Person: POYRAZOĞLU, Göktürk
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POYRAZOĞLU
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ArticlePublication Open Access Determination of price zones during transition from uniform to zonal electricity market: A case study for Turkey(MDPI AG, 2021-02) Poyrazoğlu, Göktürk; Electrical & Electronics Engineering; POYRAZOĞLU, GöktürkIn the electricity market, different pricing models can be applied to increase market competitiveness. Different electricity systems use different market structures. Uniform marginal pricing, zonal marginal pricing, and nodal marginal pricing methods are commonly used market structures. For markets wishing to move from a uniform pricing structure to a more competitive zonal pricing structure, the determination of price zones is critical for achieving a competitive market that generates accurate price signals. Three different pricing zone detection algorithms are analyzed in this paper including the k-means clustering and queen/rook spatially constraint clustering. Finally, the results of a case study for the Turkish electricity system are shared to compare each method.ArticlePublication Open Access Co-optimization of transmission maintenance scheduling and production cost minimization(MDPI, 2019-08-01) Poyrazoğlu, Göktürk; Oh, H.; Electrical & Electronics Engineering; POYRAZOĞLU, GöktürkRegular transmission maintenance is important to keep the infrastructure resilient and reliable. Delays providing on-time maintenance increase the forced outage rate of those assets, causing unexpected changes in the operating conditions and even catastrophic consequences, such as local blackouts. The current process of maintenance schedule is based on the transmission owners' choice, with the final decision of system operator about the reliability. The requests are examined on a first-come, first-served basis, which means a regular maintenance request may be rejected, delaying the tasks that should be performed. To incorporate optimization knowledge into the transmission maintenance schedule, this study focuses on the co-optimization of maintenance scheduling and the production cost minimization. The mathematical model co-optimizes generation unit commitment and line maintenance scheduling while maintaining N-1 reliability criterion. Three case studies focusing on reliability, renewable energy delivery, and service efficiency are conducted leading up to 4% production cost savings as compared to the business-as-usual approach.
ArticlePublication Metadata only A stochastic value estimation tool for electric vehicle charging points(Elsevier, 2021-07-15) Poyrazoğlu, Göktürk; Göktürk, Elvin Çoban; Industrial Engineering; Electrical & Electronics Engineering; GÖKTÜRK, Elvin Çoban; POYRAZOĞLU, GöktürkA stochastic value estimation tool serves as a planning tool with embedded modules for electrical and financial valuation of electric vehicle charging points. The tool is developed in stochastic nature for selected service and technology options. The tool is also valuable as a research tool to create a data set for a possible charging station with details of vehicle brands, state-of-charge at the arrival, charge duration, and waiting time. A case study for one of the biggest shopping malls in Istanbul, Turkey, where welcomes 350-400 electric vehicles per day is analyzed. The results are discussed on performance metrics such as the average waiting time in the queue, utilization of the station and each socket, profit, customer satisfaction, energy, and power consumption.Conference ObjectPublication Metadata only Prediction algorithm & learner selection for European day-ahead electricity prices(IEEE, 2020-10) Ülgen, Toygar; El Sayed, Ahmad; Poyrazoğlu, Göktürk; Electrical & Electronics Engineering; POYRAZOĞLU, Göktürk; Ülgen, Toygar; El Sayed, AhmadThe prediction of day-ahead electricity prices with higher accuracy is always helpful for the market players of the power exchange. This study was intended in the first place to find out the best time series prediction method for the selected 14 European countries. The test results of four time-series methods show that the next day prices were more in line with the previous day prices in 87% of the selected countries; Later, a classification approach is followed by 33 different features of each country to answer the question of which method would be the best for the other countries, that were not studied in this paper, would be? As a result, the support vector machine algorithm results in 57% accuracy in classifying an unknown European country to determine the best prediction