IMPLEMENTATION OF SOLAR
TRACKING SYSTEM FOR MAXIMUM
POWER OUTPUT
S. B. SRIDEVI1, A.SAI SUNEEL2, K. NALINI3,
1,2,3 M.Tech., Faculty, Department of ECE, SE&T, SPMVV, Tirupati, India.
ABSTRACT- This paper shows the potential system benefits of simple tracking solar system Solar power generation had been used as a renewable energy since years ago. The main objective of this project is to present development of an automatic solar tracking system in which solar panels will keep aligned with the Sunlight in order to maximize in harvesting solar power and also to display the voltage generating from the solar panel. The system focuses on the controller design where the system is able to track the maximum intensity of Sunlight. When the intensity of Sunlight is decreasing, this system automatically changes its direction to get maximum intensity of Sunlight. LDR light detector acts as a sensor is used to trace the coordinate of the Sunlight by detecting brightness level of Sunlight. While to rotate the appropriate position of the panel, a DC motor is used. The system is controlled by a microcontroller as a main processor. This project is designed for low power and residential usage applications. From the hardware testing, the system is able to track and follow the Sunlight intensity in order to get maximum solar power at the output. This project is designed with AT89S52 Microcontroller unit. Depending upon the light falls on LDR the data will be read by the Microcontroller and the direction of the motor will be changed. With this direction the Solar panel which is attached to the motor also rotates to gain the maximum sun rays. A solar tracking system is designed, implemented and experimentally tested. The design details and the experimental results are shown.
Keywords-Renewable Energy, Power Optimization.
I INTRODUCTION
Most of the electricity in India comes from fossil fuels like coal, oil and natural gas. Today the demand of electricity in India is increasing and is already more than the production of electricity whereas the reserves
of the fossil fuel are depleting every day. We can feel this fact from the electricity-cuts during summer. Luckily sun throws so much energy over India, that if we can trap few minutes of solar energy falling over India we can provide India with electricity for whole year. Most parts of India get 7KWH/sq-meter of energy per day averaged over a year. The main aim of this project is to generate the maximum power from solar panel by continuously tracking the sun rays.The purpose of the project is to implement a system to continuously track the sun rays with the help of the solar panel and grasp the maximum power from the sun by rotating the solar panel according to the sun rays direction. In present situation everyone is facing the problem with power cuts which is creating very much trouble to the people. So, to solve this problem we have a solution that is the sun. By using sun radiation we can get power i.e., the solar energy using which we generate the power. There are so many renewable energy sources like solar, wind, geothermal etc. Solar energy system is very simple and easy to implement. But the main drawback of the solar tracking system is that it is very poor efficient system.
By using this project we can improve the efficiency of solar tracking system.In this system the solar panel will turn according to the sun rotation. The system focuses on the controller design where the system is able to track the maximum intensity of Sunlight. When the intensity of Sunlight is decreasing, this system automatically changes its direction to get maximum intensity of Sunlight. LDR light detector acts as a sensor is used to trace the coordinate of the Sunlight by detecting brightness level of Sunlight. While to rotate the appropriate position of the panel, a DC motor is used. The system is controlled by a microcontroller as a main processor. So by using DC motor we rotate the solar panel. Whenever the radiation of the sun falls on the solar panel it grasps the radiation and stores in it and it will send the message to the controller about its
power. Microcontroller will receive this information and display on LCD. From the hardware testing, the system is able to track and follow the Sunlight intensity in order to get maximum solar power at the output.
II OVERVIEW OF SOLAR TRACKERS
Solar tracker and the components which made up Solar Tracker. Solar cells are converters. They take energy from the sunlight and convert that energy into electricity. Most solar cells are made from silicon, which is a “semi-conductor” or a “semi-metal”. Solar cells are made by joining two types of semi-conducting material: P-type and N-type. At the atomic level, light consists of pure energy particles, called “photons”. The photons from the sun penetrate the solar cells. These photons knock electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. This process of converting light (photons) to electricity (voltage) is called the photovoltaic (PV) effect. Solar cells or PV cells rely on the photovoltaic effect to absorb the energy of the sun and generate electricity.
