• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.144-146
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• 2003

This paper presents a new speed sensorless control algorithm of a permanent magnet synchronous motor based on instantaneous reactive power. The proposed algorithm is constructed by instantaneous reactive power in the stationary reference frame and is not affected by mechanical motor parameters, because mechanical equation is not used. The effectiveness of the proposed algorithm is verified by the experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.4
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• pp.124-134
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• 2011

A new dead time compensation scheme that can exactly estimate the dead time and inverter nonlinearity under parameter variations is proposed for a PWM inverter-fed PMSM drive. The proposed scheme uses the fact that the sixth harmonic component in total disturbance estimated under the presence of various uncertainties is mainly caused by the dead time and inverter nonlinearity. The total disturbance due to the parameter variations as well as the dead time and inverter nonlinearity is estimated by the adaptive scheme. The sixth harmonic component is extracted from this total disturbance through harmonic analysis. The obtained sixth harmonic is processed by the PI controller to estimate the disturbance caused by the dead time and inverter nonlinearity in the stationary reference frame. The effectiveness of the proposed scheme is verified. Without requiring an additional hardware, the proposed scheme can effectively compensate the dead time and inverter nonlinearity even under the parameter variations.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.93-94
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• 2017

본 논문은 quasi P+MR 전압 제어를 활용한 삼상 인버터의 계통 동기화 방식을 제안한다. 계통동기화 과정 시 시스템이 고정자 좌표계하에서 제어 또는 모델링된다면 독립운전에서의 정전압 및 정주파수를 갖는 교류 지령 전압은 교류 계통 전압으로 즉각 대체되며 이때 인버터의 실제 전압과 계통 전압 간의 위상차에 기인하여 상당한 제어 오차가 발생할 수 있고 이는 심각한 전압 동특성 저하를 야기하기도 한다. 게다가 인버터 출력단에 비선형 부하가 연결될 경우 부하로부터 발생하는 고조파로 인해 이러한 전압 품질에 대한 문제가 더욱 증대된다. 본 논문에서는 독립 운전 모드에서의 전압제어를 위하여 이러한 비선형 부하의 고조파 영향을 고려한 고정자 좌표계 기반의 PR 제어를 사용한 매끄러운 계통 동기화 방식이 제안되었다. 제안된 매끄러운 계통 동기화 방식의 타당성은 기존의 고정자 좌표계 기반의 계통 동기화 방식과의 비교 사례연구를 기반으로 한 실험을 통해 입증된다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.46-51
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• 1993

본 연구에서는 2회전자계(Two Revolving Field)이론과, 고정기준좌표계 (Stationary Reference Frame)이론을 이용하여 토오크 산출식을 유도하고 이 두 식을 비교하였다. 또한 고정자(Stator)의 전압과 전류를 측정한 결과에 고 정기준좌표계이론을 적용하여 토오크를 간접적으로 구하는 실험을 수행하여 변동토오크를 실험적으로 확인하도록 하였다. 또한 시뮬레이션(Simulation)을 통해 진동기 설계 매개변수들이 토오크의 변동성분에 미치는 영향을 파악하 고, 고정자 코일의 저항과 축전기의 영향은 실험을 통하여 확인하였으며, 더 불어 다구찌 방법을 이용하여 특정 목적 하에서 토오크의 변동성분을 줄이 는 전동기 설계 매개변수를 제시하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.11
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• pp.2723-2729
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• 1993

Moire principles are applied to the measurement of the spindle radial error motion. As opposed to conventional techniques, no master cylinder or ball is needed in the measurement so that the offset and out-of-roundness errors of the master can be inherently eliminated. Two periodic circular gratings are used, one is made on the spindle and the other is held stationary on the reference frame. When the two gratings are seen superimposed during spindle rotation, an interference fringe pattern is observed from which the information on the eccentricity between the two gratings can be extracted with high precision. The optical design and fringe analysis techniques of a prototype measurement system are described in detail with exemplary measurement results.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.304-307
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• 2002

A sensorless velocity control strategy for permanent magnet synchronous motors is presented in this paper. Two stator currents are measured and processed in discrete form in DSP. The rotor position and speed are estimated through the stator flux linkage and its derivative estimation. Flux and its derivative are calculated in the stationary reference frame and used to estimate the speed and position. The closed-loop speed control has been shown to be effective from standstill to rated speed. Moreover, a flux drift problem caused by the integration can be eliminated so that a stable sensorless starting and running operation can be achieved. Experimental results are presented to demonstrate the effectiveness of the proposed scheme.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.443-450
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• 2010

An enhanced control strategy for variable-speed unbalanced stand-alone doubly-fed induction generator-based wind energy conversion systems is proposed in this paper. The control scheme is applied to the rotor-side converter to eliminate stator voltage imbalance. The proposed current controller is developed based on the proportional-resonant regulator, which is implemented in the stator stationary reference frame. The resonant controller is tuned at the stator synchronous frequency to achieve zero steady-state errors in rotor currents without decomposing the positive and negative sequence components. The computational complexity of the proposed control algorithm is greatly simplified, and control performance is significantly improved. Finally, simulations and experimental results are presented to verify the feasibility and the robustness of the proposed control scheme.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.482-489
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• 2006

This paper presents the generalized dynamic modeling of self-excited induction generator (SEIG) using state-space approach. The proposed dynamic model consists of induction generator; self-excitation capacitance and load model are expressed in stationary d-q reference frame with the actual saturation curve of the machine. An artificial neural network model is implemented to estimate the machine magnetizing inductance based on the knowledge of magnetizing current. The dynamic performance of SEIG is investigated under no load, with the load, perturbation of load, short circuit at stator terminals, and variation of prime mover speed, variation of capacitance value by considering the effect of main and cross-flux saturation. During voltage buildup the variation in magnetizing inductance is taken into consideration. The performance of SEIG system under various conditions as mentioned above is simulated using MATLAB/SIMULINK and the simulation results demonstrates the feasibility of the proposed system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.522-527
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• 2003

This paper proposes a new speed and flux estimation method which has the robustness against the variation of the electrical parameters of the motor and the superiority in the dynamic characteristics. In the proposed method, the stator currents and the rotor fluxes are observed on the stationary reference frame using the sliding mode concept. And the rotor speed is estimated using the current estimation errors and the observed rotor fluxes based on the Lyapunov stability theory. Also a design method of the observer gain is proposed to minimize the effect of the speed estimation error on the rotor flux observation. The experimental results are shown to verify that the proposed method shows the excellent performances under the variations of motor resistance and inductance.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.270-272
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• 1994

A new current control technique for inverter-fed vector controlled induction motor drives is presented. Using a integral variable structure control(IVSC) approach, the current controller is designed in the stationary rotating reference frame. The chattering reduction technique is also considered by the full state flux observer. By employing the proposed control scheme, a good control performance is achieved in the transient and steady state. The effectiveness of the proposed scheme is demonstrated through the comparative simulations.