Name of the College : Mahatma Gandhi University
Department : Electrical and Electronics Engineering
Subject Code/Name : MEEPE103 /Power Converters
Sem : I
Website : mgu.ac.in
Document Type : Model Question Paper
Download Model/Sample Question Paper :
I : https://www.pdfquestion.in/uploads/mgu.ac.in/5049-1-MEEPE%20103%20POWER%20CONVERTERS-set1.pdf
II : https://www.pdfquestion.in/uploads/mgu.ac.in/5049-2-MEEPE%20103%20POWER%20CONVERTERS-set2.pdf
MGU Power Converters Model Question Paper
M.TECH Degree Examination :
First Semester
Model Question Paper -II
Related : MGU MEEPE106-2 Power Systems Operation & Control M.Tech Model Question Paper : www.pdfquestion.in/5051.html
Branch: Electrical and Electronics Engineering
Specialization: Power Electronics
MEEPE 103 POWER CONVERTERS
(2013 Admission on wards)
Time: Three hours
Maximum: 100 Marks
Sample Questions
1. (a) An ac voltage of 230v2 Sin(314t) V is applied through a single diode to a load of R= 2.3 O and L=33 mH connected in series. If load current is continuous, find minimum and maximum values of source current. [6 Marks]
(b) A load comprises of resistance and capacitance connected in series is fed from voltage source of VmSin(wt) through a diode. Analyze the circuit and draw the waveforms. [12 Marks]
(c) A resistance of 14 O requires average output voltage of 30 volts for a particular application. Resistance is connected to 110v2 Sin(wt)through a single SCR. Compute input power factor. [7 Marks]
OR
2. (a) A voltage of 230V dc is switched on to a resistance of 100O in series with inductance 33mH. Find the magnitude of current at t= 0.23 seconds. [5 Marks]
(b) A resistance of 100 O is connected to a voltage of 230 v2Sin(314t) through one SCR., Compute power factor if SCR is fired at p/2. [7 Marks]
(c) For a thyristor, maximum junction temperature is 1250C. The thermal resistances for the thyristor sink combinations are 0.16 and 0.080C/Watts. For a heat sink temperature of 700C, compute the total average power loss in the thyristor sink combination. In case, the heat sink temperature is brought down to 600C by forced cooling, find the percentage increase in the device rating. [13 Marks]
3. (a) What is the effect of source impedance on the output voltage of a single phase full converter. [7 Marks]
(b) A three phase full converter is fired at 90 degrees. If the output current is continuous, sketch phase voltages, line voltages, scheme of firing pulses and clearly indicate the output voltage on a graph sheet. [18 Marks]
OR
4. (a) With neat sketches, explain the operation of single phase semi converter with continuous load current. [7 Marks]
(b) A three phase semi converter is fired at 60 degrees. Sketch firing pulses, line and phase voltages and output voltage. [18 Marks]
5. With neat circuit diagram explain the operation of a boost converter in continuous and discontinuous current modes. [25 Marks]
OR
6. With neat circuit diagram explain the operation of a buck converter in continuous and discontinuous current modes. [25 Marks]
7. (a) With neat circuits and V-I diagrams, Type- A and Type- E dc chopper circuits.[7 Marks]
(b) Explain the voltage commutation in Type-A chopper with neat figures and derivations. [12 Marks]
(c) Explain the operation of multi pulse AC chopper. [6 Marks]
OR
8. (a) Briefly explain the working of half bridge Mc Murray Invereter. [10 Marks]
(b) A three phase voltage source inverter is feeing balanced star connected resistive load and operates in 120 degree mode of operation. Sketch firing signals and phase and line voltages. Provide derivations. [15 Marks]
Syllabus
Module 1 : Analysis of switched circuits
Ideal models power switches –analysis of thyristor controlled half wave rectifier- R, L, RL, RC load circuits –load circuit with electromotive force.
Module 2 : Controlled Rectifiers
Continuous and discontinuous modes of single phase half and full wave rectifiers – half controlled configurations- RL circuit with electromotive force. Effect of transformer leakage reactance- operating domains of three phase full converters and semi converters.
Module 3 : DC- DC switch mode converters
DC- DC converter systems- control of DC-Dc converters. Buck converters- continuous and discontinuous modes. Boost converters- continuous and discontinuous modes. Buck Boost converters continuous and discontinuous modes. Cuk converters continuous and discontinuous modes. DC-DC converter comparison.
Module 4 : Choppers and Inverters
Classification of DC chopper circuits- analysis of type A chopper and type B chopper- voltage, current and load commutation of choppers- step up chopper- pulse width modulated A.C. Choppers- Circuit topologies and Harmonic elimination methods.
Invereters : Characteristics- output voltage and waveform control- bridge inverters – single phase and three phase versions- MOSFET, IGBT inverters, Mc Murray Inverters- Current source inverter with induction motor load.