• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.155-161
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• 2005

This paper presents time a constant estimation of induction motor using MRAS(model reference adaptive system) fuzzy control. The rotor time constant is enabled from the estimation of rotor flux, which has two methods. One is to estimate it based on the stator current and the other is to integrate motor terminal voltage. If the parameters are correct, these two methods must yield the same results. But, for the case where the rotor time constant is over or under estimated, the two rotor nut estimation have different angles. Furthermore their angular positions are related to the polarity of rotor time constant estimation error. Based on these observation, this paper develops a rotor time constant update algorithm using fuzzy control. This paper shows the theoretical analysis as well as the simulation results to verify the effectiveness of the new method.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.86-92
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• 2009

As increasing of using induction motors, the induction motors faults cause serious damage to the industry. Therefore to find out faults of induction motor is recognized as important problem awaiting solution. But to make matters worse, the faults of induction motors often progress through long time. It means that early diagnosis is very important. Many researches have been progressed and general method of diagnosis is using vibration sensor to diagnose fault of induction motor. However, although it is reliability technique, it demands high price and it is difficult to use. This paper presents an implementation of technique for fault diagnosis of induction motor using wavelet transform based stator current and it is composed with algorithm that decides whether fault existence or not using C++ based on windows software. The algorithm will be accomplished in real-time using current data acquisition board and PC automatically with Neural Network algorithm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.4
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• pp.383-391
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• 2009

The detonation wave characteristics of JP-7 and oxygen mixture is investigated by one-step induction parameter model (IPM) obtained from a detailed chemistry mechanism. A general procedure of obtaining reliable one-step kinetics IPM for hydrocarbon mixture from the fully detailed chemistry is described in this study. The IPM is obtained by the reconstruction of the induction time database obtained from a detailed kinetics library. The IPM was confirmed by the comparison of the induction time calculations with that from detailed kinetics. The IPM is later implemented to a fluid dynamics code and applied for the numerical simulation of detonation wave propagation. The numerical results show the detailed characteristics of the detonation wave propagation in JP-7 and oxygen mixture at affordable computing time, which is not be possible by the direct application of the detailed chemical kinetics mechanism of hydrocarbon fuel combustion.

• Journal of Power Electronics
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• v.9 no.3
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• pp.456-463
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• 2009

The paper presents a method for controlling induction motors using a nonlinear internal model control (IMC) approach. The process model and the inverse model are developed in the rotor flux coordinate. The main advantage of the proposed method is that it easily specifies the performance (steady state error, transient response, etc.) and the robustness of the controller by means of the IMC filters. Simulation results illustrate the effectiveness of the proposed method. Results on a real time system show that the control system has good performance and robustness against changes in motor parameters (rotor and stator resistances, rotor and stator inductances, rotor inertia).

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.181-183
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• 2006

This paper studies the mechanical behaviors of Sn-3.5Ag solder joint against substrate(such as Au/Ni/Cu, Au/cu, Ni/Cu and Cu pad) after induction heating, a new soldering method. It was found that the solder bump formation depends on the time and current of the induction heating system. Also the heating value of the solder bump were found to vary with respect to the thermal conductivity of the pads on the substrate. In case of Au/Ni/Cu pad and Au/Cu pad, solder bump's shear strength were high for the heating time of $1.5{\sim}2sec$. For Ni/Cu pad, solder bump's shear strength were found to increase with time increment.

• 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.

• Journal of the Korean Home Economics Association
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• v.29 no.4
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• pp.37-43
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• 1991

Oxidative stability of crude wheat germ oil (WGO) was determined by the active oxygen method(Rancimat, hrs at 98$^{\circ}C$). The induction time of crude WGO was 7.6hrs as compared to 23.7hrs of crude soybean oil. However, the induction time of WGO could be extended by 2-3 times with 300ppm of mixed tocopherols and 200ppm of organic acids. The antioxidant effect of organic acids increased in the order of L-ascorbic acid > tartaric acid > citric acid > malic acid. Especially, the induction time of WGO could be extended by ca. 38hrs with 500ppm of L-ascorbic acid. This antioxiative effect of 500ppm L-ascorbic acid with mixed tocopherol(100, 200, 300 or 500ppm). It seems that the synergistic effect of L-ascorbic acid was due to the high content of tocopherols(0.4%) in WGO.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.1
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• pp.3-10
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• 2003

Application of matrix converter to vector control of induction motor using simplified Venturini algorithm which is capable of achieving the maximum output voltage is developed. This algorithm simplifies the control algorithm and therefor reduces the digital implementation time. Matrix converter is used as voltage-referenced voltage fed vector controlled induction motor drive. This paper describes the performance of vector controlled induction motor with four quadrant capability employing a matrix converter power circuit. The advantage of this system over the conventional rectifier-inverter arrangement are capability for regeneration into the utility, sinusoidal supply currents and minimum passive components. The steady-state and transient performance of the induction motor drive under the vector control technique is demonstrate with simulation and experiment results.

• Journal of Power Electronics
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• v.4 no.3
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• pp.127-137
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• 2004

This paper introduces a hybrid induction motor control using a genetically optimized pseudo-on-line method. Optimization results from the use of a look-up table based on genetic algorithms to find the global optimum of an unconstrained optimization problem. The approach to induction motor control includes a pseudo-on-line procedure that optimally estimates parameters of a fuzzy PID (FPID) controller. The proposed hybrid genetic fuzzy PID (GFPID) controller is applied to speed control of a 3-phase induction motor and its computer simulation is carried out. Simulation results show that the proposed controller performs better than conventional FPID and PID controllers. The contribution of this paper is the introduction of a high performance hybrid form of induction motor control that makes on-line and real-time control of the drive system possible.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.107-113
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• 2002

To monitor the torque of an induction motor using current, rotating speed has been measured and used to calculate the slip angular velocity. Additional sensor, however, can cause extra expense and trouble. In this paper, a new algorithm is proposed to monitor the torque of vector controlled induction motor without any speed measuring sensor. Only stator current is measured to estimate the magnetizing current which is used to calculate flux linkage, rotor velocity and motor torque. Graphical programming is used to implement the suggested algorithm and to monitor the torque of an induction motor in real time. To solve the fluctuation problem of estimated torque caused from instantly varying rotating speed of an induction motor, the rotating speed is reconstructed based on the measured current signals. From several experiments, the proposed method shows a good estimation of the motor torque under the normal rotational speed.