Browsing by Author "Onat N."

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    Comparison of Turkey's Geographical Regions in terms of Stand-Alone PV System Design and Cost Parameters
    (Hindawi Limited, 2017) Onat N.
    Stand-alone photovoltaic (SAPV) systems are widely used in rural areas where there is no national grid or as a precaution against power outages. In this study, technical and economic analysis of a SAPV system was carried out using meteorological data for 75 province centers in seven geographical regions of Turkey. Obtained results for each province center were separated by geographical area. The averages of the centers for each region are taken as output. A calculation algorithm based on MsExcel has been established for these operations. The analyses made with the developed algorithm are repeated for five different scenarios that they cover periods of time when a constant strong load is active for all seasons (winter, spring, summer, and autumn) and all year round. The developed algorithm calculates the life-cycle cost, the unit energy cost, the electrical capacity utilization rate, the amount of generated/excess energy per month, the initial investment/replacement, and operating and maintenance (O&M) costs of each element. As a result, geographical regions of Turkey are compared in terms of these outputs graphically. Further investigations may include the sale of excess energy generated, small-scale PV system cost factors parallel to the grid, and the effects of government incentives. © 2017 Nevzat Onat.
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    Home energy management system for enhancing grid resiliency in post-disaster recovery period using Electric Vehicle
    (Elsevier Ltd, 2023) Candan A.K.; Boynuegri A.R.; Onat N.
    Natural disasters such as earthquake, tsunami, storm etc. can cause power outages and limitations on the grid. Moreover, power limitations or outages up to 24 h can be applied to the disaster area as a precaution, even if there is no damage in the buildings and power system components. The reflection of the power limitations or outages can be vital for sufferers in post-disaster conditions. However, their impacts can be prevented by using electric vehicles as a mobile source in home energy systems. Electric vehicles are offering a promising technology as mobile emergency power source which ensure energy availability for critical demands in disaster conditions. Therefore, in this study a dynamic home energy management system (HEMS) algorithm that classifies all the appliances according to their importance in post-disaster conditions is proposed to enhance grid resiliency via preventing energy interruption of residential buildings. The algorithm utilizes efficient usage of local renewable energy sources (RESs) and electric vehicles (EVs). Load curtailment methods are applied considering the worst load consumption for the next 24 h according to the prospective remaining energy (PRE) of the EV battery (EVB). The main objective of the proposed algorithm is to arrange the permitted loads dynamically according to their importance levels in order to prevent energy interruption of a home. The proposed algorithm is verified with case based scenarios in MATLAB®/Simulink® environment by using experimentally gathered load and weather condition data. The energized time of the critical loads are prolonged up to %241 with the proposed algorithm. © 2023 Elsevier Ltd
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    Rare-earth Magnet Free Flux-switching Generator for Wind Turbines in Micro-grids: A Review
    (China Electrotechnical Society, 2024) Ozmen T.; Ergun B.E.; Gulbahce M.O.; Onat N.
    In traditional electricity generation plants, large powerful synchronous, induction, and direct current generators were used. With the proliferation of microgrids focused on electricity generation from renewable energy sources in today’s power grids, studies have been conducted on different types of generators. Instead of the traditional generator architecture, generators with brushless structures, particularly those utilizing magnets for excitation, have found broad applications. Flux-switching generators (FSGs) are innovative types owing to their robust structure, active stator design, and high power density capabilities. However, designs have typically relied on rare-earth element magnets. Rare-earth magnets possess negative characteristics such as price uncertainty, the potential risk of scarcity in the future, and limited geographical production, leading to research on FSGs that do not depend on rare-earth magnets. This study comprehensively examines FSGs that do not use rare-earth element magnets. The study delves into the usage areas, operational mechanisms, structural diversities, and counterparts in the literature of these generators. © 2024 CES.
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    The Effects of Rotor Delta and Embrace Parameters on the Performance of Flux-Switching Generator; [Rotor Kutup Eǧimi ve Yay-Kutup Adimi Orani Parametrelerinin Aki-Anahtarlamali Generatörün Başarimina Etkileri]
    (Institute of Electrical and Electronics Engineers Inc., 2024) Isikelekoglu T.; Ozmen T.; Ergun B.E.; Onat N.; Gulbahce M.O.
    One of the types of generators used in variable-speed wind turbine applications in microgrids is the flux-switching generator. Due to the double-salient structure of flux-switching generators, torque ripples and harmonic content are high. In addition, the magnetic flux density in the stator and rotor teeth is elevated. To overcome these issues, improvements can be made in the machine's design parameters. In this study, the effects of rotor pole skew (delta) and coil-pole pitch ratio (embrace) parameters on the machine-s output values for a 1200 min-1, 200 Hz, and 260W design were examined. It was observed that changes in the pole skew and coil-pole pitch ratio parameters affect torque, flux linkage, and induced voltage values, and can reduce magnetic stresses © 2024 IEEE.
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    A Different Approach to Eco Design Perspective for Wind Turbine Transformers
    (Institute of Electrical and Electronics Engineers Inc., 2024) Demir C.; Onat N.; Ates Y.; Yagmur Metiner B.; Alemdag O.
    The connection between production capacity and the cost of producing wind turbines is partly due to the economic value of technical equipment. The main components of wind turbines can be classified as the nacelle section (the blades, gear systems and generator located here), tower, foundation, and balance facility components (including transformer and transmission cables). The increase in wind turbine powers in the last 10 years creates new problems in the design and application stages. In transformers that increase in parallel with wind turbine power, the effects of loss costs on the total life cycle cost are reaching remarkable dimensions. This study aims to bring an innovative perspective on the approach outlined in the EN50708 standard which has been recently adopted and is used to determine the level of losses. It has been revealed that it is possible to create more economical options by also taking into account the loading ratio and the activation point of the cooling system for the idle and loaded loss values considered in the transformer efficiency index. © 2024 IEEE.
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    The Effects of the Multi-Slice Skewing Applied to the Rotor on the Performance of a Flux Switching Generator; [Aki Anahtarlamali Generatörde Rotora Uygulanan Çok Katmanli Kaykinin Makina Başarimina Etkileri]
    (Institute of Electrical and Electronics Engineers Inc., 2024) Durmaz S.T.; Isikelekoglu T.; Ozmen T.; Ergun B.E.; Onat N.; Gulbahce M.O.
    Flux-switching generators are one of the types of generators commonly used in wind turbine applications, particularly in microgrids. The torque ripple and harmonic content of flux-switching generators are significantly high due to the salient pole structure of the stator and rotor teeth. In this study, a multi-layer skewing method was applied to the rotor of a 260 W flux-switching generator, and its effects on the generator's average torque, torque ripple, and efficiency parameters were analyzed. The obtained results indicated that, due to the dominance of the second harmonic, the skewing angle did not have a significant effect on the output parameters. Furthermore, the influence of the number of layers on the generator's output parameters and production difficulty was examined. © 2024 IEEE.