Yazar "Cuma, Mehmet Ugras" seçeneğine göre listele

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    A Fast Simulation Model for Large Scale Battery Packs Used in Heavy Electric Vehicles
    (Institute of Electrical and Electronics Engineers Inc., 2019) Erdogan, Birand; Savrun, Murat Mustafa; Koroglu, Tahsin; Cuma, Mehmet Ugras; Tumay, Mehmet
    Voltage imbalance occurs in a battery pack due to the differences of internal resistance, temperature, self discharge rate, leakage current etc. reduce the usable energy over time. To overcome voltage imbalances in the battery pack, cell balancing methodologies are used. Although passive balancing methods provide cheap solutions for equalizing imbalances, active balancing methods make it possible to balance faster. This paper presents an active balancing topology for large scale battery packs in a heavy electric vehicle. In order to investigate the performance of the system, a battery pack and bidirectional flyback converter (BiFLC) based active balancing circuit equipped with switch matrix (SwM) has been simulated by using MATLAB/Simulink. A charge transfer bus, which is supplied by the first cell of the battery pack, is used to transfer energy between the source/ destination cells. Thus, the need for the auxiliary circuit/battery is eliminated. A large scale battery pack consist of 176 series cells and 22 BiFLCs is used in the simulation model. Because of using switching models of BiFLCs requires high run time and more complexity, a simple model of BiFLC using current sources is presented. © 2019 IEEE.
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    A new predictive electric bus model using big data for estimating battery pack capacity
    (Landesmesse Stuttgart GmbH, 2017) Yirik, Emrah; Irmak, Umut; Dericioglu, Cagla; Unal, Erdem; Cuma, Mehmet Ugras
    This paper describes a new predictive neural network model for electric buses by using big data analysis tools. Electric buses are often used for public transportation with many routes. Each route in a city has different parameters such as length, elevation, number of bus stops, traffic density which determines battery pack capacity. Moreover average number of passengers and ambient temperature are other important parameters that must be considered. In this paper, a new predictive model for electric buses is proposed using aforementioned parameters. To develop the model, the study takes the advantages of the Big Data Analysis tools by gathering the data from real vehicles. © 2017 MOBI - Mobility, Logistics and Automotive Technology Research Centre.
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    A Novel Solid-State Transformer with Improved Flyback Converter Equipped with Quasi Z-Source Converter for Medium-Voltage Utility Grid
    (Mdpi, 2023) Cuma, Mehmet Ugras; Anvari, Alireze Deljavan; Savrun, Murat Mustafa
    This paper introduces an enhanced solid-state transformer topology for a medium-voltage (MV) utility grid. The main objective of the current study is to develop an improved flyback converter equipped with a quasi z-source converter (qZ_iFC) having a high-voltage conversion capability for the integration of low-input voltage to the DC link of an MV modular multilevel converter (MMC). The system integrates the quasi z-source and flyback converters by operating their existing switches complementary. Furthermore, the high-gain qZ_iFC allows for a reduction in the rated voltage of the input, as well as the use of a high-frequency transformer (HFT) with a unity turns ratio that provides galvanic isolation between the input and the output ports. Thus, using an HFT just for isolation purposes without voltage gain improves the system efficiency. In addition, a controller for (i) qZ_iFC which is regulating complementary switches to prevent the shoot-through current from reaching the HFT resulting in saturation; and (ii) a controller for MMC to produce MV-level AC voltage for loads are suggested. The performance of the proposed system was evaluated for several operating conditions. Results show that the proposed SST smoothly performs the power flow between the ports during steady-state and transient conditions. The power flow capabilities and efficiency values validate the viability and effectiveness of the proposed system.
