• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.367-371
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• 2007

무(無)정전을 요구하는 특정대상의 중요 전기시설에서, 신뢰도 낮은 수전방식의 정전 가능성 대책으로 대용량의 UPS와 비상발전기를 설치 운영 중에 있다. 근래에 와서 상용전원과 발전기 또는 복수의 발전기에 CTTS (Closed Transition Transfer Switch)를 무(無)정전 전환개폐기 전용으로 사용하고 있다. 본 논문에서 CTTS를 신뢰도 높은 상용2회선 수전방식의 수전변압기 2차 측에 적용한 새로운 무(無)정전 전원설비 구축 방안을 제안하였다. 그 결과 수전설비 구성 간략화와, UPS 비상발전기 설치 최소화로 공간 및 투자절감 효과를 얻을 수 있다.

• 한국전자파학회논문지
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• 제12권5호
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• pp.686-693
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• 2001

본 논문에서는 대전력 증폭기의 비선형 전달 특성을 나타내는 Carrier Complex Power Series를 유도하였고, 이 전달함수를 이용하여 대전력 증폭기를 선형화하기 위한 전치 왜곡기의 비선형 전달 특성을 유도하고 구현하였다. 측정 시료로 제작된 IMT-2000 기지국 송신 대역 대전력 증폭기의 이득은 34.6 dB이고 P$_{1dB}$가 35.4 dBm이다. Inverse Carrier Complex Power Series를 이용한 전치 왜곡기를 제작하고, 대전력 증폭기에 부착하여 주파수가 각각 2.1375 GHz와 2.1425 GHz($\Delta$f=5 MHz)인 2-tone 신호의 출력이 25.43 dBm/tone일 때 17 dB의 개선 특성을 얻었다.다.

• 한국태양에너지학회 논문집
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• 제33권4호
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• pp.51-58
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• 2013

A study on power performance testing of a wind turbine which has no met-mast at a distance of 2~4 rotor diameter was carried out using the Nacelle Transfer Function, NTF, according to IEC 61400-12-2. The wind data for this study was measured at HanKyoung wind farm of Jeju Island. The NTF was modeled using the correlation between wind speeds from the met-mast and from the wind turbine nacelle within 2~4 rotor diameter from the met-mast. The NTF was verified by the comparison of estimated Annual Energy Productions, AEPs, and binned power curves. The Nacelle Power Curve, NPC, was derived from the nacelle wind speed data corrected by NTF. The NPC of wind turbine under test and the power curve offered by the turbine manufacturer were compared to check whether the wind turbine is properly generating electricity. Overall the NPC was in good agreement with the manufacturer's power curve. The result showed power performance testing for a wind turbine which has no met-mast at a distance of 2~4 rotor diameter was successfully carried out in compliance with IEC 61400-12-2.

• Journal of Biosystems Engineering
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• 제34권2호
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• pp.89-94
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• 2009

Aerial application using an agricultural unmanned helicopter was suggested for an alternative against current pesticide application methods. Centrifugal clutches play important roles in the performance and safety of the helicopter operation. A previous study analyzed and verified the power transfer theory of the guide type centrifugal clutch. Based on the clutch theory, optimal designs of the clutch became possible and feasible using a simulation method. Design criteria of the clutch were the power transfer capacity of 24.66 kW(33.5 PS) at the rated engine speed and the engaging range speed of 3,000${\sim}$3,500 rpm. Various designs were accomplished using the simulation. An optimal clutch was simulated by determining the values of spring constant and mass of friction sector, which were 94,700 N/m and 123.7 g, respectively. The design performed the power capacity of 24.86 kW(33.8 PS) and engagement speed of 3,069 rpm, meeting the design criteria. Using the designed clutch, an efficient transfer of the power would be possible for the unmanned agricultural helicopter.

• Journal of Power Electronics
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• 제17권3호
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• pp.835-847
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• 2017

A transmitting coil with an optimal topology and number of turns can effectively improve the performance of the wireless power transfer (WPT) systems for endoscope robots. This study proposes the evaluation parameters of the transmitting coils related to the performance of the WPT system to standardize the design of the transmitting coils. It considers both the quality factor of transmitting coils and the coupling factor between the two sides. Furthermore, an analytical model of transmitting coils with different topologies is built to exactly estimate the evaluation parameters. Several coils with the specified topologies are wound to verify the analytical model and the feasibility of evaluation parameters. In the case of a constant power received, the related evaluation parameters are proportional to the transfer efficiency of the WPT system. Therefore, the applicable frequency ranges of transmitting coils with different topologies are determined theoretically. Then a transmitting coil with a diameter of 69 cm is re-optimized both theoretically and experimentally. The transfer efficiency of the WPT system is increased from 3.58% to 7.37% with the maximum magnetic field intensity permitted by human tissue. Finally, the standardized design of the transmitting coil is achieved by summing-up and facilitating the optimization of the coils in various situations.

