Browsing by Author "Altintas, M"

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    Computationally efficient predictive torque control strategies without weighting factors
    Zerdali, E; Altintas, M; Bakbak, A; Mese, E
    Predictive torque control (PTC) is a promising control method for electric machines due to its simplicity, fast dynamics, ability to handle nonlinearities, and easy inclusion of additional control objectives. The main challenge in conventional PTC design is to determine the weighting factors in the cost function. These weighting factors are generally chosen by the trial-and-error method or metaheuristic optimization algorithms, but these methods may not apply the optimum voltage vectors according to changing operating conditions. There are also several studies on the elimination of the weighting factors. This paper proposes two weighting factorless PTC strategies with lower computational complexities than the current literature. To demonstrate the superiority of the proposed methods, their performances are experimentally compared to those of the existing methods through a test bed equipped with an induction motor. Finally, two PTC strategies with a simple design and improved performance are introduced to the literature.
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    Maximizing Energy Extraction from Direct Grid Coupled PMSG For Wind Energy Conversion Systems
    Bakbak, A; Canseven, HT; Ayaz, M; Altintas, M; Mese, E
    Direct grid coupling of permanent magnet synchronous generators (PMSG) for wind energy conversion systems provides certain advantages with the penalties of maximum power point tracking (MPPT) and reactive power control. This article proposes a novel PMSG design philosophy such that optimizing PMSG design at the initial stage would compensate for the drawbacks arising from the lack of an MPPT algorithm. Also, the ability to maintain a high PF across a wide range of operating power levels is investigated by considering reactive power in the design process. In this article, optimization of slot/pole combination is described for direct grid coupled PMSGs to extract as much energy as possible according to wind data. A new benchmark, adequacy factor, is presented to determine the slot/pole combination. Variation of the reactive power is theoretically analyzed. A relationship is established between induced electromotive force, synchronous inductance values of machines, and the PF. Fixed and variable speed operations of PMSGs are compared in terms of annual energy yield. Finally, theoretical analyses are validated through laboratory testing of prototype generators.
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    The Score for Allergic Rhinitis study in Turkey, 2020
    Cingi, C; Muluk, NB; Susaman, N; Küçükcan, N; Kar, M; Altintas, M; Altin, F; Eroglu, S; Kef, K; Ipçi, K; Güven, SG; Dizdar, SK; Çayir, S; Salcan, I; Korkmaz, MÖ; Yilmaz, AS; Topuz, B; Basak, S; Ural, A; Çobanoglu, BY; Erkan, AN; Oghan, F; Eskiizmir, G; Çakir, BÖ; Coskun, BU; Kara, CO; Gültekin, E; Üçüncü, H; Selcuk, A; Altuntas, EE; Durmus, K; Özlügedik, S; Toros, SZ; Karamese, O; Bayindir, T; Baylan, MY; Iynen, I; Yilmaz, O; Yilmaz, N; Avci, D; Aysel, A; Bal, C; Baser, S; Bozkurt, Z; Çatli, T; Çetinkaya, EA; Öner, F; Coskun, ZÖ; Dizdar, D; Eksi, E; Gümüslü, BC; Kaplan, AK; Kinar, A; Parildar, H; Resuli, AS; Köroglu, E; Yazici, D; Kurt, Y; Dilber, M; Çukurova, I; Annesi-Maesano, I
    Objective: This study aimed to determine how prevalent allergic rhinitis (AR) is in Turkey and to compare the current prevalence with the figures obtained 10 years earlier. Methods: This study included 9,017 participants. The minimum number of participants required from each center was determined via a stratified sampling technique according to regional demographic characteristics as ascertained from the last census. For each region, both men and women were administered the score for allergic rhinitis (SFAR) questionnaire and a score for each participant was calculated based on the responses supplied. Results: A total of 9,017 individuals (55.3% men and 44.7% women) took part in this study. Of these, 94.4% were urban residents and 5.6% lived in a rural setting. Of the men, 38.5% self-reported as suffering from AR. The corresponding figure in women was 40.5%. The overall prevalence of AR, as deduced on the basis of the SFAR, was found to be 36.7%. Comparing the prevalence in different regions, we found that AR was the least prevalent in the Black Sea region with a frequency of 35.8%. The highest prevalence was in the Mediterranean region, where the prevalence was 37.7%. There was no statistical significance in the apparent differences in prevalence between different geographical regions. Despite this, however, there was a clear increase in the frequency of AR over the preceding decade. This increase was most pronounced in the South-Eastern Anatolian region, where the frequency rose from 21.0% to 36.9%. Conclusion: Our results indicate that there has been a marked increase in the prevalence of AR in every region in Turkey over the last 10 years. This could be related to living conditions in urban environments. Alterations in lifestyle, urban living, air pollution causing impairments in immune defense mechanisms, and other aspects of modern lifestyles may account for the increase in AR in Turkey.