A NEW PROCEDURE FOR HIGH FREQUENCY

ELECTRONIC BALLAST DESIGN

HO TZE YUAN

APRIL 2008

I hereby declared that I have read through this report and found that it has comply

the partial fulfillment for awarding the degree of Bachelor of Electrical Engineering

(Power Electronic and Drives)

Signature : .

Supervisors Name : EN. ALIAS BIN KHAMIS

Date : 5 MEI 2008

A NEW PROCEDURE FOR HIGH FREQUENCY ELECTRONIC BALLAST

DESIGN

HO TZE YUAN

This Report Is Submitted In Partial Fulfillment Of Requirements For The

Degree Of Bachelor In Electrical Engineering (Power Electronic and Drives)

Fakulti Kejuruteraan Elektrik

Universiti Teknikal Malaysia Melaka

April 2008

ii

I hereby declared that this report is a result of my own work except for the excerpts

that have been cited clearly in the references.

Signature : .

Name : HO TZE YUAN

Date : 5 MEI 2008

iii

ACKNOWLEDGEMENT

Upon submitting this report, I would like to thank En. Alias bin Khamis, my

supervisor of Projek Sarjana Muda (PSM), for his guidance and participation in

conducting my project. His knowledge and insights were invaluable in identifying

the ways to solve my problems regarding to my project. I would also like to thank

En. Hairul Nizam, En. Zulkifilie, Dr Ismadi Bugis and Prof. Madya Dr. Zulkifilie

Bin Ibrahim for advise and provide me good idea and knowledge to complete my

final project.

http://www.kutkm.edu.my/fke/Staff_MainPage.htm##http://www.kutkm.edu.my/fke/Staff_MainPage.htm##

iv

ABSTRACT

Electronic lamp ballast is widely spread over the world because of its high

efficiency electronic control over the fluorescent lamp and make it the best choice to

save the energy absorbed by the lighting system. The high frequency electronic

ballast is an AC/ AC power converter. It converts line frequency power from the

utility to a high frequency AC power in order to drive the lamp. The high frequency

electronic ballast design consists of five parts. There are filter, AC/ DC rectifier,

ballast controller, DC/ AC half bridge inverter and final output stage to power the

lamp. This design is able to drive a 36W fluorescent lamp from a 180-255Vac input

line with frequency 50-60Hz.

v

ABSTRAK

Lampu elektronik ballast mendapat sambutan yang hangat di seluruh dunia

kerana ia mempunyai kecekapan yang tinggi dengan menggunakan kaedah kawalan

elektronik terhadap lampu berpendafluor. Ini menjadikannya sebagai satu pilihan

terbaik untuk menjimatkan tenaga dalam sistem pencahayaan. Elektronik ballast

berfrekuensi tinggi merupakan satu AC/DC penukar kuasa. Ia dapat menukarkan

frekuensi rendah daripada sumber tenaga kepada frekuensi yang tinggi untuk

menyalakan lampu. Elektronik ballast berfrekuensi tinggi terdiri daripada lima

bahagian iaitu, filter, rectifier, pengawal ballast, dan half bridge inverter untuk

menyalakan lampu. Rekaan ini mampu menyalakan lampu berpendafluor 36W

daripada sumber tenaga 180-225Vac dengan frekuensi 50-60Hz.

