International Conference on Advances in Electrical, Electronics, Information, Communication and Bio-Informatics (AEEICB16)

Automatic Dual-axis Solar Tracking System forParabolic dish

Pallavi N. Patil1Department of Instrumentation and ControlCollege of Engineering Pune, India-411005

pallavipatil.158@gmail.com

M. A. Khandekar2

Department of Instrumentation and ControlCollege of Engineering Pune, India-411005

mgj.instru@coep.ac.in

Shubham N. Patil3E & TC Department

JNEC Aurangabad, Indiashubhsnp.001@gmail.com

Abstract—In country like India demand of energyincreases with increase in population so the use ofrenewable and natural sources of energy like windenergy, tidal energy, solar energy etc is the need oftime in country. In this paper we present developmentand experimental study of two axis automatic controlof solar tracking system using Arduino. In hardwaredevelopment five light dependent resistors (LDR) hasbeen used to sense and gather maximum solar energy.Two permanent magnet DC motors are used to movethe solar dish according to the solar energy sensed byLDR. In software part we design a controller whichwill move the collector dish to track the sun. Thecontroller uses LDR sensors as input and permanentmagnet DC geared motors as an output. LDR are usedto sense the intensity of light and generate the signalswhich will be further processed by ATmega328 micro-controller. Microcontroller executes the algorithm andgives control command to motor driver. This paperdescribes development of automatic dual axis solartracking system for solar parabolic dish.

Index Terms—Arduino UNO, ATmega328 microcon-troller, Dual-axis Solar Tracker, Hercules Lite motordriver, PMDC Geared motor.

I. IntroductionRequirement of energy rapidly go on increasing with

increase in population of country. People use the energyresources like oil, gas and coal to fulfill their basic needs.These sources of energy are very limited and are verycostly and creates pollution in the environment. Thesesources of energy are not recoverable so there is lot ofdemand for use of natural as well as renewable sources likesolar energy, wind energy, geothermal energy, tidal waveenergy etc.

The earth receives 16x1018 units of solar energy peryear, which is 20,000 times larger than the requirementof human on the earth surface. Solar power generationsystem using moving dish is efficient. As the sun is re-volving around the earth, solar energy is not constant atany direction in a whole day. It is necessary to track thesolar energy in each direction to increase the efficiencyof solar system. One of the promising source of futureenergy is solar energy. There are two ways to increasethe energy from solar energy based system. First way isin manufacturing photovoltaic cell use different efficientmaterials and second way is to follow the sun use solar

tracker. Solar tracker is nothing but the automated solarpanel which helps to get maximum solar energy [1] . In thispaper disadvantage of single axis solar tracking system ismentioned because sun varies its position in the sky withchange in season as well as with time of a day [2]. Withthe help of dual axis solar tracking system we can improvethe efficiency of solar power. A computer tracking systemwhich is based on picture processing is described in [3].It include complex calculations and low accuracy so it isnot an acute method [3]. Dual axis solar tracking systemworks well even if it is cloudy season as compared to thesingle axis solar tracking system [4].

II. Solar TrackerA device on which collector or parabolic dish are fixed

which helps to track the solar energy by tracking the Sun’smotion also helps to strikes maximum sunlight on collectorwithin a day is nothing but the solar tracker. After locatingsunlight the tracker will directed towards the path wherethe maximum sunlight is collected and received [5] Thereare different ways of tracking, namely

• Passive Tracking system - It uses differential heatingof two interconnected tubes which are filled with thegaseous refrigerants, means in this type of trackingsystem there are no use of controllers, motors andgears. Thus it is called passive tracking system [6]

• Active Tracking System - It uses motors and gearwhich is commanded by the controller to respond thesolar direction. It is classified as single axis trackingand dual axis tracking.

– Single axis solar trackers: It tracks the sun’smotion from east to waste or north to southdirection daily.

– Dual axis solar trackers : It tracks the sun’smotion from east to waste as well as from northto south direction. [7]

III. Methodology

Fig.1 shows the block diagram of proposed system. Themain purpose of this project is to develop a highly efficientand high quality dual-axis solar tracking system. Herethere are three main parts i.e. sensing elements, controllerand motors. Light Dependent resistor (LDR) is used as a

978-1-4673-9745-2 ©2016 IEEE

sensing element and analog value of LDR is used as input,Arduino acts as a controller and PMDC motor will be theoutput.

Fig. 1: Block diagram of dual axis solar tracking

IV. HardwareThe hardware used for this project are solar dish, Light

Dependent Resistor (LDR), PMDC geared motor andArduino UNO board as a controller.A. Light dependent resistor(LDR)

Light Dependent Resistor (LDR) is also called as pho-tocell or photoresistor is nothing but the variable resistorwhich sense the light. The resistance is inversely propor-tional to the intensity of light, it exhibits the photocon-ductivity [8] [9] [10]

Fig. 2: Sensor(LDR) implementation on a plate

Five LDR’s are mounted on a plate in vertical tubeswhich are fitted on the surface of plate. LDR-1 andLDR-3 are used to rotate the dish vertically and LDR-2 and LDR-4 are used to rotate the dish horizontally.LDR-5 is mounted at center which is used to stop therotation of motor and at that time parabolic dish is at thecentre position. Centre tube is placed perpendicular to thesurface of the plate and other tubes are placed inclined tothe surface of the plate at an angle of 85 degree in theonward direction from the Centre tube. So that it detectsthe sun rays in maximum 20 minutes.

