PYQs Based test 24: Power Electronics

Consider an ideal full-bridge single-phase DC-AC inverter with a DC bus voltage magnitude of 1000 V. The inverter output voltage v(t) shown below, is obtained when diagonal switches of the inverter are switched with 50 % duty cycle. The inverter feeds a load with a sinusoidal current given by, $\mathrm{i}(\mathrm{t})=10\sin \left(\omega \mathrm{t}-\frac{\pi }{3}\right)$ A, where $\omega =\frac{2\pi }{\mathrm{T}}$. The active power, in watts, delivered to the load is _________. (round off to nearest integer)

The voltage at the input of an AC-DC rectifier is given by v(𝑡) = 230√2 sin 𝜔𝑡 where 𝜔 = 2𝜋 × 50 rad/s. The input current drawn by the rectifier is given by

$\mathrm{i}(\mathrm{t})=10\sin \left(\omega \mathrm{t}-\frac{\pi }{3}\right)+4\sin \left(3\omega \mathrm{t}-\frac{\pi }{6}\right)+3\sin \left(5\omega \mathrm{t}-\frac{\pi }{3}\right)$

The input power factor, (rounded off to two decimal places), is, __________ lag.

The waveform shown in solid line is obtained by clipping a full-wave rectified sinusoid (shown dashed). The ratio of the RMS value of the full-wave rectified waveform to the RMS value of the clipped waveform is ______. (Round off to 2 decimal places.)

A DC-DC boost converter, as shown in the figure below, is used to boost $360V$ to $400V$, at a power of $4kW$. All devices are ideal. Considering continuous inductor current, the rms current in the solid state switch (S), in ampere, is _________.

A 3-ϕ fully controlled converter is fed through the star-delta transformer as shown in the figure



The converter is operated at a firing angle of 30⁰. Assuming the load current (Iₒ) to be virtually constant at 1 p.u. and the transformer to be an ideal one, the input phase current waveform is