Question

Operation of two stage sequence ac voltage controller

Answer 1

Power ElectronicsAC voltage controllers (ac line voltage controllers) are employed to vary the RMS value of the alternating voltage applied to a load circuit by introducing Thyristors between the load and a constant voltage ac source. The RMS value of alternating voltage applied to a load circuit is controlled by controlling the triggering angle of the Thyristors in the ac voltage controller circuits.

Answer 2

Answer:

Explanation:

AC voltage controller with two-stage sequence control and R load

This circuit uses four thyristors and a set of thyristors that are wired antiparallel. The primary winding and secondary winding of the ac voltage are provided by the source voltage. Center tapping will be done on the secondary winding, and the two windings will be interconnected. The voltage across the second winding is V2=Vm sin⁡ωt, and the voltage from the first winding is V1=Vm sin⁡ω t.

The output of the circuit is coupled to a resistive load.

Working

Only when t=0, or when the firing angle is equal to zero, will the thyristors T3 and T4 operate. The thyristors T1 and T2 will function when the pulse is applied at a specific angle, which indicates that their firing angle will be at a specific phase. When the supply is turned on from the source voltage and a positive cycle occurs with time zero, thyristor 3 will conduct and allow current to flow from it.

When is equal to zero and the time t is equal to, the voltage will come from the secondary winding V2 and the source current will flow from the thyristor T3 at that point. Then, we will provide a trigger pulse at the gate of T1, at which point thyristor 3 will turn off and thyristor one will conduct. At that point, the voltage will come from V1+V2 and the source current will flow in T1. After the trigger pulse, the wave will move in an upward direction. This is due to the fact that there was only one voltage at initially, V1, and now that there are two volts, V1 and V2, the entire secondary winding will function.

When the source emits a negative cycle, the main and lower secondary will begin to operate. The voltage will be V2, and when we apply a trigger pulse at T4, it will begin to conduct. The output voltage will begin in the opposite direction, and the time constant will equal. The output current will also flow backwards. The output voltage is identical to V1+V2 when a trigger pulse is applied to the T2's gate.

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