Electrical Engineering
GATE EE topic:power-electronics PYQs
Build your understanding with focused practice from past exam papers.
Questions 11–20 of 66. Imported answers require independent review unless marked reviewed.
Question 48
Open questionEEMCQ2 marksNeeds review
In the following circuit, the average voltage
where
is the firing angle. If the power dissipated in the resistor is 64 W, then the closest value of
in degrees is
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Open questionEENAT2 marksNeeds review
The steady state capacitor current of a conventional DC-DC buck converter, working in CCM, is shown in one switching cycle. If the input voltage is 30 V, the value of the inductor used, in mH, is ______________ (round off to one decimal place).
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If the following switch devices have similar power ratings, which one of them is the fastest?
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 28
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A single-phase triac based AC voltage controller feeds a series RL load. The input AC supply is 230 V, 50 Hz. The values of R and L are 10
and 18.37 mH, respectively. The minimum triggering angle of the triac to obtain controllable output voltage isYour answerChoose one option.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 35
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A forced commutated thyristorized step-down chopper is shown in the figure. Neglect the ON-state drop across the power devices. Assume that the capacitor is initially charged to 50 V with the polarity shown in the figure. The load current (
) can be assumed to be constant at 10 A. Initially,
is ON and
is OFF. The turn-off time available to
in microseconds, when
is triggered, is _________ (rounded off to the nearest integer). 
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Open questionEENAT2 marksNeeds review
A single-phase half-controlled bridge converter supplies an inductive load with ripple free load current. The triggering angle of the converter is 60°. The ratio of the rms value of the fundamental component of the input current to the rms value of the total input current of the bridge is ______ (rounded off to 3 decimal places).
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A single-phase full bridge voltage source inverter (VSI) feeds a purely inductive load. The inverter output voltage is a square wave in 180° conduction mode. The fundamental frequency of the output voltage is 50 Hz. If the DC input voltage of the inverter is 100 V and the value of the load inductance is 20 mH, the peak-to-peak load current in amperes is ______ (rounded off to the nearest integer).
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 64
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In the DC-DC converter shown in the figure, the current through the inductor is continuous. The switching frequency is 500 Hz. The voltage (
) across the load is assumed to be constant and ripple free. The peak inductor current in amperes is ______ (rounded off to the nearest integer).
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 65
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A single-phase full-controlled thyristor converter bridge is used for regenerative braking of a separately excited DC motor with the following specifications:
Specification | Value |
|---|---|
Rated armature voltage | 210 V |
Rated armature current | 10 A |
Rated speed | 1200 rpm |
Armature resistance | 1 Ω |
Input to the converter bridge | 240 V at 50 Hz |
The armature of the DC motor is fed from the full-controlled bridge and the field current is kept constant. | |
Assume that the motor is running at 600 rpm and the armature terminals of the motor are suitably reversed for regenerative braking. If the armature current of the motor is to be maintained at the rated value, the triggering angle of the converter bridge in degrees should be ______ (rounded off to 2 decimal places).
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 23
Open questionEEMCQ1 markNeeds review
The chopper circuit shown in figure (i) feeds power to a 5 A DC constant current source. The switching frequency of the chopper is 100 kHz. All the components can be assumed to be ideal. The gate signals of switches S₁ and S₂ are shown in figure (ii). Average voltage across the 5 A current source is
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