Course File On Modern Power Electronics By Srinivas D Assistant ...kgr.ac.in/wp-content/uploads/2019/12/MODERN-POWER-ELECTRONI… · Year / Semester st: IV / I Department : Electrical

KG Reddy College of Engineering & Technology (Approved by AICTE, New Delhi, Affiliated to JNTUH, Hyderabad)

Chilkur (Village), Moinabad (Mandal), R. R Dist, TS-501504

Accredited by NAAC

Course File On

Modern Power Electronics

By

Srinivas D

Assistant Professor,

Electrical & Electronics Engineering

K. G. Reddy College Of Engineering and Technology

2019-2020

HOD Principal

EEE KGRCET



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COURSE FILE Subject Name : Modern Power Electronics

Faculty Name : Srinivas D

Designation : Assistant Professor

Regulation /Course Code : R16/ EE733PE

Year / Semester : IV / Ist

Department : Electrical & Electronics

Engineering

Academic Year : 2019-20



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COURSE FILE CONTENTS

S.N. Topics Page No.

1 Vision, Mission, PEO’s, & PO’s, PSOs

2 Syllabus (University Copy)

3 Course Objectives, Course Outcomes And Topic Outcomes

4 Course Prerequisites

5 CO’s, PO’s Mapping

6 Course Information Sheet (CIS)

a). Course Description

b). Syllabus

c). Gaps in Syllabus

d). Topics beyond syllabus

e). Web Sources-References

f). Delivery / Instructional Methodologies

g). Assessment Methodologies-Direct

h). Assessment Methodologies –Indirect

i). Text books & Reference books

7 Micro Lesson Plan

8 Teaching References Plan

9 Lecture Notes -Unit Wise (Hard Copy)

10 OHD/LCD SHEETS /CDS/DVDS/PPT (Soft/Hard copies)

11 University Previous Question papers

12 MID exam Descriptive Question Papers

13 MID exam Objective Question papers

14 Assignment topics with materials

15 Tutorial topics and Questions

16 Unit wise-Question bank

1 Two marks question with answers 5 questions

2 Three marks question with answers 5 questions

3 Five marks question with answers 5 questions

4 Objective question with answers 10 questions

5 Fill in the blanks question with answers 10 questions

17 Beyond syllabus Topics with material

18 Result Analysis-Remedial/Corrective Action

19 Sample Students Descriptive Answer sheets

20 Sample Students Assignment Sheets

21 Record of Tutorial Classes

22 Record of Remedial Classes

23 Record of guest lecturers conducted



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PART-2

S.NO. Topics

1 Attendance Register/Teacher Log Book

2 Time Table

3 Academic Calendar

4 Continuous Evaluation-marks (Test, Assignments etc)

5 Status Request internal Exams and Syllabus coverage

6 Teaching Diary/Daily Delivery Record

7 Continuous Evaluation – MID marks

8 Assignment Evaluation- marks /Grades

9 Special Descriptive Tests Marks

10 Sample students descriptive answer sheets

11 Sample students assignment sheets



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1. VISION, MISSION, PROGRAM EDUCATIONAL OBJECTIVES

VISION

To become a renowned department imparting both technical and non-technical skills to the students by

implementing new engineering pedagogy’s and research to produce competent new age electrical

engineers.

MISSION

To transform the students into motivated and knowledgeable new age electrical engineers.

To advance the quality of education to produce world class technocrats with an ability to adapt to the

academically challenging environment.

To provide a progressive environment for learning through organized teaching methodologies,

contemporary curriculum and research in the thrust areas of electrical engineering.

PROGRAM EDUCATIONAL OBJECTIVES

PEO 1: Apply knowledge and skills to provide solutions to Electrical and Electronics Engineering

problems in industry and governmental organizations or to enhance student learning in educational

institutions

PEO 2: Work as a team with a sense of ethics and professionalism, and communicate effectively to

manage cross-cultural and multidisciplinary teams

PEO 3: Update their knowledge continuously through lifelong learning that contributes to personal,

global and organizational growth

PROGRAM OUTCOMES

PO 1: Engineering knowledge: Apply the knowledge of mathematics, science, engineering

fundamentals and an engineering specialization to the solution of complex engineering problems.

PO 2: Problem analysis: Identify, formulate, review research literature, and analyze complex

engineering problems reaching substantiated conclusions using first principles of mathematics, natural

science and engineering sciences.

PO 3: Design/development of solutions: design solutions for complex engineering problems and

design system components or processes that meet the specified needs with appropriate consideration for

the public health and safety, and the cultural, societal and environmental considerations.

PO 4: Conduct investigations of complex problems: use research based knowledge and research

methods including design of experiments, analysis and interpretation of data, and synthesis of the

information to provide valid conclusions.



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PO 5: Modern tool usage: create, select and apply appropriate techniques, resources and modern

engineering and IT tools including prediction and modeling to complex engineering activities with an

understanding of the limitations.

PO 6: The engineer and society: apply reasoning informed by the contextual knowledge to assess

societal, health, safety, legal and cultural issues and the consequent responsibilities relevant to the

professional engineering practice.

PO 7: Environment sustainability: understand the impact of the professional engineering solutions in

the societal and environmental contexts, and demonstrate the knowledge of, and need for sustainable

development.

PO 8: Ethics: apply ethical principles and commit to professional ethics and responsibilities and norms

of the engineering practice.

PO 9: Individual and team work: function effectively as an individual and as a member or leader in

diverse teams, and in multidisciplinary settings.

PO 10: Communication: communicate effectively on complex engineering activities with the

engineering community and with society at large, such as, being able to comprehend and write effective

reports and design documentation, make effective presentations, and give and receive clear instructions.

PO 11: Project management and finance: demonstrate knowledge and understanding of the

engineering and management principles and apply these to one’s own work, as a member and leader in a

team, to manage projects and in multidisciplinary environments.

PO 12: Lifelong learning: recognize the need for, and have the preparation and ability to engage in

independent and lifelong learning in the broader context of technological change.

(E) PROGRAM SPECIFIC OUTCOMES

PSO-1: Apply the engineering fundamental knowledge to identify, formulate, design and investigate

complex engineering problems of power electronics, electrical machines and power systems and to succeed

in acquiring Ph.D.

PSO-2: Apply appropriate techniques and modern engineering hardware and software tools in power

systems and power electronics to engage in life-long learning and to get an employment in the field of

Electrical and Electronics Engineering.

PSO-3: Understand the impact of engineering solutions in societal and environmental context, commit to

professional ethics and communicate effectively.



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2. SYLLABUS (UNIVERSITY COPY)

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD.

