• Title, Summary, Keyword: Shoot-through

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Four Novel PWM Shoot-Through Control Methods for Impedance Source DC-DC Converters

  • Vinnikov, Dmitri;Roasto, Indrek;Liivik, Liisa;Blinov, Andrei
    • Journal of Power Electronics
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    • v.15 no.2
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    • pp.299-308
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    • 2015
  • This study proposes four novel pulse width modulation (PWM) shoot-through control methods for impedance source (IS) galvanically isolated DC-DC converters. These methods are derived from a PWM control method with shifted shoot-through introduced by the authors in 2012. In contrast to the baseline solution, where the shoot-through states are generated by the simultaneous conduction of all transistors in the inverter bridge, our new approach is based on the shoot-through generation by one inverter leg. The idea is to increase the number of soft-switched transients and, therefore, decrease the dynamic losses of the front-end inverter. All the proposed approaches are experimentally verified through an insulated-gate bipolar transistor-based IS DC-DC converter. Conclusions are drawn in accordance with the results of the switching loss analysis.

Analysis and Control of Z-Source Inverter using Modified Space Vector Methods (변형 공간벡터방식을 사용한 Z-Source 인버터의 해석 및 제어)

  • Chun, Tae-Won;Tran, Quang-Vinh;Kim, Heung-Gun;Nho, Eui-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.12 no.4
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    • pp.332-338
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    • 2007
  • In this paper, the three modified space vector modulation methods are suggested in order to control effectively the shoot-through time at Z-source inverter. Both the switching patterns of three modulation methods and the modulation signals with a variation of shoot-through time are analyzed. The optimum modified space vector modulation method is determined by both the control range of the shoot-through time and the symmetry of the switching pattern and modulation signal. The performances of modulation methods are verified with the simulation results with 32-bit DSP.

An Efficient In vitro Propagation of Zanthoxylum piperitum DC.

  • Hwang, Sung-Jin;Hwang, Baik
    • Korean Journal of Medicinal Crop Science
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    • v.11 no.4
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    • pp.316-320
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    • 2003
  • A protocol is described for rapid multiplication of Zanthoxylum piperitum DC. (Rutaceae), an important aromatic and medicinal plant, through shoot-tip explant cultures. Murashige and Skoog (MS) medium supplemented with various concentrations of N-6-benzyladenine (BA), N-6-benzylaminopurine (BAP) and thidiazuron (TDZ), in single or in combination with ${\alpha}-naphthaleneacetic$ acid (NAA), was used to determine the rate of shoot proliferation. N-6-benzyladenine (BA) used at 0.5mg/l, was the most effective in initiating multiple shoot proliferation at the rate of 23 microshoots per shoot-tip explants after 40 days of culture. Shoot multiplication increased 1.2-fold in each successive subculture. Induction of rooting (98%) was achieved by transferring the shoots to the same basal medium containing 2 mg/l indole-3-butyric acid (IBA). Plantlets went through a hardening phase in a controlled growth chamber, prior to in vivo transfer. These results represented that possible application for the mass production of plantlets through in vitro culture system of Zanthoxylum piperitum DC.

In vivo propagation of Paeonia lactiflora Pall. Through Shoot-Tip Culture of Winter Buds (작약(Paeonia lactiflora Pall.) 동아의 경정배양을 통한 기내증식)

  • 정재동;한증술;지선옥
    • Korean Journal of Plant Tissue Culture
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    • v.22 no.2
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    • pp.101-104
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    • 1995
  • The experiment was conducted to identify the optimal in vitro propagation condition for P. lactiflora Pall. Through apical shoot tip and axillary shoot tip culture of winter bud. When apical shoot tip and axillary shoot tips excised from winter bud were cultured on MS medium supplemented with various concentrations of plant growth regulators, all the apical shoot tips elongated regardless of the composition of the medium but axillary shoot tips responded differently. Shoot of 'Uisong' local cultivate was well elongated in the medium containing 0.01mg/L NAA. Frequency of shoot formation and subsequent shoot growth in axillary shoot tip culture were promoted in the medium containing 0.01 mg/L NAA and 5.0mg/L zeatin. 30% of the elongated shoots were vigorously rooted on the medium containing 0.1mg/L NAA with vermiculite as a support medium.

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Plant Regeneration through Leaf Explant Culture of Boxthorn (Lycium chinense Mill.)

  • Ham, In-Ki;Park, Sang-Kyu;Lee, Bong-Chun;Lee, Mi-Ae;Kwon, Kyeong-Hak;Lee, Eun-Mo;Jo, Man-Hyun
    • Korean Journal of Plant Resources
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    • v.20 no.3
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    • pp.251-254
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    • 2007
  • This study was conducted to investigate the optimal plant growth regulator level for the shoot formation of Lycium chinense Mill. In vitro plant propagation was developed for leaf explants of boxthorn. Leaf explants were cultured on MS medium supplemented with cytokinins (BA and 2-iP) alone. Plants were successfully regenerated through in vitro culture by using leaf explants of boxthorn grown in the field. After 4 weeks of culture, 58% of shoot formation had developed from the leaf explants. The shoot formation rate of 'Jangmyeong' was highest followed by 'Myeongan', ;Cheondae', and 'Bullo'. The use of 0.2mg/L BA was critical for enhanced production of shoot formation and resulted in 58% of the culture producing shoot formations. Regenerated plantlets transplanted to pots were developed and successfully acclimatized to greenhouse.

