Parallel-connected solar arrays

110 Pages·2016·4.1 MB·English

by  Majed Meshal Alabbass

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Masters Theses Student Theses and Dissertations
Spring 2013
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Majed Meshal Alabbass
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PARALLEL-CONNECTED SOLAR ARRAYS

by

MAJED MESHAL ALABBASS

A THESIS

Presented to the Faculty of the Graduate School of the
MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY
In Partial Fulfillment of the Requirements for the Degree
MASTER OF SCIENCE IN ELECTRICAL ENGINEERING
2013

Approved by

Dr. J. W. Kimball, Advisor
Dr. M. Ferdowsi
Dr. S. Baur
 2013
MAJED MESHAL ALABBASS
All Rights Reserved
iii

ABSTRACT

The purpose of this thesis is to investigate the advantages of having various
series-parallel configurations of solar arrays and make a comparison between them. The
objective is to determine the best PV system configuration and thus improve the overall
efficiency of a solar array. The primary focus of this thesis is to study the parallel
connection of PV panels for achieving maximum efficiency while extracting maximum
energy from the solar radiation. A comparison between a series connected and a parallel
connected solar PV array justifies the need for installing a parallel configured solar PV
array to achieve optimum performance. The DC-DC converter plays an important role in
delivering maximum power to the load. A solar sensor array was used to monitor the
solar radiation under various climatic conditions. Data saved using these sensors was then
analyzed using software developed with MATLAB’s Graphical User Interface (GUI)
platform. The PV-cell equations cannot be solved with the ordinary numerical method
due to both the complexity and their non-linearity. These calculation were simplified
through using the Newton-Raphson (NR) method along with other numerical
approximation approaches. The software package is capable of displaying a number of
curves including the I-V characteristic, the output power, and the output energy of the
PV-panels for different configurations. Various scenarios were simulated and compared
under different climatic conditions. The proposed method for parallel configured PV
panel was found to be an alternative to existing methods.
iv

ACKNOWLEDGEMENTS

First and foremost, it is with immense gratitude that I acknowledge the support
and help of my research advisor, Dr. Kimball. Dr. Kimball continually conveyed a spirit
of adventure with regard to both my research and motivation. He inspired and encouraged
me to my work on this project. His guidance has helped me throughout this project. I
would not have been able to complete this project successfully without his support.
Besides my advisor, I sincerely thank the members of the supervisory committee,
Dr. Baur and Dr. Ferdowsi, for their encouragement and insightful comments. They gave
me the moral support and the freedom I needed to move on.
Moreover, I am deeply grateful to the Saudi Arabian Cultural Mission (SACM)
for the research assistantship they provided. I must also thank the National Science
Foundation for supporting this work under award ECCS-0900940. Finally, I want to
express my sincerest and deepest gratitude to AL Jouf University for awarding me with a
full scholarship to pursue my degree.
Last but not the least, I would like to thank my family and friends. Special thanks
to the spirit of my precious mother and to my father for his countless efforts, support,
guidance, motivation, and inspiration. His patient love and encouragement enabled me to
complete this project. His unconditional support, both financially and emotionally,
throughout my degree has been greatly appreciated.
v

TABLE OF CONTENTS

Page
ABSTRACT ....................................................................................................................... iii
ACKNOWLEDGEMENTS ............................................................................................... iv
LIST OF ILUSTRATIONS .............................................................................................. vii
LIST OF TABLES ............................................................................................................. ix
SECTION
1. INTRODUCTION ................................................................................................... 1
1.1. LITERATURE REVIEW ................................................................................. 2
1.1.1 PV Model ............................................................................................... 2
1.1.2 The Effect of Changing the PV Model Parameters ................................ 5
1.1.3 Maximum Power Point Tracking (MPPT) ............................................. 9
2. EXPERIMENTAL METHODOLOGY ................................................................ 13
3. SOFTWARE DEVELOPMENT ........................................................................... 16
3.1. SOFTWARE THEORY OF OPERATION ................................................... 20
3.1.1. Input ..................................................................................................... 20
3.1.2 Analysis ................................................................................................ 20
3.1.3 Case Study ............................................................................................ 21
4. CALCULATED PERFORMANCE ...................................................................... 28
4.1. SCENARIO 1 ................................................................................................. 28
4.2. SCENARIO 2 ................................................................................................. 35
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4.3. SCENARIO 3 ................................................................................................. 42
4.4. SCENARIO 4 ................................................................................................. 49
5. CONCLUSIONS ................................................................................................... 57
APPENDIX ....................................................................................................................... 59
REFERENCES ................................................................................................................. 95
VITA ................................................................................................................................. 98
vii