B.Tech. IV Year I Sem. L T P C

3 0 0 3

UNIT - I

High-Power Semiconductor Devices: Introduction, High-Power Switching Devices, Diodes,Silicon-

Controlled Rectifier (SCR), Gate Turn-Off (GTO) Thyristor, Gate-Commutated Thyristor (GCT), Insulated

Gate Bipolar Transistor (IGBT), Other Switching Devices, Operation of Series-Connected Devices, Main

Causes of Voltage Unbalance, Voltage Equalization for GCTs

UNIT-II

Cascaded H-Bridge Multilevel Inverters: Introduction, Sinusoidal PWM, Modulation Scheme, Harmonic

Content, Over modulation, Third Harmonic Injection PWM, Space Vector Modulation, Switching States,

Space Vectors, Dwell Time Calculation, Modulation Index, Switching Sequence, Spectrum Analysis,

Even-Order Harmonic Elimination, Discontinuous Space Vector Modulation. Introduction, H-Bridge

Inverter, Bipolar Pulse-Width Modulation, Unipolar Pulse-Width

Modulation.

UNIT - III

Diode-Clamped Multilevel Inverters: Three-Level Inverter, Converter Configuration, Switching State

,Commutation, Space Vector Modulation, Stationary Space Vectors , Dwell Time Calculation, Relationship

Between V_refLocation and Dwell Times, Switching Sequence Design, Inverter Output Waveforms and

Harmonic Content , Even-Order Harmonic Elimination, Neutral-Point Voltage Control, Causes of Neutral-

Point Voltage Deviation , Effect of Motoring and Regenerative Operation, Feedback Control of Neutral-

Point Voltage

UNIT - IV

DC-DC Switch-Mode Converters & Switching DC Power Supplies Control of dc-dc converter, Buck

converter, boost converter, buck-boost converter, cuk dc-dc converter, full bridge dc-dc converter, dc-dc

converter comparison. Introduction, linear power supplies, overview of switching power supplies, dc-dc

converters with electrical isolation, control of switch mode dc power supplies, power supply protection,

and electrical isolation in the feedback loop, designing to meet the power supply specifications.

UNIT - V

Resonant Converters & Power Conditioners And Uninterruptible Power Supplies

Classification of resonant converters, basic resonant circuit concepts, load-resonant converters, resonant-

switch converters, zero-voltage-switching, resonant-dc-link inverters with zero-voltage switching’s, high

frequency-link integral-half cycle converters. Power line disturbances, Introduction to Power Quality,

power Conditioners, uninterruptible power supplies, Applications.



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3. COURSE OBJECTIVES AND COURSE OUTCOMES

COURSE OBJECTIVES

(a) To understand various Power Electronics devices such as SCR, TRIAC, DIAC,

IGBT, GTO etc.

(b) To understand application of aforesaid Power Electronics devices in Choppers,

Inverters and Converters etc.

(c) To understand control of Electrical Motors through DC-DC converters, AC

Converters etc.

(d) To understand the use of Inductors and Capacitors in Choppers, Inverters and

Converters.

COURSE OUTCOMES After completion of this course, the student will able to

CO1: explain various Power Electronics devices such as SCR, TRIAC, DIAC,

IGBT, GTO etc.

CO2 : apply the knowledge of Power Electronics devices in Choppers,

Inverters and Converters etc

CO3: control the Electrical Motors through DC-DC converters, AC Converters etc.

CO4 Use Inductors and Capacitors in Choppers, Inverters and Converters.



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TOPIC OUTCOMES

S.NO TOPIC TOPIC OUTCOME

UNIT-I At the end of the topic, the student will be able to

1

Introduction To The Course Recollect the Various Power Electronics

Devices.

2

High-Power Switching Devices, Diodes Operation of High Power Switching

Devices.

3

Silicon-Controlled Rectifier (SCR), Gate Turn-

Off (GTO) Thyristor

k

Operation of Silicon-Controlled

Rectifier (SCR), Gate Turn-Off (GTO)

Thyristor

4

Gate-Commutated Thyristor (GCT), Insulated

Gate Bipolar Transistor (IGBT

Operation Gate-Commutated Thyristor

(GCT), Insulated Gate Bipolar

Transistor (IGBT

5

Other Switching Devices Detailed explanation of other Switching

Devices.

6

Operation of Series-Connected Devices Operation of Series connection of

various switching devices.

7

Main Causes of Voltage Unbalance, Voltage

Equalization for GCTs

To know the Main Causes of Voltage

Unbalance, Different methods for

Voltage Equalization for GCTs

8 Tutorial Solve and Revise

9 Numerical Problems Solve the problems

UNIT-II 10 Introduction Recollect basic converters

11

Sinusoidal PWM ,Modulation Scheme,

Harmonic Content

Study of types of Sinusoidal PWM,

Types of harmonics

12

Over modulation, Third Harmonic Injection

PWM

Types of different modulation methods

and types of harmonics

13

Space Vector Modulation,

Switching States, Space Vectors

Causes of over modulation and

operation of third harmonic injection

method. Know the idea of Space vector

modulation and Space vectors.

14

Dwell Time Calculation, Modulation Index Calculation of Dwell time calculations,

analysis of modulation index

15

Switching Sequence, Spectrum Analysis

Even-Order Harmonic Elimination

Analysis of discontinuous Spectrum

Different methods to eliminate even

order harmonics

16

Discontinuous Space Vector Modulation Analysis of discontinuous space vector

modulation

17 Tutorial Revise.



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19 Introduction Recollection of basic inverters

20 H-Bridge Inverter Operation of H- Bridge Inverter.

21

Bipolar Pulse-Width Modulation

Operation Bipolar Pulse width

modulation

22

Unipolar Pulse-Width Modulation. Operation of Unipolar Pulse width

modulation.

23 Tutorial Revise.


UNIT-III

25

Three-Level Inverter Analysis of Three-Level Inverter,

Converter Configuration

26 Converter Configuration

27

Switching State, Commutation, Analysis and detailed operation of

Switching State ,Commutation, Space

Vector Modulation

28 Space Vector Modulation

29

Stationary Space Vectors Detailed operation and calculations of

Stationary Space Vectors , Dwell Time

Calculation

30 Dwell Time Calculation

31

Relationship Between V_refLocation and

Dwell Times

Operation and analysis of

V_refLocation and Dwell Times

32

Switching Sequence Design, Inverter Output

Waveforms and Harmonic Content

Analysis of Switching Sequence Design,

Inverter Output Waveforms and

Harmonic Content

33

Even-Order Harmonic Elimination Types of harmonics and Even-Order

Harmonic Elimination and operation of

Neutral-Point Voltage Control

34 Neutral-Point Voltage Control

35

Causes of Neutral-Point Voltage Deviation Types of Causes of Neutral-Point

Voltage Deviation

36

Effect of Motoring and Regenerative

Operation

Different types of Effect of Motoring

and Regenerative Operation

37

Feedback Control of Neutral-Point Voltage Operation of Feedback Control of

Neutral-Point Voltage

38 Tutorial Revise.


UNIT-IV

40

Control of dc-dc converter, Buck converter Analysis and operation of dc-dc

converter, Buck converter

41

boost converter ,buck-boost converter boost converter, buck-boost

converter

42 cuk dc-dc converter Analysis and operation cuk dc-dc



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converter, full bridge dc-dc converter

