A voltage commutated thyristor chopper circuit is shown in fig. The chopper is operated at $$500$$ $$Hz$$ with $$50\% $$ duty ratio. The load takes a constant current of $$20A$$

(a) Evaluate the circuit turn off time for the main thyristor $$T{h_1}$$
(b) Calculate the value of inductor $$L,$$ if the peak current through the main thyristor $$Th,$$ is limited to $$180$$% of the load current.
(c)Calculate the maximum instantaneous output voltage of the chopper

A single - phase full-bridge voltage source inverter feeds a purely inductive load, as shown in figure. when $${T_1},{T_2},\,\,\,\,\,{T_3},{T_4}$$ are power transistors and $${D_1},{D_2},\,{D_3},{D_4}$$ are feedback diodes. The inverter is operated in square-wave mode with a frequency of $$50$$ $$Hz.$$ If the average load current is zero, what is the time duration of conduction of each feedback diode in a cycle?

A half-wave thyristor converter supplies a purely inductive load, as shown in figure. If the triggering angle of the thyristor is $${120^ \circ }$$, the extinction angle will be

$$AC$$ to $$DC$$ circulating current dual converters are operated with the following relationship between their triggering angles $$\left( {{\alpha _1}} \right.$$ and $$\left. {{\alpha _2}} \right).$$