Automatic Solar Tracking System

This paper discusses the use of solar tracking devices to improve the efficiency of solar panels. It identifies the limitations of existing trackers and proposes a more efficient, effective, and accurate tracking device that incorporates the use of sensors, moving devices, and a microcontroller. The paper also describes the mechanical, control, and electrical systems that make up the proposed solar tracking device.

Running head: AUTOMATIC SOLAR TRACKING SYSTEM 1
Automatic Solar Tracking System
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1.0 Introduction
Energy is prime key resource in driving forward the economy of a country. Most nations
utilize energy obtained from fossil fuels as their primary source (Babrekar, Kurhekar, Mulmule,
& Mohade,2016). Energy of this type is unfriendly to the environment and limited in nature, a
fact that has resulted to an energy cataclysm worldwide (Tharamuttam & Ng, 2017). To combat
the impacts of the crisis, most nations have shifted their attention to alternative sources such as
solar, wind and hydro. However, regardless of whatever the alternative is adopted, meeting the
maximum demand requirements is still a challenge and thus getting peak outputs from the
installed generating capacities has been of key consideration (Racharla & Rajan, 2017). In the
case of solar energy, the most commonly applied method to harness optimum energy is the use
of tracking devices. This paper, therefore, identifies how to harness maximum power output from
solar panels and presents an automatic, low cost microcontroller and sensor based tracking
system that improves the tracking efficiency while at the same time maximizing the output of the
installed capacity.
1.1 Literature Review
Solar tracking devices are technologically advanced systems used to mount solar panels
or parabolic troughs and orient them toward the direction with the highest intensity of the sun.
Unlike fixed mounting devices whose efficiency is lowered when the sun passes less optimal
angle, tracking devices are designed using photo sensitive devices connected with rotating
devices such as stepper motors, servo motors or gas pistons which constantly move the panels
along the sun’s path (Vyas, 2017). This movement reduces the angle of incidence between the
incoming rays of the sun and the photovoltaic cells ensuring that they are always exposed to the
sun’s rays. The constant exposure of the panels to sunlight increases the output energy harnessed

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from the installed generating capacity by 10 to 25% depending on the geographical features and
topography of where the generating unit is installed (Racharla & Rajan, 2017). Besides
increasing the output, the trackers also booster the efficiency of the solar cells and hence
maximize power per unit area.
Trackers exist in different types, the common ones being single axis, dual axis, active and
passive trackers. Single axis trackers move either horizontally or vertically only, dual trackers
move both horizontally and vertically (Pickerel, 2017). Passive trackers utilize the principle of
compressed gas to accomplish their purpose. On the other hand, active trackers use sensors
which detect the brightness of the sun and actuate the motor to move the panels in the direction
of the sun.
Moreover, trackers can be classified as open loop or altitude based. In open loop trackers
the movement of the panels towards the sun direction is as a result of timers whereas in altitude
based trackers sun position data obtained from astronomical stations’ data is used in
determination of the sun’s actual location and the movement of the panels made by a
microcontroller. Here, the controller through a predefined set of instructions determines sun’s
location and actuates the motor drive system to move the cells in the desired direction at well-
defined sets of intervals using the angle determined from the true north to the horizontal
projection of the rays of the sun in the horizontal plane known as azimuth and the angular height
of the sun measured from the horizon of the panels (Zipp, 2013).
All the above trackers have their limitations. The active (single and dual axis) and the
passive trackers have a higher performance index during clear sunny days and their performance
is greatly reduced during poor weather conditions such as cloudy seasons or when the sensors are
blocked from the sun by barriers. On the hand, the elevation angle in azimuth or altitude based

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trackers varies by days of the year and geographic features of the location of the installation of
the generating units and due to the complex nature of sun movement, the trackers are rendered
ineffective and inefficient hence reduced accuracy (Tharamuttam & Ng, 2017).
This proposal builds on the above challenges to build a more efficient, effective and
accurate tracking device that picks on the strong features of the single, dual, active tracker and
the azimuth tracker. The device to be developed therefore incorporates the use of sensors,
moving devices (motors) and microcontroller with a special set of instructions that ensures that
the problems encountered with the latter trackers is solved. The components are connected
together to work as a unit to ensure that optimum power is harnessed from the panels with the
sole purpose of increasing the value of the installed panels.
1.2 Methodology
The proposed solar tracking device will be comprising three major systems; the electrical
system, control system and the mechanical system both of which will act as a unit to accomplish
the desired purpose. Description of the components, making and purpose of three systems is as
below:
1.2.1 The Mechanical System
This is the system responsible for the movement of the panels in the desired direction.
The system will be composed of two types of motor responsible for moving the tracker in the
desired direction and position anytime they are called to action by the sensors. The motor types
will be the servo and the stepper; the stepper will move tracker about the south and north
direction while servo motor will be responsible for east and south rotation (Tharamuttam & Ng,
2017). The schematic of the two motor is shown below:

