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Öğe A Comparison of Perturb and Observe and fuzzy-logic based MPPT methods for uniform environment conditions(International University of Sarajevo, 2017) Kandemir E.; Cetin N.S.; Borekci S.The power generation from photovoltaic (PV) system is not constant and it varies based on solar irradiance and temperature. For any environmental condition, to convert maximum available solar energy, PV systems must be operated at maximum power point. To accomplish that two different maximum power point tracking (MPPT) methods have been presented in this study. The first method can determine MPP point by measuring the derivative of PV cell power (dP) and PV cell voltage (dV) which is called Perturb & Observe (P & O) method. The second method uses fuzzy-logic-control (FLC) based MPPT method to determine MPP point for actual environment conditions. In this paper, 3kW PV system model is studied in MATLAB. According to the simulated results, FLC based MPPT method has better performance than P & O method. Compared to the P & O method, FLC-based MPPT can increase tracking accuracy and efficiency performance 0.13% under standard test conditions (STC).Öğe Conventional and soft-computing based MPPT methods comparisons in direct and indirect modes for single stage PV systems(Kauno Technologijos Universitetas, 2018) Kandemir E.; Borekci S.; Cetin N.S.Improving power efficiency for a Photovoltaic (PV) system becomes important issue for researchers. To achieve maximum power extraction from PV panels, different kinds of Maximum Power Point Tracking (MPPT) methods have been investigating in the literature. In all techniques, direct and indirect mode approaches can be implemented. Based on the physical application of the PV system under different condition, the efficiency and convergence speed become important. In this paper, a grid connected simple single stage PV system by using different MPPT methods in direct and indirect modes has been analysed to find out the best mode and technique for a specific PV system application. Three of the most preferred MPPT algorithms: the perturb & observe (P&O), incremental conductance (Inc. Cond.) and fuzzy logic control (FLC) have been performed in MATLAB Simulink and compared their performance in direct and indirect modes in terms of convergence speed and tracking accuracy by the proposed single stage PV system. The results show that direct mode MPPTs have better tracking accuracy but less convergence speed than indirect MPPTs. Therefore, indirect mode MPPTs present better performance for the rapid atmospheric changing applications. Additionally, FLC based MPPT exhibits almost best tracking performance for direct and indirect modes. © 2018 Kauno Technologijos Universitetas. All rights reserved.Öğe A FPGA simulation and implementation of a wind energy conversion system(2011) Toker K.A.; Cetin N.S.A novel approach for development of FPGA-based wind turbine control system used in isolated network in a simulation environment was proposed. The software tools in simulation environments, related design procedure and system architecture were presented. Our proposed FPGA-Field-Programmable Gate Array-based wind turbine controller receives external sensor inputs according to the operating conditions, the wind conditions and the operator's intentions. The controller also monitors operating conditions and functional sequences and makes quick, pipelined decisions. In this paper the application of FPGA for the wind turbine control is described and simulation results are presented. © 2011 IEEE.Öğe Investigation of Horizontal Solar Radiation Data Source in the World(Institute of Electrical and Electronics Engineers Inc., 2020) Bawazir R.O.; Cetin N.S.Photovoltaic (PV) power is the third global power capacity used after hydro and wind. Even though solar energy is abundant and within reach, this energy assessment confronts a big challenge in terms of obtaining measured data due to the limited and unevenly distributed ground-based meteorological stations. To overcome this issue, many studies resort to other sources of radiometric data. Some of the sources are based on satellites. As a result, there is a disagreement of readings compared with ground-based meteorological stations. Therefore, this paper attempts to mitigate the differences by proposing the nearest source compared to measured data. Four different sources (NASA POWER, PVGIS 5, Meteonorm software, and hybrid-based average data) are investigated. The measured data of stations is used as a reference in this study which has been collected from the World Radiation Data Centre (WRDC). The comparative study is made based on monthly average horizontal solar radiation using statistical methods for five continents. Twenty-eight distributed locations are examined. Based on the Global Performance Indicator (GPI), Meteonorm is a suitable data source for Asia and South American continents. In Africa, Europe, and North American continents, the solar radiation source depends on the target location. © 2020 IEEE.Öğe Neural prediction of power factor in wind turbines(2007) Ata R.; Cetin N.S.The power generated by wind turbines depends on several factors. One of them is the power factor also known as blade efficiency. In this study, the power factor is predicted using Artificial Neural Networks (ANN) and comparisons made with conventional model approach for the selected turbine profiles mostly used in practice. The study has shown that the prediction of power factors from seven input parameters by ANN yields better results than those of the conventional model.Öğe Stress analysis of shape memory alloys used in wind turbine blade root connection(2012) Kucuk M.; Cetin N.S.; Emeksiz C.In this work, the analysis is done on a blade of length 66.5cm which is designed for AIR X- 400W horizontal axis wind turbine. 4140 steel, Ni-Ti, Cu-Zn-Al and Cu-Al-Ni are used in blade root connection. Stress analysis was performed from 5 m/s to 60 m/s of wind speeds. The stresses in the wind blade are determined using the finite element method with ANSYS in which the skin and the core of the blade are modeled using solid elements, respectively. As a result of the analysis; the maximum total deformation was observed in blade root connection is Cu-Zn-Al. Generally total deformation values appeared close to each other. For parking state; the equivalent (von-Mises) stress values were smaller than the yield strength for each materials. The results for all materials released in the elastic region. For rotating state; the minimum total deformation was observed in blade root connection is Ni-Ti. Eguivalent (von-Mises) stress values were compared with yield stress parameter and the plastic deformation occurred in 4140 steel, Cu-Zn-Al and Cu-Al-Ni were used blade root connections. The plastic deformation was not observed in Ni-Ti that is used blade root connection. Results are examined in that Ni-Ti is the most appropriate material for blade root connection was concluded. © Sila Science.
