• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.11-14
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• 1996

Samsung Electronics has developed high performance velocity and position controller for induction motors and succeeded in mass production for first time in Lorea. Dynamic performance and final control accuracy of the controller are equivalent to those of AC servo motor controller. At present we adopted the controller as spindle motor drive for Samsung CNC systems and expect its wide use in industry as general purpose velocity and position controller for induction motor.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.717-719
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• 2003

In terms of induction motor analysis, magnetic energy conversion takes place into mechanical energy in air gap. Therefore, flux distribution in air Sap has to be analyzed in detail more than other place of induction motor. In this paper, the air gap permeance of induction motor, which was effected by means of skewed angle and fringing, was analyzed.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.3
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• pp.256-263
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• 2014

Torque ripple is a very essential index for evaluating the effectiveness of a switched reluctance motor (SRM). Many common design strategies for reducing torque ripples of a SRM are changing the excitation trigger angle of stator windings, delaying the cut-off time of winding excitation, adjusting the ratio of arc angle between stator and rotor, and changing the geometric shape of rotor. However, the output torque or the efficiency of the SRM may drop as the above design strategies are solely adopted. In this paper, a hybrid design model which is obtained by the Taguchi Method for optimally designing a SRM with lower torque ripple and higher efficiency is presented. A 12S/8P motor is taken as a study case, and the 3D finite element method (FEM) is applied to analyze the characteristics of the motor and optimize the design process. The results have shown that the proposed method can achieve the design goal of obtaining a high-performance SRM for light electric vehicle applications.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1806-1812
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• 2016

We propose an interior permanent magnet syhchronous motor (IPMSM) with arc-shape ferrite permanent magnets (PMs) as a substitute for the rare-earth permanent magnet, and determine its optimal design through parametric study. First, we use 2D finite element analysis to analyze 4-poles and 6-slots initial model according to performance requirements and design parameters. The current angle of the maximum average torque considered in the analysis is different compared with the current angle of the minimum torque ripple. Thus, the parametric study for optimal rotor design is performed by varying the thickness and the offset radius of the PMs according to current angle. In particular, a narrow bridge is required in conventional IPMSM for reducing flux leakage; however, the increase in cogging torque in the analysis model saturates the narrow bridge (large offset radius). Therefore, we suggest an appropriate shape considering limiting conditions such as DC link voltage, average torque, torque ripple, and cogging torque taking into account performance requirements.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.79-87
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• 2008

This paper proposes the design and implementation of a direct torque controlled induction motor drive system. The method is based on control of decoupling between amplitude and angle of reference stator flux for determining reference stator voltage vector in generating PWM output voltage for induction motors. The objective is to reduce electromagnetic torque ripple and stator flux droop which result in a decrease in current distortion in steady state condition. In addition, the proposed technique provides simplicity of a control system. The direct torque control is based on the relationship between instantaneous slip angular frequency and rotor angular frequency in adjustment of the reference stator flux angle. The amplitude of the reference stator flux is always kept constant at rated value. Experimental results are illustrated in this paper confirming the capability of the proposed system in regards to such issues as torque and stator flux response, stator phase current distortion both in dynamic and steady state with load variation, and low speed operation.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.166-172
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• 1998

Switched reluctance motor(SRM) has the advantages of simple structure, low rotor inertia and high efficiency. However, position sensor is essential in SRM in order to synchronize the phase excitation to the rotor Position. The Position sensors increase the cost of drive system and tend to reduce system reliability. This paper investigates the speed control of sensorless SRM in which the Phase current and change rate are utilized in position decision, and the period of dwell angle is variable for speed control. The proposed system consists of Position decision circuit, speed controller, digital logic commutator, switching angle controller and inverter The performances in the proposed system are verified through the experiment.

• Journal of Power Electronics
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• v.13 no.2
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• pp.264-274
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• 2013

A new sensorless position estimation method for switched reluctance motor (SRM) drives is presented in this paper. This method uses the change of the slope of the phase inductance to detect the aligned position. Since the aligned positions for successive electrical cycle of each phase are apart by a fixed mechanical angle $45^{\circ}$ in the case of 12/8 SRM, the speed of the machine can be calculated to estimate the rotor position. Since no prior knowledge of motor parameters is required, the method is easy for implementation without adding any additional hardware or memory. In order to verify the validity of this technique, effects such as changes in the advanced angle and phase lacking faults are examined. In addition, an inductance threshold based sensorless starting scheme is also proposed. Experimental results demonstrate the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.415-419
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• 1996

This paper presents motor speed and phase angle detection method using a sinusoidal AC tachogenerator. The 2-phase or 3-phase output tacho-generator can be adopted, and its' output voltages must have sinusoidal waveforms. Because the detection algorithm is simple, the proposed method can be implemented with analog devices of microprocessor conveniently. And the proposed method has a very short detection delay time. Especially in the analog implementation, there is no delay time without the settling time of analog devices. With the Experimental results, it is verified that the proposed method can accurately detect the instantaneous motor speed and phase over the wide ranges.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.52-55
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• 1996

This paper describes the bending traveling-wave type ultrasonic motor which generates the traveling wave by combining two standing waves with phase difference time and space. In $+20^{\circ}C$~$30^{\circ}C$, the USM motor operation character has represented normal condition. But the other temperature, (that is say, when long time operating condition) USM operation characteristic has abnormal condition, that is driving frequency, drive current and r.p.m is down. The recent USM has controller without temperature compensation. This study aimed at fuzzy controller which must follow the phase angle difference 90$^{\circ}$at operation temperature and them r.p.m and torque increase.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.2
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• pp.220-226
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• 2000

High precision step motor using Terfenol-D linear actuators is proposed and its performance is tested. Four Terfenol-D linear actuators are set up perpendicular to the rotor and saw-tooth current signals are applied on the actuators. It was found that the rotation angle is increased as the excitation current, the inertia of the rotor, and the contact force between the rotor and the push device are increased. The rotation angle per step of $0.001^{\circ}$ and blocking torque of 0.2Nm are achieved. The effect of the time delay between the excitation signals is also investigated.