A single - phase voltage source inverter shown in figure is feeding power to load. The triggering pulses of the devices are also shown in the figure.

If the load current is sinusoidal and is zero at $$0,\,\,\pi ,2\pi ....,$$ the node voltage $${V_{AO}}$$ has the waveform

In the figure shows on period of the output voltage of an inverter. $$\alpha $$ should be chosen such that $${60^0} < \alpha < {90^0}.$$ If $$rms$$ value of the fundamental component is $$50$$ $$V$$, then $$\alpha $$ in degree is _________.

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 $$R = 3\,\,\Omega ,\,\,L = 9.55\,\,mH.$$

Appropriate transition $$i.e,,$$ $$Zero$$ voltage switching $$(ZVS)/Zero$$ current switching $$(ZCS)$$ of the $$IGBTs$$ during turn - on/turn off is

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