B. PMDC geared motorPermanent magnet DC geared motors are used hav-

ing working principle similar as DC motor. This motoruses permanent magnetic field for excitation. Basicallystromtium ferrite magnet is used. Construction of motoris totally enclosed type, steel body is used to protect itagainst corrosion. Rotors are dynamically balanced.

Fig. 3: PMDC geared motor

Torque is important factor while motor selection.PMDC motor is a constant torque motor so it gives con-stant torque for standstill speed as well as rated speed ofmotor. Motor specifications: PMDC Motor (model TM85)

Fig. 4: Specifications of PMDC motor

As speed requirement for Dual-axis solar tracking sys-tem is very low and speed of PMDC motor is 1500 rpm.By using gear box which having ratio 150:1, the speed ofmotor is reduced to 10 rpm. This is the sufficient speedrequired for tracking.C. Motor Driver

Hercules Lite driver IC with rating 6 V to 36 V, 8 Ampsis used. Generally driver IC is used as current amplifier

which is used to drive the motor. As we want to drive themotor without using PWM so we have to connect PWMpin to 5V logic level. Here we use ON OFF controller todirectly ON or OFF the output with no middle state.By using this IC, we can move motor in clockwise andanticlockwise direction as per input provided by controller.

V. Working of solar Tracking System

Fig. 5: Setup of solar Collector dish

The parabolic collector dish is shown in the Fig.5 Thisis closed loop system giving feedback from sensors (LDR).The whole assembly is mounted at an angle of 18.53degrees which is latitude location of the city. This dishcollects the solar radiations and focuses the same at focalpoint. The dish moves over an arc length of 80 inches tothe east and 80 inches to the west and same for the northsouth direction through the day which is corresponds to90 degree in each direction.

Fig. 6: Specifications of Solar system

VI. software

Programming language used in software part was con-structed by using C programming. The code were compiledand uploaded to the arduino UNO board. The algorithmwhich indicates the flow for programming is as shown inFig.7 in the form of flowchart. LDR’s are act as a inputfor the system and were connected to the analog pins ofarduino board i.e. pin A0 to A4. ADC is already built-in the arduino which is helpful to convert analog valuesof LDR into digital values. Dish is rotate in 0, 90 and180 degrees. Positions of five LDRs were fixed which areup, down, right, left and centre were useful to detect thehighest intensity of light from sun.

Fig. 7: Algorithm of Automatic Dual Axis Solar Tracking

A. Programmer

Arduino is used as a programmer which is an opensource. Arduino consist of both hardware and software torun on our computers.

Fig. 8: Connections of Solar tracking system with arduino

As arduino itself consist of hardware so it doesn’t needof separate hardware. To load the new code onto the boardthere is need of USB cable to communicate with PC.Arduino uses a simplified version of C++ to make theprogramming very easy.

Arduino UNO board is based on a microcontroller AT-Mega328. There are total 14 digital I/O pins from which6 analog input pins and 6 PWM digital I/O pins. Havingoperating voltage 5 volt and DC current for each I/O pinis 20 mA.

VII. Readings• Testing of applied algorithm with the help of proto-

type as shown in Fig.7.

Fig. 9: Prototype implementation for dual axis solartracker

Before going to actual setup of dual axis solar tracker,prototype was developed and designed as shown in Fig.7.Motor-1 takes input signals from sensor-2 and sensor-4,

which are used for upward and downward direction track-ing. Motor-2 takes input signals from sensor-1 and sensor-3, which are used for left and right direction tracking.Each LDR is connected across the resistor and it’s voltageoutput is directly connected to analog pin of arduino.Arduino reads the input and gives the output in 0 to1024 value.By using that values V1, V2, V3, V4, and V0voltages are calculated.

Fig. 10: Readings from Arduino

First single-axis solar tracking system is implemented byusing three collinear LDR’s and one PMDC motor. Andfor this readings are taken.

Then Dual axis solar tracking system is implemented byusing five LDR’s and two PMDC motors and readings aretaken.

Dual-axis tracking system tracks maximum solar en-ergy as compared to single-axis tracking system. Usingimplemented algorithm the dual axis solar tracking systemworks automatically.

VIII. Conclusion

Closed loop automatic dual axis solar tracking has beenattempted so as to track motion of the sun for collectingmaximum energy. Logic for Automatic Dual-axis solartracking system is checked. Efficiency of power generatingwith the help of Dual-axis solar tracking system is muchmore as compared to the single-axis solar tracking system.Following are the concluding remarks:

• It has been found that ON-OFF control provides suffi-cient motion of motor for getting motion of parabolicdish.

• Microcontroller has been used that generates thecontrol commands. It has been found that controlalgorithm works satisfactorily.

• Accuracy of the system depends upon the accuracy ofsensor. Accuracy and resolution of sensor are impor-tant for successful execution of algorithm.

IX. Future Scope• For getting the precise accuracy advanced control can

be investigated.• To monitor whole system from remote area.• Use of heat sensor for generating the control com-

mand can give the novel alternative.

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