Yazar "Ozdemir, Mehmet Akif" seçeneğine göre listele

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    A novel hybrid coil design and implementation for wireless power transfer systems
    (Edp Sciences S A, 2024) Pashaei, Ali; Aydin, Emrullah; Ozdemir, Mehmet Akif; Kosesoy, Yusuf; Aydemir, Mehmet Timur
    Wireless Power Transfer (WPT) has been drawing a lot of attention in the last ten years parallel with the market increase in electric vehicles. Although conductive charging methods are still the preferred ones, WPT-based charging systems are used as clean and flexible alternatives. At the center of these systems are the transmitting and receiving coils, and different coil types have been proposed in the literature. This study proposes a square-hexagonal hybrid coil structure to increase magnetic coupling by shaping the magnetic field. In addition, this design aims to minimize the coupling coefficient variation for misaligned coils which is one of the most significant problems in WPT systems. A 3D model of the coils was created and analyzed using ANSYS, Maxwell software. Compared to the conventional square coil structure the coupling coefficient of the proposed structure is less affected by misalignment on the x and y axes, and as a result, it has a better efficiency. In addition, a WPT system operating at 50 W, 85-kHz is designed and tested in a laboratory environment. The FEA analyses and experimental application results largely overlap, and accordingly, the coil-to-coil efficiency of our WPT system was 93.5% and the overall efficiency of the system was 87%.
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    Parallel-Input Series-Output Z-Source Converters for High Voltage DC Power Supplies
    (Ieee, 2023) Ozdemir, Mehmet Akif; Aydin, Emrullah; Dag, Bulent; Tamyurek, Bunyamin; Aydemir, Mehmet Timur
    High Voltage DC power supplies typically employ a high voltage high frequency transformer to step-up the voltage generated by a high frequency inverter. Generally, the step-up ratio of the transformers is high and therefore the effect of the stray capacitance and inductance values is amplified, deteriorating the inverter operation. LCC converters utilizing these stray capacitors are suggested to generate soft switching for better efficiency, but this increases the complexity. Also, the varying nature of the stray capacitance may complicate the control. In this paper, a modular, Parallel-Input Series-Output converter utilizing two z-source dc-dc converters is proposed to step a 350V input to generate 2-kV, 2-kW output. Simulation and experimental results prove that impedance source converters which are generally used in renewable energy applications can also be used at high voltage applications.