• 에너지공학
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• 제19권2호
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• pp.81-91
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• 2010

플러그인 하이브리드자동차의 개발이 활발하다. 배전망으로부터의 전력을 수송에 사용함으로써 온실효과가스 배출과 화석연료소비를 저감시킨다. 향후 2030년까지의 플러그인 하이브리드자동차용 축전장치로는 리튬이온 이차전지가 가장 현실적인 기술이다. 리튬이온 이차전지 기술의 현황을 리뷰하고 장차 실용화될 것으로 전망되는 양극소재의 특성을 비교한다.

• 에너지공학
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• 제18권1호
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• pp.31-36
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• 2009

환경친화적인 자동차 제조 방법에는 몇 가지 방법이 있다. 하이브리드 전기자동차는 가장 현실적인 방법일 것이다. 하이브리드 전기자동차는 내연기관과 전기장치의 두 가지 동력을 사용한다. 하이브리드 전기자동차는 연료소비와 배기가스 저감을 위해서 개발되었다. 저자들은 하이브리 전기자동차의 주요 동력원으로 디젤 기관을 선택했다. 테스트는 도심버스주행모드와 고속도로주행모드가 사용되었다. 본 연구는 직렬하이브리드 전기자동차, 병렬하이브리드 전기자동차, 플러그인 직렬 전기자동차와 플러그인 병렬 전기자동차에 따른 중형디젤 하이브리드 자동차의 연료경제성과 배기가스의 시뮬레이션의 결과를 제시하고 있다.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2640-2645
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• 2021

We report the development of a gamma-ray imaging device, named Large-Area Hybrid Gamma Imager (LAHGI), featuring high imaging sensitivity and good imaging resolution over a broad energy range. A hybrid collimation method, which combines mechanical and electronic collimation, is employed for a stable imaging performance based on large-area scintillation detectors for high imaging sensitivity. The system comprises two monolithic position-sensitive NaI(Tl) scintillation detectors with a crystal area of 27 × 27 cm² and a tungsten coded aperture mask with a modified uniformly redundant array (MURA) pattern. The performance of the system was evaluated under several source conditions. The system showed good imaging resolution (i.e., 6.0-8.9° FWHM) for the entire energy range of 59.5-1330 keV considered in the present study. It also showed very high imaging sensitivity, successfully imaging a 253 µCi ¹³⁷Cs source located 15 m away in 1 min; this performance is notable considering that the dose rate at the front surface of the system, due to the existence of the ¹³⁷Cs source, was only 0.003 µSv/h, which corresponds to ~3% of the background level.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.169-172
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• 2005

A flywheel system is an electromechanical energy storage device that stores energy by rotating a rotor. The rotating part, supported by magnetic bearings, consists of the metallic shaft, composite rims of fiber-reinforced materials, and a hub that connects the rotor to the shaft. The delamination in the fiber wound composite rotor often lowered the performance of the flywheel energy storage system. In this work, an advanced hybrid composite rotor with a split hub was designed to both overcome the delamination problem in composite rim and prevent separation between composite rim and metallic shaft within all range of rotational speed. It was analyzed using a three-dimensional finite clement method. In order to demonstrate the predominant perfom1ance of the hybrid composite rotor with a split hub, a high spin test was performed up to 40,000 rpm. Four radial strains and another four circumferential strains were measured using a wireless telemetry system. These measured strains were in excellent agreement with the FE analysis. Most importantly, the radial strains were reduced using the hybrid composite rotor with a split hub, and all of them were compressive. As a conclusion, a compressive pressure on the inner surface of the proposed flywheel rotor was achieved, and it can lower the radial stresses within the composite rotor, enhancing the performance of the flywheel rotor.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2003년도 춘계 학술발표회 논문집
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• pp.211-232
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• 2003

연료전지 개발 필요성; "One of the most important technologies for the early 21st century" - Bill Clinton, "Not only to encourage research and development, but to provide tax credits to enhance the marketplace of hybrid and fuel-cell vehicles" - Bush. 연료전지 장점 - 에너지 변환 고효율(70%), 무/저공해 발전, 높은 에너지 저장력 (고용량), 시장환경 - 석유 자원 유한, 환경오염에 따른 무공해 에너지원 필요, Portable Device의 장시간 사용 Needs.(중략)

• 조명전기설비학회논문지
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• 제26권3호
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• pp.16-23
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• 2012

This paper relates to a study on the economic of electrical storage device for supplying power in sunless days, in the stand alone PV/Wind hybrid system, which it is applied to separate houses. In a photovoltaic/wind hybrid power system used in a separate house, when only the battery is used in sunless days, the capacity of the battery is become larger. For example, as in recent days, if cloudy days are frequent due to anomaly climate, it is difficult to supply power stably by only the battery based upon pre-estimated sunless days. Accordingly, in order to supply stably power of new renewable energy such as solar to any separate houses, it is preferable to reduce the capacity of battery by decreasing the number of sunless days when estimating the capacity of battery and to drive the small generator for compensation of the power shortage.

