• 반도체디스플레이기술학회지
• /
• 제13권1호
• /
• pp.101-108
• /
• 2014

The battery pack in this research consists of dozens of a small battery for energy storage. And this battery pack charges and discharges repeatedly at high capacity (25 ~ 50 V, 25 ~ 100 A). The high temperature which can be generated in this process has a bad effect to the lifetime and efficiency of batteries. Moreover these factors are related with maintenance cost. Therefore, we need to assess the thermal performance of the battery pack in advance using the experimental or numerical analysis. In this research, we analyzed voltage and surface temperature of one cell battery to calculate heat transfer using the numerical analysis. And the temperature of the battery surfaces and inside of the pack was also analyzed. As a result, we found out the appropriate pack structure which stacked five modules.

• 한국기계가공학회지
• /
• 제13권6호
• /
• pp.134-138
• /
• 2014

Power packs can change energy to hydraulic energy generated by an engine as a tool for use with civil engineering construction equipment. This paper determines which type of power pack meets the standards of construction machinery. A power pack was formulated as a three-dimensional model by using the software CATIA. A modal analysis was conducted using ANSYS Workbench, and the resonance was checked. Next, a harmonic analysis was conducted. The analytical results show that the dynamic stability of the power pack is assured.

• 한국농공학회지
• /
• 제38권1호
• /
• pp.116-127
• /
• 1996

This paper dealt with FEM analysis of foundation improved with pack drain. The theory on pack drain was scrutinized and observed values in the field were compared with numerical results. Work site of Kwangyang container pier was selected as a ease study in which measurement of settlement and pore water pressure was accurately carried out. Biot's consolidation equation was selected as governing One, coupled with modified Camclay model as constitutive one. Christian and Boehmer's numerical technique was adopted. Behavior of foundation with pack drain is not simple but very complicated. Discontinuity resulted from rigidity difference between adjacent materials, smear effect and complicated boundary conditions should be considered in the behavior analysis of foundation behavior. The results of numerical analysis were influenced by smear zone. In relevant to this effect, finite element analysis was carried out using the reduced horizontal coefficient of permeability in the smear zone; The numerical results were compared with observed values in surface settlement. including pore water pressure. However only lateral di5plaoement by numerical ana1Ysis was shown since its measurement was not performed in the field. The predication of settlement to be developed later can be effectively employed for the obtimization of construction. The predication of residual settlement using the data measured in the field was made by Hoshino, Asaoka and hyperbolic method. Among them, the hyperbolic method proved best one. Settlements accorded well between numsrical and observed values while pore pressure showed a slight difference. Lateral displacement showed largest values at constant distance from ground surface. The validation of foundation analysis improved with pack drain by computer program employed in this study selecting modified Cam-clay model was satisfactorily secured.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1999년도 제29회 춘계학술대회
• /
• pp.232-239
• /
• 1999

Generally quantity of supply oil for piston ring lubrication in an internal combustion engine may be insufficient to fill the entire volume formed in the clearance between piston ring and cylinder liner. Thus oil starvation condition should be considered for the analysis of piston ring lubrication. In order to reasonably estimate amount of oil left on the cylinder liner, adequate boundary condition should be adapted for the analysis of ring pack lubrication. In this analysis of ring pack lubrication of an internal combustion engine, oil starvation and open-end boundary conditions are considered at inlet and outlet of piston rings. It is revealed that piston rings are operated under oil starvation in most operating cycle and the result with these conditions are quite different from that with fully-flooded assumption.

