Mini Project Documentation
Mini Project Documentation
Mini Project Documentation
LIST OF ABBREVAITIONS
CHAPTER 1:INTRODUCTION
1.1 Introduction
1.2 Objective of mini project
1.3 Literature survey
1.4 organization of the Mini project report
CHAPTER 2: EXISTING METHODS
2.1 Introduction
2.2 solar panel
2.3 Design and simulation of solar panel
CHAPTER 3:PROPOSED METHOD &IMPLEMENTATION
3.1 Introduction
3.2 Block diagram
3.3 components & elplanation
3.4 pin configuration of ATMEGA328
3.5 Circuit diagram
3.6 Working
CHAPTER 4:RESULTS
4.1 Analysis
CHAPTER 5:CONCLUSION AND FUTURE SCOPE
5.1 Conclusion
5.2 Future scope
REFERENCES
APPENDIX:
CHAPTER 1
INTRODUCTION
INTRODUCTION :
India is among the tropical countries that fall between 4 degrees and 13
degrees and enjoys sunshine of 6.25 hrs daily. Presently, public electricity covers only 40% of Inian homes
and this is not still on a consistent basis. Due to lack of constant power supply in Nigeria, people have
started embracing the culture of generating their own power supply. The use of fossil fuels as a means of
generating electricity has become expensive making cost of living very high, especially in the rural part of
the country. Also the use of fossil fuel has brought about pollution to the environment which in turn is not
safe for our health. It releases carbon dioxide which causes the greenhouse effect. This brings about the
deforestation of land and also the pollution of air and water. Solar energgy is gotten solely from the sun
and as a result does not emit carbon dioxide which prevents the green-house effect. The development of
solar energy in India has the potential to create jobs. Employment in renewable energy industry would
reduce occupational hazards especially when compared to coal mining and the extraction of oil. Nowadays
solar energy is becoming one of the most reliable source of energy as a result of its surplus and
environmental friendly . According to reference system that tracks the sun will be able to know the
position of the sun in a manner that is not linear. The operation of this system should be controlled
independently . Maximum energy is produced by a solar PV panel when it is positioned at right angle to
the sun. Therefore, the aim of this research is to develop an Arduino based solar tracking for energy
improvement of solar photovolatic panel Solar energy is clean and available in abundance. Solar
technologies use the sun for provision of heat, light and electricity. These are for industrial and domestic
applications. With the alarming rate of depletion of depletion of major conventional energy sources like
petroleum, coal and natural gas, coupled with environmental caused by the process of harnessing these
energy sources, it has become an urgent necessity to invest in renewable energy sources that can power the
future sufficiently. The energy potential of the sun is immense. Despite the unlimited resource however,
harvesting it presents a challenge because of the limited efficiency of the array cells. The best efficiency of
the majority of commercially available solar cells ranges between 10 and 20 percent. This shows that there
is still room for improvement. This project seeks to identify a way of improving efficiency of solar panels.
Solar tracking is used. The tracking mechanism moves and positions the solar array such that it is
positioned for maximum power output. Other ways include identifying sources of losses and finding ways
to mitigate them. When it comes to the development of any nation, energy is the main driving factor. There
is an enormous quantity of energy that gets extracted, distributed, converted and consumed every single
day in the global society. Fossil fuels account for around 85 percent of energy that is produced. Fossil fuel
resources are limited and using them is known to cause global warming because of emission of greenhouse
gases. There is a growing need for energy from such sources as solar, wind, ocean tidal waves and
geothermal for the provision of sustainable and power. Solar panels directly convert radiation from the sun
into electrical energy. The panels are mainly manufactured from semiconductor materials, notably silicon.
Their efficiency is 24.5% on the higher side. Three ways of increasing the efficiency of the solar panels are
through increase of cell efficiency, maximizing the power output and the use of a tracking system.
