Design and Construction of Automatic Dual-Axis Solar Tracking System Using Light Dependent Resistor (LDR) Sensors
Design & construction of automatic dual-axi solar
tracking system using light dependent resistor
Department of EEE
@ World University of Bangladesh
was Dhaka—1205, Bangladesh
Early in the 21century, Nuwayhid et al. (2001) adopted the open-loop and closed-loop
tracking methods into a parabolic concentrator attached to a polar tracking system.
In 2004, Abdallah and Nijmeh designed a two axis sun tracking system, a
programmable logic controller (PLC) was used to calculate the solar vector and to
control the sun tracker so that it follows the sun’s trajectory.
In addition, Shanmugam & Christraj (2005) presented a computer program written a
Visual Basic that is capable of determining the sun’s position and thus drive a
paraboloidal dish concentrator (PDS) along the east-west axis or north-south axis for
receiving maximum solar radiation.
In 2007, Ali Al-Mohamad designed a Sun-tracking system, whereby the movement of a
photovoltaic module was controlled to follow the Sun’s radiation using a
programmable logic-controller (PLC) unit.
In 2008, Mohanad Alata, M. A. Al-Nimr and Yousef Qaroush demonstrated the design
and simulation of time controlled step sun tracking systems.
In Rajshahi University of engineering & Technology a project was done by Md.
Rokunuzzaman whereby the movement of a photovoltaic module was controlled to
follow the Sun’s radiation using a CMOS logical circuit.
Photovoltaic cells are less productive when not pointed directly at the sun and operate at
maximum efficiency when pointed directly towards the sun. This project paper puts
forward a proposal of an improved “Dual-Axis (azimuth-altitude) Solar Tracking
System” to receive maximum sunbeam that has been designed and implemented by
using “Light Dependent Resistor (LDR)” sensors, ICS and Permanent Magnet DC
motors with gear arrangements to make the tracking system simple by eliminating the
use of microcontroller. Important points of this design are using minimum energy while
tracking, stability of trajectory, maximum energy efficiency and being cheaper and
simple than the other tracking systems. This tracking system is able to track the sun
efficiently throughout the year at any weather keeping the solar panel perpendicular to
the sun. The effectiveness of the Sun tracker is confirmed experimentally.
' To design and construct a simple solar tracking system which can absorb
maximum amount of sunlight.
° To minimize the cost of installation and operation providing higher reliability.
° Information were collected from related reference books and websites to find
out the possible improvement.
° Components were collected from local electronics market.
Functional Block Diagram
E/ Jerking Principle
The dual-axis solar tracker comprises of comparator IC LM339, H-bridge motor
driver IC L293D and a few discrete components. Light-dependent resistors LDRl
through LDR4 are used as sensors to detect the panel’s position relative to the sun. 4
LDRs are fixed at the edges of the solar panel along the X and Y axis, and connected
to comparator IC LM3 39.
LDRl and LDR2 are used to track horizontal axis (x-axis). When LDR2 receives
more light than LDRl, it offers lower resistance than LDRl, providing a high input to
comparators Al and A2 at pins 4 and 7, respectively. As a result, output pin 1 of
comparator A2 goes high to rotate motor M1 in one direction (say, anti-clockwise) and
turn the solar panel.
When LDRl receives more light than LDR2, it offers lower resistance than LDR2,
giving a low input to comparators Aland A2 at pins 4 and 7, respectively. As the
voltage at pin 5 of comparator Al is now higher than the voltage at its pin 4, its
output pin 2 goes high. As a result motor Ml rotates in the opposite direction (say,
clock-wise) and the solar panel turns.
Similarly, LDR3 and LDR4 track the sun along Y axis.
Light dependent resistor
--’-—= ‘—-‘ ; . ' Load (LED Light)
it_D_/ 7} . ~.*. X— Direction motor
<~*T'v-f“. .. Charge controller circuit
Motor driving circuit
Y— Direction motor
LDR (Light dependent resistor)
Permanent Magnet DC Motors
° Mono Crystalline solar panel
° Cost effective
° More efficient and reliable
° Made of bulk type silicon
LU (Light Dependent Resistor)
° Resistance decreases with increase in intensity of light
° Used to sense or detect light
° Made of high resistance semiconductor
KC Ll€33 (Comparator)
Have four digital comparators in one IC.
Output will be either high or low.
Uses single supply unlike other comparators.
KC L293D (Motor Driving EC)
Dual H-bridge motor driver IC
Controls two DC motors simultaneously in both direction
Wide Supply-Voltage Range
Permanent Magnet DC Motors (Geared Motor)
Field poles are made of permanent magnet
Low power consumption
Two PMDC motors used in X and Y direction.
Used to transmit torque to the panel arrangement.
Comparison (Static Panel, Single-axis, Dual-axis)
Average output power is 3.501 for dual axis solar tracker, 2.958 for single axis
tracker and 2.348 for static panel.
Average practical efficiency of solar panel for dual axis tracking system is 7.75%,
where 6.55% for single axis and 5.20% for static panel.
Average power gain of the solar panel with dual axis tracking system is up to
49.06% over normal stationary arrangement and 18.32% over single axis tracking
Con: r.pa1*isoU. (Output Power Over a Day)
Power vs. Time
= Single Axis
Comparison (Average Output Power)
Static Panel Single Axis Dual Axis
List of Components with Price
SL Name Quantity Cost
Solar Panel 1 400
I PMDC Motor 2 10
Pinium 4 200
2 Stand and Boards 2000
7 Accessories cost 1000
2 Total Cost 5000
Proposed dual axis solar tracker is cost effective.
Average power gain of the solar panel with dual axis tracking system over
normal stationary arrangement is up to 40-50%.
Less power consumption by internal circuit and PMDC motors.
Ability of tracking sun light at any weather.
Installation is easy and operates automatically.
Dual axis sun tracker can be used for large & medium scale power generations.
It can also be used for power generation at remote places.
It may be used as domestic backup power systems.
It can be used in solar street lighting system
It may be used in water treatment technologies and solar heating.
The main theme of this project is to generate electricity using sun light efficiently by
developing a advance dual axis solar tracking system. Proposed dual axis solar
tracking system is more efficient than single axis & static panels and also cheaper
than the other trackers available in market.
Uses of four LDR‘s enable the tracker to keep the panel exactly perpendicular to the
sun throughout the day. It enables the panel to grab energy throughout the day, which
increase the efficiency of solar panel. Average power gain of the solar panel with
proposed dual axis tracking system is up to 40-50% over normal stationary
arrangement and 15-20% over single axis tracking system.
Basically, this project is a miniature model for large scale electrical generating
system. According to this implementation in future it can be implemented in large
scale in perspective of Bangladesh. A considerable amount of power could be
obtained if it is implemented as a large project with comparing of fossil fuel
The proposed dual-axis solar tracking system will be reliable and accurate throughout
the year and maximize the output power when compared to static system and single
axis tracking system. It will be a good and competitive solution for the market place as
it is expected to compete with more complex and expensive systems.
0 Hybrid super-capacitor energy storage system can be used to store energy quickly.
0 Solar thermal power plant may be included in large scale power generation.
0 An automatic dust sensor wiper or cleaning robot can be provided for cleaning of