• 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.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.1
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• pp.93-105
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• 2019

In order to establish an effective engagement plan of the missile defense system, both spatial and temporal performance analysis of the intercept system should be performed. However, research on existing missile defense systems has been mainly focused on spatial performance. In this study, time performance factors are defined through the composition and operational concept of missile defense system, and the target ballistic missile interception process is presented as integrated timeline through ballistic missile model and radar model. We also proposed an algorithm for deriving time performance. Simulation results confirm that the time performance factors can be used in the engagement planning for multi-engagement through the example of engagement planning.

• 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.

• Proceedings of the KIPE Conference
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• 2004.11a
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• pp.64-69
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• 2004

This paper deals with an algorithm for controlling ac output voltage of Z-source inverter using Modified SVPWM (abbreviated as MSVPWM). Unlike the conventional space vector pulse width modulation, MSVPWM has one extra shoot-through zero time $T_{sh}$. During shoot-through zero time, both switches in a leg are conducted simultaneously in order to boost inverter output voltage to any desirable value regardless the line voltage. The algorithm to control linearly the capacitor voltage is suggested to improve the performance of Z-source inverter system. The performance of Z-source inverter using above algorithms is demonstrated in simulation results using PSIM. Index terms-Z-source inverter (ZSI), shoot-through time, three-phase carrier-based PWM, space vector PWM (SVPWM), modified space vector PWM (MSVPWM).

• Journal of Power Electronics
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• v.14 no.2
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• pp.249-256
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• 2014

A novel topology generation method for the no dead-time three-phase AC/DC converter is proposed in this study. With this method, a series of no dead time topologies are generated and their operation principles are analyzed. The classic three-phase bridge AC/DC converter can realize a bidirectional operation. However, dead-time should be inserted in the driving signals to avoid the shoot-through problem, which would cause additional harmonics. Compared with the bridge topology, the proposed topologies lack the shoot-through problem. Thus, dead time can be avoided. All of the no dead time three-phase AC/DC converters can realize bidirectional operation. The operating principles of the converters are analyzed in detail, and the corresponding control strategies are discussed. Comparisons of waveform distortion and efficiency among the converters are provided. Finally, 9 KW DSP-based principle prototypes are established and tested. Simulation and experimental results verify the theoretical analysis.

• 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%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.3
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• pp.161-167
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• 1998

Root and shoot development of two rice (Oryza sativa L.) cultivars with different genetic backgrounds was studied with reference to their relative growth. Tongil type (indica-japonica hybrid) cultivar 'Kuemkangbyeo' and japonica cultivar 'Koshihikari' were grown in $5000^{-1}$ a Wagnar pots under flooded condition. Three plants with roots of both cultivars were taken in every phyllochron through the heading stage to record morphological characteristics of shoot and root system. Compared to Koshihikari, Kuemkangbyeo produced more tillers and had greater shoot weight and leaf area per hill. Length and weight of the root system in both cultivars increased exponentially with time. At the same time, root system development was significantly faster in Kuemkangbyeo than in Koshihikari after the panicle initiation stage. As a result, Kuemkangbyeo has a vigorous root system which consists of larger number of nodal roots compared to Koshihikari. Also, the root length and weight per unit leaf area of Kuemkangbyeo were larger than those of Koshihikari in the later half of growing period, which suggests possible higher physiological activity of the root system of Kuemkangbyeo which is known as a high-yielding cultivar. The relationship between root traits (crown root number, total root length, and root dry weight) and shoot traits (leaf area and leaf+culm dry weight) in both cultivars closely showed allometry until the flag leaf stage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.580-583
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• 2009

This paper introduces a gate drive IC for power modules with shoot-through immunity. A new approach uses a bootstrap diode as a high-side voltage bias and a level shift function at the same time. Therefore, the gate drive circuit becomes a simple and low-cost without conventional level shift functions such as HVIC(High-Voltage IC), optocoupler and transformer. The proposed gate drive IC is designed and fabricated using the Dongbu-Hitek's 0.35um BD350BA process. It has been tested and verified with IGBT modules.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.81-82
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• 2009

This paper introduces a gate drive IC for power modules with shoot-through immunity. A new approach uses a bootstrap diode as a high-side voltage bias and a level shift function at the same time. Therefore, the gate drive circuit becomes a simple and low-cost without conventional level shift functions such as HVIC(High-Voltage IC), optocoupler and transformer. The proposed gate drive IC is designed and fabricated using the Dongbu-Hitek's 0.35um BD350BA process. It has been tested and verified with IGBT modules.

• Journal of Power Electronics
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• v.19 no.2
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• pp.454-462
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• 2019

When compared to traditional bridge-type inverters, the dual-buck inverter has a higher reliability due to the fact that its bridge legs do not have a shoot-through problem. In this paper, the working principle of the dual-buck inverter is analyzed. A comparison of the working modes under full-cycle and half-cycle control is discussed. With half-cycle control, the inverter can realize a higher efficiency. However, this results in current zero-crossing distortion. The corresponding control strategy of the dual-buck inverter is proposed in order to realize both high efficiency and low current harmonic distortion. In addition, the system stability is analyzed. Dead-time is unnecessary due to the advantages of the topology. Thus, the current harmonic distortion can be further reduced. An inverter with the proposed control strategy has the advantages of high reliability, high efficiency and low current harmonic distortion. Finally, simulation and experimental results are given to verify the theoretical analysis.