• Journal of Advanced Marine Engineering and Technology
• /
• v.29 no.4
• /
• pp.436-442
• /
• 2005

Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. In this paper, characteristics on oscillating heat pipe according to operating conditions (environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated From the experimental results $25^{\circ}C$(environment temperature) R-141b (working fluid) $40\%$ (charging ratio) was best performace at others of inclination angle and the top heating mode of OCHP performed $80\%$ efficiency of the bottom heating mode.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.16 no.6
• /
• pp.385-391
• /
• 2023

As the use of electric vehicles has increased to minimize carbon emissions, the analyzing the state and performance of lithium-ion batteries that is instrumental in electric vehicles have been important. Comprehensive analysis using not only the voltage, current and temperature of the battery pack, which can affect the condition and performance of the battery, but also the driving data and charging pattern data of the electric vehicle is required. Therefore, a thorough analysis is imperative, utilizing electric vehicle operation data, charging pattern data, as well as battery pack voltage, current, and temperature data, which collectively influence the condition and performance of the battery. Therefore, collection and preprocessing of battery data collected from electric vehicles, collection and preprocessing of data on driver driving habits in addition to simple battery data, detailed design and modification of artificial intelligence algorithm based on the analyzed influencing factors, and A battery analysis and evaluation model was designed. In this paper, we gathered operational data and battery data from real-time electric buses. These data sets were then utilized to train a Random Forest algorithm. Furthermore, a comprehensive assessment of battery status, operation, and charging patterns was conducted using the explainable Artificial Intelligence (XAI) algorithm. The study identified crucial influencing factors on battery status, including rapid acceleration, rapid deceleration, sudden stops in driving patterns, the number of drives per day in the charging and discharging pattern, daily accumulated Depth of Discharge (DOD), cell voltage differences during discharge, maximum cell temperature, and minimum cell temperature. These factors were confirmed to significantly impact the battery condition. Based on the identified influencing factors, a battery analysis and evaluation model was designed and assessed using the Random Forest algorithm. The results contribute to the understanding of battery health and lay the foundation for effective battery management in electric vehicles.

• Journal of the Society of Disaster Information
• /
• v.20 no.2
• /
• pp.339-350
• /
• 2024

Purpose: This study analyzes accessibility of 10 hydrogen charging stations in Seoul and identifies areas that were difficult to access. The purpose is to re-analyze accessibility by adding a new location in terms of equity and safety of location placement, and then draw implications by comparing the improvement effects. Method: By applying the location-allocation model and the service area model based on network analysis of the ArcGIS program, areas with weak access were identified. The location selection method applied the 'Minimize Facilities' method in consideration of the need for rapid arrival to insufficient hydrogen charging stations. The limit distance for arrival within a specific time was analyzed by applying the average vehicle traffic speed(23.1km/h, Seoul Open Data Square) in 2022 to three categories: 3,850m(10minutes), 5,775m(15minutes), 7,700m(20minutes). In order to minimize conflicts over the installation of hydrogen charging stations, special standards of the Ministry of Trade, Industry and Energy applied to derive candidate sites for additional installation of hydrogen charging stations among existing gas stations and LPG/CNG charging stations. Result: As a result of the analysis, it was confirmed that accessibility was significantly improved by installing 5 new hydrogen charging stations at relatively safe gas stations and LPG/CNG charging stations in areas where access to the existing 10 hydrogen charging stations is weak within 20 minutes. Nevertheless, it was found that there are still areas where access remains difficult. Conclusion: The location allocation model is used to identify areas where access to hydrogen charging stations is difficult and prioritize installation, decision-making to select locations for hydrogen charging stations based on scientific evidence can be supported.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.05a
• /
• pp.773-776
• /
• 2011

전기자동차 인프라 구축을 위해서는 급속충전관련 기술 확보 및 시설확충에 관한 투자와 연구가 지속적으로 이루어지고 있는 실정이다. 본 연구에서는 이러한 급속충전시스템을 단순히 충전 하드웨어를 이용하여 충전하는데 국한하지 않고 급속으로 충전할 수 있는 주변 하드웨어와 충전 알고리즘 개발을 통하여 해결방안에 접근하였다. 산업현장 및 전장시스템의 네트워크 구성에 가장 많이 사용하는 CAN 인터페이스를 적용하여 배터리의 상태를 실시간으로 모니터링하고 이를 기반으로 배터리의 충전전략을 변경 적용하는 방식으로 급속충전시스템을 설계하고 충전 전원공급장치 설계 및 모델 시뮬레이션을 통해 그 성능을 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.05a
• /
• pp.762-765
• /
• 2011

