1
GATE EE 2021
Numerical
+2
-0

A single-phase full bridge inverter fed by a 325 V DC produces a symmetric quasi-square waveform across " $a b$ " as shown. To achieve a modulation index of 0.8 , the angle $\theta$ expressed in degrees should be $\_\_\_\_$ . (Round off to 2 decimal places)

GATE EE 2021 Power Electronics - Inverters Question 2 English(Modulation index is defined as the ratio of the peak of the fundamental component of $V_{d b}$ to the applied DC value)

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2
GATE EE 2021
Numerical
+2
-0

Consider the buck-boost converter shown. Switch $Q$ is operating at 25 kHz and 0.75 duty-cycle. Assume diode and switch to be ideal. Under steady-state condition, the average current flowing through the inductor is $\_\_\_\_$ A.

GATE EE 2021 Power Electronics - Choppers and Commutation Techniques Question 3 English
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3
GATE EE 2021
MCQ (Single Correct Answer)
+1
-0.33

Two generators have cost functions $F_1$ and $F_2$. Their incremental-cost characteristics are

$$ \frac{d F_1}{d P_1}=40+0.2 P_1 \text { and } \frac{d F_2}{d P_2}=32+0.4 P_2 $$

They need to deliver a combined load of 260 MW . Ignoring the network losses, for economic operation, the generations $P_1$ and $P_2$ (in MW) are

A

$P_1=P_2=130$

B

$P_1=160, P_2=100$

C

$P_1=140, P_2=120$

D

$P_1=120, P_2=140$

4
GATE EE 2021
MCQ (Single Correct Answer)
+2
-0.67

A 3-bus network is shown. Consider generators as ideal voltage sources. If rows 1,2 and 3 of the $Y_{h s}$ matrix correspond to bus 1,2 and 3 respectively, then $Y_{h s}$ of the network is

GATE EE 2021 Power System Analysis - Load Flow Studies Question 3 English
A

$\left[\begin{array}{ccc}-4 j & j & j \\ j & -4 j & j \\ j & j & -4 j\end{array}\right]$

B

$\left[\begin{array}{ccc}-4 j & 2 j & 2 j \\ 2 j & -4 j & 2 j \\ 2 j & 2 j & -4 j\end{array}\right]$

C

$\left[\begin{array}{ccc}-\frac{3}{4} j & \frac{1}{4} j & \frac{1}{4} j \\ \frac{1}{4} j & -\frac{3}{4} j & \frac{1}{4} j \\ \frac{1}{4} j & \frac{1}{4} j & \frac{-3}{4} j\end{array}\right]$

D

$\left[\begin{array}{ccc}\frac{-1}{2} j & \frac{1}{4} j & \frac{1}{4} j \\ \frac{1}{4} j & -\frac{1}{2} j & \frac{1}{4} j \\ \frac{1}{4} j & \frac{1}{4} j & \frac{-1}{2} j\end{array}\right]$