Question

For obtaining the output voltage control from V to 2V, the firing angle must be

(a) always 0 for T3, T4

(b) always 180 for T3, T4

(c) 0 to 180 from T3, T4

(d) none of the mentioned

The question was posed to me during an interview.

The doubt is from Sequence Controller in section Voltage Controllers of Power Electronics

Answer 1

The correct option is (a) always 0 for T3, T4

Easiest explanation: For obtaining the voltage control from V to 2V, the lower controller i.e. T3, T4 pair must always be on hence the firing angle from them must always be 0° ideally.