List of top Power Electronics and Drives Questions on DC to DC conversion asked in GATE EE

Consider the boost converter circuit shown. Assume that the semiconductor devices are ideal. In steady state, the inductor current rises linearly from \(0\) A to \(6\) A in the first \(10\ \mu\)s and then falls linearly from \(6\) A to \(0\) A in the next \(10\ \mu\)s of every switching cycle as shown. The load resistance \(R\) is \(10\ \Omega\) and the capacitance \(C\) is \(500\ \mu\)F.

Neglect the ripple in the output voltage. What is the input voltage \(V_{dc}\)?

A 3-phase grid-connected voltage source converter with DC link voltage of 1000 V is switched using sinusoidal Pulse Width Modulation (PWM) technique. If the grid phase current is 10 A and the 3-phase complex power supplied by the converter is given by \( (-4000 - j3000) \, \text{VA \), then the modulation index used in sinusoidal PWM is _________. (round off to two decimal places)}

The steady state current flowing through the inductor of a DC-DC buck boost converter is given in the figure below. If the peak-to-peak ripple in the output voltage of the converter is 1 V, then the value of the output capacitor, in μF, is _________. (round off to nearest integer)

A boost converter operates at 25 kHz with a duty cycle 0.6. Input is 15 V, load is 10 \(\Omega\). Assuming ideal components, compute the equivalent input resistance \(R_{in}\) seen by the source. (Round off to 2 decimal places.)

Consider the buck-boost converter shown. Switch Q operates at 25 kHz with a duty-cycle of 0.75. Assume diode and switch are ideal. Under steady-state, the average current flowing through the inductor is \(\underline{\hspace{1cm}}\) A.