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Figure 1:Stepper and Servo Motor
1.2.2 The Control System
The control system is composed of Arduino microcontroller and sensors as the main
components. Description of the features and purpose of this components’ is listed below:
1.2.2.1 Arduino Microcontroller
The Arduino is based on ATmega328 microcontroller. It is the heart of the project and
hence serve as center of communication between the inputs and the outputs of the tracker. It will
carry the algorithm whose purpose will be to perform logic and arithmetic operations to analyze
the data from the sensors and actuate the motors to drive the tracker in the desired direction and
position based on the intensity of the sun at a particular period. The schematic of the
microcontroller.

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Figure 2:Arduino Microcontroller
1.2.2.2 LDR Sensors and Resistors
This is a photo resistor device that’s sensitive to light. It has variable resistance which
works in such a way that when light falls on the sensor it reduces, and increases when the light
intensity reduces (Aqib, 2017). It is this behavior that makes it well suited for the project. They
are placed on the sides of the panels such that they actuate the motors to move the tracker
towards the side in which the sensor has low resistance. If the resistance on the two sensors is the
same, the motors will stop rotating. The schematic of the sensor is as below:
Figure 3:LDR Sensor

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1.2.3 The Electrical System
The electrical system is comprised of the solar panels and the power supply to the motors and the
sensors. The solar panels are the normal photovoltaic cells that converts solar energy to electrical
energy in DC form by providing a potential difference equivalent to the light intensity. It can
letter be converted to AC form using an inverter if there is necessity or there are equipment’s that
require power in AC form (Parasnis & Tadamalle, 2016). The power supply to the motors and
the sensors is provided by panels so as to minimize the need for external power.
1.3 Schedule of Work
To facilitate the completion of the project effectively, the project will be broken down
into simple tasks. Each task will take one week to complete. The different tasks will be; review
of literature, planning and collection of materials, design of prototype, testing of prototype,
adjustment of the prototype, and finalizing and documentation. The Gantt chart below shows the
individual tasks and the dates they are expected to be complete.
Figure 4:Gantt Chart

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1.4 References
Aqib, M. (2017). Arduino based sun tracking solar panel project using LDR and servo motor.
Retrieved from https://circuitdigest.com/microcontroller-projects/arduinosolar-panel
tracker
Babrekar, V. J., Kurhekar, M. S., Mulmule, K. K., & Mohade, D. B. (2016). Review on
automatic solar radiation tracking system. International Journal of Scientific &
Engineering Research, 7(2). Retrieved from https://www.ijser.org/researchpaper/Review
On-Automatic-Solar-Radiation-Tracking-System.pdf
Parasnis, N. V., & Tadamalle, A. P. (2016). Automatic solar tracking system. Journal of
Innovations in Engineering Research and Technology, 3(1). Retrieved from
https://www.ijiert.org/admin/papers/1452765913_Volume%203%20Issue%201.pdf
Pickerel, K. (2017). What is a dual-axis solar tracker? Retrieved from
https://www.solarpowerworldonline.com/2017/09/dual-axis-solar-tracker/
Racharla, S., & Rajan, K. (2017). Solar tracking system: A review. International Journal of
Sustainable Engineering, 10(2), 72-81. Retrieved from
https://www.tandfonline.com/doi/abs/10.1080/19397038.2016.1267816
Tharamuttam, J. K., & Ng, A. K. (2017). Design and development of an automatic solar
tracker. Energy Procedia, 143, 629-634. doi: 10.1016/j.egypro.2017.12.738
Vyas, K. (2017). Automatic solar tracking system development and simulation. IOSR Journal of
Electrical and Electronics Engineering, 10(1). Retrieved from
https://mnre.gov.in/file-manager/akshay-urja/june-2017/Images/18-21.pdf.
Zipp, K. (2013). How does a solar tracker work? Retrieved from
https://www.solarpowerworldonline.com/2013/04/how-does-a-solar-tracker-work/