• 한국조명전기설비학회지:조명전기설비
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• 제9권5호
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• pp.41-50
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• 1995

Single-phase induction motors are widely used in many light duty applications, especially in home and office. many applications which use these motors require adjustable speed control continuously. In general, the speed control of single-phase induction motor is accomplished at a few discrete speeds by using tapped-windings, pole switching or gear. These techniques are inefficient and complicated. In this paper, Torque controller which adjusts a generating torque using phase difference between main winding voltage and auxiliary winding voltage is proposed. The analysis includes the determination of the relationship between the auxiliary winding voltage is proposed. The analysis includes the determination of the relationship between the auxiliary winding voltage phase angle and torque. Simulation results of the torque-speed characteristics using the controlled auxiliary winding supply are shown and discussed. and the drive is tested experimentally to verify the results of the theory by using a dynamometer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.77-79
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• 1988

There are various causes for noise production in induction motors, and among them, the noise generated by magnetic vibrating distribution forces have an important meanings. In this paper, the magnetic vibrating distribution forces in squirrelcage induction motors were arranged systematically in the consideration of stator harmonics and it's forces were not considered the effection of airgap eccentricity and deformation. With the application of the finite element method in order to find magnetic flux density and with the calculation of the permeance of rotor node, the magnetic vibrating distribution forces were analyzed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권4호
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• pp.203-211
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• 1999

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

• 한국자기학회지
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• 제6권5호
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• pp.287-293
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• 1996

농형유도전동기의 회전자는 제조 과정중에 회전자 도체의 단선, 기포 발생으로 인한 회전자 도체의 저항 증가, 스큐 불량 등 여러 가지 고장이 발생될 수 있다. 이와 같은 고장은 유도전동기의 성능을 저하시키므로 회전자를 조립하기 전에 고장 유무를판단하면 조립에 드는 제조 비용을 절약할 수 있고 전동기의 신뢰성을 높일 수 있다. 본 논문에서는 이와같은 고장을 진단하는 방법의 하나로 유한요소법을 이용하여 회전자가 회전할 때 발생하는 전자석 코일에서의 유도 전류 파형을 검출하여 고장을 진단하는 방법을 제안하였다. 제안한 방법의 타당성을 검층하기 위하여 5 Hp 삼상 농형유도전동기에 대해 고장전류를 검출하고 이를 해석 결과와 비교 분석하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1887-1891
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• 2008

In this paper, we dealt with a partial discharge (PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage induction motors. The PD measurement system consists of a coupling network, a low noise amplifier, and associated electronics. A shielded box was used to reduce environmental noise. Frequency characteristic of the coupling network was estimated by a sinusoidal signal input, and the low cut-off frequency of the coupling network was 1 MHz (-3 dB). Also, we carried out a calibration test for the PD measurement system. Sensitivity of the system was of 84 m$V_{max}$/pC between stator winding and enclosure. In application test on a low-voltage three phase induction motor (5 HP), we could detect 88 pC at AC 800 $V_{max}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.51-53
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• 1997

Even though, many types of induction motors are known, most of the single phase induction motors being used are of squirrel cage type. However, basic structure of the machine has not been changed a lot during the past century. Author had been experienced many experiments with modified rotor. The modification was completed by doing two procedures: an elimination of lamination in central pan of the rotor and filling of melted aluminium in it instead. This paper demonstrates the reason for higher efficiency.

• 전기학회논문지P
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• 제57권2호
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• pp.127-134
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• 2008

In this paper, we propose a robust adaptive backstepping control of induction motors with uncertainties using nonlinear disturbance observer(NDO). The proposed NDO is applied to estimate the time-varying lumped uncertainty which are derived from unknown motor parameters and load torque, but NDO error does not converge to zero since the derivate of lumped uncertainty is not zero. Then the fuzzy neural network(FNN) is presented to estimate the NDO error such that the rotor speed to converge to a small neighborhood of the desired trajectory. Rotor flux and inverse time constant are estimated by the sliding mode adaptive flux observer. Simulation results are provided to verify the effectiveness of the proposed approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.342-344
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• 1999

This paper presents the analysis of core losses in capacitor-run single phase induction motors using the finite element methods. The double revolving field theory can be used for the analysis to assess the quantitative and qualitative performance of the single-phase induction motor. But it is difficult to evaluate accurately the core losses. It is more difficult to segregate stator and rotor core losses at no-load and load conditions. Numerical analysis such as FEM can be used effectively for the accurate calculation of core losses and motors performances. In this paper, the coupling method of core loss characteristic equation and FEM are proposed for the accurate calculation of core losses in the stator and rotor. The FFT is also used to calculate fundamental and harmonic components in the yoke and teeth parts of motor.

• 대한전기학회논문지
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• 제38권11호
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• pp.877-887
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• 1989

In this paper, we attempt to achieve high dynamic performance by means of decoupled control of rotor speed and flux. Recently developed nonlinear feedback control theories are utilized. The rotor fluxes are estimated based on the rotor circuit equations. When the estimation error of the rotor flux tends to zero, the rotor speed and flux dynamic characteristics of the induction motor with our controller become linear. To minimize the deterioration of control performance, we use an identification algorithm for the rotor resistance. We analyze the dynamic behavior of the closed loop system with our controller. Both simulation and experimental results are included to demonstrate the practical significance of our result. In particular, our experimental results show that recently developed nonlinear feedback control techniques are of practical use in control of induction motors.

• 대한전기학회논문지
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• 제38권3호
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• pp.173-181
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• 1989

A split-phase induction motor with asymmetrical magnetizing reactance axes develops starting torque and its efficiency can be high under certain conditions. In this paper, one method of producing the asymmetry of magnetizing reactance axes is described. The grain-oriented silicon steel core is used to produce the asymmetric axes instead of non-oriented silicon steel core which is used in general motors. The optimum design method for the motor is suggested and analyzed. To verify this suggestion, the permanent capacitor run type induction motors are designed to be driven at balanced condition by its asymmetrical effect, and then the oscillating torque due to the asymmetry of motor structures are analyzed. Tests of the sample motor have shown good performance comparable to ordinary types. This motor structure can be used where high effciency and reliability are required, and also the amount of core materials can be reduced due to its high permeability.