MODELING, SIMULATION AND DESIGN OF AN IMPROVED...

MODELING, SIMULATION AND DESIGN OF AN IMPROVED HIGH POWER

FACTOR BRIDGELESS SEPIC CONVERTER

IZNI BINTI MUSTAFAR

UNIVERSITI TEKNOLOGI MALAYSIA

MODELING, SIMULATION AND DESIGN OF AN IMPROVED HIGH POWER

FACTOR BRIDGELESS SEPIC CONVERTER

IZNI BINTI MUSTAFAR

A project report submitted in partial fulfilment of the

requirements for the award of the degree of

Master of Engineering (Electrical – Power)

Faculty of Electrical Engineering

Universiti Teknologi Malaysia

JANUARY 2015

iii

ACKNOWLEDGEMENT

First and foremost, “ Syukur Alhamdulillah” to Allah, the Most Gracious and

Most Merciful for ensuring myself to be healthy to carry out my study and to complete

this project.

Secondly, I would like to express my warmest gratitude to my supervisor, Dr.

Mohd Rodhi bin Sahid who has provided immeasurable support and guidance toward

the completion of my research project. His ideas and suggestions is much appreciated

My sincere appreciation also goes to my parents who has been so supportive

in all years. Thanks for giving me continuous encouragement, love and emotional

supports that they had given to me.

I also would like to give a special thanks to Dr. Naziha, Ika, Tie, Kong, Kak

Mira and Abdul Rahman for helping me throughout this procces. Last but not least I

would like to gratefully thank to all my lecturer and all my friends who had given me

helps technically and mentally throughout my journey in completing my project.

Thank You.

Wassalam

iv

ABSTRACT

Switch Mode Power Supply (SMPS) designs are normally have a power

quality issues due to the harmonic distortion produce in the system. Therefore it is

essential to incorporate a power factor correction (PFC) circuit in SMPS design.

Although, the boost converter is more popular to use with PFC circuit, SEPIC

converter can produce an input current with lower ripple value. However, since it

involved with 4 energy storage component, a bridgeless SEPIC converter were

used as the bridgeless circuit reduce the component conducted in ech switching

cycle compared to conventional SEPIC. Therefore this thesis focuses on designing

the bridgeless PFC SEPIC converter that operate in CCM with two types of

controller. The controllers are Average Current Control Mode and Peak Current

Control Mode. Simulation of the bridgeless SEPIC PFC circuit were done using

MATLAB Simulink software. The results show that the Average Current Mode

Control produce high power factor with low harmonic distortion compared to Peak

Current Mode Control. At the end of this thesis, a suitable recommendation and

suggestion were made to improve the project design.

v

ABSTRAK

Rekaan Suis Mod Bekalan Kuasa (SMPS) biasanya mempunyai isu dalam

membekalkan kuasa yg berkualiti kerana ia sering menghasilkan herotan harmonik

di dalam sistem. Oleh itu, adalh penting untuk mengaplikasikan litar pembetulan

faktor kuasa (PFC) di dalam rekaan SMPS. Walaupun penukar Boost adalah lebih

popular dalam proses mengimplemtasikan litar PFC, namun penukar SEPIC boleh

menghasilkan arus input dengan nilai riak yang lebih rendah. Walaubagaimanapun,

oleh kerana penukar SEPIC terdiri daripada 4 komponen pemyimpan tenaga,

penukar SEPIC tanpa jambatan telah digunakan kerana didalam setiap kitaran litar,

komponen yg digunakan adalah lebih sedikit. Dengan itu, tesis ini tertumpu kepada

merekabentuk penukar PFC SEPIC tanpa jambatan yg beroperasi dalam keadaan

arus berterusan (SSM) dengan due jenis pengawal litar. Jenis-jenis pengawal litar

adalah kawalan secara purata dan kawalan secara puncak. Simulasi litar SEPIC

PFC tanpa jambatan telah dijalankan mengggunakan perisian MATLAB Simulink.