43 full bridge dc-dc converter Analysis full bridge dc-dc converter

44

dc-dc converter comparison Analysis and operation dc-dc converter

comparison

45

Introduction Recollection of basic types of power

supplies

46

linear power supplies Analysis and operation linear power

supplies, overview of switching power

supplies

47 overview of switching power supplies

48

DC-DC converters with electrical isolation Analysis and operation DC-DC

converters with electrical isolation

49

Control Of Switch Mode Dc Power Supplies,

Power Supply Protection

Different types of Control Of Switch

Mode Dc Power Supplies, Power

Supply Protection

50

Electrical Isolation in The Feedback Loop Operation of Electrical Isolation in The

Feedback Loop

51

Designing to meet the power supply

specifications

Analysis and design of power supply

52 Tutorial Revise.


UNIT-V

54 Classification of resonant converters Recollect the basic converters.

55

Basic resonant circuit concepts Analysis of basic resonant circuit

concepts

56 Load-resonant converters Analysis of load-resonant converters

57 Resonant-switch converters Analysis of resonant-switch converters

58 Zero-voltage-switching Analysis of zero-voltage-switching

59

Resonant-dc-link inverters with zero-voltage

switching’s

Analysis of Resonant-dc-link inverters

with zero-voltage switching’s

60

High frequency-link integral-half cycle

converters

Analysis of High frequency-link

integral-half cycle converters

61

Power line disturbances Problems associated with Power line

disturbances

62 Tutorial Revise.


64 Introduction Power Quality Problems

65 Power Quality Causes of Power Quality Problems.

66 Power conditioners Analysis of Power conditioners

67

Uninterruptible power supplies Analysis of Uninterruptible power

supplies

68 Applications. Applications of UPS

69 Tutorial Revise.




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4. COURSE PREREQUISITES

1. Power Electronics

5) CO’S, PO’S MAPPING:

CO&PO Mappings

PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO9 PO10 PO11 PO12

CO1 3

CO2

CO3

CO4

1- Low; 2- Medium; 3- High

6. COURSE INFORMATION SHEET (CIS)

6. (a) Course description

PROGRAMME: B. Tech.

(Electrical and Electronics Engineering)

DEGREE: B.TECH

COURSE: Modern Power Electronics YEAR: IV SEM: I CREDITS: 3

COURSE CODE: EE733PE

REGULATION: R16

COURSE TYPE: CORE

COURSEAREA/DOMAIN:

Architecture/organization

CONTACT HOURS: 3+0 (L+T)) hours/Week.



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6. (b) Syllabus

Unit Details Hours

I

High-Power Semiconductor Devices: Introduction, High-

Power Switching Devices, Diodes,Silicon-Controlled Rectifier

(SCR), Gate Turn-Off (GTO) Thyristor, Gate-Commutated

Thyristor (GCT), Insulated Gate Bipolar Transistor (IGBT),

Other Switching Devices, Operation of Series-Connected

Devices, Main Causes of Voltage Unbalance, Voltage


07

II

Cascaded H-Bridge Multilevel Inverters: Introduction,

Sinusoidal PWM, Modulation Scheme, Harmonic Content,

Over modulation, Third Harmonic Injection PWM, Space

Vector Modulation, Switching States, Space Vectors, Dwell

Time Calculation, Modulation Index, Switching Sequence,

Spectrum Analysis, Even-Order Harmonic Elimination,

Discontinuous Space Vector Modulation. Introduction, H-

Bridge Inverter, Bipolar Pulse-Width Modulation, Unipolar

Pulse-Width

Modulation

11

III

Diode-Clamped Multilevel Inverters: Three-Level Inverter,

Converter Configuration, Switching State ,Commutation, Space

Vector Modulation, Stationary Space Vectors , Dwell Time

Calculation, Relationship Between V_ref Location and Dwell

Times, Switching Sequence Design, Inverter Output

Waveforms and Harmonic Content , Even-Order Harmonic

Elimination, Neutral-Point Voltage Control, Causes of Neutral-

Point Voltage Deviation , Effect of Motoring and Regenerative

Operation, Feedback Control of Neutral-Point Voltage

13

IV

DC-DC Switch-Mode Converters & Switching DC Power

Supplies Control of dc-dc converter, Buck converter, boost

converter, buck-boost converter, cuk dc-dc converter, full

bridge dc-dc converter, dc-dc converter comparison.

Introduction, linear power supplies, overview of switching

power supplies, dc-dc converters with electrical isolation,

control of switch mode dc power supplies, power supply

protection, and electrical isolation in the feedback loop,

designing to meet the power supply specifications

12



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V

Resonant Converters & Power Conditioners And

Uninterruptible Power Supplies

Classification of resonant converters, basic resonant circuit

concepts, load-resonant converters, resonant-switch converters,

zero-voltage-switching, resonant-dc-link inverters with zero-

voltage switching’s, high frequency-link integral-half cycle

converters. Power line disturbances, Introduction to Power

Quality, power Conditioners, uninterruptible power supplies,

Applications.

13

Contact classes for syllabus coverage 56

Lectures beyond syllabus 04

Tutorial classes 14

Classes for gaps & Add-on classes 02

Total No. of classes 76

6 (c) Gaps in syllabus

S.NO. DESCRIPTION PROPOSED ACTIONS

1 Multi Level Inverters PPT

2 Power Quality Problems PPT

6(d) Topics beyond Syllabus

1 Renewable Energy Sources application to DC – DC Applications Guest Lecture

2 Applications of Distributed Generation. NPTEL

6 (e) Web Source References

Sl. No. Name of book/ website

a.

b.

c.



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6(f)Delivery / Instructional Methodologies:

CHALK & TALK STUD. ASSIGNMENT WEB RESOURCES

LCD/SMART

BOARDS

STUD. SEMINARS ☐ ADD-ON COURSES

6(g)Assessment Methodologies - Direct

Assignments

Stud. Seminars Tests/Model

Exams

Univ. Examination

Stud. Lab

Practices

Stud. Viva ☐ Mini/Major

Projects

☐ Certifications

☐ Add-On

Courses

☐ Others

6(h) Assessment Methodologies - Indirect

Assessment Of Course Outcomes

(By Feedback, Once)

Student Feedback On

Faculty (Twice)

☐Assessment Of Mini/Major Projects By

Ext. Experts

☐ Others

6(i) Text books and References

T/R BOOK TITLE/AUTHORS/PUBLICATION

Text Book “M. H. Rashid”, Power electronics circuits, Devices and applications, PHI, I

edition –

1995.

Text Book “Ned Mohan, Tore M. Undeland and William P. Robbins, A”, “Power

Electronics converters, Applications and Design” John Wiley & Sons, Inc.,

Publication, 3rd Edition 2003



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Reference

Book . “Bin Wu, A”, “High-Power Converters and Ac Drives” John Wiley & Sons,

Inc.,Publication (Free down load from rapidshire.com) 2006.

