mgu.ac.in M.Tech Electrical and Electronics Engineering Question Paper Model : Mahatma Gandhi University
Name of the University : Mahatma Gandhi University
Degree : M.Tech
Name Of The Subject : Electrical and Electronics Engineering
Document type : Model Question Paper
Website : mgu.ac.in
Download Optimization Of Power System Operation Paper : https://www.pdfquestion.in/uploads/7534-POWERSYSTEM.docx
Download Power Electronic Devices And Circuits Paper : https://www.pdfquestion.in/uploads/7534-PEDCQP.pdf
MGU Power Electronic Devices & Circuits Model Paper
1. (a) Compare the switching characteristics of power MOSFETs and power transistors bringing out the advantages of one over the other. (15 marks)
Related : Mahatma Gandhi University M.Tech Civil Engineering Question Paper Model : www.pdfquestion.in/7532.html
(b) For an SCR, the gate cathode characteristics are given by a straight line passing through the origin with a gradient of 16V/A. the turn-on time is 4µs and the gate current required is 500mA. For the gate-source voltage of 15V, calculate; (i) gate power dissipation; (ii) the resistance to be connected in series with the gate. (10 marks)
OR
2. (a) Explain the Static and dynamic characteristics of IGBT?
(b) Discuss the overvoltage, over current, di/di and dv/dt protection of power semiconductor device. (10 marks)
(c) Compare the power diode with signal diode? (5 marks)
3. (a).With neat diagram and waveform, explain the operation of a single phase rectifier (uncontrolled) with RL load and capacitive filter. Derive the expression for the performance parameters of the rectifier. (15 marks)
(b). Discuss the effect of source inductance on the performance of the rectifier. (10 marks)
OR
4. (a). What are dual converters? Mention their advantages and applications. (7 marks)
(b) Explain the inversion mode of operation of converter. (8 marks)
(c). A 3-phase full converter is fed by a 400V, 3-phase 50Hz supply. The average load current is 100A. Assuming highly inductive load, for a firing angle of 600, determine.
i.Output voltage and power.
ii.Average r.m.s. and peak currents through the SCR.
iii.PIV of the SCR. (10 marks)
5. (a) Draw the circuit of a buck-boost converter and explain its working principle. (5 marks)
(b). Discuss the discontinuous conduction mode of Buck Converter? Also derive expression for voltage conversion ratio (10 marks)
(c) What is a multiphase boost converter? Explain the operation. List the merits and demerits of multiphase choppers (10 marks)
OR
6. (a) Explain the operation of the basic Cuk converter. What are its main advantages?
(10 marks)
(b) Describe the state-space modeling of buck and buck boost DC-DC converters
(c) In a step-up converter, the duty ratio is adjusted to regulate the output voltage Vo at 48V. The input voltage varies in a wide range from 12V to 36V. The maximum power output is 120W. For stability reasons, it is required that the converter always operate in discontinuous –current-conduction mode. The switching frequency is 50 kHz. Assuming ideal components and C as very large, calculate the maximum value of L that can be used (10 marks)
7. (a). With necessary waveforms explain the working of a single-phase bridge inverter. (10 marks)
(b) Explain the PWM method of voltage control in inverters. What are its advantages?
(10 marks)
(c) Compare voltage source and current source inverters.
Optimization Of Power System Operation
1. (a)Explain Fibonacci method for one dimensional minimization
(b) Find the minimum of function f=?5 – 5 ?3 _20 ? + 5 by golden section method in the interval (0, 5)
OR
2. (a)Explain univariate method
(b) Minimize f=2×1 2+x2 2 by using the steepest descent method with the startingpoint (1,2)
3.(a)Explain lagrangian method
(b)Minimize f(x)=x12 – x1 x2+3 x22- 4×2+4 subject to x1 + x2=1 x1 , x2 = 0
OR
4. (a)Explain genetic operators
(b)Maximize z= 7 x1 + 9 x2 subject to – x1 + 3 x2<6; 7×1 + x2=35
(a)Discuss economic dispatch by base point and participation factors (10 marks)
(b)Explain take or pay fuel supply contract. Explain the procedure for obtaining om posite cost curve (15 marks)
OR
6.Explain how scheduling of energy can be done using gradient search technique if there is limited supply of fuel (13 marks)
(b)The fuel cost functions for three thermal plants in Rs/hr and generator constraints are given by
C1=510+7.2P1+0.0014 P1 150= P1 =600
C2=300+7.5P2+0.0016 P2 100= P2=400
C3=80+7.8P3+0.0048 P3 50= P3=200
Where P1, P2 and P3 are in MW. The total load PD is 850 MW. Neglecting losses determine the economic operating point.