• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.1077-1078
• /
• 2008

As power plant facilities are being deteriorated, their safety is getting more importance, and more routine surveillance is being required. For this purpose, this paper presents a field robot system which performs the surveillance of power plant facilities instead of human workers from the viewpoint of the workers' safety and work efficiency.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1559-1560
• /
• 2008

As power plant facilities are being deteriorated, their safety is getting more importance, and more routine surveillance is being required. For this purpose, this paper presents an indoor localization system for field robot system which performs the surveillance of power plant facilities instead of human workers from the viewpoint of the workers' safety and work efficiency.

• Journal of Power Electronics
• /
• v.11 no.4
• /
• pp.418-423
• /
• 2011

This paper presents a simulation model and a parameter identification scheme of an induction motor drive for electric vehicle. The induction motor in automotive applications should operate in very high efficiency and achieve the maximum-torque-per-ampere (MTPA) feature even with saturated magnetic flux under very high torque. The indirect vector control which is typically adopted in traction drive system requires precise information of motor parameters, particularly rotor time constants. This work models an induction motor considering magnetic saturation and proposes an empirical identification method using the current controller in the synchronous reference frame. The proposed method is applied to a 22kW-rated induction motor for electric vehicle.

• Proceedings of the KIEE Conference
• /
• 1997.07e
• /
• pp.1688-1691
• /
• 1997

In this work, we have developed the off-line diagnostic system for power cable insulation using DC voltage decay method to diagnose the insulation degradation of underground power cables. Measurement errors of diagnostic system are less than 1% for $1T{\Omega}$ internal resistor. We have also developed measurement and diagnostic programs for win95 which is suitable for the database construction and the management of data. We could conclude that it is possible to apply this system to the multi-grounded underground cable systems.

• Journal of Magnetics
• /
• v.15 no.1
• /
• pp.36-39
• /
• 2010

The multi-degrees of freedom surface permanent-magnet motor (Multi-D.O.F. SPM) has several degrees of freedom operations that are defined as the "roll", "yaw", and "pitch". Normally, the torque that is generated to rotate a rotor includes ripples. The analysis of the torque ripples is important for improving motor performance. In terms of the electric analysis, torque ripple occurs as a result of many factors, including the rotor and stator structures, the distribution of the air-gap flux density, and the waveform of the current in the coils. In particular, the torque ripple is an important factor in the stable operation of the Multi-D.O.F. SPM. Therefore, in this work, the torque ripple was analyzed using various types of magnetization for the permanent magnet. An improved model was proposed for the Multi-D.O.F. SPM based on this analysis.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.21 no.6
• /
• pp.542-545
• /
• 2016

This work proposes a capacitive coupling-based wireless battery charging circuit that is built with vehicle glasses for electric vehicles. A capacitive coupling wireless power transfer offers many advantages, such as low metal impact and low energy transfer efficiency changes in accordance with changes in position. However, a large coupling capacitor is needed for high power transfer. Therefore, a new capacitive coupling-based wireless power transfer LLC resonant converter built with the glasses of an electric vehicle is proposed. The proposed converter is composed of coupling capacitors with glasses of an electric vehicle and two transformers for impedance transformation. The proposed LLC converter can transfer large power and obtain high efficiency with zero voltage switching. The validity and features of the proposed circuit is verified by experimental results with a 1.2 kW prototype.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.06a
• /
• pp.495-496
• /
• 1998

The measurement of the amplitude and phase of electric fields on high voltage transmission lines is important for several reasons including a) Metering and determination of power flow, b) protective relaying. and c) fault sensing. The work reported here is directed toward a major improvement to optically based, electric-field sensors. This is a signal processing based technique for overcoming the instabilities of conventional, optically-based, electric-field sensors to changes in optical power or temperature.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.4
• /
• pp.1578-1585
• /
• 2018

This work investigates two different motor drive technologies, switched reluctance motor (SRM) and induction motor (IM). They are designed optimally to meet the desired performances for electric scooters. The comparison of both motors is described in terms of performances and material cost. With the similar constraint, induction motor performs slightly better than switched reluctance motor. But this must be traded-off with higher weight and cost. Both drive systems are, however, suitable for electric scooter application. Finally, the range simulations are conducted on a European urban driving cycle, ECE15 driving cycle and a more realistic cycle, Bangkok driving cycle. The e-scooter ranges are varied from 36 to 109 km depending on driving cycle, motor technology and number of passengers.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1825-1826
• /
• 2007

세계적으로 현장업무는 현장에서 접수하여 즉시 처리하는 방식으로 패러다임이 변화하고 있다. 현재 전력업무의 대표적인 모바일 시스템으로 기동보수/순시점검 모바일시스템이 시범운영되고 있으나, 자동처리 기능개선, 네비게이션 기능개발 등 자동화 및 지능화 기술개발이 필요하며 작업차량의 위치와 상태와 무관하게 운영되고 있는 업무들을 통합적으로 처리할 수 있는 모바일시스템 개발이 필요하다. 따라서 본 논문에서는 효율적인 배전운영 현장업무 처리를 위한 통합형 모바일시스템을 설계한다. 모바일 서버, 무선통신망, 단말기용 모바일시스템에 대한 전반적인 시스템의 구성방안 설명하고, 핵심적인 요소기술 개발사항과 방법을 제시한다.

• Korean Chemical Engineering Research
• /
• v.59 no.2
• /
• pp.247-253
• /
• 2021

Electrocoalescence is an active technique in petroleum industry, formation of raindrop in cloud, and digital microfluidics. In the present work, electrocoalescence of two droplets under the constant electric potential in air was studied. Through this experiment, we found that the electrocoalescence process could be divided three phases; deformation, formation of liquid bridge, and merging. And the condition for formation of liquid bridge between two droplets was obtained. For the connection of experimental result in constant potential condition with general case in constant charge condition, relationship of charge and potential difference was deduced by numerical computation. In high electric potential case, flat interfaces after recoiling were observed. It was interpreted through a numerical simulation of electric field.