• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.3
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• pp.282-290
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• 2001

The accurate identification of the motor parameters is crucially important to achieve high dynamic performance of induction motors. In this paper, th motor parameters such as stator(rotor) resistance, stator(rotor) leakage inductance, mutual inductance, and rotor inertia are measured in off-line. Stator(rotor) resistance and stator(rotor) leakage inductance are measured based on the stationary coordinate equations of induction motors. On the other hand, mutual inductance are measured under the scalar control. Finally, the inverse rotor time constant is identified in on-line using an extended kalman filter algorithm. To demonstrate the practical significance of the results, Some experimental results are presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.481-484
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• 2001

High voltage induction motors are widely used in industrial factory because have many benefits. But the insulated materials of induction motor are aged by using time, electrical, thermal, circumstantial stresses and so on. Motor failures are occurred by these deterioration phenomena and give rise economic problems to user. In many motor failures, insulated material problems of stator winding happen frequently and occupy high percentages in the failure source. In this paper, the testing specimen(motorette) is manufactured by modeling of stator winding of high voltage induction motor and accelerating test is carried out. Partial discharge signals detected by RF sensor are used to analyze deterioration condition of stator windings. According to aging time, the 3D ( ${\Phi}$-Q-N) distribution and skewness of partial discharge signals are changed.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.6
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• pp.738-747
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• 1999

Vector controlled induction motor have been widely used in high performance applications. How-ever the performance is sensitive to the variations of motor parameters especially the rotor time constant which varies with the temperature and the saturation of the magnetizing inductance. In this paper the authors propose new identifying method for time-varying parameters of an induction motor which is based on adaptive vector control with serial block algorithm. Vector con-trol system realized on synchronous frame and parameter identification system realized on sta-tionary frame are not easily affected by the vector control frame. Parameter mismatch in the control system results in heavy transient variation in speed and torque response. In order to compensate degradation of the responses at the middle and low speed region adaptive identifier is introduced. To verify the feasibility of this technique compute simu-lations carried out.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.675-679
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• 1992

In industry, the speed control of single-phase induction motor in domestic use is generally controlled by a simple ON-OFF or PID control method. However, in this case, in order to have a good speed regulating characteristics, itself should be modified in accordance with the optimum PID factors which are varied each time operating speed changes. Shortening the development time and saving the cost which are needed to modify the controller is a major problem to be solved now in industry. In order to alleviate the above difficulties, it is proposed to apply adaptive control technique using MRFAC(Model Reference Following Adaptive Control) for the speed control of single-phase induction motor which has scarcely been studied. In this paper, the above speed control technique is achieved using MCS-96 one chip micro controller with a good speed control characteristics and it is expetted to open a wide application field in the speed control of single-phase induction motor in the future.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.3
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• pp.136-142
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• 2001

In this research a Simulink/RTW-baed realtime control system was developed for an induction motor vector control. On the Simulink window, the control system is designed in the form of block diagrams, program codes are produced automatically with the RTW(Real Time Workshop), then an DSP c compiler compiles the program codes. With this automatic program producing method rapid prototyping is realized with the least time-consuming manual programming procedures. To show effectiveness of the proposed system designing scheme a DSP-based induction motor vector controller was constructed and implemented.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.281-289
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• 1991

Neurospora crassa (KCTC 6079) produces tyrosinase (EC 1.14.18.1) during sexual differentiation under derepressed conditions in the presence of inducers such as amino acid analogues, antimetabolites or protein synthesis inhibitors. The selection of inducer concentration and induction time as well as inducer type are critical for the optimization of the enzyme production. The best inducer was found to be cycloheximide. Since cycloheximide was toxic to the cells, an optimal inducer concentration and an optimal induction time were determined to maximize the enzyme production from batch cultures. Mathematical models for the cell growth and the enzyme production were proposed and used for process optimization. By optimizing the induction conditions, maximum tyrosinase productivity was increased significantly.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.73-75
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• 1999

The time harmonics of an inverter output voltage cause high frequency currents in the rotor bars of a squirrel cage induction motor, so that the harmonic copper loss density increases in the upper lesion of the bars. Such an higher loss density makes an nonuniform thermal source and deforms the bars due to the thermal stress. Therefore, in this paper, the copper loss distribution in the rotor bar of an inverter-fed induction motor, which is the source of the thermal stress, is analyzed by the time-stepping finite element method. As a result, the harmonic copper losses of 11 subregions in a bar are calculated and compared with those of sinusoidally fed induction motor.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.283-287
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• 2013

This paper presents a method for calculating iron losses in three-phase induction motors under the inverter supply through the field-circuit coupled time-stepping finite element method (FEM). Iron losses are calculated by using the three-term iron losses separated model and modifying the loss coefficients obtained by the iron losses curves which are provided by the manufacturer under the sinusoidal supply. Simulation results by the presented method are verified by the measured results with an error lower than 5%, confirming the validity of the proposed method. Finally, iron losses distribution of the inverter-fed three-phase induction prototype motor is shown.

• Korean Journal of Metals and Materials
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• v.48 no.2
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• pp.141-147
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• 2010

An Ni-Al intermetallic coating has been produced by induction heating on mild steel. The effect of the induction heating conditions on the microstructure of the coating has been investigated. The reaction synthesis of the intermetallic compounds was promoted while increasing the heating rate and the holding time at reaction temperature. Especially, an NiAl phase corresponding to the initial composition of mixed powder was predominantly formed. However, the synthesis at low reaction temperatures occurred by solid state diffusion during the holding time and an Fe-Al reaction layer was formed at the interface with the substrate, regardless of the heating rate. The combustion synthesis of the intermetallic compound occurred at a temperature higher than 1023 K and resulted in an almost single phase NiAl structure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.45-51
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• 2014

Synchronous generators and induction generators are mainly used in hydroelectric power generation. Synchronous generator is mainly applied to large hydroelectric plants but induction generator is applied to the small hydro power plants. Stability of induction generator is slightly less than the synchronous generator. However, induction generator has many advantages rather than a synchronous generator in terms of price and maintenance. So Induction generator is used primarily in small hydroelectric power station less than 1,000kW recently. Squirrel cage induction generator generates a high inrush current at the grid-connection. This high inrush current causes a voltage drop on the grid. In order to reduce the voltage drop and to analyze the power flow, the analysis for operating characteristics of the induction generator should be reviewed in advance. In this study, we analyzed the voltage drop and power flow analysis when a 1500kW induction generator is connected to the grid. The voltage drop is slightly higher than the acceptable range of distributed power supply voltage and the power flow of the generator is performed well.