method. Therefore, this paper focuses now on two correlated studies to find out the best time series prediction methods and a classification approach for selected countries.Conference ObjectPublication Metadata only Design of the circuitry, battery management system, and wireless communication of an electric vehicle(IEEE, 2019-06) Kurt, Atakan; Dolu, Uğur; Kaya, Burak; Poyrazoğlu, Göktürk; Electrical & Electronics Engineering; POYRAZOĞLU, Göktürk; Kurt, Atakan; Dolu, Uğur; Kaya, BurakElectric vehicles start to take an essential place in our lives to support the sustainability and energy efficiency. In order to train the required workforce, a team of engineering students is assigned to develop an in-house electric vehicle in a university in Turkey. The resultant electric vehicle participates in an electric vehicle efficiency challenge to compete against other teams. This study summarizes the details of two important components of an electric vehicle, the battery management system and wireless communication. The study also covers the complete circuitry of the designed vehicle for the hope to help the interested audience to demonstrate a high quality work on vehicle design.Conference ObjectPublication Metadata only Capacity planning for forming sustainable and cost-effective nanogrids(IEEE, 2023) Sayed, Ahmad El; Poyrazoğlu, Göktürk; Ahmed, Eıhab Elgaıly Elmukshfı; Electrical & Electronics Engineering; POYRAZOĞLU, Göktürk; Sayed, Ahmad El; Ahmed, Eıhab Elgaıly ElmukshfıThis paper proposes a new strategy for nanogrid capacity planning as a bilevel programming mathematical model with look-ahead logic. The first program, the Planner, is a linear program that solves for the optimal size of the Nano-grid comprising a PV solar system and a battery energy storage system. The second program, the Operator, is a mixed integer linear program that uses resultant sizes from the Planner and other data and then solves for the optimal asset dispatch on an hourly basis throughout the whole horizon. 24-hours is used as the main optimization window, to be consistent with real case operations of day-ahead scheduling but longer windows were also tested with the Lookahead (LA) logic. A sensitivity to LA logic was applied for an analysis conducted on cost-effectiveness, system sustainability, and local energy sufficiency. It was shown that implementing two days of LA logic reduces the import cost by 44%. Nano-grid was considered in this study to test the capacity planning strategy, but the methodology is also applicable to larger schemes.Conference ObjectPublication Metadata only In-vehicle qi-compliant inductive wireless charging solutions: A review(IEEE, 2023) Güvercin, Ezgi; Poyrazoğlu, Göktürk; Electrical & Electronics Engineering; POYRAZOĞLU, Göktürk; Güvercin, EzgiIn-vehicle wireless charging systems are becoming increasingly popular in modern vehicles, providing a convenient and efficient way to recharge electronic devices while on the move. This article aims to provide an overview of the standard applied for wireless chargers in these systems, as well as the various inductive wireless power transfer methods used. It covers the design of transmitter and receiver circuits, including key design topologies such as coil selection, compensation methods, and quality factor, and explores the importance of choosing the most optimal methods and parameters for efficient and safe wireless charger design. The paper also highlights the crucial role of the Qi standard in ensuring compatibility and interoperability between different wireless charging devices, as well as the importance of prioritizing efficiency and security in the design of in-vehicle wireless charging systems. In particular, it examines two security solutions that are commonly used in these systems: Near Field Communication (NFC) and Foreign Object Detection (FOD). NFC technology allows two electronic devices, such as a smartphone and an in-vehicle wireless charger, to communicate with each other when they are nearby. This can help ensure that only authorized devices can access the wireless charger, preventing unauthorized access and ensuring safe and secure wireless charging. FOD technology, on the other hand, detects foreign objects that may be in the proximity of the wireless charger, such as metal objects or coins, and prevents the charger from operating if it detects such objects. This helps to prevent damage to the charger, or the electronic device being charged. Overall, this paper emphasizes the necessity and importance of developing efficient and secure in-vehicle wireless charging systems that comply with the Qi