1. BUCK-BOOST CHOPPER TYPE AC VOLTAGE CONTROLLER
Presented By: K. Bhagya Lakshmi, ME(PED).

2. Introduction
AC voltage regulation is an important part of power conversion.
A winding transformer is widely used in voltage regulation fields such as power system, motor speed control and so on.
There are also other researches which use thyristor phase controlled circuit to do voltage regulation.But they have some disadvantages and those arise problems.
These problems can be solved by using high switching frequency AC chopper i.e. Buck-Boost chopper type AC voltage controller.

3. Purpose
This device is used to increase or decrease the voltage levels according to requirement.
Best speed control is possible with this controller as it has fast response speed.
To decrease the losses at conversion devices in AC- AC systems it’ll well suitable i.e. transformer has iron losses which effects on its efficiency.

4. Buck-Boost Chopper Type AC Voltage Controller

5. Is there any devices doing the same job as this controller?
There are two devices, can perform the AC Voltage regulation:
1. Transformer
2. Phase Controlled Thyristor circuit
These devices has certain disadvantages and these disadvantages are eliminated in our Buck-Boost chopper type AC voltage controller.

6. 1000MVA Transformer And 500KV & 20KA Thyristors

7. Advantages over existing devices:
Efficiency
Power
factor
Losses
Intial
Cost
Maint.
Harmonic
Injection
Space
occupies
T/F
95-99% for Tr.T/F
50% for Disb. T/F
Low on light loads
More
High
Never
Phase
Controlled
Thyristor
circuit
94-99%
Low
Less
BBCACVC
97-99% for Both Tr.,Disb
Always high
(Unity)
No Harmonics
Very Less

8. ADVANTAGES
It can regulate the output voltage and can maintain constant voltage at load terminals.
This can be achieved by giving feedback signal to our Voltage Controller from load terminals through PI controller.
Due to this feedback it can automatically regulates the output voltage irrespective of Voltage ‘sags’ & ‘swells’.

9. Outstanding Application of Our Converter

10. Automatic Regulation Of Output Voltage At Load Terminals

11. Results with phase controlled thyristor controller:

12. Results for Buck-Boost chopper type voltage controller:

13. Conclusion
The Buck-Boost chopper type AC voltage regulator has many advantages compared to the winding transformer and thyristor phase controlled voltage regulator.
The Buck-Boost chopper type AC voltage regulator can improve the PF and reduce the power loss caused by the reactive and harmonic currents.