• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.221-224
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• 1998

A PWM inverter with an induction motor often has a problem with a high-frequency leakage current that flows through the distributed electrostatic capacitance from the motor windings to ground. This paper presents an equivalent circuit for high-frequency leakage currents in PWM inverter feeding an induction motor, which forms an LCR series resonant circuit.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.33-34
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• 2006

When high-voltage motors are started, inrush current is rising as a serious power quality problem in terms of electric power line. So, this study is measured electrical data from induction motor's various starting method and is proposed the most appropriate starting method for induction motor at WTPs.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.166.2-166
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• 2001

This paper is concerning a vector control of wound-rotor induction motor from the secondary side. When the wound-rotor induction motor is vector controlled from the secondary side, it has the possibility that the vector control can be accurately done because the disturbance input, that is, primary voltage and all state variables, that is, primary currents and secondary currents can be detected. We consider it is deserve research that the vector control of wound-rotor induction motor from the secondary side, because there is the merit that we can reduce the inverter capacity to on the order of half of the motor capacity when we choose twice of the synchronous speed to the rated speed, though there is the problem of the brush maintenance. In this paper, the vector control method of wound-rotor induction ...

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.485-493
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• 2007

This paper deals with the problem of detection of induction motor incipient faults. Artificial Neural Network (ANN) approach is applied to detect two types of incipient faults (1). Interturn insulation and (2) Bearing wear faults in single-phase induction motor. The experimental data for five measurable parameters (motor intake current, rotor speed, winding temperature, bearing temperature and the noise) is generated in the laboratory on specially designed single-phase induction motor. Initially, the performance is tested with two inputs i.e. motor intake current and rotor speed, later the remaining three input parameters (winding temperature, bearing temperature and the noise) were added sequentially. Depending upon input parameters, the four ANN based fault detectors are developed. The training and testing results of these detectors are illustrated. It is found that the fault detection accuracy is improved with the addition of input parameters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.683-692
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• 2007

An inverter driven induction motor has more superior dynamic characteristic than sine wave driven induction motor. But it has a problem with shaft voltage and bearing current in drive-motor system. This paper presents the analysis of bearing current in inverter-fed induction motor. The proposed method is based on using numerical method (FEM) to derive parasitic parameters in motor. Using the electric field analysis with FEM, the stored energy in dielectric materials of the motor can be calculated and the parasitic capacitances are obtained. Then we compared the proposed method with a conventional method in variable frequency and load conditions. From the comparision of simulation and experiment result, we confirmed that the proposed method is valid.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.544-548
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• 1999

Using Observer, on the sensorless vector control system is a novel techniques for modern induction motor control. In this paper, a speed estimation algorithm of an induction motor using an extended kalman filter was proposed. Extended kalman filter can solve the problem, that have steady state error of estimated speed in flux and slip estimation method. The extended Kalman filter is employed to identify the speed of an induction motor and rotor flux based on the measured quantities such as stator current and DC link voltage. In order to confirming above proposal, computer simulation carried out using Matlab Simulink and show the effectiveness of the control drives for induction motor speed estimation.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.249-254
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• 1998

A control approach for the robust position control of induction motors based on the improved binary disturbance observer is described. The conventional binary disturbance observer is used to remove the chattering problem of a sliding mode disturbance observer. However, the steady state error may be existed in the conventional binary disturbance observer because it estimates external disturbance with a constant boundary layer. In order to overcome this problem, a new binary disturbance observer with an integral augmented switching hyperplane is improved. The robustness is achieved, and the continuous control is realised by employing the improved observer without the chattering problem and the steady state error. The effectiveness of the improved observer is confirmed by the comparative experimental results.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.1
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• pp.55-71
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• 2006

We perform a computational study on 0-1 knapsack problems generated under explicit correlation induction. A total of 2000 100-variable test problems are solved. We use two solution methods: (1) a well known heuristic and (2) a representative branch and bound type algorithm. Two different performance measures are considered: (1) the number of nodes needed to find an optimal solution and (2) the relative error of the heuristic solution. We also examine the effect of different joint probability mass functions (pmfs) for the coefficient values on the performance of the solution procedure.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1221-1224
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• 1992

To obtain a robustness which is one of important characteristics needed in servo drive, the sliding mode control method is used as a control strategy. However, the undesired phenomenon of chattering is a serious problem. In this paper, an adaptive chattering alleviation algorithm for variable structure system control is proposed to solve this serious problem. Digital controller using the theory of chattering alleviation control is applied to the position control problem of an induction motor system. Comparisons of this algorithm with other variable structure system control algorithms indicate that the chattering can be alleviated. This controller is implemented using IBM-PC(8088 CPU) which controls current controlled PWM inverter consisted of IGBT as a switching device to drive motor.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.420-425
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• 1996

In this paper a robust speed controller for an induction motor is proposed. The speed controller consists or a fuzzy sliding adaptive controller(FSAC) and a sliding mode torque observer(SMTO). FSAC removes the problem or oscillations caused by discontinuous inputs of the sliding mode controller. The controller also provides robust characteristics against parameter and sampling time variations. Although, however, the performance of FSAC is better than PI controller and fuzzy controller in robustness, it generates the problem of slow response time. To alleviate this problem, a compensator, which performs feedforward control using torque signals produced by SMTO, is added. The simulation and hardware implementation results show that the proposed system is robust to the load disturbance, parameter variations, and measurement noises.