• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1165-1168
• /
• 2001

The effect of sensor faults in DTC based induction motor drives is analyzed and a fault detection problem is treated. An adaptive gain scheduling observer is proposed for the design of DTC controller and a fault detection system. The observer provides not only the estimate of stator flux, a key variable in DTC system, but also the estimates of stator current, rotor speed that are useful for fault detection purpose. Simulations for various type of sensor faults are performed to evaluate the performance of the overall control system and the proposed sensor fault detection scheme.

• Proceedings of the KIEE Conference
• /
• 1989.11a
• /
• pp.264-267
• /
• 1989

In the vector controlled induction machine drives, mechanical speed sensors such as shaft encoder and resolver have been used. However, the mechanical speed sensors present some problems and restrict the wide applications of high performance AC drives. This paper describes the vector control strategy with the speed estimation algorithm in which motor slip frequency is calculated. Also, the angle deviation of the rotor flux vector is calculated and instaneously compensated to keep the q axis flux zero in the rotationary reference frame.

• Journal of KIEE
• /
• v.11 no.1
• /
• pp.62-68
• /
• 2001

In this paper it is proposed an advanced modified sliding mode control of a rotor field oriented control of induction motor. The application of this unconventional control has very good results, such as disturbance rejection and nice dynamic properties. Stability can be guaranteed even in the worst situation. A conventional "sliding mode" controller is characterised by fast switching control signal, which causes the chattering of the drive system. To overcome this problem, a modified law is used, by introducing a hysteresis band and a continuous control, which modifies the conventional law. The control is accomplished with dual TMS320C44 floating-point digital signal processor. The validity of the proposed method was verified by experiment on the propulsion system simulator, used for the development of Korean High-Speed Railway Train(KHSRT).in(KHSRT).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.4
• /
• pp.610-616
• /
• 2008

This paper presents a new robust sensorless control system for high performance induction motor drives fed by a matrix converter with variable structure. The lumped disturbances such as parameter variation and load disturbance of the system are estimated by a variable structure approach based on model reference adaptive scheme. A Reduced Order Extended Luenberger Observer(ROELO) is also employed to bring better responses at the low speed operation. Experimental results are shown to illustrate the performance of the proposed system.

• Proceedings of the KIEE Conference
• /
• 1995.07a
• /
• pp.216-218
• /
• 1995

In this article a neural network adaptive observer is proposed and applied to the case of induction motor control. The high performance vector control drives require exact knowledge of rotor flux. Because rotor time constant is needed to observe rotor flux, the accurate estimation of rotor time constant is important. For these problems, proposed observer which comprises neural network flux observer and neural network torque observer is trained to learn the flux dynamics and torque dynamics and subject to further on-line training by means of a backpropagation algorithem. Therefore it has been shown that the robust control of induction motor neglects the rotor time constant variations.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1990.10a
• /
• pp.47-52
• /
• 1990

This paper presents a cyclocoverter with a LC resonant circuit for a induction motor dr-ive. The cycloconverter can provide variab-le voltage and frequency three phase output while keeping the input displacement factor at 1.0. The input current wave forms are sinusoidal, and the wide output frequency ran-ge is appropriate for variable speed AC motor drives.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.394-398
• /
• 1999

Direct Torque Control method for an Induction Motor is presented which is quite different from field-oriented control. It carries out a precise and quick control of the stator flux and electromagnetic torque of an IM without calling for coordinate transformation, speed measurement, and stator current control. In principle, moreover, DTC operation requires only the knowledge of the stator resistance.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.386-389
• /
• 1999

In this paper a Direct Torque Control(DTC) scheme for PWM three level inverter-fed induction motor drives, is presented and discussed. In orde to deal with DTC scheme applied three level inverter, the selection of voltage vector is proposed to minimize switching frequency and torque ripple. The simulation results shows a validity of the control scheme.

• Proceedings of the KIEE Conference
• /
• 1989.11a
• /
• pp.273-277
• /
• 1989

This paper concerns to drive Induction Motor with open delta winding, and improve general performance, speed response, operation region and flexibility of control, etc. And a control algorithm, which reduces large zero-phase current at this operation, is presented.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.4
• /
• pp.432-439
• /
• 1999

Several methods of induction motor drives which used speed estimators instead of shaft encoders have been reported. However those speed sensorless systems with estimators employing stator voltates and currents usually deteriorates as the speed gets lower because it is difficult to calculate the accurate rotor flux under the influence of DC-offset and saturation of integrators. In this paper to calculate rotor flux at low speed the new rotor flux estimator which replaces integra-tors with two lag circuits is proposed. Simulation and experiment results confirm the validity of this control scheme.