7. MICRO LESSON PLAN

S.N. Topic Schedule date Actual Date

UNIT-1 At the end of the topic, the student will be able to

1 Introduction To The Course

2 High-Power Switching Devices, Diodes

3

Silicon-Controlled Rectifier (SCR), Gate Turn-

Off (GTO) Thyristor

4

Gate-Commutated Thyristor (GCT), Insulated

Gate Bipolar Transistor (IGBT)

5 Other Switching Devices

6 Operation of Series-Connected Devices

7

Main Causes of Voltage Unbalance, Voltage


8 Tutorial

9 Numerical Problems

UNIT-II

10 Introduction

11

Sinusoidal PWM ,Modulation Scheme,

Harmonic Content

12

Over modulation, Third Harmonic Injection

PWM

13

Space Vector Modulation,

Switching States, Space Vectors

14 Dwell Time Calculation, Modulation Index

15

Switching Sequence, Spectrum Analysis

Even-Order Harmonic Elimination

16 Discontinuous Space Vector Modulation

17 Tutorial


19 Introduction

20 H-Bridge Inverter

21

Bipolar Pulse-Width Modulation

22 Unipolar Pulse-Width Modulation.

23 Tutorial


UNIT-III

25 Three-Level Inverter



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26 Converter Configuration

27 Switching State, Commutation,

28 Space Vector Modulation

29 Stationary Space Vectors

30 Dwell Time Calculation

31

Relationship Between V_refLocation and

Dwell Times

32

Switching Sequence Design, Inverter Output

Waveforms and Harmonic Content

33 Even-Order Harmonic Elimination

34 Neutral-Point Voltage Control

35 Causes of Neutral-Point Voltage Deviation

36

Effect of Motoring and Regenerative

Operation

37 Feedback Control of Neutral-Point Voltage

38 Tutorial


UNIT-IV

40 Control of dc-dc converter, Buck converter

41 boost converter ,buck-boost converter

42 cuk dc-dc converter

43 full bridge dc-dc converter

44 dc-dc converter comparison

45 Introduction

46 linear power supplies

47 overview of switching power supplies

48 DC-DC converters with electrical isolation

49

Control Of Switch Mode Dc Power Supplies,

Power Supply Protection

50 Electrical Isolation in The Feedback Loop

51

Designing to meet the power supply

specifications

52 Tutorial


UNIT-V

54 Classification of resonant converters

55 Basic resonant circuit concepts

56 Load-resonant converters

57 Resonant-switch converters

58 Zero-voltage-switching

59

Resonant-dc-link inverters with zero-voltage

switching’s



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60

High frequency-link integral-half cycle

converters

61 Power line disturbances

62 Tutorial


64 Introduction

65 Power Quality

66 Power conditioners

67 Uninterruptible power supplies

68 Applications.

69 Tutorial


8) Teaching Schedule

Subject MODERN POWER ELECTRONICS

Text Books (to be purchased by the Students)

Book 1 ““M. H. Rashid”, Power electronics circuits, Devices and applications, PHI, I edition –

1995.

Book 2 “Ned Mohan, Tore M. Undeland and William P. Robbins, A”, “Power Electronics

converters, Applications and Design” John Wiley & Sons, Inc., Publication, 3rd Edition

2003

Book 3 . “Bin Wu, A”, “High-Power Converters and Ac Drives” John Wiley & Sons,

Inc.,Publication (Free down load from rapidshire.com) 2006.

Unit

Topic Chapters No’s No of classes

Book 1 Book 2

I

Silicon-Controlled Rectifier (SCR),

Gate Turn-Off (GTO) Thyristor 7 - 2

Operation of Series-Connected

Devices 2 2

Sinusoidal PWM 6 13 2

Modulation Scheme, Harmonic

Content 6 - 2

II Over modulation, Third Harmonic 6 3 2



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Injection PWM

III Three-Level Inverter 9 3 2

Switching State 9 6 2

Stationary Space Vectors 6 - 2

IV

Control of dc-dc converter, Buck

converter 5 5 2

boost converter, buck-boost

converter 5 - 2

cuk dc-dc converter, full bridge dc-dc

converter 5 -

V Resonant-switch converters 8 9 2

Zero-voltage-switching 8 - 2

Contact classes for syllabus coverage 56

Tutorial classes,

Lecture beyond

syllabus and gaps in

the syllabus

20

Total No. of classes 76



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11.Mid Exam Descriptive Question Paper KG Reddy College of Engineering & Technology

(Approved by AICTE, New Delhi, Affiliated to JNTUH, Hyderabad)


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College Code

QM

Name of the Exam: I Mid Examinations Marks: 10

Year-Sem& Branch: IV – I & EEE Duration: 60 Min

Subject: Modern Power Electronics Date & Session

Answer ANY TWO of the following Questions 2X5=10

Q.NO Question Bloom’s

Taxonomy Level Course Outcome

1 Explain the operation of IGBT? Analysis CO1

2 Explain about static characteristics of SCR? Analysis CO1

3

Explain about SCR Series Connection?

Analysis CO1

4 Explain about single pulse width modulation method? Analysis CO1



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KG Reddy College of Engineering & Technology

(Approved by AICTE, New Delhi, Affiliated to JNTUH, Hyderabad)


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College Code

QM

Name of the Exam: II Mid Examinations Marks: 10

Year-Sem & Branch: IV-I & EEE Duration: 60 Min

Subject: Modern Power Electronics Date & Session 21-09-2019

AN

Answer ANY TWO of the following Questions 2X5=10

Q.NO Question Bloom’s

Taxonomy Level Course Outcome

1

Discuss about detailed operation of cascaded H bridge

multi level Inverter? Analysis CO2

2

Discuss about detailed operation of Diode clamped multi

level Inverter? Analysis CO3

3 With necessary equation and wave forms explain about

CUK Regulator? Analysis CO4

4 With necessary equation and wave forms explain about

Push Pull converter? Analysis CO4



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12.Mid Exam Objective Question Paper

IV B.TECH I SEM (R16) EEE I MID EXAMINATIONS, SEPTEMBER-2019

SUBJECT NAME: MODERN POWER ELECTRONICS

OBJECTIVE EXAM

NAME_____________________________HALL TICKET NO

Answer all the questions. All questions carry equal marks. Time: 20min. 10 marks.

I choose correct alternative:

1. A GTO is a _______________ controlled _______________ carrier device [ ]

A. Current,

majority

B. voltage, Majority C. current, Minority D. voltage, minority

2. The reverse voltage blocking capacity of a GTO is small due to the presence of

_______________.

[ ]

A. cathode shorts B. cathode opens C. anode opens D. anode shorts

3. After a GTO turns on the gate current can be _______________. [ ]

A. avalibale B. removed C. increases D. decreases

4. A conducting GTO reverts back to the blocking mode when the anode current falls

below _______________ current.