• Tribology and Lubricants
• /
• 제15권3호
• /
• pp.233-239
• /
• 1999

Generally quantity of supply oil for piston ring lubrication in an internal combustion engine may be insufficient to fill the entire volume formed in the clearance between piston ring and cylinder liner. Thus oil starvation condition should be considered for the analysis of piston ring lubrication. In order to reasonably estimate amount of oil left on the cylinder liner, adequate boundary condition should be adapted for the analysis of ring pack lubrication. In this analysis of ring pack lubrication of an internal combustion engine, oil starvation and open-end boundary conditions are considered at inlet and outlet of piston rings. It is revealed that piston rings are operated under oil starvation in most operating cycle and the result with these conditions are quite different from that with fully-flooded assumption.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 추계학술대회 논문집
• /
• pp.37-38
• /
• 2006

• 전력전자학회논문지
• /
• 제23권6호
• /
• pp.408-414
• /
• 2018

Given that lithium-ion batteries are expected to be used as power sources for electric and hybrid vehicles, thermodynamics experimentation and prediction based on experimental data were performed. Thermal, electrochemical, and electrochemical/electrical-thermal models were used for accurate battery modeling. Various applications of different battery packs were demonstrated, and thermal analysis was performed using the same experimental conditions for square and rectangular battery packs. Accurate thermal analysis for a single cell should be prioritized to determine the thermal behavior of the battery pack. The energy balance equation, which contains heat generation and heat transfer factors, defines the thermal behavior of the battery pack. By comparing battery packs of different shapes tested under the same condition, this study revealed that the rectangular battery pack is superior to the square battery pack in terms of the maximum temperature of inner cells and temperature variation between cells.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 하계학술대회 논문집
• /
• pp.292-292
• /
• 2010

Bimodal Tram is driven by both engine and Lithium Polymer battery pack which consists with 168 cells of LPB(80Ah, 650Vdc). LPB pack is very frequently charged and discharged in driving. Temperature inside of LPB pack makes an great effect on both charging and discharging capacity which seem to be related with LPB internal resistance. LPB internal resistance is increasing or little decreasing with the decreased temperature under 10 - $20^{\circ}C$ and the increased temperature over $30^{\circ}C$ which is similar to the temperature characteristics of single LPB cell. This paper has analyzed the driving characteristics of LPB pack for bimodal tram is running with either battery mode or hybrid mode.

• 에너지공학
• /
• 제25권4호
• /
• pp.30-36
• /
• 2016

전동스쿠터용 배터리팩은 상온보다 고온일수록 내부저항이 감소하여 충전효율은 상승하나 배터리 안전성 문제로 인하여 냉각시스템을 필요로 한다. 본 연구의 목적은 냉각용 공기 흡입과 배출 방법과 시기를 다르게 하여 냉각 효율성을 분석하는 것이다. 배터리팩 내부에서 각각의 배터리 사이에 큰 온도편차가 존재하는 경우 배터리의 성능과 효율이 저감된다. 따라서, 배터리팩 냉각성능을 입-출구 냉각팬의 작동 방법 및 시기 변화에 의해 배터리의 성능과 효율을 개선시키도록 한다. 연구에 사용된 수치해석 상용코드는 17.0버젼의 ANSYS CFX이다.

• Journal of Power Electronics
• /
• 제15권5호
• /
• pp.1380-1391
• /
• 2015

This paper provides a loss analysis and comparison of high power semiconductor devices in 5MW Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) Wind Turbine Systems (WTSs). High power semiconductor devices of the press-pack type IGCT, module type IGBT, press-pack type IGBT, and press-pack type IEGT of both 4.5kV and 6.5kV are considered in this paper. Benchmarking is performed based on the back-to-back type 3-level Neutral Point Clamped Voltage Source Converters (3L-NPC VSCs) supplied from a grid voltage of 4160V. The feasible number of semiconductor devices in parallel is designed through a loss analysis considering both the conduction and switching losses under the operating conditions of 5MW PMSG wind turbines, particularly for application in offshore wind farms. This paper investigates the loss analysis and thermal performance of 5MW 3L-NPC wind power inverters under the operating conditions of various power factors. The loss analysis and thermal analysis are confirmed through PLECS Blockset simulations with Matlab Simulink. The comparison results show that the press-pack type IGCT has the highest efficiency including the snubber loss factor.