IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> Fig. 5 <s> A new very simple, reliable solar tracker is described. The solar tracker is based on a new arrangement of auxiliary bifacial solar cell connected directly to D.C. motor. Auxiliary solar cells (panels) can both sense and provide energy for tracking. <s> BIB001 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> Fig. 5 <s> Solar tracking is used in large grid-connected photovoltaic plants to maximise solar radiation collection and, hence, to reduce the cost of delivered electricity. In particular, single vertical axis tracking, also called azimuth tracking, allows for energy gains up to 40%, compared with optimally tilted fully static arrays. This paper examines the theoretical aspects associated with the design of azimuth tracking, taking into account shadowing between different trackers and back-tracking features. Then, the practical design of the trackers installed at the 1.4 MW Tudela PV plant is presented and discussed. Finally, this tracking alternative is compared with the more conventional fully stationary approach. Copyright © 2002 John Wiley & Sons, Ltd. <s> BIB002 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> Fig. 5 <s> This paper shows the potential system benefits of simple tracking solar system using a stepper motor and light sensor. This method is increasing power collection efficiency by developing a device that tracks the sun to keep the panel at a right angle to its rays. A solar tracking system is designed, implemented and experimentally tested. The design details and the experimental results are shown. XTRACTING useable electricity from the sun was made possible by the discovery of the photoelectric mechanism and subsequent development of the solar cell - a semi- conductive material that converts visible light into a direct current. By using solar arrays, a series of solar cells electrically connected, a DC voltage is generated which can be physically used on a load. Solar arrays or panels are being used increasingly as efficiencies reach higher levels, and are especially popular in remote areas where placement of electricity lines is not economically viable. This alternative power source is continuously achieving greater popularity especially since the realisation of fossil fuel's shortcomings. Renewable energy in the form of electricity has been in use to some degree as long as 75 or 100 years ago. Sources such as Solar, Wind, Hydro and Geo- thermal have all been utilised with varying levels of success. The most widely used are hydro and wind power, with solar power being moderately used worldwide. This can be attributed to the relatively high cost of solar cells and their low conversion efficiency. Solar power is being heavily researched, and solar energy costs have now reached within a few cents per kW/h of other forms of electricity generation, and will drop further with new technologies such as titanium- oxide cells. With a peak laboratory efficiency of 32% and average efficiency of 15-20% (1-4) , it is necessary to recover as much energy as possible from a solar power system. This includes reducing inverter losses, storage losses, and light gathering losses. 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, and the closer to perpendicular, the greater the power (1-7). If a flat solar panel is mounted on <s> BIB003 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> Fig. 5 <s> paper presents the hardware design and implementation of a system that ensures a perpendicular profile of the solar panel with the sun in order to extract maximum energy falling on it. Renewable energy is rapidly gaining importance as an energy resource as fossil fuel prices fluctuate. The unique feature of the proposed system is that instead of taking the earth as its reference, it takes the sun as a guiding source. Its active sensors constantly monitor the sunlight and rotate the panel towards the direction where the intensity of sunlight is maximum. The light dependent resistor"s do the job of sensing the change in the position of the sun which is dealt by the respective change in the solar panel"s position by switching on and off the geared motor. The control circuit 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. With the implementation of the proposed system the additional energy generated is around 25% to 30% with very less consumption by the system itself. In this paper, an improvement in the hardware design of the existing solar energy collector system has been implemented in order to provide higher efficiency at lower cost. <s> BIB004 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> Fig. 5 <s> Abstract A new single-axis solar tracking device is designed and explored, which is able to lift and lower the photovoltaic panels. The photovoltaic panels can be tilted to east-west directions in the process of tracking the sun. In windy weather, the solar panels can be placed close to horizontal rail by using stent, which can minimize the frontal area. What's more, the mechanical strength of this device is better than traditional single-axis solar tracking system, so as to enhance wind resistance in windy weather. The device in this paper is suitable for PV power plants on building roofs because it can meet the strict requirements of wind resistance capacity and safety. <s> BIB005 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> Fig. 5 <s> Photovoltaic solar energy has been explored as an energy solution to the decline of energy production, as well as environmental concerns. However, generate electricity through the sun still considered uncompetitive freight to other sources, cause it presents low efficiency and high production cost. In attempt to make it more attractive from a financial point view, solar trackers has been used to increase the photovoltaic systems efficiency. Considering its facts, this paper aims to perform a comparative study between a static photovoltaic solar panel and a one-axis mobility panel, installed in the city of Mossoro/RN. The city in study is located in the Brazilian semiarid, under high solar radiation levels, in a dry climate and hot region, reaching high temperatures during the day. After assembly the proposed systems, were performed operating analysis and performance comparative study between the static and mobile systems, which allowed to conclude that the panel using the sun tracking showed a low average gain in power generated relative to the fixed panel to the region where the systems installed. <s> BIB006
Single-axis solar tracker  Tudorache and Kreindler  executed a single-axis solar tracking device for a photovoltaic conversion panel to assess its performance. The tracker has been designed by making use of two light sensors mounted normal to the panel separated by an opaque plate. Based on the difference in the detected signals, the movement of the solar panel is decided. This ensures that the panel moves for a significant change in light intensity preventing intermittent, frequent and unnecessary movements. It was concluded that the proposed design was advantageous when compared to fixed PV conversion panels. A single-axis solar tracking system with two small solar panels facing each other in a triangular setup was designed by Rizk and Chaiko BIB003 . The panel movement was dependent on the difference in the detected voltage from the small panels. A power increase of 30% was observed with respect to a fixed horizontal array. Saravanan, Panneerselvam and Christopher BIB004 designed a low cost tracking system that uses the sun as its guiding source instead of taking the earth as the reference. The panel movement was controlled by the circuit based on the signal received from the sensors. The proposed system was observed to attain an increase of 25 to 30% in energy conversion at low cost and minimum maintenance. Poulek and Libra BIB001 designed a solar tracker using a bifacial solar cell connected to a DC motor. The arrangement was made use of in bifacial solar arrays with the tracking panel perpendicular to the array. The effect of using a single-axis solar tracking system in large-grid connected photovoltaic plant was studied by Lorenzo et al BIB002 . The study was carried out in Tudela in a plant of capacity 1.4 MW. The tracking system was examined taking into account the effects of shadowing between the trackers and the back-tracking features. It was observed that azimuth tracking resulted in an increase in energy gain of up to 40% when compared with optimally tilted static arrays. Vieira et al BIB006 performed a comparative study between a static photovoltaic solar panel and a mobile panel fitted with single-axis solar tracker. The study was carried out in Mossoro, Brazil, near the equator where there is no large variation in the position of the sun throughout the day. The study showed an increase in the generated power in the mobile panel when compared to the static panel. Song et al BIB005 designed a single axis tracking device that lifts and lowers the photovoltaic panels based on the previously available data without the use of a sensing system. The proposed design consisted of a bidirectional sliding axle for solar azimuth tracking. Mounting of the panel on the slide way enabled the control of gravitational center of the panel. The design allowed the fixing of the panel horizontal to the building surface when strong winds were encountered. The simple assembling, easy installation on building, wind resistance and light weight of the system made it suitable for installation on roof-tops and for building integration.