08-03-2015, 09:28 PM
ABSTRACT: Solar energy systems have emerged as a viable source of renewable energy over the past two or three decades, and are now widely used for a variety of industrial and domestic applications. Such systems are based on a solar collector, designed to collect the sun’s energy and to convert it into either electrical power or thermal energy. In general, the power developed in such applications depends fundamentally upon the amount of solar energy captured by the collector, and thus the problem of developing tracking schemes capable of following the trajectory of the sun throughout the course of the day on a year. This project is designed with ARM7TDMI processor. The ARM7TDMI processor does the job of fetching the input from the sensor and gives command to the motor to run in order to tackle the change in the position of the sun. Keywords: Solar collector, Light Dependent Resistor (LDR), ARM7TDMI processor. I. INTRODUCTION Solar energy is the energy extracted from the rays issued from the sun in the form of heat and electricity. This energy is essential for all life on Earth. It is a renewable resource that is clean, economical, and less pollution compared to other resources and energy. Therefore, solar energy is rapidly gaining notoriety as an important means of expanding renewable energy resources. As such, it is vital that those in engineering fields understand the technologies associated with this area. Our paper includes the design and implementation of a microcontroller-based solar tracking system. Solar tracking allows more energy to be produced because the solar panel is tracking the maximum power point of the sun’s position. To get an efficient solar tracker system, a small solar panel is used instead of a large one to obtain a graphical position data of the sun when it is detected and send this data to the large panels. This system can be installed anywhere in the world without knowing the sun directions and seasons. II. SOLAR SYSTEM TRACKER A solar tracker is an electro-mechanical system used on behalf of orienting a solar photovoltaic panel in the direction of the sun. It is used in many applications such as the transportation signaling, lighthouses, emergency phones installed in the highways, etc… Its main objective is to find the maximum sun radiations in order to get maximum charge for the batteries. Electricity can be generated from the sun in several ways. Photovoltaic’s (PV) has been mainly developed for small and medium-sized applications, from the calculator powered by a single solar cell to the PV power plant. For large -scale generation, concentrating solar thermal power plants have been more common, however new multi-megawatt PV plants have been built recently. A photovoltaic cell (PV cell) is a specialized semiconductor that converts visible light into direct current (DC). Some PV cells can produce DC electricity from infrared (IR) or ultraviolet (UV) radiation. Photovoltaic cells are an integral part of solar-electric energy systems, which are becoming increasingly important as alternative sources of power utility. Solar cells generate DC electricity from light, which in turn can be used in many applications such as: charging batteries, powering equipment, etc. They produce currents as long as light shines, as shown in Fig.1. Figure1. block diagram of the solar energy system The detection of the position of the sun undergoes several steps as shown in Fig.2. A digital system (LPC2148) is used to calculate the maximum sun radiation. It is connected to a stepper motor and to light dependent resistors to redirect the panel to the sun. It sends the received data (position of the sun) to the stepper motors in order to position it toward the sun. The position angles are stored in the processor registers and can be displayed on an LCD or can be transmitted to a remote system. Figure2. block diagram of the solar tracker 2.1 Solar Tracker A solar tracker is an electro-mechanical device for orienting a solar photovoltaic panel toward the sun trackers, especially in solar cell applications require a high degree of accuracy to ensure that the concentrated sunlight is directed precisely to the powered device. Solar trackers can be active or passive and may
