PE 304 Lect 6 Thyristor Rectifier Circuits.pdf

Copyright © 2003
by John Wiley & Sons, Inc.
Lectures 6
Thyristor Converters
• Controlled conversion of ac into dc
Chapter 6 Thyristor Converters
6-1

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by John Wiley & Sons, Inc.
Thyristor Converters
• Two-quadrant conversion
Chapter 6 Thyristor Converters
6-2

Primitive circuits
with thyristors
v
L
whereξ
is the variable of
v
di
(t) = L = vs
− v
dt
where vR = Ri
i( ω t) =
L
i( ω t) =
=
1
ω L
1
ω L
di
L
dt
ωt
ω t
[ v
v
v
− E
( ξ ) - E
Copyright © 2003
by John Wiley & Sons, Inc.
∫
θ
2
∫
α
=
s
L
s
( ξ )dξ
integration
d
d
R
] dξ
Chapter 6 Thyristor Converters
6-3

i
s
(ω t) =
I
I
s1
sh
I
s
% THD
2I
2
=
π
Is1
=
h
= I
2I
= 100 ×
Copyright © 2003
by John Wiley & Sons, Inc.
d
s1
sin(ω t -α
) +
d
I
=
2
s
0.
9I
I
− I
s1
d
2
s1
=
2I
s3
48.
38%
sin[3(ω t -α
)] +
Chapter 6 Thyristor Converters
2I
s5
sin[5(ω t -α
)] + .....
6-4

• ICs available
Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Triggering
α
o =
180
o
V
control
V ˆ
Chapter 6 Thyristor Converters
st
6-5

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by John Wiley & Sons, Inc.
Full-Bridge Thyristor Converters
• Single-phase and three-phase
Chapter 6 Thyristor Converters
6-6

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by John Wiley & Sons, Inc.
Single-Phase Thyristor Converters
• Two groups with two thyristor each
Chapter 6 Thyristor Converters
6-7

1-Phase Thyristor Converter Waveforms
• Assuming zero ac-side inductance
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-8

Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-9
α
α
ω
ω
α
α
ω
ω
α
α
π
α
π
α
α
cos
I
0.9V
V
I
dt
v
T
1
I
P
dt
i
v
T
1
p(t)dt
T
1
I
P
)
cos
1
(
V
9
.
0
V
V
V
V
9
.
0
V
2
2
2
t)
td(
sin
V
2
π
1
V
cos
0.9V
cos
V
2
2
2
t)
td(
sin
V
2
π
1
V
d
s
d
d
T
0
d
d
T
0
d
d
T
0
d
s
d
do
d
s
s
0
s
do
s
s
s
d
=
=
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
=
=
=
−
=
−
=
Δ
=
=
=
=
=
=
∫
∫
∫
∫
∫
+

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by John Wiley & Sons, Inc.
Average DC Output Voltage
• Assuming zero ac-side inductance
Chapter 6 Thyristor Converters
6-10

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by John Wiley & Sons, Inc.
Input Line-Current Waveforms
• Harmonics, power and reactive power
Chapter 6 Thyristor Converters
6-11

Power, Power Factor, and Reactive Volt-
Amperes
With
Copyright © 2003
by John Wiley & Sons, Inc.
Q
a
1
PF
=
S
1
DPF
V
=
P
s
=
I
I
I
P
=
s1
V
constant
s1
s
s
=
=
I
I
s1
d
cosθ
DPF
V
s
sinθ
I
0.9V
1
=
s1
2
1
Chapter 6 Thyristor Converters
s
1
I
d
(P
cosθ
2
, P, S ( =
= cosα
= 0.9cosα
1
cosα
= 0.
9V
+ Q
V
s
s
I
I
s
d
)
sinα
1/2
), Q
1
and S
1
6-12

Copyright © 2003
by John Wiley & Sons, Inc.
1-Phase Thyristor Converter
• Finite ac-side inductance; constant dc output
current
Chapter 6 Thyristor Converters
6-13

Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-14
d
s
d
d
s
u
du
s
d
s
d
s
s
u
u
α
α
s
u
d
s
Id
Id
-
s
s
u
α
α
s
s
s
L
s
I
L
2
-
Vscos
9
.
0
V
I
L
2
A
V
V
2
I
L
2
-
cos
u)
cos(
I
L
2
u)]
cos(
-
[cos
V
2
A
t)
td(
sin
V
2
A
I
L
2
di
L
t)
td(
sin
V
2
dt
di
L
v
v s
ω
π
α
π
ω
π
ω
α
α
ω
α
α
ω
ω
ω
ω
ω
ω
=
=
=
Δ
=
+
=
+
=
=
=
=
=
=
∫
∫
∫
+
+

Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Converter Waveforms
• Finite ac-side inductance
Chapter 6 Thyristor Converters
6-15

Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-16
d
d
d
d
(T)
I
(0)
I
d
d
d
0
d
d
0
d
d
d
d
d
d
d
min
d,
s
s
d
s
d2
s
d
s
s1
d
d
s1
s
E
I
r
V
E
di
T
L
dt
i
T
r
dt
v
T
1
E
dt
di
L
i
r
v
I
L
2
-
cos
V
9
.
0
V
u/2)
cos(
V
I
L
)
(2/
-
cos
I
0.9V
I
I
V
DPF
I
V
)
2
1
cos(
DPF
d
d
+
=
+
+
=
+
+
=
≅
+
=
=
+
≅
∫
∫
∫
T
T
u
ω
π
α
α
ω
π
α
α

