• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.67-75
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• 2011

The development of electric vehicle power electronics system control, composed of DC-AC inverters and DC-DC converters, attract much research interest in the modern industry. A DC-AC inverter supplies the high-power motor torques of the propulsion system and utility loads of electric vehicles, whereas a DC-DC converter supplies the conventional low-power and low-voltage loads. However, the need for high-power bidirectional DC-DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters. The nonlinear control of power converters is an active research area in the field of power electronics. This paper focuses on the use of the fuzzy sliding mode strategy as a control strategy for buck-boost DC-DC converter power supplies in electric vehicles. The proposed fuzzy controller specifies changes in control signals based on the surface and knowledge on surface changes to satisfy the sliding mode stability and attraction conditions. The performance of the proposed fuzzy sliding controller is compared to that of the classical sliding mode controller. The satisfactory simulation results show the efficiency of the proposed control law, which reduces the chattering phenomenon. Moreover, the obtained results prove the robustness of the proposed control law against variations in load resistance and input voltage in the studied converter.

• KSTLE International Journal
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• v.9 no.1_2
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• pp.36-38
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• 2008

The electrical and rheological behavior of the hollow polyaniline glutarate suspension in silicone oil was investigated. Hollow polyaniline glutarate suspension showed a typical ER response (Bingham flow behavior) under a DC electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 0.95 power on the electric field. The experimental results for the hollow polyaniline glutarate suspension behaved as an ER fluid.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.249-256
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• 2019

A full-scale test line was established to verify the electrical environmental interferences caused by the HVDC ±500 kV Double Bipole overhead transmission line with metallic return conductor, which is scheduled for construction in Korea and the fullscale test was conducted for one year. And through the human perception test of the DC electric-field under the HVDC Double Bipole line, the threshold value at which the human detects DC electric field was investigated to verify the validity of the design guide for the HVDC ±500 kV Double Bipole overhead transmission line. The polarity configuration of the HVDC ±500 kV Double Bipole test line was arranged diagonally with the same polarity in terms of the electrical environment disturbance and operation. The test line utilized the 6-bundle arrangement to prevent the corona discharge taking into account the domestic social acceptability. The test results show that the HVDC ±500 kV Double Bipole transmission line generated very little corona discharge from the conductors. Therefore, both DC electric field and ion current density met the domestic design guide for DC overhead transmission lines. Also, the human perception test of DC electric fields under the test line showed that 70% of participants did not recognize the DC electric field even when exposed to 23 kV/m.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.503-504
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• 2011

주파수가 다른 계통을 연계하거나, 장거리 선로 운전시 손실이 낮은 HVDC 송전은 환경문제로 인한 민원으로 새로운 선로건설을 위한 부지확보가 전 세계적으로 어려운 실정이다. 이 문제를 해결할 수 있는 방안으로 기존의 AC선로에 DC를 적용하여 동일철탑에 AC와 DC 선로를 같이 설치하는 하이브리드(Hybird) 선로가 제시되었다. 그러나 AC와 DC가 공존한 상태에서의 전기환경기준이 제시되지 못하고 있는 실정이다. 따라서 본 논문에서는 국내에서 운용중인 345kV 2회선 철탑에 DC선로를 적용한 하이브리드 선로의 축소모델을 제작하였고, DC선로의 도체 구성별 하이브리드 선로의 이온류 특성을 시험하였다.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.176-187
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• 2015

DC bias will cause abnormal vibration of transformers. Aiming at such a problem, transformer vibration affected by DC bias has been studied combined with transformer core and winding vibration mechanism use multi-physical field simulation software COMSOL in this paper. Furthermore the coupling model of electromagnetic-structural force field has been established, and the variation pattern of inner flux density, distribution of mechanical stress, tension and displacement were analyzed based on the coupling model. Finally, an experiment platform has been built up which was employed to verify the correctness of model.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.423-433
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• 2020

Direct current (DC) electric fields have been used for electro-osmotic dewatering. Under DC conditions, however, the electrical contact resistance between the electrode and the dewatering material increases considerably during the process of dewatering. Such a circumstance hinders the continuation of effective electro-osmotic dewatering. To reduce this hindrance, an applied pulse electric field with periodic reversals of the electrode polarity should improve electro-osmotic dewatering. In this study, electro-osmotic dewatering under pulse conditions was experimentally investigated for electrode polarity reversals. During the dewatering process, the pulse electric field was able to reduce the hindrance caused by the DC, resulting in an increased final dewatered amount relative to that under a DC electric field. For a constant applied voltage, the reversed polarity condition, under which the electric current passing through the material was almost unchanged with time, yielded the maximum final dewatered amount. This technique can be used to enhance drainage from a water storage facility during a period of extreme drought and the seawater desalination plants using reverse osmosis in drought stricken coastal regions.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.427-430
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• 2002

This paper has been studied a new geoelectric survey and instrunmentation using Low Frequency Electric Field .sensing Antenna. “Low Frequency Electric Field Sensing” is a technology in new method of survey to use array type antenna, the power of operation in antenna is using AC or DC pulse instead of DC current. The architecture of system embodied transceiver system using a microprocessor(PIC) of Microcllip Technology Inc. An array antenna design and il control transmission of antenna to use CDMA in this system. It is using array type antenna for the earth、earth's crust to survey explain from theory and experience.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.8
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• pp.720-723
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• 2005

We studied the quantitativity of the image sticking which is occured by the resicual DC in the fringe-electric field switching (FFS) mode. Actually, in the FFS mode driven by the strong fringe electric field, the asymmetric residual DC was formed in the bottom substrate. It made the impurity ion stick to the alignment layer such as polyimde layer. Thus, the differnece of the luminance existes after the stress check pattern is applied to the panel so that we can see the image sticking. This image sticking decreases as the residual DC value between specific patterns decreases. Therefore, it is necessary to control the residual DC for the FFS mode with the high image quality. It is possible to eliminate the image stiking when the extra pixel voltage is applied through the circuit tunning for reducing the difference of residual DC accroding to the panel position.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.6
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• pp.1-6
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• 2010

We present simulation results on DC characteristics of AlGaN/GaN HEMT having stair-type gate electrodes, in comparison with those of the conventional single gate AlGaN/GaN HEMTs and field-plate enhanced AlGaN/GaN HEMTs. In order to reduce the internal electric field near the gate electrode of conventional HEMT and thereby to increase their DC characteristics, we applied three-layered stacking electrode schemes to the standard AlGaN/GaN HEMT structure. As a result, we found that the internal electric field was decreased by 70% at the same drain bias condition and the transconductance (gm) was improved by 11.4% for the proposed stair-type gate AlGaN/GaN HEMT, compared with those of the conventional single gate and field-plate enhanced AlGaN/GaN HEMTs.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.462-464
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• 1995

In this paper, experiments were carried out to study the decrease of NOx in simulated flue gases (initial concentration of NO 1000, 750, 400 ppm, : $N_2$ balance gas). Characteristics of NOx reduction are measured and analysed in corona discharge of multi needles to plane electrode structure and magnetic field. The best characteristics of NO reduction is measured when electric and magnetic field were supplied to reactor, at same time. Consumption power applied electric and magnetic field were higher than that of discharge applied only electric field.