LIST OF ILUSTRATIONS
Page
Figure 1.1 Equivalent Circuit of a PV Cell ......................................................................... 3
Figure 1.2 Effects of Solar Radiation Variation ................................................................. 6
Figure 1.3 Effects of Shunt Resistance Variation ............................................................... 7
Figure 1.4 Effects of Series Resistance Variation .............................................................. 8
Figure 1.5 DC-DC Converters Across Each PV Panel [18] ............................................. 11
Figure 1.6 Micro-inverter Across Each PV Panel [18] ..................................................... 11
Figure 1.7 Parallel Connected with DC-DC Converters across Each PV Panel ............... 12
Figure 2.1 Solid Line Represents the Schematic Diagram of the Sensor Circuit Board
and the Dash Line Represents the Actual Size of Kyocera Modules ............. 13
Figure 2.2 Schematic Diagram of the Sensor Circuit Board ............................................ 14
Figure 3.1 Main Menu ...................................................................................................... 17
Figure 3.2 Insolation Menu ............................................................................................... 18
Figure 3.3 Editor for Entry................................................................................................ 18
Figure 3.4 Main Menu ...................................................................................................... 21
Figure 3.5 PV Module Selection Pop-up Menu ................................................................ 22
Figure 3.6 Parameter Entry Interface ................................................................................ 23
Figure 3.7 Insolation Menu ............................................................................................... 24
Figure 3.8 Random Generation ......................................................................................... 25
Figure 3.9 Manual Insolation Input .................................................................................. 25
Figure 3.10 Random Sun Radiation Value ....................................................................... 26
Figure 3.11 Editor for Entry.............................................................................................. 26
Figure 3.12 I-V Characteristic Curves .............................................................................. 26
Figure 3.13 Power versus Voltage Curve ......................................................................... 27
Figure 3.14 Power versus Current Curve .......................................................................... 27
Figure 4.1 The Insolation Data as a Function of time....................................................... 29
Figure 4.2 Array Characteristics of (2S4P) Without IPC ................................................. 30
Figure 4.3 Array Characteristics of (1S8P) ....................................................................... 31
Figure 4.4 Array Characteristics of (4S2P) ....................................................................... 32
Figure 4.5 Array Characteristics of (8S1P) ....................................................................... 34
viii

Figure 4.6 %Theoretical vs. Resistance ............................................................................ 35
Figure 4.7 The Insolation Data as a Function of Time ..................................................... 36
Figure 4.8 Array Characteristics of (2S4P) Without IPC ................................................. 37
Figure 4.9 Array Characteristics of (1S8P) ....................................................................... 38
Figure 4.10 Array Characteristics of (4S2P)..................................................................... 39
Figure 4.11 Array Characteristics of (8S1P)..................................................................... 41
Figure 4.12 %Theoretical vs. Resistance .......................................................................... 42
Figure 4.13 The Insolation Data as a Function of Time ................................................... 43
Figure 4.14 Array Characteristics of (2S4P) Without IPC ............................................... 44
Figure 4.15 Array Characteristics of (1S8P)..................................................................... 45
Figure 4.16 Array Characteristics of (4S2P)..................................................................... 46
Figure 4.17 Array Characteristics of (8S1P)..................................................................... 48
Figure 4.18 %Theoretical vs. Resistance .......................................................................... 49
Figure 4.19 The Insolation Data as a Function of Time ................................................... 50
Figure 4.20 Array Characteristics of (2S4P) Without IPC ............................................... 51
Figure 4.21 Array Characteristics of (1S8P)..................................................................... 52
Figure 4.22 Array Characteristics of (4S2P)..................................................................... 53
Figure 4.23 Array Characteristics of (8S1P)..................................................................... 55
Figure 4.24 %Theoretical vs. Resistance .......................................................................... 56