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    An improved and fast balancing algorithm for electric heavy commercial vehicles
    (Elsevier, 2021) Erdogan, Birand; Savrun, Murat Mustafa; Koroglu, Tahsin; Cuma, Mehmet Ugras; Tumay, Mehmet
    Nowadays, the tendency towards electric vehicles is increasing and various studies are being carried out in order to eliminate the shortage of battery life. One way to improve battery life is to overcome imbalances between cells in battery packs. The imbalances due to structural differences arising from production and changing operating conditions reduce the utilization of available energy. Passive and active balancing methods are used in order to eliminate these imbalances. Due to the slow equalization speed and energy inefficiency of passive balancing circuits, the trend towards active balancing is increasing. In this paper, an active balancing system with a new balancing algorithm that features fast balancing, multiple charge transfers, and suitable for large battery packs used in electric heavy commercial vehicles is proposed to increase usable energy. To test the algorithm, battery module and bidirectional dc-dc converter based active balancing system simulation study has been performed in Matlab-Simulink. The performance of proposed algorithm is compared with other algorithms and simulation results show that the proposed algorithm has better balancing performance.
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    Design and implementation of algorithms for one pedal driving in electric buses
    (Elsevier - Division Reed Elsevier India Pvt Ltd, 2021) Cuma, Mehmet Ugras; Unal, Cagla Dericioglu; Savrun, Murat Mustafa
    Nowadays, the interest in electric vehicles (EVs) is increasing in parallel with falling prices of batteries, developing battery technology and willing to reduce carbon emissions. However, the most important problem of EVs is still range anxiety. The one pedal driving (OPD), which uses only accelerator pedal to accelerate and decelerate the vehicle, is an alternative solution to further increase the energy efficiency by managing the regenerative braking operation of EVs. In this study, OPD algorithms are developed for an electric bus (E-Bus), which is equipped with a 100 kW electric motor. Algorithms manage the vehicle traction torque without compromising the comfort of the passengers in the vehicle. To evaluate the performance of the developed OPD algorithms for the heavy vehicle, experimental studies have been conducted. The energy efficiency performance of OPD has been tested under different speed profiles as urban traffic, constant speed and stop-and-go traffic. The energy recovery potential of OPD algorithms for different experience levels and driving characteristics of drivers, the adaptability of drivers to OPD driving have been examined for heavy electric vehicles first time. The results show that the OPD performs a precise energy efficiency by managing the regenerative braking operation. (C) 2021 Karabuk University. Publishing services by Elsevier B.V.
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    DSP controlled voltage disturbance generator
    (Engineering & Scientific Research Groups, 2018) Savrun, Murat Mustafa; Tan, Adnan; Koroglu, Tahsin; Cuma, Mehmet Ugras; Bayindir, Kamil Cagatay; Tumay, Mehmet
    Voltage disturbance generator (VDG) is a kind of device used to generate voltage disturbances that may occur in the network in order to test and evaluate the performance of the power quality devices such as Dynamic Voltage Restorer (DVR) and Uninterruptible Power Supply (UPS). Some of the voltage disturbance generator systems which are available in the literature and commercially available are complex and expensive while the others are simple, inexpensive but less functional. In this paper, a new transformer based, digital signal processor (DSP) controlled VDG is designed which can generate balanced and unbalanced voltage sag/swell and interruption and can adjust the depth, duration and initiation point of disturbances. The proposed system is composed of bidirectional switches, variable transformers and DSP based controller. 3 phase 20 kVA experimental setup is developed to verify the performance of the designed system with linear and non-linear loads. Moreover, the performance of VDG is also investigated in the compensation tests of DVR and UPS.
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    DSP controlled voltage disturbance generator
    (Engineering and Scientific Research Groups, 2018) Savrun, Murat Mustafa; Tan, Adnan; Köroglu, Tahsin; Cuma, Mehmet Ugras; Bayindir, Kamil Çagatay; Tümay, Mehmet
    Voltage disturbance generator (VDG) is a kind of device used to generate voltage disturbances that may occur in the network in order to test and evaluate the performance of the power quality devices such as Dynamic Voltage Restorer (DVR) and Uninterruptible Power Supply (UPS). Some of the voltage disturbance generator systems which are available in the literature and commercially available are complex and expensive while the others are simple, inexpensive but less functional. In this paper, a new transformer based, digital signal processor (DSP) controlled VDG is designed which can generate balanced and unbalanced voltage sag/swell and interruption and can adjust the depth, duration and initiation point of disturbances. The proposed system is composed of bidirectional switches, variable transformers and DSP based controller. 3 phase 20 kVA experimental setup is developed to verify the performance of the designed system with linear and non-linear loads. Moreover, the performance of VDG is also investigated in the compensation tests of DVR and UPS. © JES 2018.