vi

CONTENTS

CHAPTER TITLE PAGE

ACKNOWLEDGEMENT iii

ABSTRACT iv

ABSTRAK v

CONTENTS vi

LIST OF TABLES viii

LIST OF FIGURES ix

LIST OF ABBREVIATION xii

LIST OF APPENDIX xiii

I INTRODUCTION

1.1 Problem Statements 5

1.2 Project Objectives 5

1.3 Problem Scopes 5

1.4 Thesis Outline 6

1.5 Project Planning 8

II LITERATURE REVIEW

2.1 Conventional Ballast 10

2.2 Problems Caused By Conventional Ballast 11

2.3 Electronic Alternatives 12

2.4 Electronic Ballast 12

2.5 Full Bridge Rectifier 13

2.6 Half Bridge Inverter 16

2.7 Filter 19

2.8 Summary 19

vii

III METHODOLOGY

3.1 Flow Chart 21

3.2 Fourier Analysis 23

3.3 OrCAD 26

3.4 Fluke Quality Analyzer 31

3.4.1 Measuring Lighting Load 31

3.4.1.1 Inrush current 31

3.4.1.2 Power And Power Factor 33

3.4.1.3 Total Harmonic Distortion 35

3.5 Illuminometer 36

3.5.1 Features 37

3.5.2 Operating Instructions 38

3.5.2.1 Preparations For Measurement 38

3.5.2.2 How To Make Measurements 38

IV RESULTS AND DISCUSSIONS

4.1 Calculation And Simulation 42

4.1.1 Magnetic Ballast 42

4.1.2 Electronic Ballast 49

4.1.2.1 Fourier Analysis 49

4.1.2.2 Transient Analysis 50

4.1.2.3 Steady State Analysis 51

4.2 Hardware And Analysis 55

4.2.1 Circuit Operation 55

4.2.2 Magnetic Ballast 65

4.2.3 Electronic Ballast 67

4.3 Summary 70

V CONCLUSION

5.1 Recommendation 73

REFERENCES 75

APPENDIX A 76

viii

LIST OF TABLES

NO TITLE PAGE

1.1 Gantt chart 8

3.2 Recommended average illuminance levels 40

3.3 Adequate light levels for working area 41

4.1 Electronic ballast components 64

4.2 Comparison between magnetic ballast and electronic ballast 70

5.1 Comparison between electronic ballast and conventional ballast 72

5.2 Component lists 73

ix

LIST OF FIGURES

NO TITLE PAGE

1.1 Electromagnetic spectrum 1

1.2 (a) Energy distribution of an incandescent lamp. (b) Energy

distribution of a fluorescent lamp.

2

1.3 (a) Discharge potential drop versus current. (b) The effect of

series resistance in stabilizing lamp current.

