• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.15-18
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• 2001

This paper describes a control scheme for direct torque and flux control of induction machines. The proposed predictive flux control scheme has directly calculated the reference voltage space vector based on flux errors in order to control the torque and flux. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux, torque, and/or current error, thereby improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations and experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.293-296
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• 2002

This paper presents an implementation of Direct torque control(DTC) of Reluctance Synchronous Motor(RSM) drives for an industrial servo drive system with stator current space vector. The estimation of the stator flux magnitude are obtained by using the neural network from measuring the modulus and angle of the stator current space vector. The develolled digitally high-performance control system are shown a good response characteristic of control results and high performance features using 1.0kW RSM.

• Journal of Power Electronics
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• 제17권5호
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• pp.1211-1222
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• 2017

In order to decrease the parameter sensitivity of deadbeat direct torque control (DB-DTC), an improved deadbeat direct torque control method for surface mounted permanent-magnet synchronous motor (SPMSM) drives is proposed. First, the track errors of the stator flux and torque that are caused by model parameter mismatch are analyzed. Then a sliding mode observer is designed, which is able to predict the d-q axis currents of the next control period for one-step delay compensation, and to simultaneously estimate the model parameter disturbance. The estimated disturbance of this observer is used to estimate the stator resistance offline. Then the estimated resistance is required to update the designed sliding-mode observer, which can be used to estimate the inductance and permanent-magnetic flux linkage online. In addition, the flux and torque estimation of the next control period, which is unaffected by the model parameter disturbance, is achieved by using predictive d-q axis currents and estimated parameters. Hence, a low parameter sensitivity DB-DTC method is developed. Simulation and experimental results show the validity of the proposed direct control method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.17-20
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• 1996

An adaptive current control scheme of a permanent magnet (PM) synchronous motor with the simultaneous estimation of the magnitude of the flux linkage and stator resistance is proposed. The adaptive parameter estimation is achieved by a model reference adaptive system (MRAS) technique. The adaptive laws are derived by the Popov's hyperstability theory and the positivity concept. The predictive control scheme is employed for the current controller with the estimated parameters. The robustness of the proposed current control scheme is compared with the conventional one through the computer simulations.

• Journal of Power Electronics
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• 제18권2호
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• pp.492-501
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• 2018

In the rotor-flux oriented control used in induction motors, the electrical parameters of the motors should be identified. Among these parameters, the mutual inductance and rotor resistance should be accurately tuned for better operations. However, they are more difficult to identify than the stator resistance and stator transient inductance. The rotor resistance and mutual inductance can change in operations due to flux saturation and heat generation. When detuning of these parameters occurs, the performance of the control is degenerated. In this paper, a novel method for the concurrent identification of the two parameters is proposed based on recursive least square estimation and model reference adaptive control.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.65-68
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• 2001

In the vector control methods of induction motor, the stator current is divided into the flux and torque component current. By controlling these components respectively, the methods control independently flux and torque as in the DC motor and improve the control effects. To apply the vector control methods, the position of the rotor current is identified. The indirect vector control use the parameters of the machine to identify the position of rotor flux. But due to the temperature rise during machine operation, the variation of rotor resistance degrades the vector control. To solve the problem, the q-axis is aligned to reference frame without phase difference by comparing the real flux component with the reference flux component. Then to compensate the slip, PI controller is used. The proposed method keeps a constant slip by compensating the gain of direct slip frequency when the rotor resistance of induction motor varies. To prove the validations of the proposed algorithm in the paper, computer simulations is executed.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1156-1165
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• 2018

This paper presents a detailed realization of direct torque controlled induction motor drive for elevator applications. The drive is controlled according to the well-known space vector modulated direct control scheme (SVM-DTC). As the elevator drives are usually equipped with speed sensors, flux estimation is carried out using a current model where two stator currents are measured and accurate instantaneous rotor speed measurement is used to overcome the need for measuring stator voltages. Speed profiling for a comfortable elevator ride and other supervisory control activities to provide smooth operation are also explained. The drive performance is examined and controllers' parameters are fine-tuned using MATLAB/SIMULINK. The blocks used for flux and torque estimation and control in the offline simulation are compiled for real-time using dSPACE Microlabox. The performance of the drive has been verified experimentally. The results show good performance under transient and steady state conditions.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.26-30
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• 1999

The constraint condition is the stator voltage and the stator current to operate the motor in the flux weakening region. The maximum current is limited by the inverter current rating and the machine thermal rating. Given DC link voltage to control the motor in the flux weakening the maximum voltage is determined by considering PWM strategy, dead time, voltage drop of the inverter switching device, and the margin of the voltage for current forcing. In this paper, the new method to determine the available maximum voltage is derived by the analythic method and by considering the factors of the voltage drop. So Determining the maximum voltage is very useful to enlarge the speed operation region in the flux weakening operation, the utility of the maximum voltage is increased.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.742-747
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• 2006

This paper describes online stator-resistance estimation of a linear induction motor(LIM) with cage-type secondary using direct thrust control(DTC), where the resistance value is derived from stator-winding temperature estimation using thermocouple. In this paper, corrected stator resistance has an error in actuality measurement resistance. So compensation coefficient $\kappa$ which is decided through comparison and verifying several times relation of calculated resistance and measured motor line-line resistance. The stator-winding temperature information can also be used for monitoring, protection, and fault-tolerant control of the machine. Also, this paper reports the LIM's responses of the flux measured by the proposed stator resistance compensation algorithm.

• Journal of Advanced Marine Engineering and Technology
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• 제33권8호
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• pp.1261-1267
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• 2009

직접토크제어는 일정한 히스테리시스 범위 내에서 전동기의 자속과 토크를 제어하는 방법으로서 최적 스위칭 테이블을 사용한 고정자 전압 공간 벡터에 의해 전동기의 자속과 토크를 제어하게 된다. 그리고 본 논문에서 사용한 센서리스 제어법은 실제 전동기와 수식 모델의 전류가 수렴하도록 고정자 전압을 인가하면 실제 전동기 회전자 속도가 속도 지령치인 수식 모델의 회전자 속도에 접근하는 제어방식이다. 이 방식들을 접목하면 PI 제어기가 필요하지 않는 간단하면서도 강인한 제어를 구현할 수 있는데 본 논문에서는 컴퓨터 모의실험을 통해 이의 유효성을 입증한다.