Maximum power point tracking (MPPT) is the process of maximizing the power output from the solar
panel by keeping its operation on the knee point of P-V characteristics. MPPT technology will only offer
maximum power which can be received from stationary arrays of solar panels at 2 any given time. The
technology cannot however increase generation of power when the sun is not aligned with the system.
Solar tracking is a system that is mechanized to track the position of the sun to increase power output by
between 30% and 60% than systems that are stationary. It is a more cost effective solution than the
purchase of solar panels. There are various types of trackers that can be used for increase in the amount of
energy that can be obtained by solar panels. Dual axis trackers are among the most efficient, though this
comes with increased complexity. Dual trackers track sunlight from box axes. They are the best option for
places where the position of the sun keeps changing during the year at different seasons. Single axis
trackers are a better option for places around the equator where there is no significant change in the
apparent position of the sun. The level to which the efficiency is improved will depend on the efficiency of
the tracking system and the weather. Very efficient trackers will offer more efficiency because they are
able to track the sun with more precision. There will be bigger increase in efficiency in cases where the
weather is sunny and thus favorable for the tracking system
1.2 Objectives of miniproject
The project was carried out to satisfy two main objectives:
Design a system that tracks the solar UV light for solar panels.
Prove that the tracking indeed increases the efficiency considerably.
The range of increase in efficiency is expected to be between 30 and 40 percent.
literature survey
A solar cell is a device which converts light energy to electrical energy through photovoltaic effect.
Solar cells are the building blocks of photovoltaic modules known as solar panels. In solar tracking
system, the module’s surface tracks the position of the sun automatically as the day runs by. The
position of the sun varies as the sun moves across the sky. For a solar powered equipment to work
best, it must be placed near the sun and the solar tracker can increase the efficiency of that
equipment at any fixed position. Based on sophistication, costs and performance. One common
type of tracker is the heliostat, a movable mirror that reflects the position of the sun to a fixed
location. A solar trackers accuracy depends on the application. Concentrators, especially in solar
cell applications, require a high degree of accuracy to make sure that the concentrated sunlight is
directed exactly to the powered device, which is close to the focal point of the reflector or lens.
Without tracking, concentrator systems will not work at all, therefore single-axis tracking is
mandatory . Non-concentrating applications require less accuracy, and many are likely to work
without any tracking. However, tracking with great effect can improve both the amount of total
output power produced by a system and that produced during critical system demand periods
(usually late afternoon in hot climates) . Researches have been done to improve the energy
production of solar panels. These researches include; double-sided panels , conversion stages
improvement , building panels integration geometrically and so on. Maximum energy is produced
by a solar PV panel when it is positioned at right angle to the sun. For this reason, several
researches developed different types of solar panel tracking systems . Therefore, the primary
purpose of this work is to develop a solar panel tracker based on Arduino advances so as to enhance
the energy production of solar panel.
CHAPTER 2
EXISITING METHODS
2.1 Introduction:
Solar energy represents the largest energy input into the terrestrial system. Despite its relatively low power
density, this resource could potentially satisfy the global energy demand on its own. The challenges that
need to be addressed to make solar energy viable and competitive on a large scale include: enhancing the
performance of solar energy conversion systems through increased efficiency and use of durable materials;
reducing the material, fabrication, and installation costs so that these systems can be deployed at a large
scale; and overcoming the intermittent nature of the resource to allow supply to meet demand at all times.
