Yazar "Kuwahara, Kyoka" seçeneğine göre listele

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    The development of an led lighting circuit using high gain buck-boost converters
    (IJEETC, 2019) Kuwahara, Kyoka; Ishibashi, Takaaki; Eguchi, Kei
    his paper presents an LED driver using high gain buck-boost converters. By combining a traditional buck-boost converter and a Switched-Capacitor (SC) DC-DC converter with flying capacitors, the proposed driver can achieve the following features: 1) High voltage gain realized by cascade connection, 2) controllability of conversion ratio owing to the hybrid topology, and 3) small volume with only one inductor. The characteristics of the proposed driver, such as output voltage and power efficiency, were investigated by Simulation Program with Integrated Circuit Emphasis (SPICE) simulations. Furthermore, the feasibility of the proposed driver was confirmed by experiments. The simulation and experiment show the effectiveness of the proposed driver.
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    A small direct sc ac-ac converter with cascade topology
    (International Journal of Innovative Computing, Information and Control, 2018) Eguchi, Kei; Kuwahara, Kyoka; Ishibashi, Takaaki; Oota, Ichirou
    To realize a small inductor-less AC-AC converter, this paper presents a cascade direct AC-AC converter using switched-capacitor (SC) techniques. The proposed AC-AC converter has cascade topology, where converter blocks with the conversion ratio of 1/2 or 2 are connected in series. Owing to the cascade topology, multiple conversion is performed to realize high conversion ratio. Furthermore, each converter block consists of only two capacitors and four switches, because no flying capacitor is necessary to realize AC-AC conversion. By reducing the number of capacitors, the proposed converter can achieve smaller circuit components and higher input power factor than conventional converters. To clarify the effectiveness of the proposed AC-AC converter, characteristic evaluation was performed by using simulation program with integrated circuit emphasis (SPICE) simulations and theoretical analysis. In the conversion ratio of 1/4, the SPICE simulation result demonstrated that the proposed AC-AC converter can improve 8% power efficiency and 0.4 input power factor from the conventional direct AC-AC converter using flying capacitors.