The Voltage Source Inverter $$(VSI)$$ shown in the figure below is switched to provide a $$50$$ $$Hz,$$ square-wave $$ac$$ output voltage ($${V_0}$$) across an $$R$$-$$L$$ load. Reference polarity of $${V_0}$$ and reference direction of the output current $${I_0}$$ are indicated in the figure. It is given that $$R = 3\,\,\Omega ,\,\,L = 9.55\,\,mH.$$

In the interval when $${V_0} < 0$$ and $${i_0} > 0$$ the pair of devices which conducts the load current is

In the $$3$$-phase inverter circuit shown, the load is balanced and the gating scheme is $${180^ \circ }$$ -conduction mode. All the switching devices are ideal.

If the $$dc$$ bus voltage $${V_d} = 300\,\,V,$$ the power consumed by $$3$$-phase load is

In the $$3$$-phase inverter circuit shown, the load is balanced and the gating scheme is $${180^ \circ }$$ -conduction mode. All the switching devices are ideal.

The $$rms$$ value of load phase voltage is

The Current Source Inverter shown in Figure is operated by alternately turning on thyristor pairs $$\left( {{T_1},\,\,{T_2}} \right)$$ and $$\left( {{T_3},\,\,{T_4}} \right).$$ If the load is purely resistive, the theoretical maximum output frequency obtainable will be