• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1109-1113
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• 2010

Recently, important for the safety has been increasing together economic developments. The leakage only is measured by the voltage difference. This method is a way to contact the electric leakage area. It can cause electric shock at users. We propose a non-contact method to detect a short circuit in this paper. We investigate magnetic field at electric leakage area to present non-contact method. Simulated environment created a short circuit in the flooded areas. Voltage is supplied 50, 150 and 200[V]. Magnetic field was measured at 0, 5 and 10[cm]. Magnetic flux was reduced about $0.4[{\mu}T/cm]$ depending on the distance changes in the steady region. But we confirmed that magnetic flux is measured the same value depending on the distance changes in the electric leakage area.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.514-518
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• 2005

In this paper an adaptive fuzzy PI controller with feedback linearizing meth od is implemented to controlling flux and torque separately in induction motor. In this paper first decoupling of torque and flux which are outputs to be controlled, is achieved by using feedback linearization methodology. Then for reducing the effect of noise and rejection of disturbance, main part of controller which is adaptive PI fuzzy controller, is designed. Coefficients of PI controller are determined by defined fuzzy rules due to error dynamic. Inputs of fuzzy system are defined sliding surfaces which consist of torque and flux errors. The main contribution of this paper is effect reduction of noise and disturbance on torque and flux which is based on fuzzy logic and nonlinear control. At last the effectiveness of the proposed control scheme in presence of noise and load disturbance is simulated and comprised to applying sliding method. The results verify better effectiveness of the proposed method for effect reduction of noise and disturbance.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.26-30
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• 1999

The constraint condition is the stator voltage and the stator current to operate the motor in the flux weakening region. The maximum current is limited by the inverter current rating and the machine thermal rating. Given DC link voltage to control the motor in the flux weakening the maximum voltage is determined by considering PWM strategy, dead time, voltage drop of the inverter switching device, and the margin of the voltage for current forcing. In this paper, the new method to determine the available maximum voltage is derived by the analythic method and by considering the factors of the voltage drop. So Determining the maximum voltage is very useful to enlarge the speed operation region in the flux weakening operation, the utility of the maximum voltage is increased.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.776-777
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• 2008

It is important to understand the relationship accurately between linkage flux distributions and machine characteristics for better design of multilayer-buried interior permanent magnet synchronous machines(IPMSM). This paper presents a improved calculation method for linkage flux of multilayer-buried IPMSM. From the analysis result, The proposed method shows that the calculated d,q linkage flux reflects a electromagnetic characteristic well in analysis model.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.185-191
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• 2004

This study describes the scheme of vector drive system without speed sensor for AC servo motor using theory of a flux observer and based on the field oriented vector control. The new method of speed estimation is presented from operate with the position and magnitude of the secondary flux which obtain from the voltage reference and detected current. As the estimated speed is settled by the flux and the machine-specific parameters. this method don't need to adjust the gain of the parameter. Based on the derived theory for vector control. the scheme for sensorless vector drive of AC servo motor is designed and realized. And the experiment verifies it passable to realize the sensorless vector drive based on a field-oriented type.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.308-310
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• 2001

This paper investigates a novel speed sensorless control method of I.M considering the secondary resistance identification based on the transientless torque control technique. Especially, this paper aimed at the identification of the secondary resistance simultaneously with speed estimation superposing of sinusoidal flux wave to a constant flux value. Furthermore, the secondary flux with some frequency is controlled independently on torque control. The proposed speed estimation method is derived from a motor circuit equation theoretically and also it can be conducted easily by detecting primary motor currents and primary voltage commands at every sampling time. Some numerical simulations with the assumption of using a pulse width modulation(PWM) voltage source inverter are performed to verify the proposed method.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.88-95
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• 2001

Stator core loss has significant adverse effects when an induction motor is controlled by the conventional vector control method. Therefore, taking core toss into account should make it possible to control the torque very precisely. This paper proposes a speed sensorless vector control method for an induction motor at optimum efficiency and high response taking core loss account. The proposed vector control system consists of a speed adaptive rotor flux observer which takes core loss into account and employs a direct vector control which compensates for the influence of core loss. Also, in this paper, a vector controlled induction motor with a deadbeat rotor flux controller is developed. The method ensures optimum efficiency in the steady state without degradation of the dynamic response. The validity of the proposed technique is confirmed by simulation results for induction motor drive system.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.626-633
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• 2011

This paper presents a novel maximum efficiency control scheme for convergence improvement in stator-flux-oriented induction motor drives. Three input powers are calculated at three different flux levels, respectively. A quadratic curve is obtained using the quadratic interpolation method using the three points. The flux level at the lowest point of the interpolated curve is calculated, which is not the real minimum input power of the motor, but an estimated one. Hence, the quadratic interpolations are repeated with three new points chosen using the selection method for new points for refitting until the convergence criteria are satisfied. The proposed method is verified by simulation results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1165-1173
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• 2018

Recently, owing to environmental problems and instability of rare earth resources market, non-rare earth electric motors are attracting attention. As a non-rare earth motor type, a wound rotor synchronous motor(WRSM) has high power density and wide driving range further it can reduce loss by field current control during field weakening control at high speed. However, since the d-axis flux of the WRSM is coupled with the rotor circuit, the fluctuation in the d-axis flux linkage affects the rotor circuit, which causes ripple of the field current and torque. In this paper, we propose the field current ripple compensation method by injecting the feedforward voltage. the proposed compensating method was demonstrated by simulation and experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.739-745
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• 2011

This paper proposes a method for reducing the negative spatial harmonics of the radial flux density of an interior-type permanent magnet (IPM) motor. The reliability of the motor is increased by minimizing its vibrations under dynamic eccentricity (DE) state and normal state due to reduction of a negative spatial harmonics component through the influx of a zero spatial harmonics component in the radial flux density. To minimize the vibrations, optimal notches corresponding to the distribution shape of the magnetic field are designed on the rotor pole face. The variations of vibration computation by finite element method (FEM) and the validity of the analysis and rotor shape design are confirmed by vibration and performance experiments.