• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.111-119
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• 2013

This paper present stabilization control of fixed speed wind generator by using variable speed permanent magnet wind generator in a wind farm connected with multi-machine power system. A novel direct-current based d-q vector control technique of back to back converter integrated with Fuzzy Logic Controller for optimal control configuration is proposed, in which both active and reactive powers delivered to a power grid system are controlled effectively. Simulation analyses have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is very effective to enhance the voltage stability of the wind farm during fault condition.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.37-39
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• 2004

This paper deals with the prediction of armature reaction field produced by 3-phase stator windings whose current waveform contains significant harmonics. On the basis of 2-d analytical technics, we derived governing equation and predicted magnetic field distribution according to rotor position. The results of predictions from the analysis are compared with corresponding FE (finite element) analyses.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.460-467
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• 2008

This paper presents a new numerical algorithm for the fault location estimation and arcing fault detection when a single-phase arcing ground fault occurs on a transmission line. The proposed algorithm derived in the spectrum domain is based on the synchronized voltage and current samples measured from the PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. In this paper, the algorithm uses DFT(Discrete Fourier Transform) for estimation. The algorithm uses a short data window for real-time transmission line protection. Also, from the calculated arc voltage amplitude, a decision can be made whether the fault is permanent or transient. The proposed algorithm is tested through computer simulation to show its effectiveness.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.144-149
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• 2013

This work deals with the optimal design of a coreless PMLSM (Permanent Magnet Linear Synchronous Motor) with consideration of rising winding temperature. The temperature distribution caused by copper loss in the coreless PMLSM was analyzed using a FEM (Finite Element Method). The thrust and current density where the winding temperature reaches the allowable temperature were calculated. The optimal model provides maximum thrust per unit weight.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.820-821
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• 2015

본 논문에서는 영구자석형 기기의 RT(Real Time) 모델을 이용하여 실 제어상태의 PWM 스위칭 전류를 계산하고 철손과 회전자 영구자석의 손실을 현실적으로 해석하는 프로세스가 제시된다. 이러한 계산 프로세스는 전동기 구동 시스템의 실제 제어 환경과 전동기의 모델링을 고려하였다. 전동기 구동시스템의 모델링은 상용 소프트웨어인 MATLAB/Simulik 와 JMAG-RT 모델을 결합하여 구현되었으며, 전류 제어기의 PWM 스위칭 전류를 이용하여 영구자석 전동기의 철손이 계산되었다. 제안된 프로세스는 기 제작된 설계 모델을 대상으로 적용 타당성이 검증되었다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.892-893
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• 2015

This paper deals with a characteristic that varies the number of magnetic pole in permanent magnet (PM) motor in order to reduce energy consumption. The pole changing memory motor (PCMM) can change the number of magnetic poles and produce two types of torque. When the motor operates with eight poles, it produces a magnetic torque at low rotational speeds. When the motor changes to four poles, it produces both magnetic torque and reluctance torque at high speeds. The paper explain the principle and basic characteristics of the motor by using a finite element method magnetic-field analysis, which consists of a PM magnetized by a pulse d-axis current of the armature winding. The results of our experiment show that the proposed motor reduces core loss by 10% and 55% under no-load and load conditions, and doubles the speed range of the motor.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.737-739
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• 2015

In this paper, a novel method of sensorless control scheme is proposed to apply on a single phase hybrid SRM used in high speed operation. The proposed method utilizes beneficially permanent magnet field whose performance is motor parameter independent to estimate the rotor position. Also, the current slope is adopted to complete the sensorless control when the motor running with heavy torque at high speed condition. Through this approach, the adjustable turn on/off position can be achieved without prior knowledge of inductance profile which is always employed by many sensorless schemes. And this paper may offer an available method to do the sensorless control in hybrid SRM used for high speed running.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.898-899
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• 2015

This paper present a transient experiment to verify the performance of limited angle torque motor(LATM) designed using electromagnetic transient analysis. LATM requires access to the transitional state to the torque performance evaluation. Because LATM moves the rotor using a magnetic torque generated by the interaction of the permanent magnet and the armature winding. A separate control is not applied, it is switched on at the same time under the conditions that the current applied to the armature winding. It was compared to the transient analysis of the experimental data of LATM for the verification of approach method in the transitional state.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.860-861
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• 2015

본 논문에서는 대용량 착자요크의 설계과정에서 최대입력 전류의 크기를 산정하기 위하여 해석적인 방법을 이용하여 산정하였다. 착자요크의 등가회로로부터 회로방정식을 도출하고 2차 미분방정식으로 표현하여 입력전류를 산정하였다. 산정된 입력전류는 회로해석 툴 및 유한요소해석을 이용한 상용소프트웨어와 비교하여 해석방법의 타당성을 검증하였다.

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.54-63
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• 1998

This paper proposes a theoretical analysis of a closed loop adaptive speed control system for control the inverter driven permanent magnet synchronous motor(PMSM). This control system utilizes a mechanically sensorless state observer for the generation of all controller feedback information. The observer processes measurements of stator frame voltage and current to produce estimates of rotor position and speed and rotor frame currents. It is shown that the identity observer, when properly formulated, has the same linearized error dynamics as the extended kalman filter(EKF). Consequently, it is shown that the gains within the identity observer can be designed in a manner identical to that of the EKF. In this way, the designability of the nonlinear observer is assured, as is the optimality of its performance for small errors. A sequence of simulation are performed and they demonstrate the successful performance.