Short Notes: AC - AC Converters | Short Notes for Electrical Engineering - Electrical Engineering (EE) PDF Download

 Page 1


 
 
 
 
 
 
 
 
  
 
 
These circuits control AC power. They are of 2 types: 
1) AC voltage regulator 
2) Cyclo-converter 
 
AC voltage regulator 
These transfer AC power from 1 circuit to another by controlling output voltage & fixed 
frequency. 
 
Single phase half wave ACVR 
? 
? ?
? ?
? ? ?
?
m
O avg
V
V cos 1
2
 
? ?
? ?
? ? ?
?
m
O avg
V
I cos 1
2R
 
? 
? ?
? ?
??
? ? ? ? ? ?
??
???
1
2
m
O rms
V 1
V 2 sin2
2
2
 
? 
? ?
??
? ? ? ? ? ? ?
??
???
1
2
or
sr
V11
pf 2 sin2
V2
2
 
 
 
Page 2


 
 
 
 
 
 
 
 
  
 
 
These circuits control AC power. They are of 2 types: 
1) AC voltage regulator 
2) Cyclo-converter 
 
AC voltage regulator 
These transfer AC power from 1 circuit to another by controlling output voltage & fixed 
frequency. 
 
Single phase half wave ACVR 
? 
? ?
? ?
? ? ?
?
m
O avg
V
V cos 1
2
 
? ?
? ?
? ? ?
?
m
O avg
V
I cos 1
2R
 
? 
? ?
? ?
??
? ? ? ? ? ?
??
???
1
2
m
O rms
V 1
V 2 sin2
2
2
 
? 
? ?
??
? ? ? ? ? ? ?
??
???
1
2
or
sr
V11
pf 2 sin2
V2
2
 
 
 
 
 
 
 
 
 
Single phase fully controlled ACVR 
 
 
 
 
 
 
 
? 
? ?
?
o avg
V0 
? 
? ?
? ?
??
? ? ? ? ? ?
??
???
1
2
m
o rms
V 1
V sin2
2
2
 
? If R – L load is used, then in steady state 
O
I lags 
O
V by an angle ? 
 
1
wL
tan
R
???
??
??
??
 
? If r ?? , then above formulas remain valid & output voltage is controllable by controlling a. 
? If r ?? , output voltage is not controllable & 
or sr
VV ? 
So, range of firing angle is ? ? ? ?
0
180 
Integral cycle control (ON/OFF) control 
If in fully controlled ACVR, thyristors conduct for m cycle & are OFF for n cycle then 
? ?
1
2
O sr
rms
m
VV
mn
??
?
??
? ??
 
For R – load, 
1
2
or
sr
V m
pf
V m n
??
??
??
? ??
 
Page 3


 
 
 
 
 
 
 
 
  
 
 
These circuits control AC power. They are of 2 types: 
1) AC voltage regulator 
2) Cyclo-converter 
 
AC voltage regulator 
These transfer AC power from 1 circuit to another by controlling output voltage & fixed 
frequency. 
 
Single phase half wave ACVR 
? 
? ?
? ?
? ? ?
?
m
O avg
V
V cos 1
2
 
? ?
? ?
? ? ?
?
m
O avg
V
I cos 1
2R
 
? 
? ?
? ?
??
? ? ? ? ? ?
??
???
1
2
m
O rms
V 1
V 2 sin2
2
2
 
? 
? ?
??
? ? ? ? ? ? ?
??
???
1
2
or
sr
V11
pf 2 sin2
V2
2
 
 
 
 
 
 
 
 
 
Single phase fully controlled ACVR 
 
 
 
 
 
 
 
? 
? ?
?
o avg
V0 
? 
? ?
? ?
??
? ? ? ? ? ?
??
???
1
2
m
o rms
V 1
V sin2
2
2
 
? If R – L load is used, then in steady state 
O
I lags 
O
V by an angle ? 
 
1
wL
tan
R
???
??
??
??
 
? If r ?? , then above formulas remain valid & output voltage is controllable by controlling a. 
? If r ?? , output voltage is not controllable & 
or sr
VV ? 
So, range of firing angle is ? ? ? ?
0
180 
Integral cycle control (ON/OFF) control 
If in fully controlled ACVR, thyristors conduct for m cycle & are OFF for n cycle then 
? ?
1
2
O sr
rms
m
VV
mn
??
?
??
? ??
 
For R – load, 
1
2
or
sr
V m
pf
V m n
??
??
??
? ??
 
 
 
 
   
 
? ?
??
?
??
??
??
m
T1 avg
V m
I
R m n
 
? ?
??
?
??
?
??
1
2
m
T1 rms
V m
I
2R m n
 
R = load resistance ; 
m
V is maximum value of 
S
V