• 패션비즈니스
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• 제5권1호
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• pp.35-51
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• 2001

The purpose of this study is to have a new understanding of the freewheeling beauty inhering in the Korean western costumes, traditionally the freewheeling beauty has been the root of Korean beauty expressed in the Korean feeling. First, the theoritical inquiry for this study was processed to understand formativeness of the Korean popular arts, folk painting, pottery, pansori(dramatic song), masked dance. The results of the theoritical analysis were as follows; the korean beauty inherited in the Korean popular arts, was represented plastic words as good-humor, unsophisticated, homely, plainness, simplicity, artless, unartificial, crudely etc, the freewheeling beauty implied the beauty of good-humor, the beauty of naivety. In conclusion, the creative Korean beauty reflected in the western costumes by Korean designers was derived from freewheeling characteristics of Korean feeling. After this study, I came to conclusion that it‘s very important to recover, reperceive, revaluate the inner meanings inherited Korean western costumes.

• Journal of Power Electronics
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• 제15권4호
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• pp.920-928
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• 2015

Transformerless solar inverters have a higher efficiency than those with an isolation link. However, they suffer from a leakage current issue. This paper proposes a family of single phase six-switch transformerless inverter topologies with an ac bypass circuit to solve the leakage current problem. These circuits embed two unidirectional freewheeling current units into the midpoint of a full bridge inverter, to obtain a freewheeling current path, which separates the solar panel from the grid in the freewheeling state. The freewheeling current path contains significantly fewer devices and poor performance body diodes are not involved, leading to a higher efficiency. Meanwhile, it is not necessary to add a voltage balancing control method when compared with the half bridge inverter. Simulation and experiments are provided to validate the proposed topologies.

• 전력전자학회논문지
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• 제27권4호
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• pp.339-347
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• 2022

This study proposes the mitigation method for overcurrent and oscillation motor current in an active short-circuit operation. This operation is attracting attention as the safe state of electric vehicle traction inverters. However, the active short-circuit operation generates oscillation and overcurrent of motor currents during a transient state. The proposed method uses two different safe states in PMSM, such as active short circuit and freewheeling. The active short circuit is used for safe state in a steady state. To reduce the overshoot and oscillation, a freewheeling state is injected between active short-circuit operation by comparing the motor phase current with an analytically calculated steady-state motor current. Freewheeling state is only used in a transient state. The performance is demonstrated through simulations and experimental results. The peak current of the motor was reduced from 52 A to 40 A, and oscillation time was reduced.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.685-688
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• 2015

기존의 컨버터에서 널리 사용되는 위상천이 풀브리지 컨버터(Phase-Shifted Full-Bridge Converter) 경우 입력 전원 변화에 출력 전압의 변동이 있는 경우 듀티 변화에 따른 Freewheeling 구간이 존재하게 되며 효율을 감소시키는 요인이 된다. 본 논문에서는 고효율을 요구하는 ESS 시스템에서 컨버터/인버터의 효율 향상 방안을 제시한다. Freewheeling 구간에서 ZVS(Zero Voltage Switching) 실패문제를 해결하기 위한 듀티 제어 기법을 사용하여 구현하였으며 실험 결과 효율을 향상시켰다.

• 복식
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• 제62권3호
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• pp.96-111
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• 2012

This study is to analyze fashion phenomenon according to the concept of the characteristics of freewheeling to explain the de-constructive, eclectic, avant-garde tendencies in Contemporary Fashion. This study is to elicit the aesthetic characteristics through 400 pieces of visual data analysis from 2001S/S to 2011F/W that have the characteristics of freewheeling, nontechnical experiments do away with the classical form. The oriental ideas include the thoughts of different tastes that break the stereotypes according to the Western values and the pursuit of unconventional beauty. These also insist that everything in the world including human-being, nature and creation is not divided into two equal parts, and even beauty and ugliness originated from one. This study is to find the possibility of interpreting oriental aesthetics with open concepts that transcends the boundaries of full availability, unlike the Western values that accommodate the relative concept of the pursuit of diversity. Therefore, integrated and systematic approaches of oriental aesthetics that place much value on the coexistence of antithetic concepts are needed to understand the ambiguity of complexity and diversity in Contemporary fashion design.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권1호
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• pp.1-8
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• 2005

This paper presents a characteristic analysis of switched reluctance motor (SRM) considering switching control method and DC link voltage ripple by using time-stepped voltage source finite element method in which the magnetic field is combined with drive circuit. We also examine the influence of freewheeling diodes and DC link voltage ripple on the performance of the SRM such as torque ripples and radial force on the surface of the teeth. The freewheeling diodes and DC link voltage ripples must be taken into account to predict the performance of SRM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.872-874
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• 2004

This paper presents a charcteristcic analysis switched reluctance motor (SRM) considering hard chopping and DC link voltage ripple by using time-stepped voltage source finite element method in which the magnetic field is combined with drive circuit. We also examine the influence of freewheeling diodes and DC link voltage ripple on the performance of the SRM such as torque ripples and radial force on the surface of the teeth The freewheeling diodes and DC link voltage ripples must be taken into account in predicted the performance of SRM

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.714-716
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• 2003

This paper deals with the characteristic analysis of a brushless DC motor (BLDC) and taking into consideration the freewheeling diodes and DC link voltage ripple using a time-stepped voltage source finite element method. By comparing with the experimental results, we show that the proposed computational method is useful for the analysis and design of a BLDC motor. We also examine the influence of freewheeling diodes and DC link voltage ripples on the performance of a BLDC motor such as torque ripples and radial force on the surface of the teeth.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.249-256
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• 2007

This paper presents a new circuit topology and its digital control scheme for a half-bridge resonant inverter. As the proposed half-bridge inverter can be operated in load-freewheeling modes, the pulse-width modulation (PWM) method can be used for the output power control. The proposed half-bridge inverter is based on the resonant frequency-tracking algorithm with the goal of maintaining the unity of the output displacement factor of the load impedance even in varying conditions. In this paper, the operation principle, electrical characteristics, and detailed digital control scheme of the proposed half-bridge resonant inverter are described. The experimental results of the prototype experimental setup to verify the validity of the proposed half-bridge inverter are presented and discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1160-1162
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• 2003

This paper presents ZVZCS(Zero-Voltage and Zero-Current Switching) Dual TTFC(Two-Transistor Forward Converter) without primary freewheeling diodes. The principle of operation, feature and design considerations are illustrated and verified through the ecperiment with a 1.8kW 55kHz MOSFET based experimental circuit.