• Journal of Electrical Engineering and Technology
• /
• v.13 no.5
• /
• pp.1927-1934
• /
• 2018

In this paper, we studied the state of charge (SOC) estimation algorithm of a high-capacity lithium secondary battery for electric vehicles (EVs) considering temperature characteristics. Nonlinear characteristics of high-capacity lithium secondary batteries are represented by differential equations in the mathematical form and expressed by the state space equation through battery modeling to extract the characteristic parameters of the lithium secondary battery. Charging and discharging equipment were used to perform characteristic tests for the extraction of parameters of lithium secondary batteries at various temperatures. An extended Kalman filter (EKF) algorithm, a state observer, was used to estimate the state of the battery. The battery capacity and internal resistance of the high-capacity lithium secondary battery were investigated through battery modeling. The proposed modeling was applied to the battery pack for EVs to estimate the state of the battery. We confirmed the feasibility of the proposed study by comparing the estimated SOC values and the SOC values from the experiment. The proposed method using the EKF is expected to be highly applicable in estimating the state of the high-capacity rechargeable lithium battery pack for electric vehicles.

• Proceedings of the KIEE Conference
• /
• 1994.11a
• /
• pp.172-174
• /
• 1994

Due to the environmental considerations and the energy crisis, there has been a revival of electric vehicles since 1960s. Research and development work concerning with electric vehicles (EVs) was becoming more intense in last decade. As compared with conventional internal combustion engine (ICE) cars, EVs have the advantages of clean, quiet, better energy efficiency, less maintenance and improving the load factor of electric power systems. However, EVs usually have a snort running range, bad acceleration performance and high initial cost. The main reason for these shortcomings is the low figure of energy density and the high per energy cost of battery at present technology state. So it is very important to optimize the overall drive system design with respect to the maximum utilization of battery, energy, motor torque and inverter power. This paper describes a demonstration model of electric car which is driven by 4-wheel direct method using the vector control.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.5
• /
• pp.582-590
• /
• 2023

Stress granules (SGs) are cytoplasmic aggregates of RNA-protein complexes that form in response to various cellular stresses and are known to restrict viral access to host translational machinery. However, the underlying molecular mechanisms of SGs during viral infections require further exploration. In this study, we evaluated the effect of SG formation on cellular responses to coxsackievirus B3 (CVB3) infection. Sodium arsenite (AS)-mediated SG formation suppressed cell death induced by tumor necrosis factor-alpha (TNF-a)/cycloheximide (CHX) treatment in HeLa cells, during which G3BP1, an essential SG component, contributed to the modulation of apoptosis pathways. SG formation in response to AS treatment blocked CVB3-mediated cell death, possibly via the reduction of mitochondrial reactive oxygen species. Furthermore, we examined whether AS treatment would affect small extracellular vesicle (sEV) formation and secretion during CVB3 infection and modulate human monocytic cell (THP-1) response. CVB3-enriched sEVs isolated from HeLa cells were able to infect and replicate THP-1 cells without causing cytotoxicity. Interestingly, sEVs from AS-treated HeLa cells inhibited CVB3 replication in THP-1 cells. These findings suggest that SG formation during CVB3 infection modulates cellular response by inhibiting the release of CVB3-enriched sEVs.

• Broadcasting and Media Magazine
• /
• v.19 no.1
• /
• pp.48-55
• /
• 2014

One of the recent noticeable evolutions in mobile communication systems is that wideband-codec is deployed rapidly in VoLTE (Voice over Long Term Evolution) service or HD voice. This paper is concerned with next generation HD voice or VoLTE service that is coined to describe high quality communication with super-wideband voice codec. 3GPP EVS (Enhanced Voice Service) Codec is being standardized to develop the super-wideband voice codec. This paper deals with the codec design constraints, performance requirements, the status of standardization, and finally perspective on VoLTE service in future.

• ETRI Journal
• /
• v.37 no.2
• /
• pp.273-282
• /
• 2015

Vehicle-to-grid presents a mechanism to meet the key requirements of an electric power system, using electric vehicles (EVs) when they are parked. The most economic ancillary service is that of frequency regulation, which imposes some constraints regarding the period and duration of time the vehicles have to be connected to the grid. The majority of research explores the profitability of the aggregator, while the perspective of the EV fleet owner, in terms of their need for usage of their fleet, remains neglected. In this paper, the optimal allocation of available vehicles on a day-ahead basis using queuing theory and fuzzy multi-criteria methodology has been determined. The proposed methodology is illustrated on the daily scheduling of EVs in an electricity distribution company.

• Proceedings of the KIPE Conference
• /
• 2012.11a
• /
• pp.83-84
• /
• 2012

본 논문에서는 전기자동차 (Electric Vehicles, EVs) 및 플러그인 하이브리드 자동차 (Plug-in Hybrid Electric Vehicles, PHEVs)용 통합형 배터리 충전기의 토폴로지 구성에 따른 동작 및 성능 특성을 비교한다. 기존에 제안된 통합형 배터리 충전기를 토대로 개별 모듈에 적용 가능한 토폴로지를 검토한다. 또한, 검토한 모듈의 통합을 위한 양방향 구현 시 동작 및 성능을 비교한다. 이를 통해 선정된 토폴로지들이 가질 수 있는 조합들을 구성하고, 상호간의 영향을 분석한다. 분석한 결과를 기반으로 각각의 조합의 성능 및 특성의 시뮬레이션을 통한 비교추이를 제시한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.8
• /
• pp.98-105
• /
• 2014

In this paper, we have analyzed the power consumption property of EVs(Electric Vehicles) chargers established in a public place, proposed reasonable demand factors by the number of established EV chargers and its control method in apartments. The optimization of power system and the suppression of the peak load can be controlled through the proposed demand factors and charging scheduling control algorithm. In this paper, electrical design and an case analysis were carried out on a sample apartment complex to prove the effectiveness of the power system. As a result, emergency power transformer capacity has been reduced by approximately 25%, and we have confirmed that the electric rates saving and the control of peak load value is possible.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.1
• /
• pp.114-120
• /
• 2012

Eco-driving technique for electric vehicles (EVs) is investigated in this paper. Many findings on EVs have been reported; however, they did not deal with eco-driving from the viewpoint of theoretical study. The authors have developed an energy-saving driving technique - the so-called "eco-driving" technique based on dynamic programming (DP). Optimal speed profile of an EV, which minimizes the amount of total energy consumption, was determined under fixed origin and destination, running time, and track conditions. DP algorithm can deal with such complicated conditions and can also derive the optimal solution. Using the proposed method, simulations were run for some cases. In particular, the author ran simulations for the case of a gradient road with a traffic signal. The optimization model was solved with MATLAB.

• Journal of Sensor Science and Technology
• /
• v.32 no.6
• /
• pp.462-469
• /
• 2023

Electric vehicles (EVs) have recently been in the spotlight and have been rapidly developed to reduce the carbon emission with respect to the transport sector. Most EVs currently employ lithium-ion batteries (LIBs) as power sources because they have a higher energy density and a lower self-discharge than other batteries. However, the LIBs cannot respond to high power demands when the state of health (SOH) falls below 80%. Therefore, the SOH of the LIBs must be accurately measured or estimated. To date, many methods have been studied and proposed for measuring or estimating the SOH. In this paper, representative methods among them are reclassified and introduced.

• TTA Journal
• /
• s.153
• /
• pp.67-72
• /
• 2014