[ ]

A. latching B. holding C. anode D. cathode

5. The MOSFET combines the areas of _______ & _________ [ ]

A. field effect &

MOS technology

B. semiconductor & TT C. mos technology &

CMOS technolog

D. none of the

mentioned

6. Choose the correct statement [ ]

A. MOSFET is a

uncontrolled

device

B. MOSFET is a voltage

controlled device

C. MOSFET is a current

controlled device

D. MOSFET is a

temperature controlled

device

7. In the internal structure of a MOSFET, a parasitic BJT exists between the [ ]

A. source & gate

terminals

B. source & drain

terminals

C. drain & gate terminals D. there is no parasitic

BJT in MOSFET

8. MOSFET has greatest application in digital circuit due to [ ]

A. Low power

consumption

B. Less noise C. Small amount of space it

takes on a chip

D. All of the above

A



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9. In an IGBT, during the turn-on time [ ]

A. Vge decreases B. Ic decreases C. Vce decreases D. none of the

mentioned

10. A latched up IGBT can be turned off by [ ]

A. forced

commutation of

current

B. forced commutation

of voltage

C. use of a snubber circuit D. none of the

mentioned

II Fill in the Blanks:

11. A GTO has _______________ layers and _______________ terminals.

12. A GTO can be turned on by injecting a _______________ gate current and turned off by

injecting a _______________ gate current. 13. The anode shorts of a GTO improves the _______________ performance but degrades the

_______________ performance. 14. To turn off a conducting GTO the gate terminal is biased _______________ with respect to the

_______________. 15. The _______________ current and forward _______________ current of a GTO are

considerably higher compared to a thyristor.

16. The MOSFET stands for_______________

17. The MOSFET is almost ideal as switching device because_____________

18. The body of an IGBT consists of a_______________________

19. At present, the state-of-the-art semiconductor devices are begin manufactured using__________

20. The approximate equivalent circuit of an IGBT consists of______________ and

______________



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0O0

SET NO: 2 IV B.TECH I SEM (R16) EEE I MID EXAMINATIONS, SEPTEMBER-2019


OBJECTIVE EXAM






2. A conducting GTO reverts back to the blocking mode when the anode current falls


[ ]



A. field effect &

MOS technology


CMOS technolog

D. none of the

mentioned


A. MOSFET is a

uncontrolled

device


controlled device


controlled device

D. MOSFET is a


device


A. source & gate

terminals

B. source & drain

terminals


BJT in MOSFET


A. Low power

consumption


takes on a chip

D. All of the above



mentioned


A



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A. forced

commutation of

current


of voltage


mentioned

9 A GTO is a _______________ controlled _______________ carrier device [ ]

A. Current,

majority


10 The reverse voltage blocking capacity of a GTO is small due to the presence of

_______________.

[ ]



11. The anode shorts of a GTO improves the _______________ performance but degrades the









______________ 19. A GTO has _______________ layers and _______________ terminals.


injecting a _______________ gate current.



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0O0

SET NO: 3 IV B.TECH I SEM (R16) EEE I MID EXAMINATIONS, SEPTEMBER-2019


OBJECTIVE EXAM





A. MOSFET is a

uncontrolled

device


controlled device


controlled device

D. MOSFET is a


device


A. source & gate

terminals

B. source & drain

terminals


BJT in MOSFET

3 MOSFET has greatest application in digital circuit due to [ ]

A. Low power

consumption


takes on a chip

D. All of the above

4 In an IGBT, during the turn-on time [ ]


mentioned

5 A latched up IGBT can be turned off by [ ]

A. forced

commutation of

current


of voltage


mentioned


A. Current,

majority



_______________.

[ ]


A



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8 After a GTO turns on the gate current can be _______________. [ ]


9 A conducting GTO reverts back to the blocking mode when the anode current falls


[ ]


10 The MOSFET combines the areas of _______ & _________ [ ]

A. field effect &

MOS technology


CMOS technolog

D. none of the

mentioned


11. The _______________ current and forward _______________ current of a GTO are











_______________.

0O0



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SET NO: 4

IV B.TECH I SEM (R16) EEE I MID EXAMINATIONS, SEPTEMBER-2019


OBJECTIVE EXAM




2 A conducting GTO reverts back to the blocking mode when the anode current falls


[ ]



A. field effect &

MOS technology


CMOS technolog

D. none of the

mentioned


A. MOSFET is a

uncontrolled

device


controlled device


controlled device

D. MOSFET is a


device


A. source & gate

terminals

B. source & drain

terminals


BJT in MOSFET


A. Low power

consumption


takes on a chip

D. All of the above



mentioned


A. forced

commutation of

current


of voltage


mentioned


A



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A. Current,

majority



_______________. [ ]
















0O0



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SET NO: 1 IV B.TECH I SEM (R16) EEE II MID EXAMINATIONS, SEPTEMBER-2019

MODERN POWER ELECTRONICS

OBJECTIVE EXAM

NAME___________________________HALLTICKET NO



1. A Step down chopper can produce an output voltage from? [ ]

B. –Vs to Vs B. Vs to -Vs C. 0 to Vs D. above Vs

2. The switching angles of the inverter can be preselected to eliminate certain harmonics on the _______ voltages?

[ ]

A. input B. output C. both D. none

3. The harmonic elimination techniques that are suitable only for _______ output voltage. [ ]

A. variable B. fixed C. both D. none

4. No. of clamping diodes required for 5 level diode clamped MLI? [ ]

A. 12 B. 10 C. 8 D. 6

5. A ‘m’ level diode clamped converter typically consist of ________ capacitors? [ ]

A. (m+1) B. (m+2) C. (m -1) D. (m-2)

6. When no. of levels is high enough, the harmonic content is? [ ]

A). low (B) high C. both (D) none

7. A ‘m’ level cascade H bridge converter typically consist of ________ capacitors? [ ]

A. m-1 B. m+1 C. 2m-1 D. None of these

8. A ‘m’ level flying capacitor converter typically consist of ________ auxiliary capacitors [ ]

A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)

9. A ‘m’ level flying capacitor converter typically consist of ________ blocking capacitors [ ]

A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)

10. PWM stands for [ ]

A. Program with modulation

B. Pulse width Modulation C. both D. none

A



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11. Critical value of inductor in Buck regulator_________________

12. Critical value of capacitor in Buck regulator_________________

13. Critical value of inductor in boost regulator_________________

14. Critical value of capacitor in boost regulator_________________

15. Critical value of inductor in Buck – boost regulator_________________

16. Critical value of capacitor in Buck – boost regulator_________________

17. Critical value of inductor in CUK regulator_________________

18. Critical value of capacitor in CUK regulator_________________

19. Soft switching techniques can be used to reduce ______________ and device stresses

20. Duty ratio of DC converter ______________________

0O0



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OBJECTIVE EXAM

NAME_____________________________HALL

TICKET NO






A. 12 B. 10 C. 8 D. 6


A. (m+1) B. (m+2) C. (m -1) D. (m-2)






A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)


A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)


A. Program with

modulation



A. –Vs to Vs B. Vs to -Vs C. 0 to Vs D. above Vs

A



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[ ]