Hasil kajian menunjukkan bahawa faktor kuasa yang tinggi hasil daripada

penggunaan kawalan secara purata dengan herotan harmonik yang rendah.

vi

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

ACKNOWLEDGEMENT iii

ABSTRACT iv

ABSTRAK v

TABLE OF CONTENTS vi

LIST OF TABLES ix

LIST OF FIGURES x

LIST OF ABBREVIATIONS xiii

LIST OF SYMBOLS xiv

LIST OF APPENDICES xv

1 INTRODUCTION 1

1.1 Introduction and Background 1

1.2 Problem Statements 2

1.3 Objectives of Project 3

1.4 Scope of Project

3

2 LITERATURE REVIEW 5

2.1 Conventional Sepic Converter 5

2.1.1 Operation of SEPIC Converter 6

2.1.2 Circuit Operation for SEPIC PFC Circuit

with Full-Bridge Rectifier

7

vii

2.1.2.1 SEPIC PFC Converter Operation

Mode

7

2.2 Bridgeless SEPIC PFC Circuit 10

2.3 Controller Design 12

2.3.1 Average Current Mode Control 13

2.3.2 Peak Current Mode Control 14

2.4 State Space Averaged Model for SEPIC

Converter

16

3 METHODOLOGY 20

3.1 Introduction 20

3.2 Bridgeless PFC SEPIC Converter Design

Specification

23

3.3 Average Current Mode Conntrol Design 24

3.3.1 Multiplication and Dividing Block 25

3.3.2 PI Controller as Current Compensator 26

3.3.3 PI Controller as Voltage Compensator 28

3.4 Peak Current Mode Control 30

3.4.1 PI Controller for Voltage Compensator 30

3.5 True Power Factor

32

4 RESULT AND DISCUSSION 35

4.1 Open Loop System 35

4.2 Closed Loop System 36

4.2.1 Average Current Mode Control Scheme 37

4.2.2 Peak Current Mode Control Scheme 41

4.3 True Power Factor

46

5 CONCLUSION AND RECOMMENDATION 48

5.1 Conclusion 48

5.2 Recommendation 49

viii

REFERENCES 50

Appendix A 53

ix

LIST OF TABLES

TABLE NO. TITLE PAGE

4.1 The power factor value measured for input

voltage of 240V

46

4.2 The power factor value measured for input

voltage of 115V

47

x

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1 Operation of SEPIC converter 6

2.2 Circuit Operation for SEPIC PFC Circuit with Full-Bridge

Rectifier

7

2.3 Bridgeless SEPIC PFC Circuit[10] 10

2.4 Bridgeless SEPIC PFC Circuit during Positive Half Line

Cycle[10]

11

2.5 Bridgeless SEPIC PFC Circuit during Negative Half Line

Cycle[10]

11

2.6 Block Diagram for General Controller Design 12

2.7 Block Diagram for Average Current Mode Control 13

2.8 Multiplication and Dividing Block 14

2.9 Block Diagram for Average Current Mode Control 15

3.1 Flow Chart of Methodology Process 21

3.2 The open loop PFC SEPIC Converter simulated using

Matlab/Simulink

22

3.3 Simulation of SEPIC Converter 22

3.4 PFC SEPIC using Average Mode Current Control 24

3.5 The Multiplication and Dividing Block 25

3.6 The PI controller for Current Compensator 26

3.7 Bode Diagram for Current Compensator 27

3.8 Tracking Signal of PI controller 27

xi

3.9 The PI controller for Voltage Compensator 28

3.10 Bode Diagram for Voltage Compensator 29

3.11 Tracking Signal of PI controller 29

3.12 SEPIC PFC using Peak Mode Current Control 30

3.13 The PI controller for Voltage Compensator 31

3.14 Bode Diagram for Voltage Compensator 32

3.15 Displament PF block in Matlab Simulink 33

3.16 Distortion PF block in Matlab Simulink 33

4.1 Open Loop Design for SEPIC PFC Converter 35

4.2 PFC SEPIC using Average Mode Current Control 36

4.3 PFC SEPIC using Peak Mode Current Control 36

4.4 Voltage Output vs. Time for Vin =240V, which the load

changed from 240 W to 120 W.

38


changed from 240 W to 120 W.

