Single Phase AC Voltage Controller | Power Electronics Theory
There are various configurations of ac regulator, out of which four different types are shown in all below images. Circuit shown in below first figure consists of two thyristor connected in parallel in opposite direction.
To avoid the contacts of two cathodes together, the trigger source for the two thyristors
must be isolated from one another, otherwise the thyristors would be out of circuit.
Thus, controlling of output voltage would not be possible: In place of two thyristors, one
trial can be used as shown in below figure.
This configuration is applicable for the applications of low power i.., in this cases where the load is resistive or has only a small inductance, while if load impedance angle is high then this is not suitable.
Below figure shows the single-phase full-wave voltage controller consisting of two thyristor
(T and T2 and two diodes (Di and D2).
As both the cathodes are connected together, no isolation circuit is required between the gates and control circuit. During the positive half cycle T1 and D1 conducts whereas during the negative half cycle T2 and D2 conducts.
Below image shows a configuration which consists of bridge rectifier and only one thyristor. In this configuration isolation of gate circuit is not needed.
As a result, this scheme gives a cheap ac voltage controller. For better controllability of any type of load , transistor or MOSFET can be used in place of thyristor.
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Single Phase AC Voltage Controller | Power Electronics Theory |
To avoid the contacts of two cathodes together, the trigger source for the two thyristors
must be isolated from one another, otherwise the thyristors would be out of circuit.
Thus, controlling of output voltage would not be possible: In place of two thyristors, one
trial can be used as shown in below figure.
 |
| Single Phase AC voltage control using TRIAC |
This configuration is applicable for the applications of low power i.., in this cases where the load is resistive or has only a small inductance, while if load impedance angle is high then this is not suitable.
Below figure shows the single-phase full-wave voltage controller consisting of two thyristor
(T and T2 and two diodes (Di and D2).
 |
| Single Phase AC voltage control using Diodes |
Below image shows a configuration which consists of bridge rectifier and only one thyristor. In this configuration isolation of gate circuit is not needed.
 |
| Single Phase AC Voltage control using bridge rectifier |
As a result, this scheme gives a cheap ac voltage controller. For better controllability of any type of load , transistor or MOSFET can be used in place of thyristor.
