Ali Durusu

A New MPPT Algorithm for Vehicle Integrated Solar Energy System

Photovoltaic (PV) systems are considered as a support unit and eco-friendly energy source for the electric vehicles. If the surface of the electric vehicle is covered by PV cells, it is possible to store considerable amount of energy in the battery system. In this study, different maximum power point trackers (MPPT) with different maximum power point (MPP) tracking algorithms have been tested on a PV structure moving according to a predefined motion loop. Compatibility of each algorithm to moving systems, such as electric vehicles, is presented in a real experimental environment. As a result of these experiments, positive factors in each algorithm have been defined and a new MPP tracking algorithm convenient for moving vehicle has been proposed. The proposed MPPT algorithm shows a better performance than other MPPT algorithms under fast varying radiations. However, proposed algorithm brings slightly higher costs compared to usage of other MPPT algorithms since it requires the measurement of solar irradiance. The developed algorithm is described in detail and comparative analysis and performance evaluation with other algorithms are presented. Autor Nakir, Ismail; Durusu, Ali; Akca, Hakan; Ajder, Ali; Ayaz, Ramazan; Ugur, Enes; Tanrioven, Mugdesem Quelle Transactions of the ASME, Journal of Energy Resources Technology * Band 138 (2016) Heft 2, Seite 021601/1-9 (9 Seiten)

Photovoltaic System: Case Studies

Solar energy is one of the most important energy, which is environmentally friendly such as clean, inexhaustible and free, among the renewable energy sources. Studies on solar photovoltaic (PV) energy generation system were promoted in last two decades. The main application of PV systems are in stand-alone (water pumping, lighting, electrical vehicle, etc.), hybrid and grid-connected (PV power plants) configuration. Stand-alone PV power generation system is considered as good alternative for places that are far from conventional power generation/transmission/distribution system. PV generation systems have two big problems; PV conversion efficiency is very low and PV electricity generation is effected from changing of weather condition. PV output varies periodically in a year and in a day, and is not stable due to environmental condition. Accordingly, in order to increase PV output and PV efficiency, it is crucial to analyze PV output considering solar radiation, temperature, wind speed, shadow, etc. Maximum power point trackers (MPPTs) are employed for extracting power from photovoltaic (PV) panels. MPPTs enforce the solar modules to operate at maximum power point (MPP) under the fluctuations of ambient conditions. Therefore, they take a vital role for increasing of PV system efficiency. In this part, the case studies of MPPT system, which includes stand-alone and hybrid PV systems, will be briefly reviewed, followed by discussion of the MPPT modeling, design, etc. Several stand-alone and hybrid MPPT application will be presented. Latest developments in MPPT methods will be summarized. Finally some of the present challenges facing the MPPT techniques will be explored.

Thermal management of power LED system

LEDs are used in many areas today. Street lighting is one of them and high-power LEDs are utilized in this area. Electrical energy is converted into light with an efficiency in 10-25% range. The rest is converted into heat. The generated heat is largely caused from LED chip. Furthermore, Driver circuit would also causes heat rise. Removing of this heat from the system is important in order to LED system efficiency because increasing of temperature causes a reduction of luminous flux. Excellent thermal management plays a significant role in terms of efficiency, reliability and durability. In this study, losses are caused from the LED chip and the heat sink which are part of the LED lighting systems are examined. These elements are thermally analyzed. The impacts of these losses on efficiency will be presented.