• Journal of ILASS-Korea
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• v.29 no.1
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• pp.1-6
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• 2024

This paper is a numerical analysis study for evaluating the energy efficiency of electric vehicles. Currently, the methods for testing and evaluating the energy consumption efficiency of electric vehicles have limitations such as resources and time. Therefore, there is a need for research on developing models to predict the energy consumption efficiency of electric vehicles. In this study, a numerical analysis research is conducted to predict the energy efficiency of electric vehicles using a vehicle dynamics numerical analysis model. To validate the accuracy of the simulation model, it is compared the results of dynamometer tests with the simulation results and used the Unified Diagnostic Services (UDS) protocol to acquire internal data from the electric vehicle. It is ensured the reliability of the simulation model by comparing data such as motor speed, battery voltage, current, state of charge (SOC), regenerative braking power generation, and total driving distance of the test vehicle with dynamometer test data and simulation model results.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.309-310
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• 2016

Sealed flooded lead acid batteries are becoming popular in the industry because of their low cost as compared to their counterparts. State of Charge (SOC) estimation has always been an important factor in battery management systems. For the accurate SOC estimation, open circuit voltage (OCV) hysteresis should be modelled accurately. The hysteresis phenomenon of the sealed flooded lead acid battery is discussed in detail and its ultimate modeling is proposed based on the conventional parallelogram method. The SOC estimation is performed by using Unscented Kalman Filter (UKF) while the parameters of the battery are estimated using Auto Regressive with external input (ARX) method. The validity of the proposed method is verified by the experimental results. The SOC estimation error by the proposed method is less than 3 % all wing the 125hr test.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.253-259
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• 1997

The iron doped GaAs single crystals were grown by liquid phase epitaxial method and its some physical properties were evaluated with a view to investigate the crystal quality and emission property. The isomer shift of 0.303mm/sec is calculated from low-temperature M ssbauer spectroscopy and we know that charge state of iron ion is 3+ in GaAs crystal. In low temperature photoluminescence, the deep emission bands with wide-line width have been observed at 0.99eV and 1.15eV in addition to sharp excitonic peaks. We attributed that these deep emissions are originated from substitutional Fe-acceptor which has charge state of 3+ and 2+, respectively.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.317-318
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• 2013

State-of-Charge (SOC) is one of the most important indicators for the battery management system. Thus its precise estimation is crucial not only for effectively utilizing the energy but also preventing critical situations from happening to the powertrain of the vehicle. However, lead-acid battery is time-variant and highly nonlinear, and the hysteresis phenomenon causes large errors in estimating SOC. This paper proposes a novel SOC estimation technique for the lead-acid battery by using Extended Kalman Filter (EKF) considering hysteresis effect. The validity of the proposed technique is verified through the experiments.

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1309-1338
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• 2002

The fluorescence and photoisomerization quantum yields of trans-1-(9-anthryl)-2-(4-pyridyl)ethene (t-4-APyE), 1-(10-methyl-9-anthryl)-2-(4-pyridyl)ethene (t-4-MeAPyE), and 1-(10-chloro-9-anthryl)-2-(4- pyridyl)ethene (t-4-ClAPyE) were measured in cyclohexane, acetonitrile, and methanol at room temperature.Polar solvents result in the drastic reduction of fluorescence quantum yield and increase of photoisomerization quantum yield for all three compounds. These results are probably due to the stabilization of intramolecular charge transfer (ICT) excited state in polar solvent. The higher contribution of ICT in the presence of more electron-donating methyl substituent, manifested by largest positive fluorescence solvatochromism, indicates that the pyridine ring acts as an electron acceptor. Protonation or methylation makes pyridine ring stronger electron acceptor and causes long-wavelength ground state charge transfer absorption band and complete quenching of fluorescence. The fluorescence from t-4-APyE derivatives can be switched off responding external stimuli viz. medium polarity, protonation, or methylation.

• Journal of Information Display
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• v.3 no.4
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• pp.8-12
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• 2002

We have carried out a simulation study on an e-beam addressed liquid crystal projection display in which the liquid crystal is switched by the electric field of the charge, produced by an electron beam, on the surface of the display. We calculated the electric field produced by the surface charge, the liquid crystal director configuration and the profile of the transmitted light. We studied the factors affecting the resolution of the display and the effect of pretilt angle on the performance of the display. The e-beam addressed liquid crystal projection display potentially has the advantages of high resolution and high brightness.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.904-908
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• 2008

Every autonomous system like a robot needs a power source known as a battery. And proper management of the battery is very important for proper operation. To know State of Charge(SOC) of a battery is the very core of proper battery management. In this paper, the SOC estimation problem is tackled based on the well known Extended Kalman Filter(EKF). Combined the existing battery model is used and then EKF is employed to estimate the SOC. SOC table is constructed by extensive experiment under various conditions and used as a true SOC. To verify the estimation result, extensive experiment is performed with various loads. The comparison result shows the battery estimation problem can be well solved with the technique proposed in this paper. The result of this paper can be used to develop related autonomous system.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.418-419
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• 2010

본 논문에서는 스크리닝에 기반한 리튬이온 배터리 팩의 state of charge (SOC) 추정방법을 연구하였다. 전기화학적 특성이 서로 유사한 셀들을 미리 선별하는 스크리닝 방법을 통해 직렬, 병렬, 직/병렬팩이 구성될 때, 이러한 팩의 전기화학적 등가회로 모델은 단위 셀 대비 일정한 경향성을 보이는 용량, open circuit voltage (OCV) 등의 파라미터 정보를 토대로 기존 단위 셀 모델과 동일한 모델 구축이 가능하다. 이를 통하여 extended kalman filter (EKF)를 이용한 배터리 팩의 SOC 추정이 가능함을 보인다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1350-1352
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• 2008

Research on down conversion phosphor materials is the key for the development of solid state lighting (SSL). Especially finding alternative red phosphor for white LEDs based on blue or NUV LEDs are important research task. Under this view, we have synthesized a series of $Eu^{3+}$ substituted $La_2W_{2-x}Mo_xO_9$ (x = 0 ~ 2, insteps of 0.1) red phosphor and characterized by X-ray diffraction (XRD) and photoluminescence. XRD results reveal a phase transition from triclinic to cubic structure for $x\;{\geq}\;0$. All the compositions show broad charge transfer band due to charge transfer from oxygen to tungsten/molybdenum and red emission due to $Eu^{3+}$ ions. Select compositions show high red emission intensity compared to the commercial red phosphor under NUV/blue ray excitation. Hence, this candidate can be possible red emitting phosphors for white LEDs.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.930-932
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• 2002

We have carried a theoretical study on e-beam addressed liquid crystal projection display in which the liquid crystal is switched by the electric field of the charge, produced by an electron beam, on the surface of the display. We calculated the electric field produced by the surface charge, the liquid crystal director configuration and the profile of the transmitted light. We studied the factors affecting the resolution of the display. We also studied the effect of pretilt angle on the performance of the display. The e-beam addressed liquid crystal projection display potentially has the advantages of high resolution and high brightness.