Fig 1: Photovoltaic technology
A solar panel is a collection of solar cells. To get the most power, solar panels have to be pointed directly at the Sun. The development of solar cell technology begins with 1839 research of French physicist
Antoine-Cesar Becquerel. He observed the
photovoltaic effect while experimenting with a solid electrode in an electrolyte solution. After that he saw a voltage developed when light fell upon the electrode.
Crystalline silicon and gallium arsenide are typical choices of materials for solar panels. Gallium arsenide crystals are grown especially for photovoltaic use, but silicon crystals are available in less-expensive standard ingots, which are produced mainly for
consumption in the microelectronics industry.
Norway’s Renewable Energy Corporation (REC) has confirmed that it will build a solar manufacturing plant in Singapore by 2010 - the largest in the world. This plant will be able to produce products that can generate up to 1.5 Gigawatt (GW) of energy every year. That is enough to power several million households at any one time. A solar tracker is a device onto which solar panels are fitted which tracks the motion of the sun across the sky ensuring that the maximum amount of sunlight strikes the panels throughout the day.
III PROPOSED METHOD-
MICROCONTROLLER BASED SOLAR
TRACKER
In the microcontroller based solar tracker systems, a controller is connected to DC motors. Usually for monitoring the power generation, they also connected this tracking device to a PC by a code written in Assembly or Embedded C language. In this solar tracker design, sensors are used. For example, a light sensor or photo sensor called light-dependent resistor (LDR) to indicate the intensity of the radiation (that changes its electrical resistance from several thousand Ohms in the dark to only a few hundred Ohms when light falls upon it). The signals were then captured by the microcontroller that provides a signal to the motors to rotate the panel in order to track the solar energy for maximum power output. Hence, the main difference between the active trackers is the ability to reduce the pointing error using external sensors, thereby increasing the daily irradiation the solar cells receive and the electric energy that they produced. A comparative study shows that, the power consumption by the tracking device is only 2-3 % of the increased energy. The annual energy available to the two axis tracker was 72% higher than a fixed surface and 30% for single axis East-to-West tracker.
IV COMPARISION OF EXISTED METHODS AND PROPOSED METHOD
EXISTED METHOD PROPOSED
METHOD
Solar panels are fixed
The system can’t
automatically change its
direction to get maximum power at output.
Low efficiency
Accuracy is less.
The available annual
energy to fixed trackers is considerably low. Movable Solar panels. The system automatically changes its direction to get maximum power at output. High efficiency Highly accurate. The annual energy available to the automatic tracker is 72% higher.
Table I : Comparision of existed and proposed methods
The block diagram description of the automatic solar tracking system is
presented.
Fig 2: Block Diagram of automatic solar tracker system
AT89S52 is 8-bit microcontroller from Atmel Semiconductors. This comes into 8051 family microcontroller. This is the heart of the project. The complete control logic program is stored in this microcontroller. It sends and receives control and data signals to LCD, Stepper motor and to the other Devices based on the program logic.ADC0808 receives the analog output from LDRs and solar panel. It converts them to digital form. These digital signals are given to the microcontroller. SOLAR PANEL is a photo voltaic cell and this converts light energy into electrical energy. The output voltage of the solar panel depends on the amount of light falling on the panel. LDR SENSORS- This is a light dependent resistor. The resistance of the device is inversely proportional to the amount of light falling on its surface. If light falls on the device, its resistance drops dramatically resulting in electron flow. LDRs are used as light
sensors. L293D MOTOR DRIVER -L293D Driver
compares the LDR values and the motor is rotated accordingly. The solar panel that is attached to the motor will be rotated according to the direction of motor.
DC MOTOR-The DC motor is used to rotate the solar panel. The DC motor makes actual and exact number of turns or degrees of rotation instructed by the microcontroller. LIQUID CRYSTAL DISPLAY-16 X 2 LCD is used to display the status of the output. HD44780U is used in the project. A single HD44780U can display up to one 8-character line or two 8-character lines. The HD44780U has pin function compatibility with the HD44780S which allows the user to easily replace an LCD-II with an HD44780U. The HD44780U character generator ROM is extended to generate 208 5X8 dot character fonts and 32 5X10 dot character fonts for a total of
240 different character fonts. CRYSTAL
OSCILLATOR-
A crystal is used to supply clock
frequency to the microcontroller. The clock
frequency is 11.0592MHz. 11.0592 MHz
crystals are often used because it can be divided
to give you exact clock rates for most of the
common baud rates.
