• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.711-717
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• 2016

Recently, fuel cell generation system with high energy efficiency and low CO2 emission is energetically interconnected with distribution power system. Especially, MCFC(molten carbonate fuel cell) operating at high temperature conditions is commercialized and installed as a form of large scale power generation system. However, it is reported that power system disturbances such as harmonic distortion, surge phenomenon, unbalance current, EMI(Electromagnetic Interference), EMC (Electromagnetic Compatibility) and so on, have caused several problems including malfunction of protection device and damage of control devices in the large scale FCGS(Fuel Cell Generation System). Under these circumstances, this paper proposes countermeasure algorithms to prevent power system disturbances based on the modelling of PSCAD/EMTDC and P-SIM software. From the simulation results, it is confirmed that proposed algorithms are useful method for the stable operation of a large scale FCGS.

• Journal of Broadcast Engineering
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• v.19 no.5
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• pp.726-735
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• 2014

In accordance with 4K UHD(Ultra High Definition) LCD television's higher resolution and data expansion, LCD TV had to face problems such as increasing numbers of cables and tangible skews problems among cables. The V-by-One HS is a new interface technology in the path between the image processing IC and timing control (TCON) board. The variable speed from 600 Mbps to 3.75 Gbps effectively meets the requirements of various different pixel rates. In this paper, we use the V-by-One HS interface to illustrate our proposed simulation method of frequency resonance mode and PCB design approach to model the effects of signal integrity for high speed video signal using an IBIS models.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.2
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• pp.63-68
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• 2007

A number of process problems should be solved in the multi-layered ceramic devices such as EMI filter. In particular, it is essential to control the sintering shrinkage in co-firing of different materials for obtaining defect-free samples such as crack, camber, and delamination which usually occur near the surface and interface. We studied the effect of the powder properties of ferrite on the co-firing behavior of green ceramic layers composed of ferrite and varistor. Three kind of ferrite powder samples as a function of milling time (24, 48, and 72 hr) were prepared. Varistor and ferrite ceramic green sheet were made by means of doctor blade process using slurry (ceramic powder and binder solution). Here, slurry was prepared by mixing 55 wt% powder with 45wt% binder solution. Varistor and ferrite green sheets were laminated at $80 kg/cm^2$, and co-fired at $900^{\circ}C$ and $1000^{\circ}C$ for 3 hr. We obtained the camber-free and co-fired ferrite/varistor layer structure by controlling the milling time and sintering temperature.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.374-381
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• 2011

It has been doing to research on novel techniques for structural health monitoring by applying various sensor techniques to measure the deflection in mechanical and civil structures. Several electric-based displacement sensors have many difficulties for using them because of EMI (Electro-Magnetic Interference) noise of many lead-wires when they are installed to many points in the structures. In this paper, it is proposed an affordable intensity-based fiber optic sensor to measure small displacement solving the problems of conventional sensors. In detail, the sensor head was designed on the basis of the principle of bending loss and a basic experiment was performed to obtain the sensitivity, the linearity and the stroke of the sensor. Moreover, a prototype was designed and manufactured to be easily installed to a structure and a real-time control software was also successfully developed to drive the fiber optic sensor system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1216-1221
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• 2010

An industrial growth needs high quality of productivity and accuracy. So, the needs of power electronics became pressing. Recently both interest and demand about the technique of power electronics systems has been increased. Though power electronics has a lot of strong point, there are several problems which are harmonic effect, EMI(Electromagnetic Interference), malfunction of electric machinery, harmful effect on human, audible noise and so on. Because these problem are a potent influence on motor, so there needs the manufacture and redesign of motor. The real motors of industrial application have designed and manufactured on the basis of confidence. The study on motor using utility power source was verified sufficient to identify confidence of electric machinery on utility power source. However, a study on confidence is in progress about pulse source by switching device. An advanced company are studying to solve this problem. In this research, it is studied that each variables effecting motor reliability have correlation through experiment and more over forecasting the reliability of motor under inverter operation.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.261-265
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• 2005

This paper describes the DC-DC Converter for Ancillary Power Supply in Hybrid Electric Vehicle. DC-DC Converter is used for charging 12V auxiliary battery supplying electric power to head ramp, audio, ECU etc in automobiles. used DC-DC Converter Topology is PS-ZVS FB(Phase Shifted Zero Voltage Switching Full-Bridge) to reduce switching loss and EMI noise induced by high frequency operating condition. And For easy compensation and stable system response characteristic, current mode control method including slope compensation is employed. Constant current / constant voltage charging control method guarantee stable electric charging of auxiliary battery. Simulation toll PSIM6.0 is used for initial circuit parameter settings and H/W debuging. Thermal problems of Switching components in DC-DC Converter is improved by using Thermo Tracer.

