• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.4
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• pp.147-147
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• 2003

This paper describes the finite element analysis(FEA) for the design of electromagnet for Control Element Drive Mechanism(CEDM) in System-integrated Modular Advanced Reactor(SMART) and compared with the lifting power characteristics of prototype electromagnet. A thermal analysis was performed for the electromagnet. A model for the thermal analysis of the electromagnet was developed and theoretical bases for the model were established. It is important that the temperature of the electromagnet windings be maintained within the allowable limit of the insulation. since the electromagnet of CEDM is always supplied with current during the reactor operation. So the thermal analysis of the winding insulation which is composed of polyimide and air were performed by finite element method. As a result, it is shown that the characteristics of prototype electromagnet have a good agreement with the results of FEA. The thermal properties obtained here will be used as input for the optimization analysis of the electromagnet.

• Proceedings of the KIEE Conference
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• summer
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• pp.875-877
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• 2004

Research related to renewable energy is urgently required to cope with the depletion of fossil fuel and the environmental pollution. This paper deals with maximum power control of 1kW rating wind power generator. To implement direct-drive generator, axial flux permanent magnet generator is adopted to test the converter. The blade is attached to the surface of outer rotor disk. Generally wind power generator is operated under the rated wind speed. To capture maximum power at my given wind speed, the coordination of generator and converter is essential. Buck/Boost converter is designed to charge 24V battery and under the low wind speed it operates as boost converter.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.243-251
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• 1998

A method of establishing the tooth modification for gear transmission of vehicles to reduce gear whine noise, caused by tooth impact phenomenon of mating gear, is introduced. The major causes of tooth impact are due to the deflections of gear teeth and shafts of transmission with the loaded condition including various kinds of manufacturing errors. The theoretical shape of tooth surface to avoid tooth impact is derived by the amount of elastic deformation of gear teeth and shaft and overall manufacturing error of machine tool. The surface function is converted with respect to the conventional commercial data usually communicated to the gear inspection system. The proposed method is applied to the gearbox of four wheel drive vehicle and shows the gear whine noise decreased to the 8 dB in the sound level.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.579-588
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• 1999

This paper presents a technique for predicting the conductLu EMI(Electro Magnetic Interference) produced b by PWM inverter-induction motor drive system. To obtain the simulation models for prediction of conduct떠 n noise, high frequency model of an inverter leg with parasitic elements and multi-coil model of stator winding M are designed. Finally, the results are confirmLu from simulation and experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.152-155
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• 2020

This study proposes an input filter for a gallium-nitride-based direct matrix converter with a stepless current commutation technique. Various current commutation strategies have been adopted for reliable operation of switches. These strategies are complex to be implemented and require additional components. The stepless current commutation technique is simple to operate but causes overcurrent issues due to the occurrence of short circuit on input sources. In this study, to restrict the short circuit current, we utilized GaN devices with fast switching properties and modified the input filter. The proposed input filter was verified by experimental results of induction motor drive.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.297-298
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• 2010

산업용 인버터 시장은 부하의 운전 조건에 따라 고성능, 다기능, 단순 기능 분야로 구분된다. 당사는 고성능, 다기능 분야에 대응이 가능한 N700V 모델을 개발하여 영업 활동을 하고 있으나, 단순기능 분야에는 기능의 복잡성과 높은 가격 등으로 경쟁력이 저하되었다. 이에 당사는 단순기능 분야에 대응이 가능하도록 기능은 단순하고 가격경쟁력이 있는 맞춤형 인버터를 새로이 개발하게 되었다. 본 논문에서는 당사가 산업용 인버터 제품의 이원화를 위해 새로이 개발된 단순 기능형 인버터 N700E(5..5kW ~ 350kW) 시리즈에 대한 주요기능 및 성능에 대해 소개하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.899-902
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• 2002

In this paper, we introduce a hyper-chaos synchronization method using State-Controlled Cellular Neural Network(SC-CNN). We make a hyper-chaos circuit using SC-CNN with the n-double scroll. A hyper-chaos circuit is created by applying identical n-double scrolls with weak coupled method, to each cell. Hyper-chaos synchronization was achieved using drive response synchronization between the transmitter and receiver about each state variable in the SC-CNN.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.116-119
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• 1997

In this paper A double-layer organic electroluminescent(EL) device was fabricated using a TPD(N,N'-dipheny] -N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4.4'-diamine: aromatic diamine), as a hole-transport material and tris (8-hydroxy quinolinate) aluminum(Alq$_3$) as a an emiting material and its performance characteristics were investigated. structure of devices is ITO/TPD/Alq$_3$/Al. we have fabricated hole transport layer of two types. Doping material of Hole Transport material is Poly(methyl methacrylate)(PMMA) and PEI(Poly-Ether-Imide). Carrier injection from the electrodes to the doped PMMA and PEI layer through the dopants and concomitant electroluminescence from Alq$_3$were observed. Green emission with luminance of 40cd/m$^2$was achieved at a drive voltage of 30V

• Journal of Power Electronics
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• v.9 no.1
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• pp.36-42
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• 2009

This paper presents a review of an improved high power-high frequency III-V wide bandgap (WBG) semiconductor device, Gallium Nitride (GaN). The device offers better efficiency and thermal management with higher switching frequency. By having higher blocking voltage, GaN can be used for high voltage applications. In addition, the weight and size of passive components on the printed circuit board can be reduced substantially when operating at high frequency. With proper management of thermal and gate drive design, the GaN power converter is expected to generate higher power density with lower stress compared to its counterparts, Silicon (Si) devices. The main contribution of this work is to provide additional information to young researchers in exploring new approaches based on the device's capability and characteristics in applications using the GaN power converter design.

• Journal of Power Electronics
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• v.10 no.2
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• pp.165-170
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• 2010

This paper presents a comparative study of P and PI controllers for a current source inverter (CSI) fed induction motor drive system. A dq model has been used which incorporates the induction motor and the inverter power supply with current feedback. The model is used first to generate the steady state curves to determine the operating point through computer simulations using the software package MATLAB. Then a transient analysis has been carried out for different values of the speed and current controller parameters. The controller value is adjusted by the Ziegler-Nichols method. It has been observed that the transient time to reach the steady state value is larger with the PI controller than with the P controller.