Abstract- Energy development is the on-going attempt to supply abundant and accessible energy. through cognition. accomplishments and buildings. Solar energy is quickly progressing as an of import agencies of renewable energy resource. More energy is produced by tracking the solar panel to stay aligned to the Sun at a right angle to the beams of visible radiation. This paper attempts to depict in item the design and paradigm for solar trailing system. The solar trailing system is designed and built utilizing a simple mechanical construction utilizing with a stepper motor. visible radiation detector and a control method. The control circuit for the solar tracker is based on a PIC16F877A microcontroller ( MCU ) . This is programmed to observe the sunshine through the Light detector and so trip the motor to place the solar panel where it can have maximal sunshine.
Keywords: PIC. MCU. Solar energy. Light detector. Renewable energy.
The universe tendency nowadays is to happen a non-depletable and clean beginning of energy. Non-renewable energy. obtained from exhaustible fossil fuels. is no more satisfactory to many states. Not merely the resources ( coal. oil & A ; natural gas ) are capable to be badly reduced. but besides they are considered to be non-secure ; wars and political relations afflict its handiness and cost. Furthermore many environmental organisations address this energy production strategy as the chief subscriber to pollution and planetary heating. For a long clip. it has been thought that atomic energy would be a solution for the turning energy job. but in recent times solar energy has proved to be an efficient. more secure and safe manner of supplying energy. Concepts related to the solar energy have invariably been under heavy research and development.
The basic aim is to optimise the energy produced from photovoltaic cells. by doing the overall systems more efficient and cost effectual. Most solar panels are statically aligned. They have a fixed place at a certain angle towards the sky. Therefore. the clip and strength of direct sunshine falling upon the solar panel is greatly reduced. ensuing in low power end product from the photovoltaic ( PV ) cells. From this background. we see the demand to keep the maximal power end product from the panel by keeping an angle of incidence as stopping point to 0° as possible. By leaning the solar panel to continuously confront the Sun. this can be achieved. This procedure of feeling and following the place of the Sun is known as Solar Tracking system.
II. SYSTEM OVERVIEW
The design of Solar Tracker is to develop and implement a simplified diagram of a horizontal-axis and active tracker method type of solar tracker fitted to a solar panel. A solar panel along with the way of sunshine ; it uses a gear motor to command the place of the solar panel. which obtains its informations from a PIC16F877A microcontroller. Two light dependent resistances ( LDR ) are used for each grade of freedom. LDRs are fundamentally photoelectric cells that are sensitive to light. Software will be developed which would let the PIC to observe and obtain its informations from the two LDRs and so compare their opposition. The two LDRs will be positioned in such a manner. so that if one of the two comes under a shadow. the MCU will observe the difference in opposition and therefore trip the hoofer motor to travel the solar panel at a place where the light upon both LDRs are equal. A simple mechanical construction has been constructed for this by utilizing aluminium channel. Power MOSFET has been to plan the driver circuit of stepper motor. A 12V lead Acid battery has been used to power up the motor and shop the energy from solar panel. Charge accountant control the charging of hitter. Figure 1 shows the block diagram representation of the tracking system under design.
Figure 1: Overview of the Complete System
III. MECHANICAL STRUCTURE
Before planing the mechanical construction for solar trailing system it is of import to choose an appropriate method of alliance. There are two possible methods of alining the solar panel. The mechanical construction of a solar trailing system lot more depend on proper alliance of solar panel. The first method involves. leaning the solar panel in two axes to keep the coveted place and the 2nd method involves revolving and leaning. Since it is individual axis tracking system so the first method implemented. A CAD drawing of this construction has been done utilizing AUTOCAD 2010 package. Figure 1 shows the design of the mechanical construction.
Figure 2: Mechanical Structure Design.
The hardware construction of this solar trailing system designed used solar panel. five Aluminium Bars. hoofer motor. metal L form home base for repairing the Aluminium bars with one another. bracket and cogwheel for keeping the solar panel by motor shaft and prison guards.
IV. STEPPER MOTOR
A stepper motor is an electromechanical device which converts electrical pulsations into mechanical motions. The shaft or spindle of a stepper motor rotates in distinct measure increases when electrical bid pulsations are applied to it in the proper sequence. The motors rotary motion has several direct relationships to these applied input pulsations. A 12V 6 lead wires 1. 8°unipolar intercrossed hoofer motor has been used for this solar trailing system undertaking. The motor has been chiefly chosen depending on the weight of the solar panel and keeping torsion.
Figure 3: Stepper Motor.
V. LIGHT SENSOR THEORY
A light detector is the most common electronic constituent which can be easy found. The simplest 1 is LDR. There are two LDR used for this trailing system undertaking. If light falling on the device is of the high adequate frequence. photons absorbed by the semiconducting material give edge negatrons plenty energy to leap into the conductivity set. The ensuing free negatrons conduct electricity. thereby take downing opposition. Hence. Light Dependent Resistors ( LDR ) is really utile in light detector circuits. LDR is really high-resistance. sometimes every bit high as 1000 000? . when they are illuminated with light opposition beads dramatically. Two electromotive force splitter circuits have been developed and the end product of these two circuits has given the signal two microcontrollers. The microcontroller will observe and obtain informations from two LDR by comparing their opposition.