0O0



OBJECTIVE EXAM



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NAME_____________________________HALL

TICKET NO




A. 12 B. 10 C. 8 D. 6


A. (m+1) B. (m+2) C. (m -1) D. (m-2)






A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)


A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)


A. Program with modulation



A. –Vs to Vs B. Vs to -Vs C. 0 to Vs D. above Vs


[ ]





A



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0O0



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OBJECTIVE EXAM

NAME_____________________________HALL

TICKET NO




A. (m+1) B. (m+2) C. (m -1) D. (m-2)






A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)


A. (m+1) B. (m+2) C. (m -1)(m-2)/2 D. (m-2)


A. Program with

modulation



C. –Vs to Vs B. Vs to -Vs C. 0 to Vs D. above Vs


[ ]





A



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A. 12 B. 10 C. 8 D. 6












0O0



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14. Assignment topics with materials

1. Explain the operation of MOS-Controlled thyristors using its schematic and equivalent circuits

ANs:

The MOS controlled thyristor has developed by the V.A.K Temple. It is a voltage controller and the

Thyristor is totally controllable thyristor. The operation of a MOS controlled thyristor is quite similar to the

GTO thyristor but, it has the gates of voltage controlled insulated. It has two MOSFETs(metal–oxide–

semiconductor field-effect transistor) used for the turn ON and OFF purpose and it has in the opposite

conductivity in the equivalent circuit. If the equivalent circuit has one thyristor and used for the switched

on is called as the MOS gated thyristor.

The MOS controlled thyristor is a type of power semiconductor device. It has the capabilities of

current and thyristor voltage through the MOS gated used for the turn ON and OFF purpose. It is used in

high power applications like high power, huge frequency, low conduction and it is used in further process.

The following symbols are P-MCT and N-MCT shown below.

Working of MCT

The following diagram shows the working principle of the MOS control thyristor. It is a

combination of current and voltage capabilities with the help of MOS gated. The MOS gated is used

for the switch ON/OFF of MCT.

When the MOSFET is turned ON MCT

By using the negative voltage pulse the device is turned in ON state with respect to the

anode. The gate terminal is made negative with respect to the anode with the help of the voltage

pulse in between the anode and gate terminals. Hence the MOS control thyristor is switched ON

state. In the starting stage the MOS control thyristor is a forward bias. If the negative voltage is

applied to the negative voltage pulse, then the ON mode FET is turned ON as well as the OFF FET

mode is already existed as OFF state.

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When the FET is in ON state the current passes from the anode through the ON FET then passes through

the base current and n-p-n transistor of emitter terminal and finally current passes through the cathode.

Hence this process turns on the n-p-n transistor. The NPN transistor acts as a base current of P-N-P

transistor if the OFF FET is OFF mode. Similarly, the P-N-P transistor turned ON if both the transistors are

in ON state and relating actions takes place hence the MCT is switched on. transistor is short circuited by

the emitter and base terminals. Thus the anode current flows through the OFF FET. Hence the base current

of N-P-N transistor is decreased. Reverse voltage blocking capability is the negative point of this device.

Equivalent Circuit Diagram

The following diagram shows the equivalent circuit diagram of the MOS control Thyristor. The circuit

consists of two MOSFET transistors which are N-channel and the other one is a P-channel. The p-channel

is used for the switch on the ON FET and n-channel is used for the switch off the OFF FET. The circuit

consists of two transistors which are n-p-n and p-n-p transistors. If these two transistors are joined together

to form the structure of n-p-n-p of the MOS control Thyristor. The p channel MOSFET is identified by an

arrow which is connected from the gate terminal.

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Circuit Diagram of the MOS Control Thyristor

Applications of MCT

The applications of MCT includes the following

MCT’s are used in the circuit breakers.

It is used in higher power applications like high power conversions.

MOS control Thyristor are used in the induction heating.

UPS systems

It is also used in the converters like DC to DC converter.

Variable power factors, operations are used in the MCT’s as a force committed power switch.

Advantages of the MCT

The MOS control Thyristor have a low forward conduction drop.

It has low switching losses.

It has high gate input impedance.

It can turn ON/ OFF very fast.

IGCT:

The integrated gate-commutated thyristor (IGCT) is a power semiconductor electronic device, used

for switching electric current in industrial equipment. It is related to the gate turn-off (GTO) thyristor. An

IGCT is a special type of thyristor. It is made of the integration of the gate unit with the Gate Commutated

Thyristor (GCT) wafer device. The close integration of the gate unit with the wafer device ensures fast

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https://en.wikipedia.org/wiki/Electronics

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commutation of the conduction current from the cathode to the gate. The wafer device is similar to a gate

turn-off thyristor (GTO). They can be turned on and off by a gate signal, and withstand higher rates of

voltage rise (dv/dt), such that no snubber is required for most applications.

The structure of an IGCT is very similar to a GTO thyristor. In an IGCT, the gate turn-off current is

greater than the anode current. This results in a complete elimination of minority carrier injection from the

lower PN junction and faster turn-off times. The main differences are a reduction in cell size, and a much

more substantial gate connection with much lower inductance in the gate drive circuit and drive circuit

connection. The very high gate currents and fast dI/dt rise of the gate current mean that regular wires can

not be used to connect the gate drive to the IGCT. The drive circuit PCB is integrated into the package of

the device. The drive circuit surrounds the device and a large circular conductor attaching to the edge of the

IGCT is used. The large contact area and short distance reduce both the inductance and resistance of the

connection. The IGCT's much faster turn-off times compared to the GTO's allows it to operate at higher

frequencies—up to several kHz for very short periods of time. However, because of high switching losses,

typical operating frequency is up to 500 Hz.

IGCT are available with or without reverse blocking capability. Reverse blocking capability adds to

the forward voltage drop because of the need to have a long, low-doped P1 region. IGCTs capable of

blocking reverse voltage are known as symmetrical IGCT, abbreviated S-IGCT. Usually, the reverse

blocking voltage rating and forward blocking voltage rating are the same. The typical application for

symmetrical IGCTs is in current source inverters.

IGCTs incapable of blocking reverse voltage are known as asymmetrical IGCT, abbreviated A-

IGCT. They typically have a reverse breakdown rating in the tens of volts. A-IGCTs are used where either

a reverse conducting diode is applied in parallel (for example, in voltage source inverters) or where reverse



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voltage would never occur (for example, in switching power supplies or DC traction choppers).

Asymmetrical IGCTs can be fabricated with a reverse conducting diode in the same package. These are

known as RC-IGCT, for reverse conducting IGCT.

Applications:

The main applications are in variable-frequency inverters, drives and traction. Multiple IGCTs can

be connected in series or in parallel for higher power applications.