• 전자공학회논문지
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• 제53권1호
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• pp.22-26
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• 2016

본 논문에서는 공 모양의 구조를 이용하여 공진형 무선 전력 전송용 송 수신기를 설계 및 구현하였다. 제안된 송신기의 코일을 공 모양으로 감음으로써 3차원의 공간으로 자계 에너지를 방사하도록 하였다. 송신기의 각각의 면을 나선 구조로 함으로써 높은 Q 값을 얻을 수 있도록 설계하였다. 이것은 기존의 무선 전력 전송 시스템에서 위치에 따라서 전송효율이 변하는 문제점을 해결하였다. 그리고 3차원에서의 공진형 무선 전력 전송을 가능하게 한다. 이때의 공진주파수는 6.78 MHz이며, 송 수신기 사이 거리가 200 mm일 때, 3차원 전 방향에서 40% 이상의 전송 효율을 얻을 수 있었다.

• Journal of electromagnetic engineering and science
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• 제17권2호
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• pp.76-85
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• 2017

We investigate the indirect-fed magnetic resonant wireless power transfer (MR-WPT) system for wireless charging for mobile devices by rearranging the loops and coils. Conventional MR-WPT is difficult to apply to consumer electronic products because of the arrangement of the resonators. In addition, there are restrictions for charging using a wireless technology, which depend on the circumstances of the usage scenarios. For practical applications, we analyzed the transfer efficiency of the MR-WPT system with various combinations and positions of resonators. Three rearranged configurations (Out-Out, Out-In, In-In) have been considered and experimentally investigated using hollow pipe loops and wire copper coils. There were four types of loops and two types of coils; each one had a different diameter and thickness. The results of the measurements show that the trends of the transfer efficiencies for the three configurations were similar. A transfer efficiency of 82.5% was achieved at a 35-cm distance between the 60-cm diameter transmitter (Tx) and receiver (Rx) coils.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.321-323
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• 2009

When power failure occurs at multi-housing complex, auxiliary generator or emergency generator starts to provide power to households. This power is connected to emergency power ELB(Earth Leakage Breaker) at home distribution panel board and supplies power only for emergency light in living room but for heating system, refrigerator and other inevitable apparatuses that are in need of uninterruptible power. Since those domestic appliance are fed from common power line, they are inoperable during power failure. Our research is to resolve this problem by developing compatible relay-drive common/emergency-power ATS (automatic transfer switch) for home distribution panel board. In case of power failure, it transfers automatically and commences to provide power from emergency generator. Through this, Consumers can reach satisfaction where common power loads operate without any problem under both ordinary and power failure condition.

• 동력기계공학회지
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• 제17권3호
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• pp.28-34
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• 2013

This study is experimentally performed for using the oyster shell as a desiccant in the fluidized bed with bundle of heating pipe. The test material is oyster shell from fishery wastes which can use without costs. The main parameters of experiment are inlet air temperature, velocity of inlet air and heat flux of heating pipes. Also the geometry of heating pipe is treated as important parameter. From this study, the effect of inlet air temperature and input heat flux have much affect to increase the heat and mass transfer. On the other hand, the effect of inlet air velocity has less affect to increase the heat and mass transfer. And it is clarified that the oyster shell has sufficient probability for using as a desiccant in air-conditioning system.

• Journal of Magnetics
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• 제18권2호
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• pp.105-110
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• 2013

The design model and key parameters of the material design for the control of induced magnetic flux at the near-field and efficient power transfer in a modified wireless power transfer (WPT) system with a large air gap of wireless electric vehicles were investigated through analytical simulations for magnetic vector and time-domain transient analysis. Higher saturation magnetic core with low core loss induced a stronger vertical magnetic field by the W-type primary coil in the WPT system with a gap of 20 cm at 20 kHz, which is shown from the vector potentials of the magnetic induction. The transient analysis shows that the higher magnetic fluxes through the pick-up cores lead to a linear increment of the alternating voltage with a sinusoidal waveform in the non-contact energy transfer system.