3

1.4 Scope of constructing electronic ballast 5

2.1 Simple conventional lamp ballast 10

2.2 Electronic ballast block diagram 13

2.3 Full bridge rectifier 13

2.4 Positive half-cycle rectification 14

2.5 Negative half-cycle rectification 14

2.6 AC, half-wave and full wave rectified signals 14

2.7 Buffer capacitor 15

2.8 Half Bridge Inverter 16

2.9 Center-tapped half bridge inverter 17

2.10 Conduction Pattern for inverter 17

2.11 Circuit topology of half bridge series resonant inverter 18

2.12 Lowpass filter 19

3.1 Flow chart 21

3.2 Fundamental and harmonic component 23

3.3 Square wave 24

3.4 Harmonic spectrum 25

3.5 Capture CIS 26

3.6 Schematic diagram 26

3.7 Simulation settings 27

x

3.8 Transient output file options 27

3.9 Time plot of output voltage 28

3.10 Fourier analysis 28

3.11 Total harmonic distortion 29

3.12 Fluke quality analyzer 30

3.13 Lighting load connection 32

3.14 Inrush current menu 33

3.15 Power and power factor measurement connection 34

3.16 Power menu 34

3.17 Total harmonic distortion measurement connection 35

3.18 Total harmonic menu 36

3.19 Illuminator 36

3.20 Illuminator designations 37

4.1 Resistive lamp model 42

4.2 Magnetic ballast simplified model 43

4.3 Impedance diagram 43

4.4 Simulation model of the magnetic ballast 44

4.5 Simulation result of output voltage waveform for the magnetic

ballast

46

4.6 Simulation result of input voltage, output voltage and current

output waveform for the magnetic ballast

47

4.7 Simulation result of current waveform at load for the magnetic

ballast

48

4.8 Output voltage of half bridge rectifier 49

4.9 Resonant lamp output stage during transient 50

4.10 Resonant lamp output stage during steady state 51

4.11 Resonant lamp output stage during steady state simplified

model

52

4.12 Simulation model of the electronic ballast 53

4.13 Simulation result of lamp voltage 54

4.14 Simulation result of lamp current 54

4.15 Schematic of electronic ballast 55

4.16 Source voltage captured by fluke 56

xi

4.17 Source voltage analyzed using Fluke software 57

4.18 Bridge rectifier voltage captured by Fluke 57

4.19 Bridge rectifier voltage analyzed using Fluke software 58

4.20 Capacitor voltage captured by Fluke 58

4.21 Capacitor voltage analyzed using Fluke software 59

4.22 Half bridge inverter voltage captured by Fluke 59

4.23 Half bridge inverter voltage analyzed using Fluke software 60

4.24 Half bridge inverter voltage captured by Fluke 60

4.25 Half bridge inverter voltage analyzed using Fluke software 61

4.26 Choke voltage captured by Fluke 61

4.27 Choke voltage analyzed using Fluke software 62

4.28 Lamp voltage captured by Fluke 62

4.29 Lamp voltage analyzed using Fluke software 63

4.30 Electronic ballast 63

4.31 Front view of electronic ballast 64

4.32 PCB layout 65

4.33 Voltage and current for magnetic ballast 66

4.34 Power factor for magnetic ballast 66

4.35 Total harmonic distortion voltage for magnetic ballast 67

4.36 Total harmonic distortion current for magnetic ballast 67

4.37 Curve of fluorescent lamp efficacy versus lamp operating

frequency

68

4.38 Voltage and current for electronic ballast 69

4.39 Power factor for electronic ballast 69

4.40 Total harmonic distortion voltage for electronic ballast 69

4.41 Total harmonic distortion current for electronic ballast 70

5.1 Basic construction of electronic ballast 71

5.2 Typical application circuit for compact fluorescent lamp 73

xii

LIST OF ABBREVATION

AC - Alternating Current

DC - Direct Current

HPS - High Pressure Sodium

LPS - Low Pressure Sodium

THD - Total Harmonic Distortion

PCB - Printed Circuit Board

EM - Electromagnetic

DIAC - Diode for Alternating Current

MOSFET - MetalOxideSemiconductor Field-Effect Transistor

IC Integrated Circuit

SIP System In Package

CFL Compact Fluorescent Lamp

ZVS Zero Voltage Switching

xiii

LIST OF APPENDIX

NO TITLE PAGE

A Datasheet 76

CHAPTER 1

INTRODUCTION

Light is defined as visually evaluated radiant energy, which stimulates mans

eyes and enables him to see. Man has always sought to counter the influence of the

darkness by creating artificial light. The discovery of electric power and the

possibility of transmitting it in a simple manner facilitated the development of

modern lamps. Today there are nearly 6,000 different lamps being manufactured,

most of which can be divided into six categories: incandescent, fluorescent, mercury

vapor, metal halide, high-pressure sodium (HPS) and low-pressure sodium (LPS).

Except for incandescent lamps, all of these light sources can be termed as gas

discharge lamps.

Figure 1.1: Electromagnetic spectrum

The major characteristics to be considered when choosing a lamp are its

luminous efficacy, life, lumen depreciation and color rendering. Luminous efficacy is

the measure of the lamps ability to convert input electric power, in watts, into output

luminous flux, in lumens, and is measured in lumens per watt (lm/w). The luminous

flux of a light source is the electromagnetic radiation within the visible part of the

electromagnetic spectrum multiplied by the sensitivity of mans eyes to that part of

the light from the source. The visible portion of the spectrum covers the wavelength

range from approximately 380 nm to 780 nm as shown in Figure 1.1. The life of a

lamp is the number of hours it takes for approximately 50% of a large group of lamps

of the same kind to fail. Failure means that the lamp will no longer light or that light

output has dropped to a specific percentage value. Lumen depreciation during life is

a characteristic of all lamps. This is a process of lamp aging, an important

consideration in lighting design. Finally, there is the matter of color rendering. The

lamp types do not provide the same nominal white. Their difference in spectral

distribution can produce two effects within a lighted space. Some of the colors of

objects within that space can appear unnatural or faded reds can appear brown,

violets nearly black, etc. Second, the entire space may feel warm or cool. For

example, a mercury lamp, lacking in reds and oranges, makes a space seem cool,

whereas an incandescent lamp, with deficiencies in the blue and violets, makes a

space feels warm.