POWER SUPPLY- This project needs 5V regulated DC power supply. This power supply is built with a full wave bridge rectifier, C- filter and a three terminal voltage regulator. An LED is provided for visual identification of the power supply. 230V / 12V step down transformer is used to step down the AC 230 V to 12V AC.TRACKING PRINCIPLE
An automated solar tracker allows the panel to
perform an approximate 3-dimensional (3-D)
hemispheroidal rotation to track the sun’s movement during the day in order to maximize in harvesting solar power. Light gathering is dependent on the angle of incidence of the light source providing power (i.e. the sun) to the solar cell’s surface. Day sunlight will have an angle of incidence close to 90°in the morning and the evening. At such an angle, the light gathering ability of the cell is essentially zero, resulting in no output. As the day progresses to midday, the angle of incidence approaches 0°, causing a steady increase in power until at the point where the light incident on the panel is closer to perpendicular and maximum power is achieved. From this background, we see the need to maintain the maximum power output from the panel by maintaining an angle of incidence as close to 0° as possible. By tilting the solar panel to continuously face the sun, this can be achieved. This process of sensing and following the position of the sun is known as Solar Tracking.Two LDR light detectors act as sensors to trace the coordinate of the Sunlight by detecting brightness level of Sunlight.
When LDR1 has higher light intensity than LDR2 then the resistance of LDR1 is smaller than that of LDR2 then voltage at CH-1 is higher than that of CH-2 and the DC motor rotates the solar panel in the counter clockwise direction.
When LDR2 has higher light intensity than LDR1 then the resistance of LDR1 is larger than that of LDR2 then voltage at CH-1 is smaller than that of CH-2 and the DC motor rotates the solar panel in the clockwise direction.
The stable position is when the two LDRs having the same light intensity
The system is controlled by a microcontroller as the main processor. When the intensity of Sunlight is decreasing, this system automatically changes its direction to get maximum intensity of Sunlight and generate maximum power at the output.
FLOW CHART
Fig 3: Flow chart of solar tracking system
5.1 FLOW CHART DESCRIPTION
The process of sensing and following the position of the sun is known as Solar Tracking.Two LDR light detectors act as sensors to trace the coordinate of the Sunlight by detecting brightness level of Sunlight.The system reads the LDR signals and sends them to the Analog-to-Digital converter.
The Analog-to-Digital converter converts
these analog signals to digital form.
The digitally converted signals are then
compared by the L293D motor driver and the DC motor is rotated accordingly.
When LDR1 has higher light intensity than
LDR2 then the resistance of LDR1 is smaller than that of LDR2 then voltage at CH-1 is higher than that of CH-2 and the DC motor rotates the solar panel in the counter clockwise direction.
When LDR2 has higher light intensity than LDR1 then the resistance of LDR1 is larger than that of LDR2 then voltage at CH-1 is smaller than that of CH-2 and the DC motor rotates the solar panel in the clockwise direction.
The stable position is when the two LDRs having the
samelightintensity.
The system is controlled by a microcontroller as the main processor. When the intensity of Sunlight is decreasing, this system automatically changes its direction to get maximum intensity of Sunlight and generate maximum power at the output.
IMPLEMENTATION USING KEIL
SOFTWARE
Keil compiler is a software used where the machine language code is written and compiled. After compilation, the machine source code is converted into hex code which is to be dumped into the microcontroller for further processing. Keil compiler also supports C language code.
