PYQs Based test 22: Power Electronics

Thyristor T₁ is triggered at an angle α (in degree), and T₂ at angle 180° + α, in each cycle of the sinusoidal input voltage. Assume both thyristors to be ideal. To control the load power over the range 0 to 2 kW, the minimum range of variation in α is: (Assume that the load is inductive load)

A three-phase voltage source inverter with ideal devices operating in 180° conduction mode is feeding a balanced star-connected resistive load. The DC voltage input is V${}_{dc}$. The peak of the fundamental component of the phase voltage is

The figure below shows the circuit diagram of a controlled rectifier supplied from a 230 V, 50 Hz, 1-phase voltage source and a 10 : 1 ideal transformer. Assume that all devices are ideal. The firing angles of the thyristors T₁ and T₂ are 90° and 270° respectively.



The rms value of the current through diode D₃ in amperes is ________

A dc to dc converter shown in the figure is charging a battery bank, B2 whose voltage is constant at 150 V. B1 is another battery bank whose voltage is constant at 50 V. The value of the inductor, L is 5 mH and the ideal switch, S is operated with a switching frequency of 5 kHz with a duty ratio of 0.4. Once the circuit has attained steady-state and assuming the diode D to be ideal, the power transferred from B1 to B2 (in Watt) is ___________ (up to 2 decimal places).

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 $400V$ with power of $5kW$ from a source $V_s=220V$ (rms), $50Hz$ sinusoidal AC mains at unity p.f. If its AC side interfacing inductor is $5mH$ and the switches are operated at 20 kHz, then the phase shift $\left(\delta \right)$ between AC mains voltage $\left(V_s\right)$ and fundamental AC rms VSC voltage $\left(V_{C1}\right)$, in degree, is _________.