• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1068-1070
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• 2005

This study sorted high voltage motors by the voltage and the capacity and analyzed the property of motor-start. So we found out some problems of the starting circuit from several sites, and made the answers of the problems. If these results of our study are utilized in new WTPs, the safety of the starting circuit will be improved and the life of electric power system will be longer. We recommend this study as a reference when our company founds the standard of electric facility design.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.70-72
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• 1998

Because of using PWM inverters and converters. The problems of insulation breakdown is emerging in both high voltage motors and general motors. In conventional methods, the viewpoint of surge problems is wave propagation with or without cable and inverter. For the purpose of knowing the situation of insulation breakdown, the end-turn coil of windings in the motor winding insulation structure is modelled by FEM, and field analysis of that is done. For first step, only end-turn coil is modelled and the model is simulated with FEM by approximating the resistivity of metallic foil surrounding insulation layers with having nonlinear property. Next, the result of simulation with nonlinear resistivity are compared with the result of linear resistivity. Because of microscope analysis, there is the problem of generalization but the situation of corona discharge in end-turn coil will be explained from this simulation.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1175-1177
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• 2002

본 논문에서는 외란에 매우 강인한 특성을 갖는 유전자 알고리즘에 의한 PI 제어기를 통하여 속도 제어기를 설계하고 성능평가를 하였다. 유전자 알고리즘의 파라미터인 교배율, 돌연변이율, 세대내 개체수 세대수를 선정하여 최적해를 구하는데 적절한 선정이 필요하다. 따라서 Matlab/Simulink 환경 하에서 유도전동기 제어 시스템을 모델링하고 시뮬레이션 결과를 통해서 유전자 알고리즘의 적절한 파라미터 선정 후 제어기의 유용성을 입증하였다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.28-30
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• 1996

In the paper the authors deal with inverter fed induction motors design criteria for having a wide constant power range. In particular, the flux weakening operation is the main feature considered. The design target concerns the possibility of having a wide flux weakening region avoiding or limiting, at the same time, to oversize the motor and the inverter.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.177-181
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• 1997

In the speed control system of motors using the low resolution rotary encoder, the period of encoder pulse becomes longer than the sampling time for speed control in the range of very low speed. Therefore, it is difficult to obtain accurate speed information. In this paper, the speed estimating method at the very low speed region using reduced order torque observer, which has been widely used, is examined. The results of simulation show that the characteristics of the speed control at the very low speed region is improved by using the reduced order torque observer.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.501-504
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• 1999

과거 벡터 제어의 모델링에 있어 무시되어온 철손의 영향이 최근 여러 논문들에서 연구되어졌으며, 이의 영향이 적지 않음이 밝혀졌다. 본 논문은 속도 센서리스에서의 철손으로 인한 영향을 보상, 직접 회전자 자속 제어와 직접 고정자 자속 제어에 적용하였다. 또한 센서리스 제어에서의 철손의 영향과 그 보상 방법을 보여주며, 시뮬레이션을 통해 이러한 제안의 타당성을 보인다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.518-521
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• 1999

This paper describes high speed squirrel cage induction motor drives without speed sensors using neural network based on Kalman filter Learning. High speed motors are receiving inverasing attentions in various applications, because of advantages of high speed, small size and light weight with same power level. Larning rate by Kalman filtering is time varying, convergence time fast, effect of initial weight between neurons is small.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.1-6
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• 1998

To achieve fast control action, direct control methods should be used. "Direct Mean Torque Control" (DMTC) combines the good dynamic performance of Direct Torque Control (DTC) with the advantages of inherently constant switching frequency and time equidistant control for implementation in a digital signal processor. Since DMTC is a predictive control algorithm, the model and its correction deserves special investigations. This paper proposes a steady-state Kalman filter which is well suited for fast computation.mputation.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.540-543
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• 2003

This paper presents a method for increasing controller performance through multirate state estimation for ac machines at a low velocity. The multirate controller outputs control desired speed at each measurement Instant. The simulation results show that the performance of multirate velocity estimation and control at low velocity is improved than single rate one.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.360-364
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• 1994

This paper is concerned with extracting the diagnostic signature for motor-operated valves (MOV's) noninvasively. A torque estimator is developed and tested to obtain electical torque of the induction motors which are attached to the MOV's. Inverse filter is used to recover the gear meshing forces from the measured actuator housing vibration, which contain the gear rotation information. Frequency demodulation techniques are performed and an adaptive linear bandpass filter is implemented to improve signal-to-noise ratio. Finally, stand-alone valve experiments are carried out to validate the signature extraction scheme.