INTRODUCTION TO KEIL SOFTWARE
ABOUT KEIL:
1. Click on the Keil u Vision4 Icon on Desktop
2. The following figure will appear
3. Click on the Project menu from the title bar
4. Then Click on New Project
5. Save the Project by typing suitable project name with no extension in our own folder sited in either C:\ or D:\
6. Then Click on save button above
7. Select AT89S52
8. Then Click on “OK”
9. The following window will appear
10. Then Click either YES or NO………mostly
“NO”
11. Now our project is ready to USE
12. Now double click on the Target1, we would
get another option “Source group 1”
13. Click on the file option from menu bar and select “new”
14. Now start writing program in either in “C” or “ASM”
15. For a program written in Assembly, then
save it with extension “. asm” and for “C” based program save it with extension “ .C”
16. Now right click on Source group 1 and click
on “Add files to Group Source”
17. Now Press function key F7 to compile. Any
error will appear if so happen.
18. If the file contains no error, then press
Control+F5 simultaneously.
20. Then Click “OK”
21. Now Click on the Peripherals from menu bar,
and check required port
22. Drag the port a side and click in the program
file.Now keep Pressing function key “F11” slowly and observe. We are running program successfully
PROLOAD
Proload is software which accepts only hex files. Once the machine code is converted into hex code, that hex code has to be dumped into the microcontroller placed in the programmer kit and this is done by the Proload. Programmer kit contains a microcontroller on it other than the one which is to be programmed. This microcontroller has a program in it written in such a way that it accepts the hex file from the keil compiler and dumps this hex file into the microcontroller which is to be programmed. As this programmer kit requires power supply to be operated, this power supply is given from the power supply circuit designed above. It should be noted that this programmer kit contains a power supply section in the board itself but in order to switch on that power supply, a source is required. Thus this is accomplished from the power supply board with an output of 12volts or from an adapter connected to 230 V AC.
STEPS TO WORK WITH PROLOAD
1. Install the Proload Software in the PC.
2. Now connect the Programmer kit to the PC
(CPU) through serial cable.
3. Power up the programmer kit from the ac supply
through adapter.
4. Now place the microcontroller in the GIF socket
provided in the programmer kit.
5. Click on the proload icon in the PC. A window appears providing the information like Hardware model, com port, device type, Flash size etc. Click on browse option to select the hex file to be dumped into the microcontroller and then click on “Auto program” to program the microcontroller with that particular hex file. 6. The status of the microcontroller can be seen in
the small status window in the bottom of the page.
7. After this process is completed, remove the
microcontroller from the programmer kit and place it in your system board. Now the system board behaves according to the program written in the microcontroller.
V RESULT ANALYSIS
The data of voltage received from static solar panel and solar tracking system for a day is shown in table II below. From static solar panel, maximum voltage obtained is 1.13 Volt. Meanwhile, from solar tracking system, maximum voltage obtained is 2.00 Volts.
Hours From static solar panel From solar tracking system CH-1 CH-2 VOLTS CH-1 CH-2 VOLTS 07: 30 AM 008 010 0.00 101 004 0.30 08: 30 AM 009 009 0.00 110 004 0.90 10: 30 AM 009 009 0.00 098 008 1.60 11: 10 AM 010 010 1.00 255 179 2.00 02: 00 PM 010 010 1.13 028 110 1.52 05: 30 PM 009 009 0.00 035 103 0.80
Table II: Data from solar panel during hardware testing
The comparison of electric power
characteristic curves from static solar panel and solar tracking system is shown in Figure 7.1. It shows that solar tracking system is able to receive more Sunlight and consequently generate more power as compared to static solar panel.
Fig 5: Electric Power Vs Hours characteristic curve – comparison between static solar panel and solar tracking system.
Fig 6: Solar street lights
CONCLUSION
Single Axis Solar Tracking System prototype model is successfully developed. The designed system is
focuses on designing controller part and the main concern is to design appropriate circuits and the circuits suppose to be able to control DC motor rotation direction.The system is able to track and follow Sunlight intensity in order to collect maximum solar power.In terms of cost per Watt of the completed solar system, it is usually cheaper (for all but the smallest solar installations) to use a solar tracker and less solar panels where space and planning permit. A good solar tracker can typically lead to an increase in
electricity generation capacity of 30-50%.The
constructed system model can be applied in the residential area for alternative electricity generation especially for non-critical and low power appliances.
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