IGBT:

An insulated-gate bipolar transistor (IGBT) is a three-terminal power semiconductor device primarily used

as an electronic switch which, as it was developed, came to combine high efficiency and fast switching. It

consists of four alternating layers (P-N-P-N) that are controlled by a metal-oxide-semiconductor (MOS)

gate structure without regenerative action. Although the structure of the IGBT is topologically the same as

a thyristor with a 'MOS' gate (MOS gate thyristor), the thyristor action is completely suppressed and only

the transistor action is permitted in the entire device operation range. It is used in switching power

supplies in high power applications: variable-frequency drives (VFDs), electric cars, trains, variable speed

refrigerators, lamp ballasts, and air-conditioners.

Since it is designed to turn on and off rapidly, the IGBT can synthesize complex waveforms with pulse-

width modulation and low-pass filters, so it is also used in switching amplifiers in sound systems and

industrial control systems. In switching applications modern devices feature pulse repetition rates well into

the ultrasonic range—frequencies which are at least ten times the highest audio frequency handled by the

device when used as an analog audio amplifier.

An IGBT cell is constructed similarly to a n-channel vertical-construction power MOSFET, except the n+

drain is replaced with a p+ collector layer, thus forming a vertical PNP bipolar junction transistor. This

additional p+ region creates a cascade connection of a PNP bipolar junction transistor with the surface n-

channel MOSFET.

https://en.wikipedia.org/w/index.php?title=RC-IGCT&action=edit&redlink=1

https://en.wikipedia.org/wiki/Frequency

https://en.wikipedia.org/wiki/Inverter_(electrical)

https://en.wikipedia.org/wiki/Traction_(engineering)

https://en.wikipedia.org/wiki/Power_semiconductor_device

https://en.wikipedia.org/wiki/Thyristor

https://en.wikipedia.org/wiki/Transistor

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https://en.wikipedia.org/wiki/Switching_power_supply

https://en.wikipedia.org/wiki/Variable-frequency_drive

https://en.wikipedia.org/wiki/Electric_car

https://en.wikipedia.org/wiki/Pulse-width_modulation

https://en.wikipedia.org/wiki/Pulse-width_modulation

https://en.wikipedia.org/wiki/Low-pass_filter

https://en.wikipedia.org/wiki/Switching_amplifier

https://en.wikipedia.org/wiki/Control_system

https://en.wikipedia.org/wiki/Pulse_repetition_frequency

https://en.wikipedia.org/wiki/Power_MOSFET

https://en.wikipedia.org/wiki/Bipolar_junction_transistor

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Cross-section of a typical IGBT showing internal connection of MOSFET and bipolar device

Static characteristic of an IGBT

The IGBT combines the simple gate-drive characteristics of MOSFETs with the high-current and

low-saturation-voltage capability of bipolar transistors. The IGBT combines an isolated-gate FET for the

control input and a bipolar power transistor as a switch in a single device. The IGBT is used in medium- to

high-power applications like switched-mode power supplies, traction motor control and induction heating.

Large IGBT modules typically consist of many devices in parallel and can have very high current-handling

capabilities in the order of hundreds of amperes with blocking voltages of 6500 V. These IGBTs can control

loads of hundreds of kilowatts.

Operation of Series-Connected Devices

In many power control applications the required voltage and current ratings exceed the voltage and

current that can be provided by a single SCR. Under such situations the SCRs are required to be

https://en.wikipedia.org/wiki/Power_MOSFET

https://en.wikipedia.org/wiki/Bipolar_junction_transistor

https://en.wikipedia.org/wiki/Field-effect_transistor

https://en.wikipedia.org/wiki/Transistor

https://en.wikipedia.org/wiki/Switched-mode_power_supplies

https://en.wikipedia.org/wiki/Traction_motor

https://en.wikipedia.org/wiki/Induction_heating

https://en.wikipedia.org/wiki/Ampere

https://en.wikipedia.org/wiki/Volts

https://en.wikipedia.org/wiki/Kilowatts

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connected in series or in parallel to meet the requirements. Sometimes even if the required rating is

available, multiple connections are employed for reasons of economy and easy availability of SCRs

of lower ratings.

Like any other electrical equipment, characteristics/properties of two SCRs of same make and

ratings are never same and this leads to certain problems in the circuit. The mismatchÂing of SCRs

is due to differences in

(i) turn-on time

(ii) turn-off time

(iii)leakage current in forward direction

(iv) leakage current in reverse direction and

(v)recovery voltage.

Series Connection of an SCR

SCR Series Connection

When the required voltage rating exceeds the SCR voltage rating, a number of SCRs are

required to be connected in series to share the forward and reverse voltage. As it is not possible to

have SCRs of completely identical characteristics, deviation in characteristics lead to the following

two major problems during series connections of the SCRs:

(i) Unequal distribution of voltage across SCRs.

(ii) Difference in recovery characteristics.

Care must be taken to share the voltage equally. For steady-state conditions, voltage sharing

is achieved by using a resistance or a Zener diode in parallel with each SCR. For transient voltage

sharing a low non-inductive resistor and capacitor in series are placed across each SCR, as shown

inÂ figure. Diodes D1 connected in parallel with resistor Rl,helps in dynamic stabilisation. This

circuit reduces differences between blocking voltages of the two devices within permissible limits.

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Additionally the R-C circuit can also serve the function of ‘snubber circuit‘. Values of R1 and

C1 can primarily be calculated for snubber circuit and a check can be made for equalization. If Î”Q

is the difference in recovery charge of two devices arising out of different recovery current for

different time and Î”V is the permissible difference in blocking voltage

then C1 = Î”Q/ Î”V. The value of resistance Rx should be sufficient to over damp the circuit. Since

the capacitor C1 can discharge through the SCR during turn-on, there can be excessive power

dissipation, but the switching current from C1 is limited by the resistor R1This resistance also serves

the purpose of damping out ‘ringing’ which is oscillation of C1with the circuit inductance during

commutation. All the SCRs connected in series should be turned-on at the same time when signals

are applied to their gates simultaneously.

1. Sinusoidal Pulse width modulation

The switches in the voltage source inverter (See Fig. 1)can be turned on and off as required. In the simplest

approach, the top switch is turned on If turned on and off only once in each cycle, a square wave waveform

results. However, if turned on several times in a cycle an improved harmonic profile may be achieved.

In the most straightforward implementation, generation of the desired output voltage is achieved by

comparing the desired reference waveform (modulating signal) with a high-frequency triangular ‘carrier’

wave as depicted schematically in Fig.2. Depending on whether the signal voltage is larger or smaller than

the carrier waveform, either the positive or negative dc bus voltage is applied at the output. Note that over

the period of one triangle wave, the average voltage applied to the load is proportional to the amplitude of

the signal (assumed constant) during this period. The resulting chopped square waveform contains a replica

of the desired waveform in its low frequency components, with the higher frequency components being at

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frequencies of an close to the carrier frequency. Notice that the root mean square value of the ac voltage

waveform is still equal to the dc bus voltage, and hence the total harmonic distortion is not affected by the

PWM process. The harmonic components are merely shifted into the higher frequency range and are

automatically filtered due to inductances in the ac system.