전기자동차 인프라 구축을 위해서는 급속충전관련 기술 확보 및 시설확충에 관한 투자와 연구가 지속적으로 이루어지고 있는 실정이다. 특히 다양한 급속충전 기술 중에서 공동 인프라용으로 적합한 방식에는 어떤 종류가 있는지 살펴보고, 급속충전시스템을 이용하는 전기자동차의 충전 상태, 기타 동작 상태를 실시간으로 확인하기 위해 BMS의 CAN 통신을 기반으로 하는 전기자동차 급속충전 모니터링 시스템을 설계하는 방법을 제안한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.10a
• /
• pp.747-749
• /
• 2010

전기자동차 인프라 구축을 위해서는 급속충전관련 기술 확보 및 시설확충에 관한 투자와 연구가 지속적으로 이루어지고 있는 실정이다. 특히 다양한 급속충전 기술 중에서 공동 인프라용으로 적합한 방식에는 어떤 종류가 있는지 살펴보고, 급속충전시스템을 이용하는 전기자동차의 충전 상태, 기타 동작 상태를 실시간으로 확인하기 위해 BMS의 CAN 통신을 기반으로 하는 전기자동차 급속충전 모니터링 시스템을 설계하는 방법을 제안한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.776-778
• /
• 2011

급속충전 기술은 현재 battery의 성능 및 안전성 등 다양한 요인에 따라 동작성능이 좌우되므로 모니터링 시스템에 의한 충전상태 파악은 충전 알고리즘의 개선, 전기자동차 BMS와 연동, 사용자와의 충전 프로세스 제어 등 다양한 작업환경과 연계되어 있다. 급속충전시스템의 동작 상태를 CAN 프로토콜을 이용하여 실시간으로 감시가 가능한 시스템을 설계 제작하여 전기자동차의 battery를 최단시간에 최적화된 상태로 충전 가능하도록 설계하여 급속충전기 실시간 모니터링 시스템을 설계하는 방법을 제안한다.

• Proceedings of the KIPE Conference
• /
• 2015.07a
• /
• pp.189-190
• /
• 2015

This paper investigates an economic and highly efficient power converter topology and its modulation scheme for 60kW rapid EV charger system. The target system consists of three-phase three-switch buck-type rectifier topology. A new Carrier Based PWM scheme along with its simple implementation using logic gates is introduced in this paper. This PWM scheme replaces the diode rectifier equivalent switching state with an active switching state producing the effectively same current flowing path. As a result, the distortion of input current during the polarity reversal of capacitor line voltage can be mitigated. The proposed modulation technique is confirmed through simulation verification. The proposed modulation technique and its implementation scheme can expand the operation range of the three-phase three-switch buck-type rectifier having ac input and capacitor ripple current of high quality.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.26 no.5
• /
• pp.351-360
• /
• 2016

Rapid population growth with high living standards and high electronics use for personal comfort has raised the electricity demand exponentially. To fulfill this elevated demand, conventional energy sources are shifting towards low production cost and long term usable alternative energy sources. Hybrid renewable energy systems (HRES) are becoming popular as stand-alone power systems for providing electricity in remote areas due to advancement in renewable energy technologies and subsequent rise in prices of petroleum products. Wind and solar power are considered feasible replacement to fossil fuels as the prediction of the fuel shortage in the near future, forced all operators involved in energy production to explore this new and clean source of power. Presented paper proposes fuzzy logic based Energy Management System (EMS) for Wind Turbine (WT), Photo Voltaic (PV) and Diesel Generator (DG) hybrid micro-grid configuration. Battery backup system is introduced for worst environmental conditions or high load demands. Dump load along with dump load controller is implemented for over voltage and over speed protection. Fuzzy logic based supervisory control system performs the power flow control between different scenarios such as battery charging, battery backup, dump load activation and DG backup in most intellectual way.

• Transactions of the Korean hydrogen and new energy society
• /
• v.23 no.5
• /
• pp.448-454
• /
• 2012

In this paper, a three-dimensional hydrogen absorption model is applied to a thin double-layered annulus ZrCo hydride bed and validated against the temperature evolution data measured by Kang et al. The present model reasonably captures the bed temperature evolution behavior and the 99% hydrogen charging time. The equilibrium pressure expression for hydrogen absorption on ZrCo is derived as a function of temperature and the H/M atomic ratio based on the pressure-composition isotherm data given by Konishi et al. In addition, this present model provides multi-dimensional contours such as temperature and H/M atomic ratio in the thin doublelayered annulus metal hydride region. This numerical study provides fundamental understanding during hydrogen absorption process and indicates that efficient design of the metal hydride bed is critical to achieve rapid hydrogen charging performance. The present three-dimensional hydrogen absorption model is a useful tool for the optimization of bed design and operating conditions.