SOLAR HOME SYSTEMS
Manual for the design and
modification of
Solar Home System components
M.R. Vervaart
F.D.J. Nieuwenhout
2 ECN-C--00-019
Preface
This manual was produced by ECN in
the framework of the World Bank project: Mitigating
Global Climate Change through the
Development of a Quality Process Infrastructure for
Renewable Energy (QuaP-PV). This
manual forms the basis of a training course for
engineers
who will be involved in the design
and modification of solar home system equipment. The
current text is a modified and
extended version of a manual used in a similar training
exercise
provided by ECN at Hefei University
in China in March and April 1999, in the framework of
the China Renewable Energy Project of
the World Bank.
The authors would like to thank Enno
Heijndermans of the World Bank for funding the work
and for providing guidance in
formulating the manual. We would like to thank Jeroen
van
Twisk, Jan Pierik and Jaap Eikelboom
of ECN for their detailed comments which have
improved the text.
CONTENTS
Abbreviations and special
terms……………………………………………………………….5
1.
INTRODUCTION............................................................................................................................
6
1.1
BACKGROUND.................................................................................................................................
6
1.2 OBJECTIVES
....................................................................................................................................
6
1.3 SCOPE OF
WORK..............................................................................................................................
6
2. EXPERIENCE WITH SOLAR HOME
SYSTEMS.......................................................................
8
2.1 INTRODUCTION
...............................................................................................................................
8
2.2 NON-TECHNICAL ASPECTS RELEVANT
FOR SYSTEM SIZING AND DESIGN
.......................................... 9
2.2.1
Costs......................................................................................................................................
9
2.2.2 Ownership
............................................................................................................................
10
2.2.3 After sales services
...............................................................................................................
10
2.2.4 Feed-back from field experience
..........................................................................................
11
2.2.5 Environmental
issues............................................................................................................
11
2.3 TECHNICAL
ASPECTS......................................................................................................................
11
2.3.1 System losses
........................................................................................................................
11
2.3.2 Sizing of the PV-module
.......................................................................................................
13
2.3.3 Sizing of
components............................................................................................................
14
2.3.4
Modularity...........................................................................................................................
14
2.4 SOLAR HOME SYSTEM
COMPONENTS.............................................................................................
15
2.4.1 Modules
...............................................................................................................................
15
2.4.2 Module Support Structure
....................................................................................................
17
2.4.3 Battery Charge Regulator
....................................................................................................
17
2.4.4 Battery
.................................................................................................................................
18
2.4.5 Battery
Mounting..................................................................................................................
21
2.4.6 Lamps, ballasts and
fixtures.................................................................................................
21
2.4.7 Wiring, Switches and Outlets
...............................................................................................
22
2.4.8 Inverters
...............................................................................................................................
23
3. LIGHTING IN SOLAR HOME SYSTEMS
.................................................................................
24
3.1 DESIGN CONSIDERATIONS FOR
LIGHTS...........................................................................................
24
3.1.1 Types of lighting
...................................................................................................................
24
3.1.2 Luminous flux
.......................................................................................................................
26
3.1.3 Luminous
efficacy.................................................................................................................
27
3.1.4
Illuminance..........................................................................................................................
27
3.1.5 Measurements of luminous flux
............................................................................................
28
3.2 FLUORESCENT LAMP INVERTERS (FLI)
..........................................................................................
30
3.2.1
Introduction.........................................................................................................................
30
3.2.2 Working principle of a
fluorescent
light...............................................................................
30
3.2.3 Blackening of the fluorescent
lamp
......................................................................................
32
3.2.4 Lamp inverters with one or two
transistors..........................................................................
34
3.2.5 Different transistor
set-ups...................................................................................................
37
3.2.6 Polarity protection
...............................................................................................................
43
3.2.7 FET versus Transistor
..........................................................................................................
44
3.2.8 Effect of filament preheating
................................................................................................
45
3.2.9 Critical components and
component quality
........................................................................
47
3.2.10 Inductance calculation of the
transformer coil
................................................................
53
3.2.11 EMC &
PCB-design.........................................................................................................
56
4. CHARGE
REGULATORS.............................................................................................................
