Microcontroller based automatic solar power tracking system


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Microcontroller based automatic solar power tracking system

  1. 1. INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME & TECHNOLOGY (IJEET)ISSN 0976 – 6545(Print)ISSN 0976 – 6553(Online)Volume 4, Issue 1, January- February (2013), pp. 109-114 IJEET© IAEME: www.iaeme.com/ijeet.aspJournal Impact Factor (2012): 3.2031 (Calculated by GISI) ©IAEMEwww.jifactor.com MICROCONTROLLER BASED AUTOMATIC SOLAR POWER TRACKING SYSTEM 1 Hemlata B. Nirmal, 2 Syed A. Naveed 1 P.G. Student, Electronics and Telecommunication Dept. Jawaharlal Nehru Engineering College, Aurangabad, (M.S.) INDIA. 2 Electronics and Telecommunication Dept. Jawaharlal Nehru Engineering College, Aurangabad, (M.S.) INDIA. hemlatanirmal@rediffmail.com, sa_naveed01@rediffmail.com ABSTRACT Renewable energy resources are getting priorities in the whole world in order to provide a sustainable power production and safe world to the future generation. Solar energy is rapidly gaining the focus as an important means of expanding renewable energy uses. Solar trackers are the most appropriate and proven technology to increase the efficiency of solar panels through keeping the panels aligned with suns position. A microcontroller based design methodology of an automatic solar tracker is presented in this paper. The unit controls the movement of solar panel always aligned towards the direction of the sun, due to this maximum thermal energy would be culminated from solar panel. Sun always moves from east to west direction independent of weather condition, so with this concept without using sensors movement of the solar panel from east to west direction is done with the help of programme loaded into the microcontroller. This prototype is designed for single axis as well as for double axis to solve solstice problem. From hardware testing we come to know that solar tracking system tracks the sun precisely and provides more power at the output as compared to that static solar panel. Keywords: Solar panel, solar tracking, microcontroller, stepper motor, liquid crystal display. 109
  2. 2. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEMEI. INTRODUCTION Energy is essential factor for the development of any nation. Most of the energyproduction depends on fossil fuels. The resources of the fossil fuels are limited, so thatthere is growing demand for energy from renewable resources like solar, geothermal andocean tidal wave. Among all renewable systems photovoltaic system is the one which hasgreat chance to replace the conventional energy resources. Solar panel directly convertssolar radiation into electrical energy. Solar panel is mainly made from semiconductormaterials. To enhance the performance of solar panel the only way is to increase theintensity of light falling on it. Solar tracker is the best technology to increase theefficiency of solar panel by keeping panel aligned with the suns position. In this paper amicrocontroller based simple and easily programmed automatic solar tracker is presented.II. TECHNOLOGY TO ENHANCE POWER OUTPUT FROM SOLAR PANEL In order to increase the efficiency of photovoltaic system there are three methods.First is increasing the efficiency of solar cell, second is maximizing the power output andthird is employing a tracking system. Improvement of solar cell efficiency is an ongoingresearch work and people throughout the world are actively doing research on this.Maximum power point tracking is the process to maximize the output power from solarpanel by keeping the solar panels operation on the knee point of photovoltaiccharacteristics. A number of maximum power point tracking algorithms have beendeveloped and employed around the world [1]. At particular time, maximum power canbe received from a stationary array of solar panel in case of maximum power pointtracking technology. However, it cannot increase the power generation when the sun isnot aligned with the system. Automatic solar tracker increases the efficiency of the solarpanel by keeping the solar panel aligned with the rotating sun. Solar tracking is abasically electromechanical system to track the suns position that increases power outputof solar panel 30% to 60% than the stationary system [2]. A few design methodology ofsolar tracking system has been proposed in recent days [3]-[4]. Maximum rays from thesun reach on the earth’s surface through interaction of clouds, dusts and water. These raysare called as diffused rays which reduces the output of solar cell. If these rays reflected onthe panel through the reflectors it will increase the overall output of the panel [5].III. PHOTOVOLTAIC TECHNOLOGY Solar energy is most abundant and convenient source of renewable energy.Photovoltaic cells are the basic of solar system. In the word photovoltaic “photo” meanslight and “voltaic” means producing electricity. Therefore the photovoltaic process isproducing electricity directly from sunlight. The output power of a photovoltaic celldepends on the amount of light projected on the cell. The output power also depends onthe time of day, season, panel position and orientation. 110
  3. 3. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEMEIV. AUTOMATIC SOLAR TRACKING SYSTEM The sun moves across the sky during the day, it is advantageous to have the solarpanels track the location of the sun such that the panels are always perpendicular with theposition of the sun. But available solar trackers in the market are much more costly tointegrate with solar panel system [6]. Solar tracking presented in this paper can provide aneffective solution to such problem. The major components those are used in the system aregiven below.. Microcontroller. Stepper motor. L293D .Liquid crystal displayFig. 1 shows the schematic diagram of automatic solar power tracking system. Fig.1 Schematic of solar tracker circuitryA. Microcontroller The PIC18F452 microcontroller has been used in the system. Microcontroller is the heartof overall system. PIC 18F452 has some features such as analog comparator(AC), analog todigital converter (ADC), universal synchronous asynchronous receiver transmitter (USART),timers and parallel slave port (PSP). 111