Analysis of Common Mode Voltages at Diode Rectifier/Z-Source Inverter System (다이오드 정류기/Z-소스 인버터 시스템의 공통모드 전압 해석)

  • Tran, Quang-Vinh;Chun, Tae-Won;Lee, Hong-Hee
    • The Transactions of the Korean Institute of Power Electronics
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    • v.14 no.4
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    • pp.285-292
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    • 2009
  • In this paper, when ac motors are driven by the diode rectifier/Z-source inverter system, the common-mode voltages of system are analyzed in details under both the shoot-through state and non-shoot-through state through equivalent circuits. Then a modified space vector modulation strategy is suggested for attenuating the negative common-mode voltage by eliminating the zero voltage vector, and also controlling the shoot-through time. Through the simulation studies with PSIM and experiments with 32-bit DSP, it is verified that the negative common-mode voltage can be reduced by more than 50%.

Eliminating Potato Virus Y (PVY) and Potato Leaf Roll Virus (PLRV) Using Cryotherapy of in vitro-grown Potato Shoot Tips

  • Yi, Jung-Yoon;Lee, Gi-An;Jeong, Jong-Wook;Lee, Sok-Young;Lee, Young-Gyu
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.59 no.4
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    • pp.498-504
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    • 2014
  • Potato virus Y (PVY) and potato leafroll virus (PLRV) are among the most damaging potato viruses and prevalent in most potato growing areas. In this study, cryopreservation was used to eradicate PVY and PLRV using two cryogenic methods. Potato shoot tips proliferated in vitro were cryopreserved through droplet-vitrification and encapsulation-vitrification using plant vitrification solution 2 (PVS2; 30% glycerol + 15% dimethyl sulfoxide + 15.0% ethylene glycol + 13.7% sucrose) and modified PVS2. Both cryogenic procedures produced similar rates of survival and regrowth, which were lower than those from shoot tip culture alone. The health status of plantlets regenerated from shoot tip culture alone and cryopreservation was checked by reverse transcription-polymerase chain reaction. The frequency of virus-free plants regenerated directly from highly proliferating shoot tips reached 42.3% and 48.6% for PVY and PLRV, respectively. In comparison, the frequency of PVY and PLRV eradication after cryopreservation was 91.3~99.7% following shoot-tip culture. The highest cryopreserved shoot tip regeneration rate was observed when shoot tips were 1.0~1.5 mm in length, but virus eradication rates were very similar (96.4~99.7%), regardless of shoot tip size. This efficient cryotherapy protocol developed to eliminate viruses can also be used to prepare potato material for safe long-term preservation and the production of virus-free plants.

The characteristics of seed production in an Adonis multiflora (Ranunculaceae) population

  • Min, Byeong-Mee
    • Journal of Ecology and Environment
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    • v.37 no.4
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    • pp.165-175
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    • 2014
  • A natural population of Adonis multiflora, a spring ephemeral herb growing in temperate deciduous forests, was studied to determine the seed production characteristics. Plant size, flowering time, and seed number were monitored from February 2009 to May 2011 in main growing season (i.e., from March through May). The biomass rates of the shoot and the root in the A. multiflora population were 22-24% and 76-78%, respectively, and the biomass of the root was proportional to that of the shoot. The flowering rate was 60% in the plants with 1 to 2 g of shoot biomass, and 100% in the plants with >2 g of shoot biomass. In the plants with root biomass between 4 and 6 g, the flowering rate was 43% and, in the plants with the root biomass over 8 g, it was 100%. The shoot biomass was a better predictor of the flower production probability than the root biomass. The number of flowers and seeds was closely correlated to shoot biomass at 1% significance level. The size of the plant that produced seed excessively instead of the shoot biomass in one year typically decreased in the next year and vice versa. The flowering time and its duration were closely related to the number of faithful seeds but not to that of total seeds. The number of faithful seeds was proportionate to flowering duration and inversely proportionate to flowering time (year day, YD). In a plant, the number of faithful seeds noticeably decreased with the inflorescence (i.e., order of flower in a plant), and this difference between the two successive flowers was significant at the 1% level between the first and the third flower in 2009 and 2011 but not between the third and the fourth. However, the number of total seeds was mostly similar in the first through the fourth flower for all three years.

Analysis of Z-Source Inverters in Wireless Power Transfer Systems and Solutions for Accidental Shoot-Through State

  • Wang, Tianfeng;Liu, Xin;Jin, Nan;Ma, Dianguang;Yang, Xijun;Tang, Houjun;Ali, Muhammad;Hashmi, Khurram
    • Journal of Power Electronics
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    • v.18 no.3
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    • pp.931-943
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    • 2018
  • Wireless power transfer (WPT) technology has been the focus of a lot of research due to its safety and convenience. The Z-source inverter (ZSI) was introduced into WPT systems to realize improved system performance. The ZSI regulates the dc-rail voltage in WPT systems without front-end converters and makes the inverter bridge immune to shoot-through states. However, when the WPT system is combined with a ZSI, the system parameters must be configured to prevent the ZSI from entering an "accidental shoot-through" (AST) state. This state can increase the THD and decrease system power and efficiency. This paper presents a mathematical analysis for the characteristics of a WPT system and a ZSI while addressing the causes of the AST state. To deal with this issue, the impact of the system parameters on the output are analyzed under two control algorithms and the primary compensation capacitance range is derived in detail. To validate the analysis, both simulations and experiments are carried out and the obtained results are presented.

In vitro Propagation using Shoot Tip Culture of Curcuma longa L. (울금의 경정배양에 의한 기내번식)

  • 최성규
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.48 no.6
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    • pp.438-441
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    • 2003
  • The present study was carried out to assess the possibility of rapid multiplication of Curcuma longa Linne through in vitro culture of shoot-apex. The factor investigated was effect of various growth regulators on shoot-apex culture. The shoot-apex cultured of MS(Murashige and Skoog) medium developed into plantlet in 16 Weeks. M.S. medium containing NAA at 0.5 ppm and BA 5.0 ppm was found to be optimal for growth of in vitro plantlet