Photovoltaic energy conversion efficiency has increased steadily in the past decade through enhanced
photon absorption and charge transport. Moreover, continuous development of novel device concepts,
materials, and fabrication processes has contributed to lowering the cost of solar power. Thin-film solar cells
are regarded as a promising route for low-cost energy conversion. Inorganic thin films are relatively mature
technologies with record efficiencies around 20%. Organic solar cells are at an earlier stage of development
with efficiencies reaching around 11% for polymeric heterojunctions and dye-sensitized cells. Further
research in thin-film technologies is required to increase their efficiency up to the thermodynamic limits, to
enhance their stability, and to further reduce their fabrication cost. Solar thermal technologies are
appropriate for large-scale energy production and can be combined with thermal energy storage systems to
offer a practical solution to smooth supply intermittency over time periods of several hours. Photo
electrochemical systems are another option under investigation to circumvent the intermittency issue of solar
power. They hold the promise to efficiently harvest solar energy and convert it into chemical fuels with a
single, potentially low-cost device. This conversion strategy allows for the carbon-free – or even carbon-
negative when CO2 is used as a feedstock – synthesis of fuels for electricity and/or transportation, and
provides a solution to the intermittency problems without requiring the use of ancillary energy storage
systems to match supply and demand
3.1 Introduction:
A solar tracker is a device used for orienting a photovoltaic array solar panel or for concentrating
solar reflector or lens toward the sun. The position of the sun in the sky is varied both with seasons
and time of day as the sun moves across the sky. Solar powered equipment work best when they are
pointed at the sun. Therefore, a solar tracker increases how efficient such equipment are over any
fixed position at the cost of additional complexity to the system. There are different types of
trackers.
Extraction of usable electricity from the sun became possible with the discovery of the
photoelectric mechanism and subsequent development of the solar cell. The solar cell is a
semiconductor material which converts visible light into direct current. Through the use of solar
arrays, a series of solar cells electrically connected, there is generation of a DC voltage that can
be used on a load. There is an increased use of solar arrays as their efficiencies become higher.
They are especially popular in remote areas where there is no connection to the grid.
Photovoltaic energy is that which is obtained from the sun. A photovoltaic cell, commonly
known as a solar cell, is the technology used for conversion of solar directly into electrical
power. The photovoltaic cell is a non mechanical device made of silicon alloy.
POWER SUPPLY
ARDUINO
L MICROCONTROLLER
SERVO
D
MOTOR
R
1
L
D
R SOLAR PANEL
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Figure : suntracking solarpanel block diagram
3.3 Components&explanation:
Light sensors theory&cicuit of sensor used
3.3.1 Light Dependent Resistor Theory
3.3.2 The concept of using two LDRs
3.3.3 Light sensor design
3.3.4 Servo motor
3.3.5 Components of the servo motor
3.3.6 How the servo is controlled
3.3.7 Advantages and disadvantages of servo motors
3.3.8 Microcontroller
3.3.8.1 ATmega328P
3.9 The design tool Arduino cc
3.10Algorithm for Motor Control
Concept of using two LDRs for sensing is explained in the figure above. The stable position is when the
two LDRs having the same light intensity.When the light source moves, i.e. the sun moves from west to
east, the level of intensity falling on both the LDRs changes and this change is calibrated into voltage using
voltage dividers. The changes in voltage are compared using built-in comparator of microcontroller and
motor is used to rotate the solar panel in a way so as to track the light source.
Rpot/
Vi = Vcc { }
LDR + Rpot
In this case,
Vi =- input voltage into the microcontroller R=Resistance of the [potentiometer which is10K Vcc= Supply
voltage to Microcontroller and LDRs Vi=Input voltage to the Microcontroller
Servo motor
Servo motors are used for various applications. They are normally small in size and have good energy
efficiency. The servo circuitry is built inside the motor unit and comes with a positionable shaft that is
fitted with a gear. The motor is controlled with an electric signal that determines the amount of shaft
movement.
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When the shaft of the motor is at the desired position, power supply to the motor is stopped. If the shaft is
not at the right position, the motor is turned in the right direction. The desired position is sent through
electrical pulses via the signal wire. The speed of the motor is proportional to the difference between the
actual position and the position that is desired. Therefore, if the motor is close to the desired position, it
turns slowly. Otherwise, it turns fast. This is known as proportional control .
How the servo is controlled
Servos are sent through sending electrical pulses of variable width, or pulse width modulation (PWM),
through the control wire. There is a minimum pulse, maximum pulse and a repetition rate. Servos can
usually turn only 90 degrees in either direction for a total of 180 degrees movement. The neutral position
of the motor is defined as that where the servo has the same amount of potential rotation in both the
clockwise and counter-clockwise direction. The PWM sent to the motor determines the position of the
shaft, and based on the duration of the pulse sent through the control wire the rotor will turn to the position
that is desired [7].
