Download Sathyabama Univarsity M.E Dec 2010 Analysis of Rectifiers and

Register Number
SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act, 1956)
Course & Branch: M.E-W-PEL/PEL
Title of the Paper: Analysis of Rectifiers and Choppers
Max. Marks: 80
Sub. Code: SEEX5001
Time: 3 Hours
Date: 09/12/2010
Session: FN
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1.
PART - A
(6 X 5 = 30)
Answer ALL the Questions
An RL load is fed from single phase supply through a thyristor.
Derive an expression for load current in terms of supply voltage,
frequency etc.
2.
Explain the effect of source inductance on the performance of
three phase controlled rectifiers.
3.
Design the filter component for a buck converter which has an
input voltage of 12V and output voltage of 5V. the peak to peak
output ripple voltage is 20mV and peak to peak ripple current of
inductor is limited to 0.8A. The switching frequency is 25 kHz.
4.
For a single phase voltage controller connected to resistive load,
draw the wave form of source voltage, gating signals, output
voltage and voltage across an SCR.
5.
Explain the principle and working of matrix converter.
6.
Compare between circulating current mode and non circulating
current mode of dual converter.
PART – B
(5 x 10 = 50)
Answer ALL the Questions
7.
8.
Analyze the work of single phase dual converter with a neat
sketch and wave forms.
(or)
Derive an expression to find the average Value of output current
of a single phase semi converter that delivers power to RLE load.
Assume continuous conduction. Also find the same when R =
5, L = 10mH and E = 80V.
9.
For a three phase dual converter, derive an expression for output
using circulating current scheme. Sketch the relevant wave forms.
(or)
10. A half controlled three phase bridge rectifier is supplied at 220V
from a source of reactance 0.24/phase, neglecting resistance
and device volt drops determine mean load voltage for level load
current of 40A at a fixing delay angle of 45 and 90 degrees.
11. List the various types of switched mode regulators and explain
the working of CUK converter in detail.
(or)
12. With necessary circuit and wave forms explain the principles of
step up chopper. Derive an expression for the output voltage in
terms of input DC voltage and duty cycle. State the assumptions
made.
13. Explain the operation of three phase bi-directional data connected
controllers.
(or)
14. A step down DC chopper has a resistive load of R = 10 and the
input voltage is Vs = 220V. When the chopper switch remains on,
its voltage drop is 2V and the chopping frequency is 1 kHz.If the
duty cycle is 50%, determine
(a) the average output voltage V0,
(b) the rms output voltage,
(c) the chopper efficiency
(d) the effective input resistance of the chopper
15. Explain with circuit and wave forms, the operation of single
phase to single phase step down cycle converter for the following
(a) Discontinuous load current
(b) Continuous load current
(or)
16. Explain the current of controllers. Apply the same for explaining
for the operation of AC voltage controllers.