26-11-2012, 12:06 PM
5A Design of Low Power Single Axis Solar Tracking System Regardless of Motor Speed
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Abstract:
Solar power generation had been used as a renewable energy since years ago. Residential that uses solar power as their alternative power supply will bring benefits to them. The main objective of this paper is to present development of an automatic solar tracking system whereby the system will caused solar panels will keep aligned with the Sunlight in order to maximize in harvesting solar power. The system focuses on the controller design whereby it will caused the system is able to tracks the maximum intensity of Sunlight is hit. 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-geared motor is used. The system is controlled by two relays as a DC-geared motor driver and a microcontroller as a main processor. This project is covered for a single axis and 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 regardless motor speed.
Introduction
In last ten years, many of residentials around the world used electric solar system as a sub power at their houses. This is because solar energy is an unlimited energy resource, set to become increasingly important in the longer term, for providing electricity and heat energy to the user. Solar energy also has the potential to be the major energy supply in the future. Solar tracker is an automated solar panel that actually follows the Sun to increase the power [3]. The sun's position in the sky varies both with equipment over any fixed position. One well-known type of solar tracker is the heliostat, a movable mirror that reflects the moving sun to a fixed location, but many other approaches are used as well. Active trackers use motors and gear trains to direct the tracker as commanded by a controller responding to the solar direction. The solar tracker can be used for several application such as solar cells, solar day-lighting system and solar thermal arrays [1]. The solar tracker is very useful for device that needs more sunlight for higher efficiency such as solar cell.
Results and Analysis
The system is focusing on the controller design. The constructed system has been tested and some data from hardware measurement have been collected and discussed. Typical solar panel has been used and the purpose only to prove the designed system is able to operate accordingly. Therefore the surrounding effects, for instance, weather condition are not seriously considered during hardware testing.
Reading Data From Solar Panel During Hardware Testing
Table 5 shows the data of voltage, current and power received from static solar panel and solar tracking system for a day. From static solar panel, maximum voltage, current and power is 21.1 V, 5.94 mA and 125.334 mW respectively. Meanwhile, from solar tracking system, maximum voltage, current and power is 21.6 V, 6.35 mA and 137.160 mW respectively. Figure 8 shows the comparison of electric power characteristic curves from static solar panel and solar tracking system. It shows that solar tracking system is able to receive more Sunlight and consequently generate more power as compared to static solar panel.
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-gear motor rotation direction without considering motor speed. The system is able to track and follow Sunlight intensity in order to collect maximum solar power regardless of motor speed. The unique of developed system, motor speed is not critical consideration because the DC-geared motor offers low output rated speed and high output rated torque. Therefore any types of DC-geared motor can be used for this system regardless of motor speed controller unit as long as the speed and torque of the motor are following the given specification. The constructed system model can be applied in the residential area for alternative electricity generation especially for non-critical and low power appliances.