• Transactions on Electrical and Electronic Materials
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• 제10권6호
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• pp.208-211
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• 2009

The authors have demonstrated the various characteristics of hybrid white organic light-emitting diodes (HWOLED) using fluorescent blue and phosphorescent red emitters. We also demonstrated that two devices showed different characteristics in accordance with thickness of the 4,4′-N,N′-dicarbazole-biphenyl (CBP) spacer (CS) inserted between the blue and the red emitting layer. It was found that the device with a CS thickness of 70 $\AA$ showed a current efficiency 2.5 times higher than that of the control device with a CS thickness of 30 $\AA$ by preventing the triplet Dexter energy transfer from the red to the blue emitting layer. The HWOLED with the CS thickness of 70 $\AA$ exhibited a maximum luminance of 24500 cd/$m^2$, a maximum current efficiency of 42.9 cd/A, a power efficiency of 37.5 lm/W, and Commission Internationale de I'Eclairage coordinates of (0.37, 0.42).

• Smart Structures and Systems
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• 제4권6호
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• pp.809-828
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• 2008

Real-time hybrid testing is an attractive method to evaluate the response of structures under earthquake loads. The method is a variation of the pseudodynamic testing technique in which the experiment is executed in real time, thus allowing investigation of structural systems with time-dependent components. Real-time hybrid testing is challenging because it requires performance of all calculations, application of displacements, and acquisition of measured forces, within a very small increment of time. Furthermore, unless appropriate compensation for time delays and actuator time lag is implemented, stability problems are likely to occur during the experiment. This paper presents an approach for real-time hybrid testing in which time delay/lag compensation is implemented using model-based response prediction. The efficacy of the proposed strategy is verified by conducting substructure real-time hybrid testing of a steel frame under earthquake loads. For the initial set of experiments, a specimen with linear-elastic behavior is used. Experimental results agree well with the analytical solution and show that the proposed approach and testing system are capable of achieving a time-scale expansion factor of one (i.e., real time). Additionally, the proposed method allows accurate testing of structures with larger frequencies than when using conventional time delay compensation methods, thus extending the capabilities of the real-time hybrid testing technique. The method is then used to test a structure with a rate-dependent energy dissipation device, a magnetorheological damper. Results show good agreement with the predicted responses, demonstrating the effectiveness of the method to test rate-dependent components.

• 전기학회논문지
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• 제63권11호
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• pp.1615-1621
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• 2014

A wireless tram which runs without catenary and instead uses batteries installed in the tram has been recently researched actively. This paper presents a new method maximizing absorption of regenerative energy of a wireless tram and extending life cycle of the energy storage device in the wireless tram by applying line-optimized charging and discharging scenario. Energy efficiency and life cycle of energy storage system (ESS) are highly dependent on the characteristic of operating conditions. For example, frequent charge and discharge with high power cause the problems that decrease the battery life cycles. Hybrid energy storage system (HESS) is combination of two ESSs which have complementary characteristics to each other. HESS can provide even better functionality and performance than the battery only ESS due to the synergy effect of two ESSs. This paper also provides a power distribution strategy and driving scenarios which increase the life cycle and energy efficiency of the HESS consisting of a battery and an ultra-capacitor. The developed strategy was tested and verified by a hardware-in-the-loop-simulation (HILS) system which emulates the a wireless tram.

• 한국정보전자통신기술학회논문지
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• 제12권5호
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• pp.499-506
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• 2019

본 논문은 SiC Hybrid module를 적용한 7kW 인버터의 동작 안정성에 관한 것으로 손실 방정식과 시뮬레이션 결과를 비교하여 시뮬레이션 결과의 유효성을 검증하였으며, 시뮬레이션을 통해 Si module과 SiC Hybrid module의 스위치 손실과 다이오드 손실을 비교하였다. 손실 방정식 계산을 통하여 SiC Hybrid module의 도통 손실은 168W, 스위칭 손실은 9.3W, 다이오드 손실은 10.5nW의 결과를 나타내었으며, 시뮬레이션 결과와 비교하였을 때 유사한 값을 나타내었다. 이를 바탕으로 Si module과 SiC Hybrid module의 시뮬레이션 결과 값 비교 결과, Si module의 총 소자 손실값은 246.2W, SiC Hybrid module의 총 소자 손실 값은 189.9W를 나타내었으며, 손실 차이 값은 56.3W로써 약 0.8W의 효율 차이를 보였다. 이로 인하여 SiC SBD의 Reverse recovery 특성을 검증하였다. 또한 고온 포화상태에서 SiC Hybrid module 및 Si module의 안정성을 확인하기 위하여 온도 포화 테스트를 진행하였으며, Si module의 경우, 출력전력 4kW에서 동작을 멈추었고, SiC Hybrid module은 7kW까지 동작을 확인하였다. 이를 바탕으로, 효율 그래프와 온도 그래프를 제시하였으며, Si module은 4kW까지, SiC Hybrid module은 7kW까지 그래프로 나타내었다.