• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.298-302
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• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, UM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1,100kVA inverter with four 210kW traction motors.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.135-138
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• 2005

This paper focuses on emergency source and control of substation against the consequence of power system breakdown or outage. the aim of the paper is to provide ideas and guidance concerning methods of using AC/DC combined emergency source for power system control to restore power system after unforseen events, such as outages caused by natural disaster. so the emergency source and lamp is very important for restoration control of substation after outage. therefore, this paper proposes countermeasure and method for security of substation emergency source and lamp which is restored at breakdown.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1109-1111
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• 1997

The purpose of this paper is to analyze the effects of switching-over control for power system stabilization. Switching-over control is applied to western part of korea electric power system to improve transient stability and short-circuit capacity. It's effectiveness is demonstrated in terms of fault current level and critical clearing time which is quantitative evaluation means of transient stability. The effect of generator tripping for power system stabilization is also presented.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.289-292
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• 2008

This paper represents the electric energy saving using light control system. Without Light Control System(LCS), it is very hard to classify the amount of electric energy saving for lighting, since it is determined by the end-user's preference in times. Typical LCS has an fixed algorithm to control each light's intensity by ON/Off Control, Step Control, or Dimming Control. We have studied the electric energy saving effect in a LCS equiped building with natural lighting. The electric power consumption at the peak power consumption time with LCS reduced up to 65% of the non-controled case.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.526-528
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• 2006

An adaptive output-feedback neural control problem of SISO strict-feedback nonlinear system is considered in this paper. The main contribution of the proposed method is that it is shown that the output-feedback control of the strict-feedback system can be viewed as that of the system in the normal form. As a result, proposed output-feedback control algorithm is much simpler than the previous backstepping-based controllers. Depending heavily on the universal approximation property of the neural network (NN) only one NN is employed to approximate lumped uncertain nonlinearity in the controlled system.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.105-108
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• 2015

A digital Governor (GOV) has been developed for being used for a Francis hydro turbine, and the validity of the GOV has been tested. As for the hardware system for the GOV, we purchased a basic digital control system that already had proven its reliability in the power industry. We developed a set of new GOV software and integrated it with the hardware system, and finally verified the performance of the whole GOV system. For the human-machine interface (HMI), we configured and implemented appropriate graphic interfaces for the turbine operations. This paper describes the major GOV control functions, approaches we took in developing the GOV control logics, and the validity tests and the results.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.728-733
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• 2003

In human-mechanical cooperative systems, a significant issue is to improve the control performance and the maneuvering feeling of human operation. However, since it is not easy to evaluate the feeling of operators numerically, control engineers design controllers only through experience. Thus, in this paper, a new evaluation method for control performance of human-mechanical cooperative system is proposed based on the reserge waveform. Various distortions of waveform represent deteriorations of control performance and maneuvering feeling. In some cases, since there is a tradeoff between the control performance and the maneuvering feeling, it is difficult to compensate for both of them by usual feedback controllers. To overcome this situation, the two degrees of freedom control system is applied to human-mechanical cooperative system. Some numerical simulation results for an electric power steering system are shown to confirm the effectiveness of proposed control design method.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2319-2328
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• 2018

This paper introduces a control method for a transformerless MMC-HVDC system. The proposed method can effectively control the grid currents of the MMC-HVDC system under unbalanced grid conditions such as a single line-to-ground fault. The proposed method controls the currents of the positive sequence component and the negative sequence component without separating algorithms. Therefore, complicated calculations for extracting the positive sequence and the negative sequence component are not required. In addition, a control method to regulate a zero sequence component current under unbalanced grid conditions in the transformerless MMC-HVDC system is also proposed. The validity of the proposed method is verified through PSCAD/EMTDC simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.3
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• pp.311-318
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• 1997

In this paper, a controller with monitoring functions is proposed for controlling temperature of an electric furnace system. The controller includes holding and ramp control functions, and the control program for the temperature process monitor of the electric furnace. For this purpose, the implementation and performance of auto tuning algorithms in a computer¬based controller is studied in relation to control of a nonlinear electric furnace system which is characterized with large time delay. The communicator of a control and detection signals, between the controller and the electric furnace is implemented by an I/O data card. Experiments for the practical electric furnace are performed to illustrate the performance of the proposed controller.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.70-73
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• 1992

With regard to the supply of electric power in better quality, the problem of lightning is becoming more and more important in the operation of an electric power system. In this article a description is given of the new lightning position and tracking system which will be installed in KEPCO. The system is based on the principle of time-of-arrival (TOA) rather than the conventional direction-finding (DF) method.