Q1
MCQ[1 Mark]
Using the diode forward characteristic graph (V_0 = 1.0 V at 0 A, 1.8 V at 50 A), calculate the power loss for a continuous 15 A current.
Type:
Power Semiconductor Devices & Converters
8 QuestionsQ2
MCQ[1 Mark]
Based on the MOSFET turn-off voltage overshoot waveforms for gate resistances R_1, R_2, R_3, which option correctly compares them?
Q3
NAT[1 Mark]
Find the peak diode current for v_s = 325 sin(wt) V, L = 500 uH, R = 10 ohm.
Q4
MCQ[2 Marks]
For a boost converter operating in DCM with peak inductor current 6 A (t_1 = 10 us, t_2 = 10 us, T = 20 us), R = 10 ohm, find input voltage V_dc.
Q5
NAT[2 Marks]
For a single-phase rectifier circuit with v_s = 100 sin(wt) V, V_dc = 50 V, R = 10 ohm, find the average diode current.
Q6
MCQ[1 Mark]
Among the given power switching devices with similar ratings, which is the fastest?
Q7
MSQ[1 Mark]
Which semiconductor switch combinations can block unidirectional voltage (V > 0) and carry bidirectional current?
Q8
MCQ[1 Mark]
A low-voltage high-frequency laptop charger (100 W, 20 V, 200 kHz) is best implemented using which power semiconductor device?
Inverters & AC-DC/DC-DC Topologies
23 QuestionsQ9
MCQ[2 Marks]
In a single-phase H-bridge inverter with triangular inductor current (peak 5 A), find the RMS current through switch S1.
Q10
MCQ[2 Marks]
Given converter input voltage v(t) and current i(t) with harmonics, find the input power factor.
Q11
NAT[1 Mark]
For a DC-DC converter setup where MOSFET has duty cycle 0.4, current source I = 10 A, voltage V = 15 V, find power delivered by current source.
Q12
MCQ[2 Marks]
In a 3-phase SPWM inverter with modulation index M = 0.8 and DC link voltage 600 V, find per phase fundamental RMS motor voltage.
Q13
MCQ[2 Marks]
An AC voltage source feeds an inductor L = 100 mH through an SCR with firing angle alpha = 0°. Find the peak inductor current.
Q14
MCQ[2 Marks]
Given converter average voltage V_o and resistor power dissipation 64 W (with R = 1 ohm and 500 V DC source in circuit), find firing angle alpha in degrees.
Q15
NAT[2 Marks]
For a DC-DC buck converter in CCM with V_in = 30 V and capacitor current ripple waveform parameters, find inductor value in mH.
Q16
MCQ[1 Mark]
For a triac AC voltage controller feeding RL load (R = 10 ohm, L = 18.37 mH at 50 Hz), find the minimum triggering angle for controllable output.
Q17
NAT[1 Mark]
Calculate the turn-off time available to thyristor Th in microseconds for the given step-down chopper circuit.
Q18
NAT[2 Marks]
For a single-phase half-controlled bridge converter with alpha = 60° and ripple-free load current, find the ratio of fundamental input current RMS to total input current RMS.
Q19
NAT[2 Marks]
A single-phase full-bridge VSI with 100 V DC input feeds L = 20 mH at 50 Hz. Find the peak-to-peak load current in amperes.
Q20
NAT[2 Marks]
For the given DC-DC converter with f_s = 500 Hz, L = 2 mH, V_i = 20 V, V_o = 40 V, R = 10 ohm, find the peak inductor current in amperes.
Q21
NAT[2 Marks]
For regenerative braking of a DC motor at 600 rpm with armature current at rated 10 A, find the converter bridge triggering angle in degrees.
Q22
MCQ[1 Mark]
A chopper feeds a 5 A DC constant current source with f_s = 100 kHz and given gate duty cycles. Find the average voltage across the 5 A source.
Q23
MSQ[2 Marks]
For the given circuit with diodes and current/voltage sources, which statements regarding switch S states are true?
Q24
NAT[2 Marks]
A thyristor is turned ON in the RLC resonant circuit with V = 100 V, C = 1 uF, L = 4 uH, R = 4 ohm. Find the conduction duration in microseconds before turn-off.
Q25
NAT[2 Marks]
For the single-phase thyristor-diode rectifier feeding 10 A load with given firing angles and input V_in = 100 sin(100 pi t) V, find average load voltage V_0.
Q26
NAT[1 Mark]
A single-phase full-bridge diode rectifier feeds R = 50 Ω from a 200 V, 50 Hz AC supply. Find active power drawn by load in watts.
Q27
NAT[1 Mark]
Given rectifier input voltage and current harmonic expressions, find the input power factor lagging.
Q28
NAT[2 Marks]
An ideal full-bridge single-phase inverter with 1000 V DC bus feeds load current i(t) = 10 sin(wt - pi/3) A with square-wave voltage (50% duty cycle). Find active power in watts.
Q29
NAT[2 Marks]
For the ideal single-phase bridge rectifier with I_dc = 15 A and firing angle alpha = 45°, find the amplitude of the fundamental source current component in amperes.
Q30
NAT[2 Marks]
A 3-phase grid-connected VSC with V_dc = 1000 V supplies S = -4000 - j3000 VA with phase current 10 A. Find the SPWM modulation index.
Q31
NAT[2 Marks]
For a DC-DC buck-boost converter with inductor current waveform (min 12 A, max 16 A over t_on = 20 us, t_off = 30 us) and output voltage ripple 1 V, find the output capacitance in µF.
