• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.2
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• pp.102-108
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• 2007

The issues of preventive and condition-based maintenance, online monitoring, system fault detection, diagnosis, and prognosis are of increasing importance. This study introduces a technique to detect and identify faults in induction motors. Stator currents were measured and stored by time domain. The time domain is not suitable for representing current signals, so wavelet transform is used to convert the signal; onto frequency domain. The raw signals can not show the significant feature, therefore difference values are applied. The difference values were transformed by wavelet transform and the features are extracted from the transformed signals. The dynamic time warping method was used to identify the four fault types. This study describes the results of detecting fault using wavelet analysis.

• Journal of Power Electronics
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• v.6 no.4
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• pp.322-329
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• 2006

In the last decade, the increasing restrictions imposed on the exhaust emissions from internal combustion engines and traffic limitations have increased the development of electrical propulsion systems for automotive applications. The goal of electrical and hybrid vehicles is the reduction of global emissions, which in turn leads to a decrease in fuel resource exploitation. This paper presents a novel approach for control of Induction Motors (IM) using the Particle Swarm Optimization (PSO) algorithm to optimize the parameters of the Proportional Integral Controller (PI-Controller). The overall system is simulated under various operating conditions. The use of PSO as an optimization algorithm makes the drive robust and insensitive to load variation with faster dynamic response and higher accuracy. The system is tested under variable operating conditions. The simulation results show a positive dynamic response with fast recovery time.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1857-1861
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• 2003

This paper proposes a method for controlling energy distribution to 1 phase induction heating coil by using the Binary Rate Modulation (BRM) Technique. Such method provides proper frequency to the heating coil's requirement by control the frequency at the resonance point, that is, 64-kHZ frequency band. System design are classified to 2 parts. The first part determines main frequency , and the second part generates the frequency from the 8-bit BRM derived from IC no. PAL22V10 in order to control the frequency for Full-bridge connected inverter when supplying the energy required by the 1 phase induction heating coil. Therefore, efficiency of the energy supply can be increate.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.466-469
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• 2001

In this paper, closed loop V/f control of induction motor has been implemented by the estimated speed. Closed loop V/f control improve the performance of induction motor drive system at low speed compared to open loop V/f control. However, closed loop V/f control need speed sensor. By using the estimated speed, closed loop V/f control is possible without speed sensor. Rotor speed is calculated from the difference between synchronous frequency and slip angular frequency. 3-phase voltage reference is obtained from synchronous frequency. And the PWM technique using space vector PWM is applied in this scheme. In the space vector PWM, effective time of 3-phase voltage reference is used to simplify the calculation of effective voltage time. This scheme is simple to implement and one chip microprocessor was used in experimental system.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.605-610
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• 1991

In inverter system for driving induction motor, the output harmonics are hamrful in induction motor drive because it leads to ripple torque and induction interference. For electrical drives using PWM(Pulsewidth Modulation) inverters and ac motors, the methods for efficiency optimal control have been developed. In this paper, two different PWM methods for inverter and voltage control technique are described. In order to reduce or minimize losses, various forms of PWM strategy such as, PM (Positive Modulation) and NM (Negative Modulation) are discussed. The results show the feasibility of obtaining practically sinusoidal output waveforms which are highly desirable in most inverter application.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1099-1100
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• 2011

This study deals with the dynamic characteristics analysis of Linear Induction Motor (LIM) using finite element method in which the moving mesh technique is considered. The focus of this paper is to show the appropriate of on-line observer system for position sensorless control of a LIM under the phase asymmetry, saturation and iron loss. Comparisons are given with angle of the observer and that of proposed FEA method of linear induction motor, respectively. The position sensorless control system is realized, and the effective of the observer system is verified by experimental results.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2219-2226
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• 2017

This paper deals with artificial neural network approach for automatic detection of severity level of stator winding fault in induction motor. The problem is faced through modelling and simulation of induction motor with inter coil shorting in stator winding. The sum of the absolute values of difference in the peak values of phase currents from each half cycle has been chosen as the main input to the classifier. Sample values from workspace of Simulink model, which are verified with experiment setup practically, have been imported to neural network architecture. Consideration of a single input extracted from time domain simplifies and advances the fault detection technique. The output of the feed forward back propagation neural network classifies the short circuit fault level of the stator winding.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.05a
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• pp.329-337
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• 2007

Case-based reasoning (CBR) methods are applied to various target problems on the supposition that previous cases are sufficiently similar to current target problems, and the results of previous similar cases support the same result consistently. However, these assumptions are not applicable for some target cases. There are some target cases that have no sufficiently similar cases, or if they have, the results of these previous cases are inconsistent. That is, the appropriateness of CBR is different for each target case, even though they are problems in the same domain. Thus, applying CBR to whole datasets in a domain is not reasonable. This paper presents a new hybrid datamining technique called two-step filtering CBR and Rule Induction (TSFCR), which dynamically selects either CBR or RI for each target case, taking into consideration similarities and consistencies of previous cases. We apply this method to three medical diagnosis datasets and one credit analysis dataset in order to demonstrate that TSFCR outperforms the genuine CBR and RI.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1337-1344
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• 2013

This paper presents a simplified modulation strategy for the three-leg VSI fed two-winding induction motor. The strategy provides independent unbalanced voltage control for the main and auxiliary windings. This make the motor can be reversed rotation through the range of motor speed operation without limitation of voltage boost of the auxiliary winding. To study the advantages of the proposed drive, the experimental results such as voltage stresses, hysteresis band of the currents in locus, and also acoustic noise levels of the three-leg VSI are compared with those of the conventional two-leg topology. The results obviously show that the proposed technique achieves superior performance compared with the traditional scheme in case of dramatic increase of DC bus utilization, effective reduction of harmonic voltages content, and also significant enhancement of motor efficiency.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1179-1181
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• 2001

For high performance induction motor drives such as mill drives, elevator, spindle drive, NC and so on, smart speed controls is usually required, that requires a precise current control. This paper is proposes design of fuzzy controller which makes use of the output voltage of the space vector PWM inverter. Also, proposes the performance fuzzy controller for high performance vector control of induction motor drive system. The performance of a fuzzy controller is compared with that of an PI controller in an internal loop. The validity of the proposed technique is confirmed by simulation results for induction motor drive system.