Yazar "Shafiee, Qobad" seçeneğine göre listele

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    A hybrid LED sink driver using a nesting-type switched-inductor/switched-capacitor buck-boost converter
    (Elsevier, 2020) Eguchi, Kei; Bevrani, Hassan; Shafiee, Qobad; Shibata, Akira
    This paper presents a novel light emitting diode (LED) sink driver with a high voltage gain for LED-based lighting applications. Unlike conventional LED sink drivers, the proposed driver has the nested switched-inductor/switched capacitor (SI/SC) topology consisting of an SI buck-boost converter block and a nesting-type SC cell. Owing to the nested SI/SC topology, the proposed driver offers not only a high voltage gain but also a flexible controllability of the LED currents and transformer-less structure. The effectiveness of the proposed driver is justified by some simulation results in SPICE software environment and laboratory experimental tests. In the performed simulations, the proposed driver in comparison of conventional drivers improved almost 6% power efficiency when the output power was 500 mW. Furthermore, in the performed experiments, the feasibility of the proposed topology is confirmed by demonstrating a high voltage gain and the output controllability.
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    Implementation of inductor-less 13-level inverter topology with reduced number of required component
    (Elsevier, 2020) Eguchi, Kei; Bevrani, Hassan; Shafiee, Qobad; Do, Wanglok
    This paper presents an inductor-less multilevel inverter (MLI) with a 13-level ac output. The proposed MLI consists of only 11 switches, 2 capacitors, and 2 input sources. Owing to the inductor-less symmetrical topology, the proposed MLI can reduce the component count in comparison of conventional MLIs. This leads to reduction of power loss and hardware cost. To clarify the effectiveness of the proposed MLI, the characteristic evaluation is given in detail. Some computer-based simulations in SPICE simulator environment as well as breadboard-based experimental tests are conducted concerning the proposed 13-level inverter. In the performed simulations, the power efficiency of the proposed MLI reaches about 85% and 88% at 1 kW in the case of a sinusoidal output and a triangular output, respectively. The proposed MLI improves power efficiency more than 2.5% comparing with the conventional K-type MLI when the output power is 1 kW. Furthermore, the experimental result proves the physical feasibility of the proposed topology by demonstrating the 13-level ac output. ?