VI. TRACKING CONTROLLER ALGORITHM
A tracking accountant scheduling has been developed by utilizing C linguistic communication. The MPLAB IDE has been used to compose the codification for the tracking accountant circuit. The parallel to digital transition ( ADC ) characteristic has been used to embedded the codification. The light detector will supply the parallel signal to the PIC and the PIC will change over the linear signal to digital signal to probide pulse in stepper motor. A PIC16F877A MCU has been embeded for this undertaking. It has five input/output PORTS with 40 pins. It has 256 byte memory.
Figure 4: PIC Pin Configurations.
The flow chart of the tracking accountant algorithm has shown below figure 5.
Figure 5: Flow chart of PIC Program Code.
VII. TRACKING CONTROLLER CIRCUIT
A microcontroller based tracking accountant circuit has been designed and implemented in this undertaking. The chief constituents of this tracking accountant circuit are PIC165877A. PC817. N channel power Mosfet IRF830. rectifying tube 1N4148. oscillator. A electromotive force supply of 12V is applied to the circuit which is so passed through a 5V electromotive force regulator. The regulated electromotive force is so supplied to the PIC. The end product which drives the motor is obtained from port RB0 to RB3. MCLR reset input port is besides connected to 5V supply. The external clock determines MCU cardinal operating features ; therefore it needs to be selected sagely. A 20Mhz oscillator clock was selected.
Figure 6: Schematic of Tracking Controller Circuit.
To drive the stepper motor four power MOSFET has been used with 1N4148 rectifying tubes. This MOSFET has chosen because it is capable to manage high current and the rectifying tubes used to take the spikes during the switchin of transistor.
VIII. CHARGE CONTROLLER CIRCUIT.
The charge accountant is designed to command bear downing storage battery. Its map is to modulate the power fluxing from a photovoltaic panel into a rechargeable battery. It features easy apparatus with one potentiometer for the float electromotive force accommodation. an equalize map for periodic overcharging. and automatic temperature compensation for better battery charging over a broad scope of temperatures. The control is fundamentally to protect the battery from over charge or electromotive force.
Figure 7: Schematic of Battery Charge Controller.
Figure 8: Complete Structure of Tracking System.
The visible radiation detector has been positioned top of the PV panel. The detectors are mounted inside a plastic box and a splitter has given in between two detectors. This has been done because the LDR is excessively light sensitive. In given figure shows the detector place.
Figure 9: Sensor Position.
Ten. RESULTS AND DISCUSSION
Time| PV Output Power|
9. 00 am| 5. 01W|
10. 00am| 6. 46W|
11. 00am| 7. 47W|
12. 00pm| 8. 67W|
01. 00pm| 9. 53W|
02. 00pm| 9. 57W|
03. 00pm| 8. 11W|
04. 00pm| 7. 00W|
05. 00pm| 4. 01W|
06. 00pm| 3. 32W|
Figure 10: Fixed System Data.
Time| PV Output Power|
9. 00 am| 6. 03W|
10. 00am| 7. 11W|
11. 00am| 8. 13. W|
12. 00pm| 9. 47W|
01. 00pm| 9. 53W|
02. 00pm| 9. 57W|
03. 00pm| 9. 01W|
04. 00pm| 7. 00W|
05. 00pm| 3. 88W|
06. 00pm| 3. 14W|
Figure 11: Trailing System Data.
Figure 12: A compareable graph between tracking and fixed system. If we observed the fixed system value and tracking system value the tracking system generated more power than the fixed system until 3pm. Normally after 2 pm the Sun light becomes low down. As a consequence power besides becomes low. But after 3pm the trailing system generated power became less than fixed system values. This is happened because conditions alteration. The sky covered by cloud thatis why the generated power became low for those peculiar hours. The power distribution graph is plotted against the 9am-5pm period as shown in below figure.
A solar tracker was proposed. designed and constructed. The system has been tested under the Sun and overall efficiency besides observed comparing with fixed PV system. The system is rather efficient and the consequences are quotable. The system has some restrictions with the mechanical construction and tilting of PV panel. By using the double axis tracking system and improved mechanical construction will be able to supply more efficient consequence in hereafter.
[ 1 ] A. A. Khalil. M. El-Singaby. “Position control of Sun tracking system” . Proceedings of the 46th IEEE International Midwest Symposium. Vol. 3. December 27-30. 2003. pp. 1134 – 1137.
[ 2 ] B. Amrouche. M. Belhamel and A. Guessoum. “Maximum Power Point Tracking Acceleration by utilizing Modified P & A ; O Method for Photovoltaic Systems. ” Second International Congress on Environment and Renewable Energies. Mahdia. Tunisia. 6-8 November 2006.
[ 3 ] Joao M. G. Figueiredo. Jose M. G. Sa district attorney Costa. “Intelligent Sun-Tracking System for Efficiency Maximization of Photovoltaic Energy Production” . IDMEC-IST – Technical University Lisbon. Portugal
[ 4 ] M. A. Ghias. K. S. Karimov. S. I. A. Termizi. M. J. Mughal. M. A. Saqib. I. H. Kazmi. “A Photo-Voltaic System with Load Control” . ICEE07. April 11-12. 2007. Int. Conference on Elect. Engineering.
[ 5 ] J. Rizk. and Y. Chaiko. “Solar Tracking System: More Efficient Use of Solar Panels. ” World Academy od Science and Technology 41. 2008.
[ 6 ] Benjamin C. Kuo “Theory and Application of Stepper Motor. ” University of Illinois at Urbana-Champaign.
[ 7 ] Iovine John. PIC Microcontroller Project Book 2nd Edition. Singapore: Mc Graw-Hill. 121-123 ; 2000.