Yazar "Yildiriz, Emin" seçeneğine göre listele

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    Comparative review of disk type and unconventional transverse flux machines: performance analysis
    (Tubitak Scientific & Technical Research Council Turkey, 2021) Tuncel, Erhan; Yildiriz, Emin
    Transverse flux machines (TFM) can be designed with high pole numbers, so they are very useful in direct drive systems with high torque density. Although many TFM models have been proposed to date, no detailed classification and comparison has been made before. Conventional TFMs have a high power and torque density, but low power factors and high cogging torques have prevented them from being widely used. However, especially with the new disk type TFMs proposed in recent years and the methods developed, these drawbacks have been reduced. In this paper, the TFMs proposed in recent years have been classified and their performances in terms of power factor, cogging torque, torque density, and efficiency have been examined. According to the results of this review, the performances of the new generation TFMs are competitive. Especially double-sided disk type TFMs are seen as an important topology with their high magnet utilization and flexibility in design.
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    Design and Implementation of a 1-kW Wireless Power Transfer System for EV Charging
    (Ieee, 2019) Kosesoy, Yusuf; Aydin, Emrullah; Yildiriz, Emin; Aydemir, M. Timur
    Electric vehicles are seen as an alternative option in response to the depletion of resources. In order to increase the use of EVs in daily life, practical and reliable methods to charge batteries of EVs are quite important, accordingly wireless power transfer (WPT) is considered as a solution to charge batteries. In this study, a system which has 1 kW power rating and 20 kHz operation frequency is designed and implemented. Finite Element Analysis (FEA) simulation that verifies the coil design and inductance calculation has been carried out by using ANSYS Maxwell software. Waveforms of power parameters are obtained. Power loss at each stage and the efficiency of overall system are determined and interpreted.
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    Excitation of synchronous machine by contactless power transfer - review from the perspective of electric vehicles
    (Tubitak Scientific & Technological Research Council Turkey, 2025) Tuncel, Erhan; Yildiriz, Emin
    Electrically excited synchronous machines (EESMs) are one of the best choices for propulsion motor application in electric vehicles (EVs) due to their wide torque-speed characteristics. Moreover, the air gap flux density can be easily controlled by varying the excitation current. Despite these advantages, it is difficult to transfer the current required by the rotating excitation winding into the motor under conventional methods, so it is not widely used in EVs. In this study, the emerging literature on contactless power transfer methods is reviewed for applicability to an EESM that can operate as an EV propulsion motor. Design criteria such as resonance topologies, operating frequency, winding and core approaches are examined for applicability to EESMs that can be used in EVs. Consequently, an inductive power transfer excitation that uses segmented toroidal windings and parallel connected Series-Series resonance circuits of these windings is proposed.
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    A new semi-analytical approach for self and mutual inductance calculation of hexagonal spiral coil used in wireless power transfer systems
    (Springer, 2021) Aydin, Emrullah; Yildiriz, Emin; Aydemir, M. Timur
    Several methods have been proposed in the literature for the calculation of self and mutual inductance. These methods include the use of complex integral analysis, the necessity of having primary and secondary coils with the same dimensions and the limitations of the ratio of the coil dimension to the distance between the coils. To overcome these restrictions, a new semi-analytical estimation method has been proposed in this paper. Calculation the self and mutual inductance by using the same basic formula which is based on Biot Savart Law prevents the formation of complex integrals and helps create a simple solution method. In order to verify the results obtained with the analytical approach, two hexagonal coils with 10 and 20 cm outer side lengths were produced by using litz wire with a conductive cross section of 1.78 mm(2). The results obtained with the new approach are compared with the finite element analysis, other work presented in the literature and experimental results in order to prove the accuracy of the proposed method.
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    The use of concentric loops and double-layered coils for compact design of wireless charging pads
    (Springer, 2024) Yildiriz, Emin
    The secondary pad is desired to be as light as possible and take up less space in the wireless charging applications such as e-bikes. In this paper, a novel disc coil arrangement is proposed to reduce the surface area occupied by the secondary pad. This coil pair has two concentric spiral windings on the primary side and a spiral double-layered coil on the secondary-side. The analytical approaches used to calculate inductance and parasitic capacitance have been generalized, applied to the novel coil arrangement. Analytical results have been confirmed by measurements and FEA. The electromagnetic field noises of the air-core reference coil pair and the novel coil arrangement were examined by using 2D FEA, and the superiority of the proposed coil arrangement in terms of leakage magnetic fields was shown. The self-resonance frequency and quality factors were also examined. On the other hand, since the total wire length used on the primary and secondary sides decreased, up to 3% improvement has been achieved in power transfer efficiency (PTE). The usage area of the secondary pad decreased by 22.13%, but a higher magnetic coupling according to the initial planar coil pair has been measured in the case of up to 40% misalignment.