Ozturk, U. Kemal; Abdioglu, Murat; Mollahasanoglu, Hakki

The vertical levitation force, guidance force, and magnetic stiffness values, and thus the loading capacity and movement stability of high-temperature superconducting (HTS) Maglev systems, are aimed to be increased in this study by using auxiliary permanent magnets (PMs) in the onboard unit together with the multisurface HTS-permanent magnetic guideway (PMG) arrangement (hybrid multisurface arrangement). First, the magnetic levitation force, guidance force, and stiffness performances of the hybrid multisurface arrangement were investigated at different field cooling heights (FCH). Then, to compensate for the negation of instability that results from the higher repulsive force between the onboard PMs and the PMG and to obtain an optimal magnetic field medium, we have changed the vertical position of the auxiliary onboard PMs (ZPM) to ZPM = 0, 2, and 4 mm, at the cost of a bit of adecrement in the vertical levitation force. The bigger levitation force, together with the guidance force values for FCH = 25 mm and ZPM = 0 mm, indicates that the hybrid multisurface HTS-PMG arrangements are beneficial to increasing the practical applicability of Maglev systems.

AtıfScopus16·WoS14·OpenAlex14

İncele

Ozturk, Ufuk Kemal; Abdioglu, Murat; Ozkat, Erkan Caner; Mollahasanoglu, Hakki

A 2-D numerical finite-element model of a linear synchronous motor (LSM) is extended based on the magnetic field and moving mesh properties to investigate the magnetic flux and magnetic force characteristics of the high-speed electromagnetic levitation Maglev system, by using high-temperature superconductor (HTS) coils rather than lower current-carrying copper coils on the onboard unit and permanent magnets (PMs) on the ground. In this 2-D LSM model, the transient time-dependent solver is used to obtain the magnetic flux densities. Both the propulsion and levitation forces increased with increasing supercurrent Jc0 values indicating the advantage of using the superconducting windings in PM-LSM of Maglev vehicles as compared with the copper wires. It was also determined that, although the propulsion force is obtained on a comparable level with the studies in the literature, the lower levitation force issue than the electrodynamic suspension (EDS), despite the better propulsion to levitation force ratio, can be overcome by using the high flux trapping capacity bulk HTSs on the onboard unit together with the superconducting coils. The determined higher propulsion force in this PM-LSM Maglev model indicates that the Maglev vehicle can reach higher velocities in a short distance, and thus, this vehicle can be effectively used in short-distance travels in addition to the long-distance transportation. On the other hand, since the EDS system to be accelerated in a certain time interval via conventional wheels to achieve sufficient levitation, PM-LSM system can be integrated into the EDS Maglev system to ensure higher acceleration in a short time interval in addition to the higher levitation and propulsion force performances.

AtıfScopus10·WoS10·OpenAlex8

İncele

Abdioglu, Murat; Ozturk, Kemal; Ekici, Mehmet; Savaskan, Burcu; Celik, Sukru; Cansiz, Ahmet

In this article, we have designed and constructed a new multisurface (MS) high temperature superconductor (HTS) Maglev measurement system to investigate the enhancement of magnetic force properties of Maglev systems via MS HTS configurations above conventional permanent magnetic guideway (PMG). We have investigated both the static force and stiffness behavior and dynamic response characteristics of these MS HTS-PMG arrangements in different field cooling heights (FCHs). Optimum cooling height is determined as FCH 20-30 for both six- and four-HTS configurations. The maximum levitation force values of HTS-PMG arrangement with six-HTS were obtained bigger than that of four-HTS in the unit cryostat volume of MS arrangement, indicating that the HTSs at the bottom side of the cryostat make contribution to the loading capacity of Maglev systems. In the present article, it is observed that the magnetic flux density of bottom surface in addition to upper surface of the PMG can make a contribution to loading performance, vertical and lateral stability of Maglev systems. It is thought that the designed measurement facility and results of this study will be beneficial to increase the magnetic flux density in the unit volume via MS HTS-PMG arrangements for future design and construction of the HTS Maglev systems.

AtıfScopus16·WoS6·OpenAlex15

İncele

Ozturk, Kemal; Badia-Majos, Antonio; Abdioglu, Murat; Dilek, Durukan Burak; Gedikli, Hasan

We have designed multisurface Halbach high temperature superconductor-permanent magnetic guideway (HTS-PMG) arrangements for magnetically levitated transportation (Maglev) and investigated the static force parameters in addition to the dynamic response characteristics. Three different Halbach HTS-PMG arrangements were used with multisurface (6 HTS, 4 HTS) and single surface (2 HTS) configurations and static and dynamic measurements were carried out in three different field cooling heights (FCHs). The bigger vertical loading capacity and wider loading gap were obtained with multisurface Halbach HTS-PMG arrangements. In addition, nearly four times bigger guidance force values of multisurface arrangements than that of single surface one indicates that the side HTSs in multisurface arrangements make a significant contribution to the guidance force and thus lateral movement stability of Maglev systems. Both the vertical and lateral dynamic stiffness values increased with decreasing FCH and it can be also said that the dynamic stiffness properties of Maglev systems can be enhanced especially in lateral direction by using the multisurface Halbach HTS-PMG arrangements. Understanding of these experimental observations is supported by dedicated theoretical modelling through a 2-D approximation of the system. We show that by using a single material parameter (the critical current density J_bf c) for the whole superconducting set, one may satisfactorily predict the complete series of experiments. The static and dynamic parameters obtained from this study and the results of dedicated theoretical modeling for single-surface and multisurface HTS-PMG arrangements are thought to be helpful for the researchers working on static and dynamic performances of HTS Maglev systems.

AtıfScopus28·WoS22·OpenAlex26

İncele

Ozturk, Kemal; Abdioglu, Murat; Sahin, Ercin; Celik, Sukru; Gedikli, Hasan; Savaskan, Burcu

In this paper, the levitation force measurements have been carried out by the magnetic force measurement system under both field-cooling and zero-field-cooling regimes, whereas the magnetic field distribution over the permanent-magnet guideway (PMG) was calculated by numerical analysis based on the finite-element method. It was shown in this study that the vertical levitation capability and stability of Maglev systems can be improved depending on the cooling regime, pole number, and suitable arrangement of the PMG. In this paper, it was shown that when the pole number increases, the levitation force density increases. It also appeared that the reasonable position of the supplementary permanent magnet and appropriate cooling heights are key parameters for both levitation performance and stabilization of the high-temperature superconductor (HTS) Maglev. It is believed that the numerical and experimental data in this paper are useful for relative design and practical application of HTS Maglev systems.

AtıfScopus38·WoS33·OpenAlex36

İncele