When the modulating signal is a sinusoid of amplitude Am, and the amplitude of the triangular carrier is Ac,

the ratio m=Am/Ac is known as the modulation index. Note that controlling the modulation index therefore

controls the amplitude of the applied output voltage. With a sufficiently high carrier frequency (see Fig. 3

drawn for fc/fm = 21 and t = L/R = T/3; T = period of fundamental), the high frequency components do not

propagate significantly in the ac network (or load) due the presence of the inductive elements. However, a

higher carrier frequency does result in a larger number of switchings per cycle and hence in an increased

power loss. Typically switching frequencies in the 2-15 kHz range are considered adequate for power

systems applications. Also in three-phase systems it is advisable to use so that all three waveforms are

symmetric.



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Note that the process works well for . For , there are periods of the triangle wave in which there is no

intersection of the carrier and the signal as in Fig. 4. However, a certain amount of this “over modulation” is

often allowed in the interest of obtaining a larger ac voltage magnitude even though the spectral content of

the voltage is rendered somewhat poorer. Note that with an odd ratio for fc/fm, the waveform is anti-

symmetric over a 360 degree cycle.. Hence an even number is not recommended for single phase inverters,

particularly for small ratios of fc/fm.

2. EXPLAIN ABOUT SPACE VECTOR MODULATION?

Multilevel inverters generate sinusoidal voltages from discrete voltage levels, and pulse width

modulation (PWM) strategies accomplish this task of generating sinusoids of variable voltage and

frequency. Modulation methods for Hybrid Multilevel Inverter can be classified according to the switching

frequency methods. Many different PWM methods have been developed to achieve the following: Wide

linear modulation range, less switching loss, reduced Total Harmonic Distortion (THD) in the spectrum of

switching waveform: and easy implementation and less computation time.

The most widely used techniques for implementing the pulse with modulation (PWM) strategy for

multilevel inverters are Sinusoidal PWM (SPWM) and space vector PWM (SPWM). The SVPWM is

considered as a better technique of PWM implementation as it has advantages over SPWM in terms of

good utilization of dc bus voltage, reduced switching frequency and low current ripple is presented in Beig

et al (2007), Gupta and Khambadkone (2007), and Franquelo et al (2006). SVPWM is considered a better

technique of PWM implementation, as it provides the following advantages, (i) Better fundamental output



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voltage.(ii) Useful in improving harmonic performance and reducing THD. (iii) Extreme simplicity and its

easy and direct hardware implementation in a Digital Signal Processor (DSP). (iv) SVPWM can be

efficiently executed in a few microseconds, achieving similar results compared with other PWM methods.

In this chapter, a space vector is defined in a two-dimensional (2-D) plane and a SVM is performed in the

2-D plane. Furthermore, a three dimensional (3-D) space vector has been defined in this chapter for

cascaded H-bridge multilevel inverter. All the existing space vector modulation schemes are implemented

in a two-dimensional, and are therefore unable to deal with the zero-sequence component caused by

unbalanced load. Complexity and computational cost of traditional SVPWM technique increase with the

number of levels of the inverter as most of the space vector modulation algorithms proposed in the

literature involve trigonometric function calculations or look-up tables. Previous works on three-

dimensional space vector modulation algorithms have been presented in Prats et al (2003) and Oscar Lopez

et al (2008) for diode-clamped inverter. However, unequal dc sources cannot be applied to diode-clamped

inverter. Meanwhile, the first 3-D space vector modulation for cascaded H-bridge inverter is presented in

Karthikeyan and Chenthur Pandian (2011), which is capable of dealing with zero-sequence component

caused by unbalanced load. The three-dimensional space vector modulation schemes are supersets of, and

thus are compatible with, conventional two-dimensional space vector modulation schemes. A new

optimized 3-D SVPWM (3-D OSVPWM) technique was proposed by Karthikeyan and Chenthur Pandian

(2011), which is similar to already existing 3-D SVPWM presented in, following a similar notation. The

proposed SVPWM technique calculate the nearest switching vectors sequence to the reference vector and

the on-state durations of the respective switching state vectors by means of simple addition and comparison

operation, without using trigonometric function calculations, look-up tables or coordinate system

transformations. Such very low complexity and computational cost make them very suitable for

implementation in low cost devices. It is important to notice that these 3-D OSVPWM techniques can be

applied with balanced and unbalanced systems. Implementation of the 2-D SVPWM and 3-D OSVPWM

techniques is carried out. Both SVPWM algorithms are implemented into a Field Programmable

Gate Arrays (FPGA) from Xilinx Foundation. Matlab Simulink is used to develop all simulation works.

Finally, both algorithmic implementations have been tested with a cascaded H-bridge multilevel inverter.



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16. Unit wise-Question bank

OBJECTIVE QUESTIONS

1.A Step down chopper can produce an output voltage from?

[ ]

D. –Vs to Vs

B. Vs to -Vs

C. 0 to Vs

D. above Vs

2.The switching angles of the inverter can be preselected to eliminate certain harmonics on the _______ voltages?

[ ]

A. input

B. output

C. both

D. none

3. The harmonic elimination techniques that are suitable only for _______ output voltage.

[ ]

A. variable

B. fixed

C. both

D. none

4. No. of clamping diodes required for 5 level diode clamped MLI?

[ ]

A. 12

B. 10

C. 8

D. 6



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5.A ‘m’ level diode clamped converter typically consist of ________ capacitors?

[ ]

A. (m+1)

B. (m+2)

C. (m -1)

D. (m-2)

6.When no. of levels is high enough, the harmonic content is?

[ ]

A). low

(B) high

C. both

(D) none

7.A ‘m’ level cascade H bridge converter typically consist of ________ capacitors?

[ ]

A. m-1

B. m+1

C. 2m-1

D. None of these

8.A ‘m’ level flying capacitor converter typically consist of ________ auxiliary capacitors

[ ]

A. (m+1)

B. (m+2)

C. (m -1)(m-2)/2

D. (m-2)

9.A ‘m’ level flying capacitor converter typically consist of ________ blocking capacitors

[ ]

A. (m+1)

B. (m+2)



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by NAAC

C. (m -1)(m-2)/2

D. (m-2)

10.PWM stands for [ ]

A. Program with modulation B. Pulse width Modulation

C. both

D. none

11.Critical value of inductor in Buck regulator_________________

12.Critical value of capacitor in Buck regulator_________________

13.Critical value of inductor in boost regulator_________________

14.Critical value of capacitor in boost regulator_________________

15.Critical value of inductor in Buck – boost regulator_________________

16.Critical value of capacitor in Buck – boost regulator_________________

17.Critical value of inductor in CUK regulator_________________

18.Critical value of capacitor in CUK regulator_________________

19.Soft switching techniques can be used to reduce ______________ and device stresses

20.Duty ratio of DC converter ______________________

Documents

Course File On Modern Power Electronics By Srinivas D Assistant ...kgr.ac.in/wp-content/uploads/2019/12/MODERN-POWER-ELECTRONI… · Year / Semester st: IV / I Department : Electrical