Browsing by Author "Ebrahimi, Asqar"

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    Maximum efficiency conditions of wireless power transfer between two helical wire antennas
    (Видавництво Львівської політехніки, 2011) Shilandari, Arash; Niazmandian, S. Mostafa; Ebrahimi, Asqar; Malahzadeh, Alireza
    The aim of the study is to codify a computational procedure for the study and analysis of the wireless power transfer between two helical wire antennas. Using this method, we can study the effective factors such as distance, loading and antennas’ sizes on wireless power transfer and delineate the conditions which maximize the efficiency of the wireless power transfer. In the suggested method, using the applied method of moment (MOM) in FEKO software, current distribution and scattering parameters of a two-port wireless power transfer system for different distances are determined. Subsequently, using circuit analysis, we appoint the efficiency of wireless power transfer for different amounts of load resistance and different amounts of transfer distances and the angles between the axle of two helixes and then we compare them with each other. Using repeater helical wire which has the similar structure of the previous helix structures, we can improve the efficiency of wireless power transfer in 3meter distance to 35 percent.
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    Quasi static approximation of wireless power transfer systems through coupled resonance and improving power transfer efficiency
    (Видавництво Львівської політехніки, 2011) Shilandari, Arash; Niazmandian, S. Mostafa; Ebrahimi, Asqar; Malahzadeh, Alireza
    The aim of the study is to transfer power wirelessly through the resonance of the source and the device antennas. Since transferring system frequency from the frequency of the antenna resonance strongly decreases power transfer efficiency, in this paper, a wireless power transfer system consisting of two helix resonance antennas is analyzed through quasi-static approximation in a circuit model and among the scientific papers; few works have been done in this regard. The presented circuit model reveals the difference between the two possible driving methods in wireless power transfer systems via coupled resonances. It also shows that the presented quasi-static approximation of wire helix resonant frequency is in a good agreement with the experimental results. In addition, the equivalent circuit elements of the wireless power transfer system via strongly coupled resonances are presented and measured to improve the transferred power and the maximum quality factor.