  4. 4. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEMEB. Stepper motor Stepper motors are commonly used in precision positioning control applications. Fivecharacteristics of stepper motor have been considered while choosing stepper motor for solartracker. Stepper motor is brushless, load independent, has open loop positioning capability,good holding torque and excellent response characteristics. The stepper motor that has beenused in the system has the specifications of 4.4volts, 4 resistance, 1.8º per step, 2 phases,bipolar.C. L293D L293D is quadruple high-current half-H driver. All inputs are TTL compatible. Eachoutput is a complete totem-pole drive circuit with a Darlington transistor sink and a pseudo-Darlington source. The L293D has some features such as wide supply voltage range 4.5V to36V, separate input logic supply, thermal shutdown, high noise immunity inputs, outputcurrent 600mA per channel, peak output current 1.2mA per channel and output clamp diodesfor inductive transient suppression.D. Liquid crystal display 16X2 character Liquid crystal display is used in this system to display solar panel voltageand number of cycles completed.V. OPERATION OF THE SOLAR TRACKER Solar tracker provides three ways of operation and control mechanism through theprogramme written in the microcontroller. The three ways of operation includes normal daylight condition, bad weather condition and bidirectional rotation. Whether there is normal daylight or bad weather sun always present in the sky. With this programme loaded into themicrocontroller to move the panel from east to west direction automatically. Once the day of24 hours completed panel brought to initial position to start the new day. The entire day is divided into 24x6=144 parts of 10 minute each. The day light isassumed to be present for 10 hours that is 60 parts of 10 minutes. Stepper motor hasresolution of 1.8ºper step. The worm gear ratio that has been used is 30:1. With this thenumber of steps required by the stepper motor to move the panel through 2.4º is 40. Withbeginning of the daylight from a reference point the system starts counting the steppingcycles each of 40 steps. Three counters used counter1 for day light, counter2 for whole dayand conuter3 for season correction. After every one month the light emitting diode willturned ON to indicate there is need to do correction to solve elevation problem. For thispurpose a separate mechanism of fine pitch of lead screw is used for compensating theelevation of the sun. Once the counter1 reaches 60 counts there will be no further movementof the stepper motor. But the counting of the cycles continues up to 144 in counter2. Thiscompletes the day of 24 hours. The numbers of days are calculated in counter3. As numberof days is not equal to 365 then panel is brought to initial position by counting 60 cyclesbackward. Then start the new day. But whenever number of days is equal to 365 thenresetting of all counters is required. A 6volt lead acid rechargeable cell is used as storageelement for the motor drive as well as the power supply for the other circuits. Operationalflow of the solar tracker is given in fig.2 112
  5. 5. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME Fig.2 Operational flow chart of solar trackerVI. HARDWARE TESTING OF SOLAR PANEL Table I shows the data of voltage, current and power received from solar trackingsystem and static solar panel for a day. Fig. 3 shows the comparison of electric powercharacteristic curves from solar tracking system and static solar panel. It shows that solartracking system is able to receive more Sunlight and consequently generate more power ascompared to static solar panel. TABLE I Observations of solar panel during hardware testing 113
  6. 6. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME Fig. 3 Electric Power vs. Hours characteristic curveVII. CONCLUSION The proposed sun tracker automatically tracks the sun capturing maximum solarpower with help of microcontroller. The system tracks the sun both in normal and badweather condition. The tracker can initialize the starting position itself which reduce the needof any more photo resistor. Summer solstice and winter solstice problem is solved manuallyby tilting the panel with the help of fine screw arrangement.REFERENCES[1] C. Hua and C. Shen (1998) Comparative study of peak power tracking techniques forsolar storage system’’, Applied Power Electronics Conference and Exposition, vol. 2, pp.679-685.[2] A. K. Saxena and V. Dutta (1990), “A versatile microprocessor based controller for solartracking’’, Photovoltaic Specialists Conference, vol. 2, pp. 1105-1109.[3] B. Koyuncu and K. Balasubramanian (1991), “A microprocessor controlled automatic suntracker’’, IEEE Transactions on Consumer Electronics, vol. 37, no. 4, pp. 913-917.[4] Md. Tanvir Arafat Khan, S. M. Shahrear Tanzil, Rifat Rahman, S M Shafiul Alam (2010)“Design and construction of an automatic solar tracking system”, international conference onelectrical and computer engineering, Dhaka, Bangladesh.[5] R. U. Rahman, D. I. Ahmed, M. A. Fahmi, T. Tasnuva M. F. Khan (2009), “Performance Enhancement of PV solar system by diffused refection”, Intl. Conf. on theDevelopments in Renewable Energy Technology, PP. 96-99.[6] WATTSON™ SOLAR TRACKER RETAIL PRICE AND DATA SHEET.[Online].Available: http://www.wattson.com/prices.html[7] “Microcontroller” datasheet. [Online] Available:http://www.microchip.com/downloads/en/devicedoc/ 39564c.pdf.[8] “L293D” datasheet. [Online]. Available: http://idmax.free.fr/Aide/stepper/i293.pdf[9] “LM317” datasheet. [Online]. Available:http://www.ee.baffalo.edu/courses/elab/LM117.pdf.[10] Neeraj Tiwari, D. Bhagwan Das and Prabal Pratap Singh, “Design, Development AndHardware Realization Of X-Beebased Single Axis Solar Tracking System” InternationalJournal of Electrical Engineering & Technology (IJEET), Volume 3, Issue 3, 2012,pp. 8 - 20, Published by IAEME 114