• 전력전자학회논문지
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• 제16권6호
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• pp.610-617
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• 2011

본 논문은 공간벡터펄스 변조법(SVPWM, Space Vector Pulse Width Modulation)을 사용하는 3상 인버터의 새로운 데드타임 직접 보상 방법을 제안한다. 제안된 데드타임 보상방식은 인버터에 인가되는 데드타임을 중간상 전류의 방향에 따라, 유효전압이 인가되는 유효전압벡터 인가시간에서 직접 보상하는 방식이다. 3상 인버터에서 각상에 인가되는 전압의 크기는 유효전압이 인가되는 시간에 의해 결정되고, 데드타임의 영향에 따라, 실제로 유효전압이 인가되는 스위칭 시간은 전류의 방향에 따라 손실이 발생하게 된다. 제안된 방식에서는 실제로 전류의 방향에 따라 손실이 발생하는 유효전압벡터의 인가시간에 직접적으로 손실 시간을 더하여 유효전압벡터의 인가시간을 계산하는 방식으로 별도의 전압오차를 보상하기 위한 제어기와 복잡한 d-q 변환을 필요로 하지 않는 장점이 있다. 제안된 방식은 3상 R-L 부하에 대하여 컴퓨터 모의해석과 실험을 통하여 제안된 방식의 데드타임 보상을 검증하였다.

• 전력전자학회논문지
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• 제10권1호
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• pp.38-44
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• 2005

전압형 인버터에서 데드 타임은 직류단 단락을 방지하기 위하여 필요하다. 데드 타임 효과는 출력 전압, 출력 전류의 왜곡으로 나타난다. 최근 많은 논문에서 데드 타임 보상 방법에 대한 연구가 이루어졌다. 본 논문에서는 데드타임을 보상하는 것이 아니라 데드 타임이 없는 인버터를 제안한다. 부하전류를 측정할 필요도 없으며 데드 타임보상을 위한 계산도 필요 없다. 이는 인버터의 각 레그에 트랜스포머를 추가함으로써 가능하다. 제안된 방법의 각 모드 해석이 선행되고 타당성을 위한 시뮬레이션 결과가 제시된다.

• Journal of Chest Surgery
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• 제25권8호
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• pp.850-855
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• 1992

Dead space of empyema occurrs from incomplete obliteration of infected pleural space from pulmonary tuberculosis, pyogenic infection, esophageal disease and post pulmonary resection. Chronic empyema can be treated by obliteration of dead space with autologous tissues such as, extrathoracic muscle flap and omental flap and thorachoplasty. Between May, 1986 to July, 1991 we treated 17 chronic empyema patients with autologous tissues and analysed the result. 1. Sex distribution was 14 males and 3 females between 5~62 years old. [mean 39.7 years old] 2. The volume of the dead space ranged from 100 to 450cc. [mean 213. 76cc] 3. The majority of used muscle flap were serratus anterior and latissimus dorsi, and there were 2 cases of am ntal flap. 4. The majority of underlying disease were pulmonary tuberculosis and there were 8 BPF[47%] in 17 patients 5. In 7 cases, thorachoplsty was needed. 6. Three cases recurred and there were no death.

• 한국진공학회지
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• 제15권5호
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• pp.451-457
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• 2006

벌집형 양극 셀 구조를 가지는 스퍼터 이온펌프를 제작하여 그 성능을 측정하고 기존의 원통형 구조와 비교하였다. 원통형 구조는 원통과 원통 사이에 기체의 이온화에 크게 기여하지 못하는 공간(dead space)이 전체의 10 % 정도 존재하는데, 벌집형 구조에서는 이러한 공간이 없으므로 이론적으로는 배기성능 또한 최대 10 % 정도 향상될 것으로 예측된다. 이러한 점에 착안하여 본 연구에서는 원통형 및 벌집형 셀 구조의 스퍼터 이온펌프를 제작하여 배기성능을 측정하여 서로 비교하였다. 그 결과 벌집형 구조가 원통형 구조에 비해 압력 구간에 따라서 $5%{\sim}11%$ 정도 배기속도가 높은 것으로 나타났다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 추계학술대회
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• pp.71-72
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• 2011

This paper presents a novel and direct dead time compensation method of the 3 phase inverter using space vector pulse width modulation(SVPWM) topology. In the turn on time calculation of the effective voltage, the dead time effect is directly compensated according to the current direction of the midium voltage reference. Since the turn on time of the effective voltage vector is affected by the dead time, the loss time is compensated to turn on time of the effective voltage vector. And the dead time is added to the calculated voltage vector switching times according to the current direction. For the more effective compensation, the direction of the midium phase current is considered by the practical direction and voltage drops in the power devices. The proposed method can compensate the dead time which is considered feedback error or direction of middle phase current without coordinate transform in added controller. The proposed dead time compensation scheme is verified by the computer simulation and experiments of 3 phase R L load.

