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

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.

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.

Buck-Boost Chopper Type AC Voltage Controller

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.

1000MVA Transformer And 500KV & 20KA Thyristors

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

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’.

Outstanding Application of Our Converter

Automatic Regulation Of Output Voltage At Load Terminals

Results with phase controlled thyristor controller:

Results for Buck-Boost chopper type voltage controller:

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.