59
4.1 INTRODUCTION
..............................................................................................................................
59
4.2 OBJECTIVES AND SCOPE OF
WORK..................................................................................................
60
4.3 DESIGN IDEAS
...............................................................................................................................
60
4.3.1 Series / shunt type regulators:
Pros and cons
......................................................................
60
4.3.2 Positive switching / negative
switching
................................................................................
62
4 ECN-C--00-019
4.3.3 HVD-Switching in the
battery-line: pros and
cons...............................................................64
4.3.4 On-Off- charging / PWM-
charging
.....................................................................................65
4.3.5 Boost
Charging.....................................................................................................................69
4.3.6 Special function IC’s
............................................................................................................70
4.3.7 Digital or analogue
set-up....................................................................................................72
4.4 MODIFICATION
POINTS...................................................................................................................73
4.4.1 Quiescent current reduction
.................................................................................................73
4.4.2 Safety precautions: reverse
polarity
protection....................................................................75
4.4.3 Reduction of the number of
components...............................................................................76
4.4.4 Safety precautions: overload
protection / short circuit
protection.......................................76
4.4.5 Lightning surge
induction.....................................................................................................78
4.4.6 Oscillation problems without
battery
...................................................................................80
5. DC/AC
CONVERSION...................................................................................................................82
5.1 SCOPE OF
WORK............................................................................................................................82
5.2 TYPES OF INVERTER:
PRINCIPLES...................................................................................................83
5.3 DC-VOLTAGE SUPPLY IMPERFECTION.
INPUT FILTER
...................................................................87
5.4 SINGLE-PHASE INVERTERS TOPOLOGIES
........................................................................................90
5.4.1 Single-Phase Inverter with
Centre-Tapped Transformer
.....................................................90
5.4.2 Single-Phase Half-Bridge
Inverter
.......................................................................................91
5.4.3 Single-Phase Full-Bridge
Inverter........................................................................................92
5.5 GALVANIC
ISOLATION....................................................................................................................93
5.6 COMPARISON OF THE REQUIRED
COMPONENTS AND CHARACTERISTICS
.......................................96
5.7 SQUARE-WAVE VERSUS PWM
SWITCHING.....................................................................................97
5.7.1 Square-wave switching
principle..........................................................................................97
5.7.2 PWM switching scheme
........................................................................................................97
5.8 SEMI-CONDUCTOR SWITCHES AND
DRIVER CIRCUITS
.....................................................................99
5.8.1 Semiconductor-switches
.......................................................................................................99
5.8.2 Gate and base drive circuits
...............................................................................................100
5.9 COMPONENT TEMPERATURE CONTROL AND
HEAT
SINKS..............................................................109
5.9.1 Control of semiconductor device
temperatures
..................................................................109
5.9.2 Heat transfer by conduction
...............................................................................................109
5.10 EXAMPLES
...............................................................................................................................112
5.10.1 150VA HF
inverter.........................................................................................................112
5.10.2 DC/AC Isolated Battery
inverter using the integrated circuit HIP4082
........................114
6. ADVISORY SERVICES BODY FOR
IMPROVING BOS-COMPONENTS..........................117
6.1 ESTABLISHING AN ADVISORY SERVICES
BODY
.............................................................................117
6.2 PROCEDURES OF AN ADVISORY
SERVICES
BODY...........................................................................117
7. PRACTICAL PART OF THE TRAINING
COURSE...............................................................119
7.1 FLUORESCENT LAMP
INVERTERS..................................................................................................119
7.1.1 Measuring fluorescent lamp
inverters
................................................................................119
7.1.2
Modifications.....................................................................................................................120
7.2 CHARGE REGULATORS
.................................................................................................................120
7.2.1
General..............................................................................................................................120
7.2.2
Measurements....................................................................................................................121
7.2.3
Modifications.....................................................................................................................121
7.3 DC/AC-CONVERTERS
..................................................................................................................122
7.3.1
General..............................................................................................................................122
7.3.2 Measurements at
DC/AC-converters
..................................................................................122
7.3.3
Modifications.....................................................................................................................123
Appendix 1 to
10…………………………………………………………………………………………125