This document summarizes a seminar on single phase converters. It discusses different types of single phase converters including half wave and full wave rectifiers as well as controlled rectifiers using thyristors. It provides equations for calculating the average output voltage and current for resistive and resistive-inductive loads. The operation and triggering of thyristors in a single phase converter is explained. Graphs of input voltage and output voltage and current are shown. The effect of an output inductor and finite commutation interval are also discussed.

1. SEMINAR ON SINGLE
PHASE CONVERTER
By
Vinod Srivastava
M.E. Modular I & C
Roll No.151522

2. INTRODUCTION
AC(~) DC(--)
Diode rectifiers are uncontrolled rectifiers
The level of DC output voltage can not be
controlled.
e.g. single phase half wave and full wave
rectifiers.

3. Single phase Full Wave Bridge
Rectifier
.
A.C. in
D.C. out

4. CONTROLLED RECTIFIER
 Rectifier designed with SCR’s are
controlled rectifier.
 AC is converted into regulated DC.
 The phase relationship between i/p
voltage & o/p current can be controlled.
 Level of the voltage can be regulated by
varying firing angle α.

5. Classification-
• Single phase converter
Half wave converter
Full wave converter
• Three phase converter
Half wave converter
Full wave converter

6. Single Phase Half Wave Rectifier
Fig(a) Half wave rectifier for resistive load

7. Average value of output voltage





ttdvv iav sin2
2
1
On solving
)cos1(
2
 i
av
v
v

8. RESISTIVE – INDUCTIVE
LOAD

9. Contd….
 Thyristor turns ON at ωt= α & voltage
appears across Load & current starts
building up.
 Inductor does not changes current
instantaneously, so load current does not
become zero at ωt = π.

10. Average value of output voltage





ttdvv iav sin2
2
1
)cos(cos
2
, 

 i
av
v
vonsolving

11. SINGLE PHASE CONVERTER
Fig-single phase thyristor controlled rectifier with Ls=0

12. Input and output response

13. Operation
 In the positive half cycle T1 and T2 are
forward biased.
 In the negative half T3 and T4 are forward
biased.
 T1 and T2 continue to conduct till T3 and
T4 are triggered.

14. Contd….
 T1T2 α to π + α
 T3T4 π + α to 2π + α
 α to π Vo +ve
 α to π Io +ve
 π to π + α Vo -ve
 π to π + α Io +ve
 α to π L stores the energy.
 π to π + α L releases the energy.

15. AVERAGE VALUE OF
OUTPUT VOLTAGE
ttdvV mav 



sin
1





cos
2 m
av
v
V 
onsolving
Thus, Vav is +ve from o ˂α ˂ π/2
Vav is –ve from π/2 ˂ α ˂ π
Vo
Io
-Vo

16. Line Current

17. Contd….
Eq…(1)
Eq…(2)
Eq…..(
3)
Eq…..(4)
Eq…..(5)
The current Is in fig a can be expressed in terms
of its fourier components as-
Where only odd harmonics are present
Rms value of
is1

18. Power, power factor and reactive
volt amperes
(a)
(2), (4) &
(6)
(2
)
(6
)
8
Eq…(6)
Eq…(7)
Eq…(8)
Eq…(9)
Eq…(10)
Eq…(11)

19. Effect of Ls
Fig (c)
Fig (e)
Fig (d)

20. Contd….
 The effect of inductance can not be
ignored in practical thyristor
converters.
 The current commutation takes a finite
commutation interval u as in fig (d)

21. Fig(c)
Eq…(12
)
Eq…(13
)
(13)
Eq…(14)
(14) (13)
Eq…(15
)
Eq…(16
)
Eq…(17)

22. Contd….
Eq……(18)