• Nuclear Engineering and Technology
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• v.47 no.6
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• pp.729-737
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• 2015

Wireless communication technologies, especially smartphones, have become increasingly common. Wireless technology is widely used in general industry and this trend is also expected to grow with the development of wireless technology. However, wireless technology is not currently applied in any domestic operating nuclear power plants (NPPs) because of the highest priority of the safety policy. Wireless technology is required in operating NPPs, however, in order to improve the emergency responses and work efficiency of the operators and maintenance personnel during its operation. The wired telephone network in domestic NPPs can be simply connected to a wireless local area network to use wireless devices. This design change can improve the ability of the operators and personnel to respond to an emergency situation by using important equipment for a safe shutdown. IEEE 802.11 smartphones (Wi-Fi standard), Internet Protocol (IP) phones, personal digital assistant (PDA) for field work, notebooks used with web cameras, and remote site monitoring tablet PCs for on-site testing may be considered as wireless devices that can be used in domestic operating NPPs. Despite its advantages, wireless technology has only been used during the overhaul period in Korean NPPs due to the electromagnetic influence of sensitive equipment and cyber security problems. This paper presents the electromagnetic verification results from major sensitive equipment after using wireless devices in domestic operating NPPs. It also provides a solution for electromagnetic interference/radio frequency interference (EMI/RFI) from portable and fixed wireless devices with a Wi-Fi communication environment within domestic NPPs.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.33-37
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• 2010

It is very important to prevent the electromagnetic interference and to prevent malfunction of electronic equipments mounted on ships. To solve these problems, in this paper, the EMC filter was designed, fabricated, and tested. The Ni-Zn ferrite beads with high permeability were used to make large inductance as the inductor and the feed-through capacitors without any resonance points. As a result, excellent attenuation characteristics of 25~70 dB were obtained from the 0 kHz~1.5 GHz band. In addition, when the Electric Fast Transient (EFT) of 4 kV in the level 4 of IEC 61000-4-4 was induced the EFT reduced to 600 V. Therefore, it was clearly shown that the developed EMC felter can be used for suppressing the electromagnetic interference on-board electronic devices and equipments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.543-550
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• 2018

The rapid growth of IoT technology induced by the fourth industrial revolution has resulted in research into various types of wireless sensors, and applications based on this technology are prevalent in many areas. However, among the various sites where this technology is used, railway bridges and tunnels with lengths of tens of kilometers have problems with data acquisition, due to the signal noise induced by the long distance measurement and EMI induced by the high voltage power feeding system, when conventional electric sensors are used. To overcome these problems, many studies on fiber optic sensors have been conducted as a substitute for the conventional electric sensors. However, restrictions on the types of fiber optic sensors have limited their application in railways. For this reason, a hybrid measurement system with IoT based wireless data communication, in which both electric and fiber optic sensors can be applied simultaneously, has been developed. In this study, in order to evaluate the applicability of the hybrid measurement system developed in the previous study, a real-time test for 4 types of measurement environments, which reflect possible railway sites, is performed. As a result, it was confirmed that the signals from both the electric and fiber optic sensors, which were acquired at a remote area in real-time, showed good agreement with each other and that this measurement system has the potential to handle sensors with a sampling rate of 2.5 kHz. In the future, it is expected that the IoT-based hybrid measurement system will contribute to the improvement of structural safety by enabling real-time structural health monitoring when applied to various measurement sites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5550-5558
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• 2015

Recently, fuel cell with high energy efficiency and low CO2 emission is energetically interconnected with power system. Especially, FCGS(Fuel Cell Generation System) which usually operates at high temperature, is being developed and installed in the form of large scale system. However, it is reported that power system disturbances related to surge, harmonic and EMI have caused several problems such as malfunction of protection device and damage of control device in the large scale FCGS. In order to solve these problems, this paper presents a modeling of operation characteristics of FCGS by PSCAD/EMTDC, ETAP, P-SIM software. And also, this paper proposes countermeasure algorithms to prevent power system disturbances. From the simulation results, it is confirmed that the proposed algorithm is useful method for the stable operation of large scale FCGS.