standard and incorporate NFC and FOD technologies to ensure reliable and convenient charging for modern vehicles.Conference ObjectPublication Metadata only Current balancing circuit design for parallel LED strings in QDOT high bright TV with dual-transformer LLC resonant topology(IEEE, 2022) Ersoy, Melisa; Poyrazoğlu, Göktürk; Electrical & Electronics Engineering; POYRAZOĞLU, Göktürk; Ersoy, MelisaNew LED technologies demand slim designs with increased backlight power. When the parallel-connected LED strings are driven by multiple transformers, the magnetic coupling difference and the LED string voltage difference cause backlight current mismatch problem. This imbalance causes the line with low voltage to draw more current hence to create heat spots on the backlight causing reduced lifetime. This problem is observed as backlight fluctuation at the end-user side. In this study, a cost-effective balancing circuit is simulated and implemented for eight parallel-connected LED strings using two transformers in an LLC half-bridge resonant topology while meeting the power demand in a relatively slim design. For the 145W backlight power, the current mismatch was 57.59% when there was an 8% deviation in transformer leakage inductance and a 10% variation between LED string voltages. The temperature difference between the strings was measured as 31. 8°C taken at room temperature with the open back cover. With the balancing circuit, the LED current difference being reduced to 9.99%. When the string voltages are the same, the maximum deviation in the current is measured as 2.59%.Conference ObjectPublication Metadata only Multi-criteria decision model for the assessment of offshore wind energy potential of Tunisia(IEEE, 2021-05-05) Zahmoul, Houda; El Sayed, Ahmad; Poyrazoğlu, Göktürk; Electrical & Electronics Engineering; POYRAZOĞLU, Göktürk; Zahmoul, Houda; El Sayed, AhmadThis paper investigates the potential for the development of offshore wind power plants in Tunisia. The goal of this research is to increase the possibility of using renewable energy available in the country and reduce the dependence on fossil fuels. The data used for the analysis is obtained from remote sensing satellites and weather stations located across the country's coastal regions. A multi-criteria decision model is built to perform geographic and technical analysis of the study area. This research reveals locations suitable for wind turbine installations. The results of this study aid the transition to wind energy with its optimal adaptation in Tunisia. Only 7% of Tunisian offshore territory is found fit for the deployment of fixed-bottom wind farms. Six locations, in particular, were chosen in the Gulf of Tunisia, Gabes, Sousse, Sfax, Bizerte, and Djerba. The GIS-based methodology proposed in this paper can be applied to other offshore wind farm allocation investigations. The environmental impact of proposed wind farms on GHG reduction and employment opportunities are investigated. The suggested wind farms will reduce the GHG emissions and the energy price in Tunisia as well as create new jobs for society.Conference ObjectPublication Metadata only The potential and economic analysis of grid-connected solar PV power in Kenya(IEEE, 2019-06) Samu, Remember; Poyrazoğlu, Göktürk; Fahrioglu, M.; Electrical & Electronics Engineering; POYRAZOĞLU, Göktürk; Samu, RememberThis present study is aimed at minimizing the dependence on fossil fuels thus reducing greenhouse gas (GHG) emissions and also to curb for the rising energy demands in Kenya. 23 locations are considered for their techno-economic potential of installation of a 10MW grid-connected photovoltaic (PV). The sites are scattered across the country yet are mostly concentrated in the Eastern region and are selected based on their accessibility to the power grid and availability of their meteorological parameters from the NASA Solar Energy Dataset. RETScreen software 4.0 version is employed for the analysis. The capacity factor, simple payback, equity payback, the net present value, annual life cycle savings, energy production cost, net annual greenhouse gas emission reduction and the equivalent barrels of crude oil not consumed are outlined. Energy accounting is performed and the results are used to conclude the feasibility of the PV investment. The average capacity factor of the PV power plants of these 23 different locations is 14.23%. All the locations under study are feasible for the construction of these 10MW plants. On average, investment capital of US$18,050,000 and a total of 51,020m2 of land are required for the installation of the 10MW PV plant.