Figure 1.2: (a) Energy distribution of an incandescent lamp (b) Energy distribution of

a fluorescent lamp

Figure 1.3: (a) Discharge potential drop versus current (b) The effect of series

resistance in stabilizing lamp current

Although gas discharge lamps have tremendous advantages over

incandescent lamps, they require an auxiliary apparatus called a ballast to run with

them because gas discharge lamps have negative incremental impedance. Figure

1.3(a) shows a typical curve of discharge potential drop versus current when a lamp

is operated from a DC power source. The curve can also be regarded as the locus of

points (i,v) for which the time rate of change of electron density, dne/dt, is zero. For

points above and to the right, dne/dt is greater than zero (production exceeds loss),

and electron density would increase with time. For points below and to the left,

dne/dt is less than zero, and electron density would decrease with time. Obviously,

the slope of the curve, defined as incremental impedance r dv/di, is negative. The

negative increase impedance characteristic poses a circuit problem for operating

lamps. In general, a starting voltage Vs that is higher than the steady-state operation

voltage is needed to establish ionization in the gas. After the discharge begins, the

operating point (i,v) of the discharge would lie somewhere on the line of the constant

V =Vs, which is in the domain for which the ionization rate exceeds the loss rate, and

thus electron density ne increases continuously with time. Consequently, the

discharge current increases without any regulation, and eventually causes system

failure.

As a result, gas discharge lamps cannot be directly connected to a voltage

source. Certain impedance must be placed between the discharge lamp and the

voltage source as a means to limit lamp current. For example, Figure 1.3(b) shows

the effect of series resistance in stabilizing lamp current. The dotted lines and

show the voltage potential across the discharge and resistor, respectively, and the

solid line VAB shows the potential across the pair in series.

Upon application of a starting voltage to the lamp-resistor system and

establishment of ionization, the operating point (i,v) is in the domain of positive

dne/dt, increasing the lamp current until it reaches the point (iss,Vs). A further

increase in current would move the operating point into the region of negative dne/dt,

forcing the current back to iss. The resistor R helps to establish the stable operating

point of the discharge lamp and acts as the ballast.

Obviously, the resistive ballast incurs large power loss and significantly

reduces the system efficiency. Fortunately, most discharge lamps are operated in

alternating-current (AC) circuits so that inductive or capacitive impedance can be

used to provide current limitation. AC operation also balances the wearing of two

electrodes and maintains a longer lamp life. The inductor ballast represents the

conventional ballasting approaches, and is known as magnetic ballasts.[1]

Nowadays, a great amount of produced electrical energy in the world is

consumed in the form of artificial illumination, and any improvement in the

efficiency of illuminating systems is desirable. The use of fluorescent lamps reduce

the consumption of electrical energy when compared to incandescent lamps, because

the former present higher efficacy (lm/W). The performance of fluorescent lamps are

improved when they are supplied by electronic ballasts instead of electromagnetic

ones, due their features, such as high efficacy, low audible noise, longer lamp useful

life, small size, light weight, and flicker absence. The drive circuit is easily employed

with self-oscillating circuit to use in electronic ballasts. When it uses the self-

oscillating gate drive circuit, it brings additional improvements, such as reliability,

low cost, and little energy consumption. Beyond of features of high frequency

operation; the main attractiveness is the simplest configuration, and zero voltage

switching operation.