Thyristor Converters: Inverter Mode
• Assuming the ac-side inductance to be zero
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-17

Thyristor Converters: Inverter Mode
• Family of curves at various values of delay angle
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-18

Thyristor Converters: Inverter Mode
• Importance of extinction angle in inverter mode
2
E d = Vd
= Vdocosα
- ω LsI
d
π
o
γ = 180 − ( α + u)
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-19

Thyristor Converters: Inverter Mode
• Waveforms at start-up
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-20

Copyright © 2003
by John Wiley & Sons, Inc.
3-Phase Thyristor Converters
• Two groups of three thyristors each
Chapter 6 Thyristor Converters
6-21

3-Phase Thyristor Converter Waveforms
• Zero ac-side inductance; purely dc current
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-22

V
V
dα
Aα
=
V
do
vac
dα
P
=
=
=
Copyright © 2003
by John Wiley & Sons, Inc.
3 2
π
V
α
∫
0
do
2V
d
−
V
2V
3 2
=
π
= V I
d
α
π / 3
LL
V
LL
A
= 1.
35V
sin ω t
LL
LL
cosα
= 1.35V
= 1.35V
LL
I
d
LL
sin ω td( ω t) =
cosα
LL
α
2V
cosα
= V
Chapter 6 Thyristor Converters
∫
0
LL
( 1
− cosα)
do
cosα
6-23

i
a
DC-side voltage waveforms
assuming zero ac-side inductance
( ω
t) =
+
2I
s1
2I
sin( ω t -α
) -
s11
sin[11( ω t -α
)] +
- 2I
s17sin[17(
ω t -α
)] -
h = 6n ± 1 (n = 1,2,...... )
Is1
= 0.
78I
d
Is1
Ish
=
h
Is
=
2
I d
3
= 0.816Id
Is1
3
= = 0.
955
Is
π
THD = 31.08%
Copyright © 2003
by John Wiley & Sons, Inc.
2I
s5
sin[5( ω t -α
)] -
2I
2I
s19
s13
2I
s7
sin[13( ω t -α
)]
sin[19( ω t -α
)] .....
sin[7( ω t -α
)]
Chapter 6 Thyristor Converters
6-24

Copyright © 2003
by John Wiley & Sons, Inc.
Input Line-Current Waveform
• Zero ac-side inductance
Chapter 6 Thyristor Converters
6-25

Input line-current
waveforms
assuming zero acside
inductance
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-26

Copyright © 2003
by John Wiley & Sons, Inc.
Three-Phase Thyristor Converter
• AC-side inductance is included
Chapter 6 Thyristor Converters
6-27

Current Commutation Waveforms
• Constant dc-side current
Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-28

Copyright © 2003
by John Wiley & Sons, Inc.
Input Line-Current Waveform
• Finite ac-side inductance
Chapter 6 Thyristor Converters
6-29

Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-30
dt
di
L
-
v
v
dt
di
L
-
v
v
I
L
3
-
cos
V
2
3
V
2
I
L
di
L
A
t)
d(
v
A
dt
di
L
v
v
-
v
v
I
3
/
V
05
.
0
L
c
s
cn
Pn
a
s
an
Pn
d
s
LL
d
d
s
I
0
a
s
u
L
u
a
s
L
L
an
Pn
s1
LL
s
d
s
s
s
=
=
=
=
=
=
=
=
≥
∫
∫
+
π
ω
α
π
ω
ω
ω
ω
α
α
u

Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 6 Thyristor Converters
6-31
d
LL
s
s
LL
I
0
a
s
LL
a
ac
cn
an
a
s
cn
an
Pn
c
a
c
a
d
c
a
s
cn
an
Pn
I
V
2
L
2
-
cos
u)
cos(
t)
td(
sin
L
2
V
2
di
L
2
t
sin
V
2
t)
d(
di
2
v
2
v
2
v
dt
di
L
)
v
v
(
2
1
v
dt
di
dt
di
interval
n
commutatio
during
constant
be
to
assumed
is
)
i
i
(
I
Since
dt
di
dt
di
2
L
2
v
v
n)
commutatio
during
(
v
d
ω
α
α
ω
ω
ω
ω
ω
ω
α
α
=
+
=
=
=
−
=
+
=
−
=
+
=
⎟
⎠
⎞
⎜
⎝
⎛
+
−
+
=
∫
∫
+u

Copyright © 2003
by John Wiley & Sons, Inc.
Input Line-Current Harmonics
• Finite ac-side inductance
Chapter 6 Thyristor Converters
6-32

Copyright © 2003
by John Wiley & Sons, Inc.
Input Line-Current Harmonics
• Typical and idealized
Chapter 6 Thyristor Converters
6-33

Copyright © 2003
by John Wiley & Sons, Inc.
Three-Phase Thyristor Converter
• Realistic load
Chapter 6 Thyristor Converters
6-34

Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Converter Waveforms
• Realistic load; continuous-conduction mode
Chapter 6 Thyristor Converters
6-35

Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Converter Waveforms
• Realistic load; discontinuous-conduction mode
Chapter 6 Thyristor Converters
6-36

• Constant dc current
Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Inverter
Chapter 6 Thyristor Converters
6-37

Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Inverter Waveforms
• Finite ac-side inductance
Chapter 6 Thyristor Converters
6-38

Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Inverter
• Family of curves at various values of delay angle
Chapter 6 Thyristor Converters
6-39

Copyright © 2003
by John Wiley & Sons, Inc.
Thyristor Inverter Operation
• Importance of extinction angle
Chapter 6 Thyristor Converters
6-40