 30) sin 7(t 30) sin 11(t 30)
5
7
11
1
1
1
sin 13(t 30) sin 17(t 30) sin 19(t 30) ....
13
17
19
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
12-pulse SCR Rectifier
Topic 4
• Fourier Analysis (continued)
• Secondary currents referred to the primary side
ia
ia~
3
1
1
1
1
I d {sin t sin 5t sin 7t sin 11t sin 13t
5
7
11
13
1
1
sin 17t sin 19t ....}
17
19
3
1
1
1
1
I d {sin t sin 5t sin 7t sin 11t sin 13t
5
7
11
13
1
1
sin 17t sin 19t ....}
17
19
• Primary line current
i A ia ia~
2 3
I d {sin t
1
1
1
sin 11t sin 13t sin 23t
11
13
23
1
sin 25t ....}
25
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
12-pulse SCR Rectifier
Topic 4
• Line Current THD
• Secondary side
I a2 I a21 I a25 I a27 I a211 I a213 ...
THDia
I a1
I a1
1/ 2
31.1%
• Primary side
I A2 I A21 I A211 I A213 I A2 23 I A2 25 ...
THDi A
I A1
I A1
1/ 2
15.3%
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
12-pulse SCR Rectifier
Topic 4
• Line Current Waveform (Ls 0 )
1.50
0.75
ia
2
ia1
0.00
-0.75
-1.50
(a)
1.50
0.75
2
iA
0.00
i A1
-0.75
-1.50
0
Harmonics
n
I an / I a1 (%)
I An / I A1 (%)
2
(b)
5
7
11
13
3
17
19
4
23
25
THD
(%)
18.8 12.7 6.78 5.05 2.77 2.01 1.01 0.75 24.6
0
0
6.78 5.05
0
0
1.01 0.75 8.61
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
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EE8407
Topic 4
12-pulse SCR Rectifier
• THD and PF
16
THD (%)
A: L s=0
B: L s= 0.05pu
C: L s= 0.10pu
13
1.0
PF
A
B
0.8
L lk= 0.05pu
= 0 °
10
C
A
0.6
A: = 0 °
B: = 20 °
C: = 40 °
B
7
4
C
0
0.2
0.4
0.6
(a)
0.8
IA1 (pu)
0.4
0.2
0
L s= 0
Llk= 0.05pu
0.2
0.4
0.6
0.8
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
IA1 (pu)
25
EE8407
Topic 4
18-pulse SCR Rectifier
• Rectifier Configuration
i A ia ia~ ia
Z
Llk
ia
I d Ld
20
Ls i A
Llk
ia~
Llk
ia
0
Z
L
O
A
D
vd
20
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
26
EE8407
18-pulse SCR Rectifier
• Waveforms
0.60
Topic 4
ia~
0.30
ia~ 1
2 3
0.00
-0.30
-0.60
(a)
0.60
i a
ia
0.30
0.00
-0.30
-0.60
(b)
1.50
iA
0.75
0.00
-0.75
-1.50
Harmonics
n
/ I a 1 (%)
I an
I An / I A1 (%)
2
(c)
0
5
7
11
13
3
17
19
4
23
25
18.8 12.7 6.78 5.05 2.77 2.01 1.01 0.75
0
0
0
0
2.77 2.01
0
0
THD
(%)
24.6
3.54
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
27
EE8407
Topic 4
18-pulse SCR Rectifier
• Line Current THD
10
THD (%)
10
A: L s = 0
B: L s = 0.05pu
C: L s = 0.10pu
8
A
6
2
0.2
0.4
B
8
A
6
C
0
C
L lk = 0.05pu
= 0 °
B
4
THD (%)
A: = 20 °
B: = 40 °
C: = 60 °
4
0.6
0.8
2
IA1(pu)
Ls = 0.05pu
Llk= 0.05pu
0
0.2
0.4
0.6
0.8
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
IA1 (pu)
28
EE8407
Topic 4
24-pulse SCR Rectifier
• Rectifier Configuration
Id
Z
Llk
Ld
ia
15
i A ia ia~ ia ia
Ls
iA
Llk
ia~
0
Z
Vd
Llk
ia
15
Llk
ia
30
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
29
EE8407
Topic 4
24-pulse SCR Rectifier
• Line Current THD
8
THD (%)
8
A: L s = 0
B: Ls = 0.05pu
C: Ls = 0.10pu
6
THD (%)
C
6
B
L lk = 0.05pu
= 0 °
A
4
4
A: = 20 °
B: = 40 °
C: = 60 °
A
B
2
0
2
C
0
0.2
0.4
0.6
0.8
0
IA1 (pu)
L s = 0.05pu
L lk = 0.05pu
0
0.2
0.4
0.6
0.8
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
IA1 (pu)
30
EE8407
Topic 4
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley - IEEE Press, 2006
31