• 한국주거학회논문집
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• 제7권2호
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• pp.19-27
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• 1996

The aim of this study is to analyze the intrinsic meaning of housing according to meaning of ritual space in Korean housing. At a traditional housing the rites give a sacred characteristic and grade of ranks to space. According to rites Malu(Dae-Chung) is a male's space and An-Bang is a female's space. At a present housing the central characteristic of An-Bang and sexual division of space are weakened and the space of dead person is disappered. But the rites and ritual space give sacred characteristic stability and identification in housing.

• 한국주거학회논문집
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• 제26권4호
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• pp.63-73
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• 2015

'Alley' is the community space as the fundamental living space for local residents and also it's the space which characterize the local community. Research is needed to rediscover the value of alleys which are disappearing due to urban planning. This research focuses on Seochon (current Saejong village) alleys and classify the types of alleys where residential density is seen. Further, this research aims the analysis of dwellings which use the alleys and the characteristics of the layout of alleys. Followings are the research results; 1) Major classifications are 'through alleys' and 'dead end alleys' and there is higher ratio for dead end alleys. 2) Majority of Seochon alleys have the width of more than 1.5 m and less than 3.6 m. 3) There are four types of alleys and straight alleys are most common. 4) Various type of alleys can be found where the width is wider. 5) In case of dead end alleys, there is a tendency of both sides layout rather than one side layout of dwellings. 6) Clusters of hanok can be found at Chebu-dong, Tongin-dong, Nuha-dong and Tongui-dong whereas modern dwellings and villas are more common in Nusang-dong and Ogin-dong. This research analyzes the current status of Seochon alleys and rediscover the value of alleys. This research also provides and presents the basic data materials for continuous sustainable method to keep alleys which characterize the local area.

• Journal of Power Electronics
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• 제9권3호
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• pp.438-446
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• 2009

The performance of direct torque controlled (DTC) interior permanent magnet (IPM) machines is poor at low speeds due to a few reasons, namely limited accuracy of stator voltage acquisition and the presence of offset and drift components in the acquired signals. Due to factors such as forward voltage drop across switching devices in the three phase inverter and dead-time of the devices, the voltage across the machine terminals differ from the reference voltage vector used to estimate stator flux and electromagnetic torque. This can lead to instability of the IPM drive during low speed operation. Compensation schemes for forward voltage drops and dead-time are proposed and implemented in real-time control, resulting in improved performance of the space vector modulated DTC IPM drive, especially at low speeds. No additional hardware is required for these compensators.

• Journal of Power Electronics
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• 제13권1호
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• pp.77-85
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• 2013

This paper proposes a new dead time compensation method of independent six-phase permanent magnet synchronous motors (IS-PMSM). The current of the independent phase machines contains odd-numbered harmonics because of the dead time and the nonlinear characteristics of the switching devices. By using the d-q-n three-dimensional vector analysis, these harmonics can be extracted at the n-axis current. Thus, the current distortion can be compensated by controlling the n-axis current of the IS-PMSM to zero. The proposed method is simple and can be easily implemented without additional hardware setup. The validity of the proposed compensation method is verified with simulations and several experiments.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권9호
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• pp.618-625
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• 2000

Recently PWM inverters are widely utilized for many industrial applications e.g. high performance motor drive and PWM techniques are newly developed for an accurate output voltage. Among them space voltage vector PWM(SVPWM) inverter has high voltage ratio and low harmonics compared to the conventional sinusoidal PWM inverter. However output voltage of PWM inverter is distorted and has error duet o the conducting voltage drop of switching devices and the dead time that is inevitable to prevent the shoot-through phenomenon. This paper investigates 3-phase SVPWM inverter which has a new compensation method against dead time and voltage drop. Proposed algorithm calculates gate pulse periods which directly compensates the dead time and nonlinear voltage drop without modification of reference voltages. Direct compensation of gate pulse periods produces exact output voltage and does not need additional circuits. The propose algorithm is verified through the simulation and experiments.