38

4.6 Inductor Current waveform for Vin = 240 V 39


4.8 Inductor Current vs. Time for Vin = 240 V with load

variation from 240 W to 120 W

40

4.9 Inductor Current vs. Time for Vin = 115 V with load


40

4.10 Input Current in Phase with Input Voltage 41


changed from 240 W to 120 W

42


changed from 240 W to 120 W

42



xii

4.15 Inductor Current vs. Time for Vin = 240 V with with load


44

4.16 Inductor Current vs. Time for Vin = 115 V with with load


45

4.17 Input Current in Phase with Input Voltage 45

xiii

LIST OF ABBREVIATIONS

AC - Asychrounous Current

DC - Direct Current

PFC - Power Factor Correction

SMPS - Switch Mode Power Supplies

SEPIC - Single-Ended Primary Inductor Converter

CCM - Continuous Conduction Mode

MDB - Multiplication And Dividing Block

PF - Power Factor

THD - Total Harmonic Distortion

DF - Distortion Power Factor

PWM - Pulse Width Modulation

xiv

LIST OF SYMBOLS

VL - Voltage across inductor

VCS - Voltage across series capacitor

VCO - Voltage across capacitor output

S - Switch

Q - Power Switch

D - duty ratio

L - inductance

C - capacitance

R - load

D - diode

xv

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Calculation of Transfer Function 54

CHAPTER 1

INTRODUCTION

1.1 Introduction and Background

Nowadays, the input of power supplies often to be an AC sources, and therefore

the use of full wave rectifier is very important to convert the AC input to a DC output

since many of electronic equipment use DC voltage as a power supplies. With the

extensive use of electrical and electronic equipment, there is a large demand for a

power supplies that draw current with low harmonic content and also have high power

factor value [1].

Thus, it can be said that the AC mains utility supply is supposed to be free from

high voltage spikes and harmonics. However with the use of rectifier, the resulting

input current is highly non-sinusoidal which produce a high value of total harmonic

distortion which leads to a disturbance that can have a bad impact on electrical and

electronic circuit [2].

2

The large value of total harmonic distortion can be mitigated using power

factor correction (PFC) circuit. There are two types of power factor correction circuits,

which are active PFC and passive PFC [3]. Passive PFC consists of reactive elements

that will correct output impedance at a given frequency [3]. Thus, it will only mitigate

at one specific frequency and if the disturbance occurs out of the expected range, the

harmonic distortion will not be corrected [3]. Differ from passive PFC, the active PFC

circuit have been designed to detects the actual output impedance of the circuit and

dynamically re-adjust the power factor [3]. As a result, the active PFC can mitigate

the harmonic better than the passive PFC circuit.

Therefore, the active PFC circuits are preferable compared to the passive PFC

circuit. Most active PFC circuit consists of a front-end full bridge rectifier followed

with a DC to DC converter. Apart from that since the full bridge rectifier contribute

to a high value of conduction losses, therefore the efficiency value is decrease. Hence,

there are lots of effort to design and control the bridgeless power factor correction

circuit in order to cater this issue. Thus, the bridgeless PFC circuit will be studied in

this project and discussed in this thesis.

1.2 Problem Statements

Switch Mode Power Supplies (SMPS) is an electronic device that is widely use

to convert electrical power. However it have harmonic distortions produce by main

switch and leads to a disturbance. For this reason, it is desirable to design an SMPS

with a unity power factor. In order to solve this problem, a power factor correction

circuit is incorporated in the converter system.

There are several well-known topologies for PFC converter such as buck,

boost and buck-boost converter. However a SEPIC converter is less popular topology

3

for PFC converter design due to the complex control part where it reaches the 4th order

[4].

In spite of that, the PFC SEPIC converter offer an advantage compared to 2nd

order converter which it have two inductors on the same wound [4]. Consequently, it

has a lower input current ripple compared to other converter topology. Thus, the

bridgeless SEPIC PFC converter with a closed-loop control will be studied in this

project to observe the total harmonic produce by SEPIC PFC circuit [5].

1.3 Objectives of Project

There are two objectives in this project, which are as follow:

1. To study and design bridgeless SEPIC power factor circuit (PFC)

converter with a close loop controller in Continuous Conduction Mode

(CCM).

2. To compare the performance of controller by using two methods which are

the average mode control method and peak mode control method.

1.4 Scope of Project

The scopes for this project are as follows:

1. Study on the conventional and bridgeless SEPIC PFC converter.

4

2. Understand the performance of controller especially the current mode

control

3. Design the closed loop compensator such that the converter operates

within the desired operating condition using Matlab/Simulink.

4. Identify the effect and performance of bridgeless SEPIC PFC converter

with two commonly used current control method.

REFERENCES

1. Rajappan, S.C; Sarabose, K; and John, N. (2013). An Efficient AC/DC

Converter with Power Factor Correction. International Journal of Emerging

Technology and Advanced Engineering. 3(3), 815-820

2. Daniel, W. H. (2011). Power Electronics. (International ed.) New York, USA

Mc Graw Hill.

