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Department of Electrical Engineering
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Pre-University
Test : 19/04/2017
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6EE4A:
Advanced Power Electronics
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Attempt all questions.
Internal options are given in each question. All questions have been asked in previous
year RTU Papers
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1
a)
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A single phase ac voltage controller has
resistive load of 10 Ω, input voltage Vs = 120 Volts, 60 Hz, the
delay angle of thyristor T1 is α
=
 . Determine
i)
RMS Value of output voltage
ii)
Input Power Factor
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RTU
2015
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8
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b)
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For 1
phase ac voltage regulator, develop a relation between conduction angle γ and
firing angle α,
and plot their variation as a function of load phase angle ϕ. Under what condition,
conduction angle γ becomes equal to Π.
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2014
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8
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OR
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1
a)
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For a single phase full wave controller with RL
load, draw the waveform of output voltage, output current and voltage across
thyristor. Determine the expression for rms output voltage.
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2010
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8
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b)
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An ac voltage controller has a resistive load of
R= 10 Ω.
The input voltage (rms) Vs= 10 Volts, 60 Hz. The thyristor switch
is ON for m= 25 cycles and OFF for n= 75 cycles. Determine:
i)
The rms output voltage V0
ii)
The input power factor (PF)
iii)
The average and rms current of thyristor.
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2013
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8
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2
a)
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Describe the working principle of single phase to
single phase step down cycloconverter continuous conduction for bridge type
cycloconverter.
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2015
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8
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b)
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What is load commutated cycloconverter. How does
it differ from line commutated cycloconverter?
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2013
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8
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OR
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2
a)
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A 3 phase cycloconverter feeds 1 phase load of
190 Volts, 45 Amps, at a power factor of 0.7 (lagging). Determine:
i)
The required supply voltage
ii)
Thyristor rating
iii)
Power factor of supply current.
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2013
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8
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b)
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Describe the control scheme for cycloconverter
using voltage sensing principle of converter group selection. Also draw
various voltage waveforms of a control scheme.
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2010,
2014
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8
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3
a)
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A single phase full bridge inverter is connected
to DC voltage source Vs. Resolve the output wave shape into
Fourier series (Harmonic Analysis)
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2015
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8
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b)
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State the need of reduction in Harmonics in
inverter. Outline the various methods for reduction in harmonics or the
improvement in wave shape.
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2013,
2014
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8
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OR
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3
a)
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Explain the working principle of 3 phase bridge
inverter with 180o of conduction.
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2015
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8
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b)
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A 3 phase bridge inverter is fed from 200 Volts
DC source. The inverter is operated in 180o conduction mode and is
supplying inductive, star connected loa with R= 10 Ω and L= 20m.H. The inverter
frequency is fo= 50 Hz. Calculate:
i)
Instantaneous line-to-line Voltage and Current
in form of Fourier Series.
ii)
Total Harmonic Distortion
iii)
Distortion Factor
iv)
Average and RMS Switch current.
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2014
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8
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4
a)
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Explain the working of L-type ZCS (Zero Current
Switching) resonant converter
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2015
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8
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b)
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Write down short notes on ZVS resonant converter.
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2015
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8
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OR
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4
a)
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Explain all the stages working of M-type ZCS
resonant converter.
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8
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b)
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Write down the advantage and limitations of ZVS
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2015
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8
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5
a)
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Write Short notes on
i)
Resonant AC Power supply
ii)
SMPS
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2014
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8
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b)
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With a neat sketch, explain Multistage
Conversion.
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2013
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8
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OR
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5
a)
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Discuss various control application (feedback
control or others) used in ac power supplies
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2014
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8
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b)
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What is switched Mode DC Power Supplies (SMPS).
Explain the working principle of flyback converter.
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2015
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8
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