• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권4호
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• pp.151-157
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• 2001

This paper presents an identification method of parameters of induction motor which is driven by PWM voltage inverter. The method uses least square estimation based on the step voltage input and current response. Utilizing the fact that ratio of two characteristic roots is large in the induction motor circuit, we derived two 1st-order difference equations for direct computation of parameter values. experimental results are compared with conventional motor test results to demonstrate that the proposed method is capable of estimating parameters of induction motor at standstill.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권1호
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• pp.1-7
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• 2002

This paper proposes a algebraic parameter determination of MRA(Model Reference Adaptive Control) controller using block Pulse functions and block Pulse function's differential operation. Generally, adaption is performed by solving differential equations which describe adaptive low for updating controller parameter. The proposes algorithm transforms differential equations into algebraic equation, which can be solved much more easily inn a recursive manner. We believe that proposes methods are very attractive and proper for parameter estimation of MRAC controller on account of its simplicity and computational convergence.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1060-1062
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• 1996

This paper presents a discrete adaptive observer for MIMO system of an IM model in DQ reference model. The IM model in the stationary frame is discretized and it is transformed into the canonical observer form. The unknown parameter is choosen as rotor speed. The adaptive law for parameter adjustment is obtained as a set of recursive equations which are derived by utilizing an exponentially weighted normalized least-square method. The proposed adaptive observer converges rapidly and is also shown to track time-varying plant parameter quickly. Its effectiveness has been demonstrated by computer simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.468-471
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• 1994

This paper presents the digital implementation of an optimal and robust VSS controller with sliding observer. Firstly, a discrete-time VSS control law which enables the system state to move into a sliding sector where the closed-loop system is stable is designed. Then optimal control theory is used to design an optimal sliding sector. Secondly, a sliding observer which provide robust state estimation against model-plant mismatches due to parameter uncertainties is designed for the sampled-data multivariable systems. Finally, modified sliding observer which effectively reduce chattering of state variables in state estimation was proposed. The proposed scheme was applied 10 a two degree of freedom inverted pendulum with passive joint to verify robust motion control. Computer simulation results confirm the viability of the proposed observer-based controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.537-540
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• 1998

This thesis deals with the design problem of the state estimator for digital servo system. Digital servo system has input time delay, which depends on the size of control algorithm. The delayed input is a factor that brings out the state estimation error. So, in order to reduce this state estimation error of the system, we proposes a state estimator in which the delayed input of the system is considered. At first, a discrete-time state-space model is established accounting for the delayed input. Next, the state estimator is designed based on this model. we employ Kalman filter algorithm in design of the state estimator. The performance of proposed state estimator is exemplified via some simulations and experiment for servo system. And robustness of the proposed estimator to modelling error by variation of the system parameter is also shown in these simulations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.109-111
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• 1989

In this paper, we propose a new method of parameter est mat ion which modifies the exponentially weighted RLS (WRLS) method using asliding window. It can be used in adaptive control for a class of linear tine varying system. Computer simulations show that our new method tracts rapidly time varying parameters more effectively than WRLS.

• 전기의세계
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• 제31권5호
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• pp.361-367
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• 1982

The problem of parameter identification for multivariable stochastic linear systems from output measurements, which are corrupted by noises, is considered. A modified Luenberger's input/output canonical form is used for reducing the number of unknown coefficients. A computationally and conceptionally simple systematic procedure for parameter estimation is obtained using output correlation method. The estimates are shown to be asymptotically normal, unbiased and consistent. Numerical examples are presented to illustrate the identification method.

• 한국산학기술학회논문지
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• 제17권2호
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• pp.697-702
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• 2016

매입형 영구자석 동기전동기의 원활한 제어를 위해서는 전동기의 상수인 고정자 저항이나 각종 인덕턴스의 값, 그리고 쇄교 자속의 값 등을 정확하게 알아야 한다. 그러나 이러한 상수들은 전동기 운행에 따른 전동기 온도의 상승이나 각 작동점 등의 변화에 따라 계속적으로 변하기 때문에 이들의 값을 정확하게 추정하는 것은 매우 어렵다. 이러한 문제점을 극복하기 위해서 실시간으로 상수의 값을 추정하는 기법이 필요한데 본 논문에서는 MRAS(Model Reference Adaptive System) 기법을 이용한 상수의 추정 및 적응제어 기법을 제시한다. 시스템의 관계식이 이들 상수에 대해 비선형으로 구성되어 있어 일반적인 제어기법을 적용하는데 문제가 있어 일부 논문에서는 상수의 일부를 안다고 가정하였지만 본 논문에서는 이러한 가정 없이 모든 상수를 추정하는 제어기법을 제시하고 적응제어 기법의 수렴성을 입증하였다. 제시하는 알고리즘의 우수성은 시뮬레이션을 통해 입증하도록 한다.

• Journal of Power Electronics
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• 제3권2호
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• pp.99-114
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• 2003

This paper presents a feasible development on a highly accurate quick response adjustable speed drive implementation fur general purpose induction motor which operates on the basis of sensorless slip frequency type vector controlled sine-wave PWM inverter with an automatic tuning machine parameter estimation schemes. In the first place, the sensorless vector control theory on the three-phase voltage source-fed inverter induction motor drive system is developed in slip frequency based vector control principle. In particular, the essential procedure and considerations to measure and estimate the exact stator and rotor circuit parameters of general purpose induction motor are discussed under its operating conditions. The speed regulation characteristics of induction motor operated by the three-phase voltage-fed type current controlled PWM inverter using IGBT's is illustrated and evaluated fur machine parameter variations under the actual conditions of low frequency and high frequency operations for the load torque. In the second place, the variable speed induction motor drive system, employing sensorless vector control scheme which is based on three -phase high frequency carrier PWM inverter with automatic toning estimation schemes of the temperature -dependent and -independent machine circuit parameters, is practically implemented using DSP-based controller. Finally, the dynamic speed response performances for largely changed load torque disturbances as well as steady state speed vs. torque characteristics of this induction motor control implementation are illustrated and discussed from an experimental point of view.

• 전기학회논문지P
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• 제58권2호
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• pp.122-129
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• 2009

Frequency is an important operating parameter of a power system. It is essential that the frequency of a power system be maintained very close to its nominal frequency. And frequency measurement devices have need to measure a fast and accurate of frequency using voltage signals. This paper proposes a comparative study of frequency estimation techniques using the high speed FIR filter based algorithm, the DFT filter based algorithm using phasor angle between two phasors, and positive sequence component based algorithm using the half angle between two successive positions of phasor. The discussed three techniques have been formed through numerical manipulation of a discrete system. The proposed techniques have been tested using signals obtained from selected power system model using ATP simulation package. Some test results are shown in this paper.