1.1 Problem statements

The design circuit for high frequency electronic ballast must perform three

main functions:

1. Provide a start up voltage across the end electrodes of the lamp.

2. Construct a self-oscillating gate driver.

3. Maintain a constant current when lamp is operating in steady-state.

4. Assure that the circuit will remain stable.

1.2 Project objectives

These are the objectives of this project:

1. Study the characteristic of high frequency electronic ballast.

2. Design high frequency electronic ballast.

3. Develop the circuit of high frequency electronic ballast.

4. Comparison between electronic ballast with conventional ballast.

1.3 Project scopes

Figure 1.4: Scope of constructing electronic ballast

The scope of this project is to build electronic ballast according to the Figure

1.4. The electronic ballast consists of rectifier, inverter, self-oscillating gate drive,

and resonant filter. A bridge rectifier makes use of four diodes in a bridge

arrangement to achieve full-wave rectification. Bridge rectifier is used to convert AC

power to DC power. A self-oscillating gate driver is used to switch on and off

complimentary of transistors to produce a high frequency square wave of inverter

output. Then, the square wave is gone through the low-pass filter to eliminate the

undesired harmonic components. Finally, a comparison between electronic ballast

and conventional ballast will be done by doing circuit analysis.

1.4 Thesis outline

In this project, I would like to design electronic ballast to drive a 36W

fluorescent lamp. In this report, I will discuss it in detail in five sections. There are

introduction, literature review, methodology, results and discussions, and conclusion.

In chapter one (introduction), I discussed about the major characteristics to be

considered when choosing a lamp. There are more advantages of gas discharge lamps

over incandescent lamps but they require a ballast to run with them because gas

discharge lamps have negative incremental impedance. The problem statement,

project objectives, scope and thesis outline are also included in this chapter.

In chapter two (literature review), a comparison between the conventional

and electronic ballast is made. The comparison is made by discussing the operation

of conventional ballast and the problems caused by conventional ballast. Then

electronic alternatives are provided to encounter the problems. Later, each part of the

electronic ballast is discussed in detail. The full bridge rectifier, half bridge inverter,

and filter is discussed separately in their contribution to the functional of electronic

ballast.

In chapter three (methodology), I discussed about the techniques and

consideration that I applied during I carried out my PSM1 and PSM2. Fourier

analysis is an important tool to consider the harmonic components in the square

wave. In simulation part, OrCAD software is used to simulate the design circuit

before I proceed to the hardware part. The Fluke meter is used to do the analysis of

the circuit operation and comparison between magnetic ballast and electronic ballast.

Besides that, the illuminator is used to measure the lighting level.

In chapter four (results and discussions), the results are obtained using the

methodology discussed in previous chapter. The calculation using Fourier analysis is

done to determine the required filter. Then, OrCAD simulation is done to the design

circuit to ensure it functions probably. This is determined by looking at the graph

obtained during simulation. Finally, I proceed to the hardware part. Here all the

obtained results are gathered. Finally, analysis is done according to the results.

In chapter five (conclusion), a brief summary and recommendation of this

project are provided. Besides that, I also include my personal experiences during the

construction of electronic ballast. Finally, I have finished all the parts in my project

planning according to the objectives and scopes.

1.5 Project planning

Table 1.1: Gantt chart

PERANCANGAN PROJEK

PROJECT PLANNING

Senaraikan aktiviti-aktiviti utama bagi projek yang dicadangkan. Nyatakan

jangka masa yang diperlukan bagi setiap aktiviti.

List major activities involved in the proposed project. Indicate duration of each

activity to the related month(s).

2007 2008

Aktiviti Projek

Projects Activities

J J A S O N D J F M A M J

Report project PSM 1 & 2 X X X X X X X X X

Research on electronic

ballast design

X X X

Study and design circuit

using OrCAD (software)

X X X X X X X X

Presentation PSM 1 X X

Build and troubleshoot the

circuit (hardware)

X X X X X X X

Analysis circuit by doing

comparison between the

electronic ballast and

conventional ballast

X X X

Writing thesis and

presentation PSM 2

X X X

The Gantt chart shows the project planning of the major activities in PSM 1

and PSM 2. In PSM 1, I have completed the research on electronic ballast design,

study and design circuit using OrCAD, presentation, and build the circuit. In PSM2, I

have completed the analysis of electronic ballast and magnetic ballast.

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