• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.983-984
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• 2011

An effective estimation method of equivalent circuit parameters of three-phase induction motor by using FEM is presented in this paper. Arbitrary three torque-speed points at asynchronous speed on the torque-speed curve are required by using time-stepping FEM, then the equivalent circuit parameters of IM can be calculated rapidly with presented method. After obtaining the equivalent circuit parameters, the general analysis method based on equivalent circuit can be used to get entire torque-speed curve very quickly. Although the purely numerical method such as FEM also can estimate torque-speed curve directly and accurately, however, usually this process is time consuming.

• 한국유체기계학회 논문집
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• 제14권1호
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• pp.5-10
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• 2011

MTG(Micro turbine generator) operating at 400,000 rpm is under development and the impact test rig to measure the dynamic stiffness and damping coefficient of air foil bearing for high speed rotor is presented in this study. The stiffness and damping coefficient of air foil bearing depending on the rotational speed can be measured easily and effectively by using the simple configuration of impact test rig which is composed of air gun, gap sensors and high speed motor. The estimation results of stiffness and dampling coefficient using least square estimation method is presented as well.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2094-2096
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• 1998

In this paper, a new speed estimation method using neural networks is proposed and speed sensorless vector control is realized with the estimated speed. The effectiveness and the usefulness of the proposed algorithms are thoroughly verified with the experiments on the fully-digitalized 2.2kW induction motor drive systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.140-142
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• 2007

This paper presents an effective method of precise velocity control at low speed with a low resolution encoder. Multirate observer to estimate the velocity at every DSP control period is used except a constant velocity mode. The observer corrects the estimation error when detects pulse signal. Unlike the conventional methods, the multirate estimator is stable at a low speed. However, the multirate estimator shows ripples at a constant velocity. Thus, in this paper we use a velocity prediction method which uses the present velocity from the previous average velocity to reject the ripple. In a summary, at a constant speed mode, the predicted velocity is used. Otherwise, the estimated velocity by the multirate obvserver is used. The effectiveness of the multirate observer and ripple rejection at low speed is verified through various simulations.

• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.185-191
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• 2004

This study describes the scheme of vector drive system without speed sensor for AC servo motor using theory of a flux observer and based on the field oriented vector control. The new method of speed estimation is presented from operate with the position and magnitude of the secondary flux which obtain from the voltage reference and detected current. As the estimated speed is settled by the flux and the machine-specific parameters. this method don't need to adjust the gain of the parameter. Based on the derived theory for vector control. the scheme for sensorless vector drive of AC servo motor is designed and realized. And the experiment verifies it passable to realize the sensorless vector drive based on a field-oriented type.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.308-310
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• 2001

This paper investigates a novel speed sensorless control method of I.M considering the secondary resistance identification based on the transientless torque control technique. Especially, this paper aimed at the identification of the secondary resistance simultaneously with speed estimation superposing of sinusoidal flux wave to a constant flux value. Furthermore, the secondary flux with some frequency is controlled independently on torque control. The proposed speed estimation method is derived from a motor circuit equation theoretically and also it can be conducted easily by detecting primary motor currents and primary voltage commands at every sampling time. Some numerical simulations with the assumption of using a pulse width modulation(PWM) voltage source inverter are performed to verify the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2005-2007
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• 1998

The rotor speed flux information most important in the speed sensorless vector c So in the paper used current voltage model for flux information in a induction motor. Voltage realized low pass filter insted of integrator, c model realized used of current equation. And cur voltage model estimated flux compoed of Pl cont For conpensation of estimated flux error conpansation algorithm using exactly, rapidly flux obtained for conpensation of estimated flux Proposed control system used TMS320C31 DS high speed processing. The effectiveness of proposed method is verified by simulation experimental results. This method shows h characteristic speed estimation highly flux esti and stable, robust character of load regulation.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권3호
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• pp.145-153
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• 2004

A nonlinear adaptive speed observer is designed for the sensorless control of induction motors. In order to design the speed observer, the measurements of the stator currents and the estimates of the rotor fluxes are used. The sliding mode cascade observer is designed to estimate the time derivatives of the stator currents. The open-loop observer is designed to estimate the rotor fluxes and its time derivatives using the stator current derivatives. The adaptive observer is also designed to estimate the rotor resistance. Sequentially, the rotor speed is calculated using these estimated values. It is shown that the estimation errors of the corresponding states and the parameters converge to the specified residual set. It is also shown that the speed controller using these estimates is performed well. The simulation examples are represented to investigate the validity of the proposed observers for the sensorless control of induction motors.

• Wind and Structures
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• 제21권4호
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• pp.443-460
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• 2015

In this paper, an integrator based method to estimate the effective wind speed in wind turbine systems is proposed. First, the aerodynamic torque was accurately estimated through a proportional gain based observer where the generator speed is the measured output of the system. The torque signal contains not only useful frequencies of the wind, but also high frequencies and the ones due to structural vibration. The useful information of the wind signal is low frequency. A spectral analysis permitted the determination of the useful frequencies. The high frequencies were then filtered before introducing the torque signal in the wind speed observer. The desired effective wind speed was extracted through an integrator based observer using the previously estimated aerodynamic torque. The strength of the method is to avoid numerical solutions used in literature of the wind speed estimation. The effectiveness of the proposed wind speed estimator and its use to control the generator speed has been tested under turbulent situations using the FAST software (Fatigue, Aerodynamics, Structures, and Turbulence), for large scale Megawatt turbine.

• 한국산학기술학회논문지
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• 제8권2호
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• pp.212-218
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• 2007

본 논문에서는 MATLAB/SIMULINK와 dSPACE DS1104를 이용하여 유도 전동기의 속도 센서리스 벡터제어를 구현하였다. 유도 전동기의 속도 센서리스 벡터제어의 운전특성을 개선하기 위하여 전압 모델 자속 추정방식과 전류 모델 자속 추정방식을 혼합한 자속 추정기 알고리즘을 도입하여 정밀도가 높은 개선된 자속 추정방식을 사용하였다. 또한 추정된 자속을 이용하여 회전자 속도를 추정하고 이를 유도전동기의 속도 제어에 사용하였다. 전체 시스템은 직접벡터제어 방식을 기반으로 일반적인 PI 제어기를 사용한 속도 제어기, 전류 제어기, 자속 제어기로 구성하였다. MATLAB/SIMULINK를 이용하여 블록다이어그램 방식으로 속도 센서리스 벡터제어 알고리즘을 구현하였고, dSPACE DS1104의 제어보드와 Real-Time-Interface(RTI)를 이용하여 실시간 제어를 수행하였다.