FT1 Assgnment EMP2506

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FT12 EMP2506

M.S. RAMAIAH SCHOOL OF ADVANCED STUDIES - Bengaluru

Postgraduate Engineering and Management Programme [PEMP]

INSTRUCTIONS TO CANDIDATES:

1. The Assignment consists of three parts

2. Part A is for 30 Marks, Part B for 30 Marks, Part C for 35 Marks and others 5

Marks

3. The Assignment should be neatly word processed

4. The Assignment should not exceed more than 35 Pages

5. The last date for Assignment submission is 11th May 2013

6. All the units of measurement wherever applicable should be SI Units only

7. The evaluation will be based on your report. You are encouraged to discuss with the

module leader before making of your report.8. You are encouraged to discuss the problem with your colleagues and faculty

members. However the report submitted by each individual should be unique and you

should be in a position to answer any queries.

9. Any missing data should be suitably assumed.

Form – 43 Ver: 2 Date: 14-03-2011

Department Electronics and Electrical Engineering

Course Electrical Machines and Power Engineering

Batch FT 12

Module Code EMP2506

Module Title Power Electronics in Power System Engineering

Module Leader Thejaswini R

1

Assignment



FT12 EMP2506

_______________________________________________________________________

April 2013

Assignment Objective:

Power electronics is the application of semiconductor devices to the control and conversion

of electrical power. The availability of solid state power switches such as the thyristor and

GTO, BJT, MOSFET and IGBT power transistors, have created a very rapid expansion in

power electronic applications. Typical applications are low power control of domestic

appliances, high power control of industrial processes and very high power flow control

along transmission lines.In this module, design and analysis of power converters, controllers and their applications are

emphasized.

This assignment is intended to appreciate the importance of power convertors in power

systems. The assignment is divided into three parts. Part – A is a report on digital control of

power factor corrected power supply. Part - B is subsystem modeling, design and

development of inverter fed AC motor drive for variable speed operations. Part- C is

simulation of integrated subsystems for an AC drive with continuous and discrete simulation

time.

PART A 30 marks

Introduction

Power factor correction is a modern concept which deals with increasing the degraded power

factor of a power system by use of external equipments. The objective is to make the

input to a power supply appear as a simple resistor. As long as the ratio between the

voltage and current is a constant the input is resistive in nature, and the power factor

should be unity. When the ratio deviates from a constant the input will contain phase

displacement, harmonic distortion or both and either one will degrade the power

factor.

In simple words, Power factor correction (PFC) is a technique of counteracting the

undesirable effects of electric loads that create a power factor (PF) that is less than unity.

New approaches to control power factor correcting switching power supplies, made possible

with substantially more processing power than the previous generation. New control

schemes have evolved with digital processing to replace analog control schemes.

Problem Statement

Compile a report on “Digital Control of Power Factor Corrected Power Supply”.

Report should consider the following:

• Critically analyze the need for PFC and justify. Also comment on types of PFC

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FT12 EMP2506

• Discuss the recent techniques used in digital control of PFC and compare with analog

control techniques

• Challenges in digital control schemes for PFC

• Discuss the pros and cons of different topologies to achieve PFC using digital control

• Design procedure for the prioritized power factor corrected power supply

• Conclusion

Guidelines for submission:

• The report should be completed within three A4 pages

• Students are advised to use only simple sentences

• Quotes and figures can be reproduced from literature with citation

• Expression of your own views through discussions on topics you come across while

developing the essay will be appreciated• Any data required for the solution can be appropriately assumed and the same should

be stated in the report.

PART B 30 Marks

Introduction

The induction motor requires a variable-frequency three-phase source for variable-speed

operation. The source is realized by using a power converter system which consists of a

rectifier, inverter in a DC link. In industrial drive applications, the PWM inverter operates asa three-phase variable-frequency, variable-voltage source. The voltage source’s fundamental

frequency varying from zero to three times the motor nominal frequency. Inverter-fed

induction motor drive can be controlled with various schemes depending on the application,

desired performance, and controller design complexity.

Problem Statement

Design and Develop subsystem blocks for a inverter fed variable speed Induction motor

drive. The motor and inverter should have the following specifications: 50 HP, 460 V, four-

pole, 60 Hz. R s = 0.087Ω, L1s = 0.8mH, Lm = 34.7mH, R r = 0.228Ω, L1r = 0.8mH

Carry out the following:

• Choose one of the four control schemes for induction motor speed control with the

above mentioned specifications

• Model the inverter block , current regulator to provide pulses to inverter and analyze

the performance

• Develop and analyze the control scheme

• Develop a controller which maintains the zero steady state error


Form – 43 Ver: 2 Date: 14-03-2011 3



FT12 EMP2506

• It should be expressed completely in your own words. Any data, figures and tables

available in published literatures can be used to support your arguments with proper

citation.

• Any data required for the solution can be appropriately assumed and the same should

be stated in the report.

• Use Simulink to model the sub-systems

• The results/graphs should support the performance analysis of simulated sub-systems

PART C 35 Marks

Introduction

The induction motor is known as the work horse of industries. The advancement of power

electronics has made it possible to vary the frequency of the induction motor using various

control schemes. These control schemes have extended the use of induction motor in variable

speed drive applications.

Problem Statement:

Integrate the sub-system blocks for an inverter fed variable speed Induction motor drive

developed in part B. The operating conditions of the induction motor drive are as follows; the

reference speed should vary from 120 rad/s to 160 rad/s at 0.2 s and the load torque from 0

Nm to 200 Nm at 1.8 s to the drive.

Carry out the following:

•Integrate the developed sub-system blocks and analyze speed regulation of Inductionmotor

• Set an appropriate discrete simulation time for the integrated model

• Simulate the integrated model for the above mentioned operating conditions

• Obtain steady-state Motor Current, Voltage, and Torque Waveforms

• Obtain speed Regulation Dynamic Performance

• Compare the performances of continuous and discretized system


• Your report should be based on literature review carried out by referring to standard

journals.• It should be expressed completely in your own words. Any data, figures and tables

available in published literatures can be used to support your arguments with proper

citation.

• Assume suitable data which ever is required to design, report your assumptions.

Learning outcomes: (5 marks)

The students should write a paragraph on the module learning outcomes derived by solving

this assignment referring to session 0 and how the module has benefited in understanding the

various concepts of power semiconductor devices in the broad domain of power electronics.

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FT12 EMP2506

Form – 43 Ver: 2 Date: 14-03-2011 5

FT1 Assgnment EMP2506

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