Design and Simulation of a Sun Tracking Solar Power System

Global energy consumption is dramatically increasing due to higher standard of living and the increasing world population. The world has limited fossil and oil resources. As a consequence, the need for renewable energy sources becomes more urgent. With the fast development of renewable energy technology, it proposes increasing demand for the higher education. This project is funded by the National Science Foundation Transforming Undergraduate Education in STEM (TUES) program from May 2012 to April 2015. As part of the objectives of the project, a sun tracking solar power system will be designed and developed as a teaching tool for the laboratory. This paper describes the design and simulation of a sun tracking solar power system. The simulation is realized on Matlab/Simulink platform. The simulation consists of four modules: solar tracking cells, signal conditioning circuit, controller, and motor. The simulation provides an excellent platform for undergraduate engineering technology students to study the design and theory of a sun tracking solar power system. Introduction The efficiency of the photovoltaic (PV) system depends on the climate conditions of solar radiation, ambient temperature and wind speed, matching of the system with the load and appropriate placement of the solar panels. A majority of solar panels in use today are stationary and therefore do not consistently output the maximum amount of power that they can actually produce. A solar tracker will track the sun throughout the day and adjust the angle of the solar panel to make the sun normal to the solar panels at all times. The orientation of the solar panels may increase the efficiency of the conversion system from 20% up to 50%. [1-3]. The sun tracking solar power system is a mechatronic system that integrates electrical and mechanical systems, and computer hardware and software. This paper describes the Matlab/Simulink simulation of a sun tracking solar power system. The simulation will be used for demonstration and experiments to help the students study theory of the system. The solar tracker follows the sun from east to west during the day. More energy is collected by controlling the solar panel to follow the sun like a sunflower. After simulation is complete, a physical system will be implemented. Design of a Sun Tracking Solar Power System The main components in the solar tracking system are standard photovoltaic solar panels (PV), a deep cycle rechargeable battery, battery charge controller, microcontroller, signal conditioning circuits, motor, and motor drive. The block diagram of the system is shown in Figure 1. Three solar panels are used. One main solar panel powers the system, and two low voltage tracking cells to obtain information on the sun angle. The main solar panel provides all the power for the system and charges the battery. The other two small tracking cells work as angle detectors. They are mounted on two 45 degree wedges to detect the exact angle in which the main solar panel must face to gain maximum power output. When the sun is perfectly normal, the voltages on both cells are equal, and solar panel stays in its position. However, if the main solar panel is not normal to the sun, the sun angles on the two small solar panels are different [4-6]. The microcontroller gives an output to the motor based on the difference of voltages to rotate the main solar panel to be normal to the sun.