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    Implementation of a Novel Hybrid UPQC Topology Endowed With an Isolated Bidirectional DC-DC Converter at DC link
    (IEEE-Inst Electrical Electronics Engineers Inc, 2020) Koroglu, Tahsin; Tan, Adnan; Savrun, Murat Mustafa; Cuma, Mehmet Ugras; Bayindir, Kamil Cagatay; Tumay, Mehmet
    This paper introduces an original hybrid unified power quality conditioner (HUPQC) topology as an alternative solution to electrical power quality problems. The proposed HUPQC consists of the shunt hybrid active power filter (SHAPF), the dynamic voltage restorer (DVR), and the isolated bidirectional dc-dc converter (BiDC) located at the common dc link. The SHAPF enables reduction in the voltage rating of the dc-link capacitor, helps to reduce the cost and the size of the dc link, and hence reduces switching losses of the voltage source inverter. Besides the novelty of its topology, dynamic reactive power compensation capability is realized for the first time in the literature within HUPQC concept by achieving adaptively controlling dc-link voltage. The BiDC not only provides isolation and bidirectional power flow between the DVR and the SHAPF but also operates to keep the dc-link voltage of DVR constant against adaptively changing dc-link voltage of the SHAPF. In addition to these, a new hybrid voltage sag/swell detection algorithm based on the combination of the improved Clarke transformation and the enhanced phase-locked loop is developed and introduced. In order to verify the viability and effectiveness of the proposed HUPQC topology, experimental studies are carried out.
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    Isolated H-bridge DC-DC converter integrated transformerless DVR for power quality improvement
    (Inst Engineering Technology-Iet, 2020) Savrun, Murat Mustafa; Koroglu, Tahsin; Tan, Adnan; Cuma, Mehmet Ugras; Bayindir, Kamil Cagatay; Tumay, Mehmet
    This study presents a new H-bridge DC-DC converter-based transformerless dynamic voltage restorer topology (DVR). The proposed system can compensate balanced and unbalanced voltage sag/swell that are the most common electrical power quality problems and offers advantages over conventional DVR topologies by providing the isolation with high-frequency transformer (HFT) rather than bulky injection transformers and by employing shunt converter to eliminate the requirement of an energy storage unit. The system is composed of H-bridge DC-DC converter equipped with a HFT with one primary and three secondary windings and transformerless DVR. The single-phase shift modulation method is used for each series converter independently to provide the bidirectional power flow control of DC-DC converter, whereas in-phase compensation method with a hybrid detection algorithm is used to mitigate voltage sag/swell. An LC filter is employed to attenuate the switching ripple harmonics on the output of the DVR. The performance of the proposed system is verified experimentally on a three-phase, three-wire, 380 V, 10 kVA prototype.
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    Multiple harmonic elimination-based feedback controller for Shunt Hybrid Active Power Filter
    (Inst Engineering Technology-Iet, 2017) Tan, Adnan; Bayindir, Kamil Cagatay; Cuma, Mehmet Ugras; Tumay, Mehmet
    This study presents a multiple harmonic elimination-based feedback controller for shunt hybrid active power filter (SHAPF) to perform an effective harmonic compensation performance in a wide harmonic frequency band. The conventional control methods presented for SHAPF cannot perform an adequate performance, because of the disturbances such as phase delays caused by controller methods and measurement circuitries, tolerances of passive filter components and supply voltage harmonics. In the proposed controller, the conventional feedback controller is improved by using supply side individual current harmonics which are extracted by the synchronous reference frame method. To prevent the performance degradation effects of disturbances, proportional-integral controllers are applied to each d and q components of individual current harmonics. The compensation performance of the proposed method is compared with conventional methods both theoretically and experimentally. The experimental results verify the advanced harmonic compensation performance of the proposed control method.