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CHAPTER 1
INTRODUCTION
The economic development of a country depends on the strength of its
infrastructure. Energy is one of the most important components of infrastructural
facilities. The demand for energy is increasing day by day all over the world. Almost
all countries of the world are in search of new sources of energy for meeting the
increasing demand of energy. All the energy used on Earth comes from fission or
fusion of atomic nuclei or from energy stored in the Earth. The problem with both
fission and fusion is that they have dangerous radioactivity and side effects.
Therefore, most of the generation of energy in our modern industrialized society is
strongly depending on very limited non-renewable resources, particularly fossil fuels
such as coal and crude oil. Unfortunately these non-renewable forms of energy on
earth are ultimately finite sources of energy. Also burning of oil and coal in the
process of conversion to electrical power is quite harmful to the environment. This
lead to a world wide search for alternative renewable sources of energy.
Very much exploitation and research for new power was done not only in the area
of nuclear power generation but also in the area of unlimited energy sources such as
solar power generation, wind power generation etc. The renewable energy sources
like solar and wind have shown promise as possible cost efficient alternatives to fossil
fuels. Compared to wind energy, the most effective and harmless energy source is
solar energy.
Most renewable sources are based on energy from the Sun, geothermal forces and
planetary motion in the solar system. Solar, wind, small hydro power, wave energy,
tidal power, ocean thermal energy conversion, and bio fuels are renewable where as
fossil fuels constitute non- renewable.
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The Sun is the source of energy available to mankind. Solar energy is allpervasive, readily available and renewable. Solar energy is available in varying
degrees in every part of the world unlike fossil fuels which are located in few regions
only. Thus, all countries regardless of their geographical location can derive
considerable benefit from solar energy.
1.1 SOLAR ENERGY
As early as the 7 th century B.C., people used simple magnifying glasses to
concentrate the light of the Sun into beams so that they would cause wood to catch
fire. Swiss scientist Horace de Saussure built the world’s first solar collector in 1767.
In the beginning of this century, scientists and engineers began researching ways to
use solar energy in earnest. One important development was a remarkably efficient
solar boiler invented by Charles Greeley Abbott, an American astrophysicist, in 1936.
Solar energy is the solar radiation that reaches the earth. Every day Sun radiates or
sends out an enormous amount of energy. Like the other stars, the Sun is a big ball of
gases – mostly hydrogen and helium atoms. The hydrogen atoms in the Sun’s core
combine to form helium and generate energy in a process called nuclear fusion.
During nuclear fusion, the Sun’s extremely high pressure and temperature cause
hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse
or combine. Four hydrogen nuclei fuse to become one helium atom. But the helium
atom contains less mass than the four hydrogen atoms that fused. Some matter is lost
during nuclear fusion. The lost matter is emitted into space as radiant energy.
Solar radiations are collected and concentrated with the help of solar
collectors/concentrators. The resulting heat may be used to heat water, to provide heat
for cooking and crop drying, to purify and desalinate sea water, for heat space in
buildings, to provide process heat for industrial applications, provide space cooling
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with absorptions coolers, or generate power using several thermodynamic processes.
Photovoltaic refers to the creation of voltage from light. Solar photovoltaic
systems directly convert sunlight into useful electricity. This process is called
photoelectric effect. The electrical energy is generated in a solar photovoltaic system
i.e. the solar cell. Solar cells when connected in series and parallel constitute a solar
panel. A solar photovoltaic system is an energy generating system, which provides
power for different type of devices. Photovoltaic systems are classified into two types:
one that provides power generated directly from the solar panels, and the other, where
energy generated is stored and utilized when required.
The main thrust of solar energy research and development in India has been on
applications in rural areas and supplementing wherever possible commercial energy
supplies in urban areas. Broadly, following three approaches are generally followed
for utilizing solar energy.
- Absorbing solar energy directly or by using concentrators and then converting into
thermal energy for needed applications.
- Converting solar energy into electrical power using photovoltaic devices.
- Utilizing solar energy indirectly.
1.2 ORGANIZATION OF THE THESIS
Chapter 2 deals with the review of the literature.
Chapter 3 deals with the principle of operation of solar cells, their modeling along
with the governing equations and concepts of maximum power point tracking. I-V
and P-V curves obtained for 60W KL solar company module for various conditions
are presented.
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Chapter 4 gives the hardware implementation of basic model of 60W module
illustrating maximum power point tracking in solar cells. The insolation
measurements are not taken into account.
Chapter 5 describes the method of perturb and observe, incremental conductance
method where in the value of incremental conductance is made use of, constant
current method in which the current at maximum power point is assumed to be equal
to a fraction of the short circuit current of the array, and constant voltage method for
obtaining the maximum power from the given array, with the flow chart and the result
of the methods.
Chapter 6 describes the fuzzy logic based method of tracking MPP giving the
details regarding membership functions, fuzzy rules for implementing fuzzy logic
based MPP controller.; a brief introduction about artificial neural networks with its
implementation, algorithm and result; different hybrid networks and implementation
of neuro-fuzzy based maximum power point tracking with algorithm, result and
validation to 60W solar module.
Chapter 7 gives the concluding remarks for the thesis.
1.3 CONCLUSIONS
The chapter concludes that the solar energy is a possible cost efficient alternative
to fossil fuels. Regardless of the geographical locations, any place can derive
considerable benefit from solar energy. The chapter also presents the organisation of
the thesis.