The servo motor expects to see a pulse after every 20 milliseconds and the length of the pulse will
determine how far the motor will turn. For instance, a 1.5ms pulse makes the motor to turn in the 90
degrees position. If the pulse was shorter than 1.5ms, it will move to 0 degrees and a longer pulse moves it
to 180 degrees. This is shown below.
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For applications where there is requirement of high torque, servos are preferable. They will also maintain
the torque at high speeds, up to 90% of the rated torque is available from servos at high speeds. Their
efficiencies are between 80 to 90%.
A servo is able to supply approximately twice their rated torque for short periods of time, offering enough
capacity to draw from when needed. In addition, they are quiet, are available in AC and DC, and do not
suffer from vibrations.
Advantages and disadvantages of servo motors
For applications where high speed and high torque are required, servo motors are the better option. While
stepper motors peak at around 2000 RPM, servos are available at much faster speeds. Servo motors also
maintain torque at high speed, up to 90% of the rated torque is available from servos at high speeds. They
have an efficiency of about 80-90% and supply roughly twice their rated torque for short periods.
Furthermore, they do not vibrate or suffer from resonance issues. Servo motors are more expensive than
other types of motors. Servos require gear boxes, especially for lower operation speeds. The requirement
for a gear box and position encoder makes the designs more mechanicallycomplex. Maintenance
requirements will also increase.
Microcontroller
Microcontroller is a single chip micro computer made through VLSI fabrication. A microcontroller also
called an embedded controller because the microcontroller and its support circuits are often built into, or
embedded in, the devices they control. A microcontroller is available in different word lengths like
microprocessors (4bit,8bit,16bit,32bit,64bit and 128 bit microcontrollers are available today).
A microcontroller contains one or more of the following components:
Microcontrollers need to be programmed to be capable of performing anything useful. It then executes the
program loaded in its flash memory – the code comprised of a sequence of zeros and ones. It is organized
in 12-, 14- or 16-bit wide words, depending on the microcontroller’s architecture. Every word is considered
by the CPU as a command being executed during the operation of the microcontroller [1].
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Figure 3.9: Microcontroller Architecture
ATmega328P
The ATmega328P is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC
architecture. By executing powerful instructions in a single clock cycle, the ATmega328P achieves
throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption
versus processing speed.
It has 28 pins. There are 14 digital I/O pins from which 6 can be used as PWM outputs and 6 analog input
pins. The I/O pins account for 20 of the pins. The 20 pins can act as input to the circuit or as output.
Whether they are input or output is set in the software.
Two of the pins are for the crystal oscillator and are supposed to provide a clock pulse for the Atmega
chip. The clock pulse is needed for synchronization so that communication occurs in synchrony between
the Atmega chip and a device connected to it. Two of the pins, Vcc and GND are for powering the chip.
The microcontroller requires between 1.8-5.5V of power to operate.
The pin-out for the microcontroller is shown below:
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Figure 3.10: Atmega 328P
The Atmega328 chip has an analog-to-digital converter (ADC) inside of it. This must be or else the
Atmega328 wouldn't be capable of interpreting analog signals. Because there is an ADC, the chip can
interpret analog input, which is why the chip has 6 pins for analog input. The ADC has 3 pins set aside for
it to function- AVCC, AREF, and GND. AVCC is the power supply, positive voltage, that for the ADC.
The ADC needs its own power supply in order to work. GND is the power supply ground. AREF is the
reference voltage that the ADC uses to convert an analog signal to its corresponding digital value. Analog
voltages higher than the reference voltage will be assigned to a digital value of 1, while analog voltages
below the reference voltage will be assigned the digital value of 0. Since the ADC for the Atmega328 is a
10-bit ADC, meaning it produces a 10-bit digital value, it converts an analog signal to its digital value, with
the AREF value being a reference for which digital values are high or low. Thus, a portrait of an analog
signal is shown by this digital value; thus, it is its digital correspondent value [7].
