• Title/Summary/Keyword: Split voltage sources

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Two Modified Z-Source Inverter Topologies - Solutions to Start-Up Dc-Link Voltage Overshoot and Source Current Ripple

  • Bharatkumar, Dave Heema;Singh, Dheerendra;Bansal, Hari Om
    • Journal of Power Electronics
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    • v.19 no.6
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    • pp.1351-1365
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    • 2019
  • This paper proposes two modified Z-source inverter topologies, namely an embedded L-Z-source inverter (EL-ZSI) and a coupled inductor L-Z source inverter (CL-ZSI). The proposed topologies offer a high voltage gain with a reduced passive component count and reduction in source current ripple when compared to conventional ZSI topologies. Additionally, they prevent overshoot in the dc-link voltage by suppressing heavy inrush currents. This feature reduces the transition time to reach the peak value of the dc-link voltage, and reduces the risk of component failure and overrating due to the inrush current. EL-ZSI and CL-ZSI possess all of the inherent advantages of the conventional L-ZSI topology while eliminating its drawbacks. To verify the effectiveness of the proposed topologies, MATLAB/Simulink models and scaled down laboratory prototypes were constructed. Experiments were performed at a low shoot through duty ratio of 0.1 and a modulation index as high as 0.9 to obtain a peak dc-link voltage of 53 V. This paper demonstrates the superiority of the proposed topologies over conventional ZSI topologies through a detailed comparative analysis. Moreover, experimental results verify that the proposed topologies would be advantageous for renewable energy source applications since they provide voltage gain enhancement, inrush current, dc-link voltage overshoot suppression and a reduction of the peak to peak source current ripple.

Development of High Efficiency DC-DC Converter Circuit Topology for Renewable Energy Application (신재생에너지 연계용 고효율 승압형 DC-DC Converter 회로 토폴로지 개발)

  • Jung, Tae-Uk;Kim, Ju-Yong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.1
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    • pp.105-111
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    • 2010
  • This article studies the design of DC-DC Converter to convert low-voltage energy sources generated from renewable power like battery power, photovoltaic power, or fuel cells into high-voltage ones. The circuit topology of H-bridge Converter to convert input voltage, 24[V], into out voltage, 400[V], was realized through applying phase shift angle control so as to manage electric power and voltage in the output side. The advantages of the converter system suggested are the low cost as well as current stress reduction, high efficiency, reliability, and simplified maintenance. It is also found that the system is highly useful to produce residential electric power.

MnO2 co-catalyst effect on Photoelectrochemical Properties of GaN Photoelectrode (MnO2 조촉매가 코팅된 GaN 광전극의 광전기화학적 특성)

  • Kim, Haseong;Bae, Hyojung;Kang, Sung-Ju;Ha, Jun-Seok
    • Journal of the Microelectronics and Packaging Society
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    • v.23 no.4
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    • pp.113-117
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    • 2016
  • Recently, hydrogen is regarded as important energy in the future, because it is clean and renewable. The photoelectrochemical (PEC) system, which produce hydrogen using water splitting by solar energy, is one of the most promising energy systems because it has abundant energy sources and good theoretical efficiency. GaN has recently been regarded as suitable photoelectrode that could be used to split water to generate hydrogen without extra bias because its band edge position include water redox potential ($V_{redox}=1.23$ vs. SHE). GaN also shows considerable corrosion resistance in aqueous solutions and it is possible to control its properties, such as structure, band gap, and catalyst characteristics, in order to improve solar energy conversion efficiency. But, even if the band edge position of GaN make PEC reaction facilitate without bias, the overpotential of oxygen evolution reaction could reduce the efficiency of system. One of the ways to decrease overpotential is introduction of co-catalyst on photoelectrode. In this paper, we will investigate the effect of manganese dioxide ($MnO_2$) as a co-catalyst. $MnO_2$ particles were dispersed on GaN photoelectrode by spincoater and analyzed properties of the PEC system using potentiostat (PARSTAT4000). After coating $MnO_2$, the flat-band potential ($V_{fb}$) and the onset voltage ($V_{onset}$) were moved negatively by 0.195 V and 0.116 V, respectively. The photocurrent density increased on $MnO_2$ coated sample and time dependence was also improved. These results showed $MnO_2$ has an effect as a co-catalyst and it would enhance the efficiency of overall PEC system.