3. Ali Emadi, Abdolhosein Nasiri, Stoyan B. Bekiarov (2005).

Uninterruptable Power Supplies and Active Filters. (1st ed), Chicago, USA:

CRC Press.

4. Manjing, X; Bing, L; Wei, D. and Lee, F.C. (2004). Novel current-loop feed-

forward compensation for boost PFC Converter. Proceedings of the Applied

Power Electronics Conference and Exposition. 2004. IEEE: 750-755.

5. Gopinath, B. (2012). A High Performance Single Phase Bridgeless Rectifier

with Power Quality Improvement. Journals of Electrical Engineering, The

Institution of Engineers. EE3(2), 26-32.

6. Kanaan, H.Y and Al-Haddad, K. (2013) Modeling and Multi-Loop Feedback

Control Design of a SEPIC Power Factor Corrector in Single-Phase

Rectifiers. Mathematics and Computers in Simulation (MATCOM). 91(C),

274-283.

7. Sebastian, J.; Uceda, J.; Cobos, J.A.; Arau, J.; and Aldana, F (1991).

Improving Power Factor Correction In Distributed Power Supply Systems

Using PWM and ZCS-QR SEPIC Topologies. Proceedings of the Power

Electronics Specialists Conference. 24-27 Jun, Cambridge, MA: IEEE, 780-

791

8. Sindhuja, S. and Sripriya, S. (2013). Continuous Conduction Mode of

Bridgeless SEPIC Power Factor Correction Rectifier. Proceedings of the

Computation of Power, Energy, Information and Communication (ICCPEIC)

Conference. 17-18 April, Chennai. 28-30.

56

9. Kanaan, H.Y and Al-Haddad, K. (2008) Small-signal Averaged Model and

Carrier-based Linear Control of a SEPIC-type Power Factor Correction.

Proceedings of the Telecommunications Energy Conference. 14-18

September, San Diego, CA. 1-6.

10. Sahid, M.R.; Yatim, A.H.M.; and Taufik, T. (2010) A New AC-DC

Converter Using Bridgeless SEPIC. Proceedings of IECON 2010 – 36th

Annual Conference on IEEE Industrial Electronics Society, 7-10 November,

Glendale, AZ. 286-290

11. Krein, P.T. (1998). Elements of Power Electronics. (1st ed.) New York,

Oxford University Press.

12. Erickson, R.W. (2001) Fundamentals of Power Electronics.(2nd ed.)

Massachusetts, Kluwer Academic Publisher

13. Yong Zhang; Weisheng Xu and Youling Yu (2008) The PFC with Average

Current-Mode and Voltage Fuzzy Controller for the Output Voltage.

Proceedings of Intelligent Information Technology Application, 2008. IITA

'08. Second International Symposium. 20-22 December. Shanghai, 20-22.

14. Gegner, J.P and Lee, Q.C. (1996) Linear Peak Current Mode Control: A

Simple Active Power Factor Correction Control Technique for Continuous

Conduction Mode. Proceedings of Power Electronics Specialists

Conference. 23-27 June. Baveno, 196-202

15. Ray Ridley (2006). Analyzing the SEPIC Converter. Power System Design

Europe, 14-18.

16. Eng, V.; Pinsopon, U. and Bunlaksananusorn, C. (2009) Modeling of a

SEPIC Converter in Continuous Conduction Mode. Proceedings of

Electrical Engineering/ Electronics, Computer, Telecommunications and

Information Technology (ECTI-CON). 6-9 May. Pattaya, Chonburi, 136-139.

17. Su, Jung Huei; Jiang-Jong Chen, and Dong Shiuh Wu (2002) Learning

Feedback Controller Design of Switching Converters via Matlab/Simulink.

Education, IEEE Transactions. 45(4), 307-315

18. DeNardo, A.; Femia, N.; Forrisi, F.and Genato, M (2008) A Novel Design

To Prevent SEPIC’s Instability. Proceedings of Control and Modeling for

Power Electronics. 17-20 August. Zurich, 1-4

57

19. Gu, W. (2005) Small Signal Modeling for Current Mode Controlled Cuk and

SEPIC Converters. Proceedings of Applied Power Electronics Conference

and Exposition. 6-10 March. Austin, TX, 906-910

20. Redl, R. and Erisman, B.P. (1994) Reducing Distortion in Peak-Current

Controlled Boost Power Factor Correctors. Proceedings of Applied Power

Electronics Conference and Exposition. 13-17 February. Orlando, FL, 576-

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