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The last pin is the RESET pin. This allows a program to be rerun and start over. The table below gives a
description for each of the pins and their functions.
Table 3.3 Pins and their functions
Pin Number Description Function
1 PC6 Reset
2 PD0 Digital Pin (RX)
3 PD1 Digital Pin (TX)
4 PD2 Digital Pin
5 PD3 Digital Pin (PWM)
6 PD4 Digital Pin
7 Vcc Positive Voltage (power)
8 GND Ground
9 XTAL 1 Crystal Oscillator
10 XTAL 2 Crystal Oscillator
11 PD5 Digital Pin (PWM)
12 PD6 Digital pin (PWM)
13 PD7 Digital pin
14 PB0 Digital pin
15 PB1 Digital pin (PWM)
16 PB2 Digital pin (PWM)
17 PB3 Digital pin (PWM)
18 PB4 Digital pin
19 PB5 Digital pin
20 AVcc Positive voltage for
ADC
(power)
21 Aref Reference voltage
22 GND Ground
23 PC0 Analog input
24 PC1 Analog input
25 PC2 Analog input
26 PC3 Analog input
27 PC4 Analog input
28 PC5 Analog input
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There are various features that make the ATmega 328P a good choice for the project:
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START
(S2-S1)>e
STOP
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Algorithm for Motor Control
The algorithm gives the description of the general steps undertaken for the project:
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There is a reset button for positioning the panel to an initial position which is at an inclination of 40
degrees. This is done preferably in the evening after the sun has set. It makes the LDR go back to an initial
position, ready for tracking sunlight on the next day. There is also a push button for initializing the servo
motor. It switches it on, leaving it on standby mode.
Pins 7, 20 and 21 are for powering the microcontroller. It requires 5V. The inputs to the LDR are
simulated. The hardware schematic diagram is shown in figure
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CHAPTER 4
RESULTS
Results
The results for the project were gotten from LDRs for the solar tracking system and the panel that has a
fixed position. The results were recorded for four days, recorded and tabulated. The outputs of the LDRs
were dependent on the light intensity falling on their surfaces. Arduino has a serial that communicates on
digital pins 0 (RX) and 1 (TX) as well as with the computer through a USB. If these functions are thus
used, pins 0 and 1 can be used for digital input or output.
Arduino environment’s built in serial monitor can be used to communicate with the arduino board. To
collect the results, a code was written that made it possible to collect data from the LDRs after every one
hour. The values from the two LDRs are to be read and recorded at the given intervals.
The LDRs measure the intensity of light and therefore they are a valid indication of the power that gets to
the surface of the solar panel. As a result, by measuring the light intensity at a given time, it will be
possible to get the difference in efficiency between the tracking panel and the fixed one. The light intensity
is directly proportional to the power output of the solar panel.
A code was written that made it possible to obtain readings from the two LDRs at intervals of one hour.
The EEPROM came in handy in this. It is the memory whose values are kept when the board is turned off.
The ATmega 328P has 1024 bytes of EEPROM.
To get the values at the end of the day, the Arduino board was used to connect the microcontroller to the
computer. The RX and TX pins are used for the connection. The code for reading the values that were
recorded is loaded into the microcontroller. The various values are obtained and converted into volts. The
Vcc to the microcontroller and the LDRs is 5volts. The Atmega 328P has 1024 voltage steps and 5volts.
When they are converted into digital values, the values will be in the range of 0-1023. The conversion is
done using the relation below.
Equivalent Digital Output∗5
LDR Output = Volts
1023
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The results were obtained for different days. Getting results from different days was helpful in that it made
it possible to compare the various values gotten from different weather conditions. The values obtained
were recorded and used to draw graphs to show the relations.
