• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.21-24
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• 2002

The vector control system of an induction motor is the high performance drive system to achieve the instantaneous torque control. The vector control system is greatly divided into the direct control, and the indirect control that the most widely is used, The indirect vector control needs the rotor time constant, which changes widely according to the temperature, frequency, and current amplitude. The incorrect time constant leads to the saturation of magnetic flux or under-excitation phenomena. As a result, that deteriorate the control performance. Therefore, in this paper, the effect of time constant variation is investigated and its on-line tuning algorithm is proposed. The time constant using the torque angles was calculated and that of the validity of algorithm proposed was proved through the computer simulation and the experiment.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1056-1059
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• 1996

In this paper, we analyzed the effect of the change of the rotor time constant on the performance of the indirect vector control system. By employing indirect field orientation technique, we have also suggested an optimal control algorithm that allows an induction motor to maintain the maximum torque under the changing environment of rotor time constant. A computer simulation on the transient response of the output torque was demonstrated. To verify the validity of the method that has been proposed in this paper, an experiment has been performed utilizing TMS32OC31(40MHz) DSP chip which is capable of performing floating-point arithmetic in real time.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.2
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• pp.99-106
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• 1998

This paper proposed a speed control system for induction motors robust to variations in torque and parameters by feedforward compensating the current portion of load torque, adding a load torque observer to the conventional PI controller in the indirect vector controlled induction motor system. Computer simulations and exeperimental works using the proposed control confirm that the transient response for the variation of the reference speed and load torque becomes improved, compared with the conventional PI controled method.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2374-2376
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• 2000

In this paper, we propose an indirect vector control method using Adaptive Neuro-Fuzzy Inference System (ANFIS) parameter estimator. It estimates the rotor time constant when the indirect vector control of induction motor is applied. We use the stator current error that is difference between the current command and estimated current calculated from terminal voltage and current. And two induced current estimate equations are used in training ANFIS.The estimator is trained by the hybrid learning algorithm. Simulation results shows good performance under load disturbance and motor parameter variations.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.5
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• pp.367-375
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• 2000

It is proposed that the rotor time constant and inductance are compensated at the same time in the indirect vector control method of an induction motor. The proposed scheme compensates the rotor time constant using the difference between the Q-axis real stator current and estimated current that is calculated from the terminal voltage and current, and compensates inductance by using the difference between the D-axis real stator flux and estimated stator flux in the synchronous rotating reference frame. Although the rotor time constant and inductance vary at once, the proposed method compensates the rotor time constant and inductance with accuracy. In addition to, two variables can be compensated not only at the steady state condition, but also at the transient state, where the torque varies in a rectangular pulse waveform. Therefore, the performance of vector control is greatly improved as verified by experiment.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.649-652
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• 2003

In this paper, we presents a vector control method for the parallel-connected motor drive system. The new estimation scheme of rotor flux position is presented to reduce sensitivity due to load difference between the motors. To confirm the validity of the proposed control method. we compare a simulation result of the proposed control method with that of the conventional indirect vector control method. The simulation results show that the proposed control method is more effective for change in load torque and motor parameters.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.6
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• pp.333-341
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• 2003

In induction motor control systems driven by the indirect vector control scheme, the rotor speed is measured to determine the flux angle which is a key variable in the control algorithm. The most popular way to measure the angular velocity is the use of rotary encoder. Since the errorneous measurement of rotor speed results in incorrect flux angle estimate, the control input generated based on the faulty information should be far from the desired (correct) value and deteriorates the overall control performance. In this paper the effects of encoder fault on motor variables and control performance are analyzed by both theoretical approach and experimental study. A parity equation based on the Power is suggested and applied to detect the incipient fault of encoder.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.340-342
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• 2005

This paper describes the speed-sensorless vector control system of a three-phase induction motor using sliding mode flux/speed observer. The sliding mode observer estimates the rotor speed. The error between the actual and observed currents converges to zero which guarantees the accuracy of the flux observer. The convergence of nonlinear time-varying observer along with the asymptotic stability of the controller was analyzed. To define the control action which maintains the motion on the sliding manifold, an "equivalent control" concept was used. It was simulated and implemented on a sensorless indirect vector drive for 750[W] three-phase induction motor. The simulation and experimental results demonstrated the effectiveness of the proposed estimation method.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.366-370
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• 1998

Indirect vector control for induction motors requires the use of observers for estimation or observation of rotor flux magnitude and position. In this paper, authors discribe the induction motor vector control and introduce a nonlinear observer, named ELO(extended Luenberger Observer), without simulation results as a preliminary work for trial application. Normally, design of nonlinear observer need coordinate transfromation and linearization through solving the partial different equation. However, ELO requires minimal solution of nonlinear partial differential equation. Simulation was performed by under the enviroment of Matlab and Simulink without the proposed observer because we are still working. Simulation was performed with conventional flux observer, a dc-ac inverter by SVPWM technique, a vector controller armed with multiple PI controllers

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.156-160
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• 1997

This paper proposed the vector controller of induction motors using one chip microprocessor. For developing a small and cheep speed control system, we use the one chip microprocessor 80C196MC. By using the one chip microprocessor we can make an inexpensive and small-sized vector controller for induction motors. We apply indirect vector control method and space vector modulation method to this system. The experimental results show that the proposed inverter has high performance features.