A single-phase bi-directional voltage source converter (VSC) is shown in the figure below. All devices are ideal. It is used to charge a battery at 400 V with power of 5 kW from a source V_s = 220 V (rms), 50 Hz sinusoidal AC mains at unity p.f. If its AC side interfacing inductor is 5 mH and the switches are operated at 20 kHz, then the phase shift (δ) between AC mains voltage (V_s) and fundamental AC rms VSC voltage (V_C1), in degree, is _________.

A full-bridge converter supplying an RLE load is shown in figure. The firing angle of the bridge converter is 120º. The supply voltage $$${v_m}\left( t \right) = 200\pi \sin \left( {100\pi t} \right)\,V,$$$ $$$R = 20 Ω, E = 800 V$$$The inductor L is large enough to make the output current I_L a smooth dc current. Switches are lossless. The real power fed back to the source, in kW, is __________.

In the given rectifier, the delay angle of the thyristor $${T_1}$$ measured from the positive going zero crossing of $${V_s}$$ is $${30^ \circ }$$. If the input voltage $${V_s}$$ is $$100$$ $$sin$$ $$\left( {100\,\pi t} \right)$$ $$V,$$ the average voltage across $$R$$ (in Volt) under steady-state is ________.

A diode circuit feeds an ideal inductor as shown in the figure. Given $${V_s} = 100\,\,\sin \,\left( {\omega t} \right)V,$$ where $$\omega = 100\pi $$ rad/s, and $$L=31.83$$ $$mH$$. The initial value of inductor current is zero. Switch $$S$$ is closed at $$t=2.5$$ $$ms.$$ The peak value of inductor current $${i_L}\left( {in\,\,A} \right)$$ in the first cycle is __________.