Table 4.1: Results for cloudy Morning and Sunny Afternoon for ……
LDR readings for Fixed Panel LDR readings for a
Tracking
Panel
Time LDR1 LDR2 LDR12 LDR22
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6
1 LDR12
0 LDR22
1530Hrs
0630Hrs
0730Hrs
0830Hrs
0930Hrs
1030Hrs
1130Hrs
1230Hrs
1330Hrs
1430Hrs
Time (hourly)
Analysis
From the curves, it can be seen that the maximum sunlight occurs at around midday, with maximum values
obtained between 1200 hours and 1400 hours. In the morning and late evening, intensity of sunlight
diminishes and the values obtained are less that those obtained during the day. After sunset, the tracking
system is switched off to save energy. It is switched back on in the morning.
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For the panel fitted with the tracking system, the values of the LDRs are expected to be close. This is
because whenever they are in different positions there is an error generated that enables its movement. The
motion of the panel is stopped when the values are the same, meaning the LDRs receive the same intensity
of sunlight. For the fixed panel, the values vary because the panel is at a fixed position. Therefore, at most
times the LDRs are not facing the sun at the same inclination. This is apart from midday when they are
both almost perpendicular to the sun.
Days with the least cloud cover are the ones that have the most light intensity and therefore the outputs of
the LDRs will be highest. For cloudy days, the values obtained for the tracking system and the fixed
system do not differ too much because the intensity of light is more or less constant. Any differences are
minimal. The tracking system is most efficient when it is sunny. It will be able to harness most of the solar
power which will be converted into energy.
In terms of the power output of the solar panels for tracking and fixed systems, it is evident that the
tracking system will have increased power output. This is because the power generated by solar panels is
dependent on the intensity of light. The more the light intensity the more the power that will be generated
by the solar panel.
The increase in efficiency can be calculated. However, it is important to note that there will be moments
when the increase in power output for the tracking system in comparison with the fixed system is minimal,
notably on cloudy days. This is expected because there will not be much difference in the intensity of
sunlight for the two systems. Similarly, on a very hot day at midday, both systems have almost the same
output because the sun is perpendicularly above. As such, both systems receive almost the same amount of
irradiation.
A few values can be used to illustrate the difference in efficiency between the two systems:
For a bright sunny day, we can take the averages for LDR22 and LDRS 2 for the entire day. We then use 5
as the base because it is the maximum value of the LDR output. It is calculated as a percentage and the two
values compared. While this may not give the clearest indication of the exact increase in efficiency, it
shows that the tracking system has better efficiency.
Average value of LDR 22 or LDR2 * 100
5 Volts
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For LDR 22:
For LDR 2:
The difference between the two values is 23.4%. this means the LDR for the tracking system has an
increased efficiency of 23.4%.
CHAPTER 5
The input stage is designed with a voltage divider circuit so that it gives desired range of illumination for
bright illumination conditions or when there is dim lighting. This made it possible to get readings when
there was cloudy weather. The potentiometer was adjusted to cater for such changes. The LDRs were
found to be most suitable for this project because their resistance varies with light. They are readily
available and are cost effective. Temperature sensors for instance would be costly.
The control stage has a microcontroller that receives voltages from the LDRs and determines the action to
be performed. The microcontroller is programmed to ensure it sends a signal to the servo motor that moves
in accordance with the generated error.
The final stage was the driving circuitry that consisted mainly of the servo motor. The servo motor had
enough torque to drive the panel. Servo motors are noise free and are affordable, making them the best
choice for the project.
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Conclusion
A solar panel that tracks the sun was designed and implemented. The required program was
written that specified the various actions required for the project to work. As a result, tracking
was achieved. The system designed was a single axis tracker. While dual axis trackers are
more efficient in tracking the sun, the additional circuitry and complexity was not required in
this case. This is because Kenya lies along the equator and therefore there are no significant
changes in the apparent position of the sun during the various seasons. Dual trackers are most
suitable in regions where there is a change in the position of the sun.
This project was implemented with minimum resources. The circuitry was kept simple, while
ensuring efficiency is not affected.
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