• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.250-252
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• 2000

A simple analysis method for inverter-fed induction motor using F.E.M and equivalent circuit is proposed. And an optimum shape of rotor slot for 2Hp inverter-fed induction motor is determined by combining the proposed analysis method and an optimization algorithm. Conjugate gradient method is used for the optimization algorithm. The optimization is performed for higher efficiency and reduction of harmonic loss in the inverter-fed induction motor. The optimization results are verified by comparing with those of the time-step F.E.A and the experiment.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.73-75
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• 1998

Electromagnetic forces as a source of vibration and noise are analyzed and compared for an induction motor with different rotor slot number each other which drive high speed trains. Time stepped finite element method is used to analyze electromagnetic field considering the voltage harmonics supplied from a inverter. As a result, a rotor slot number is determined to reduce the harmonics of electromagnetic forces.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.33-36
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• 1987

Is this study it is proposed a method which is able to compute preciously using time-difference method to the air-gap magnetic field in electric machines take into account of eddy current induced. The air-gap magnetic field has slot harmonics which are due to the structure of machines and the shape of slot harmonics varies with the related positions of slots when the rotor moves. Accordingly, considering the influence of slot-harmonics, we coupled macro-air-gap element with first-order triangular elements in domain and used direct-convergence method for magnetic saturation.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.18-20
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• 1997

In this paper, we analyze the harmonic flux distribution of squirrel cage induction motor with the different stator/rotor slot combination(36/42 and 36/44) using Finite Element Method and fast Fourier transform. These result will be used to obtain dips & cusps (harmonic torque) in torque characteristic curve.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.975-977
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• 2005

The generator on-line diagnosis system has been developed. This system monitor the insulation condition of stator winding by on-line measurements of partial discharge and the shorted-turn condition of rotor winding by on-line measurements of slot leakage flux. Sensor, such as SSC(Stator Slot Coupler) and flux probe are used for generator on-line diagnosis.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.4
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• pp.198-203
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• 2013

There are conditions that can be unbalanced three phase currents in a large generator by untransposed lines, unbalanced loads, unsymmetrical faults, and open phases. The unbalanced conditions can producing negative sequence components of current that induce two times frequence current in the surface of the rotor, the retaining rings, the slot wedges in the field windings. These rotor currents make the rotor rapidly overheat, so the rotor can cause substantial damage in a very short time. This paper presents the digital negative sequence relay algorithm for unbalanced protection in a generator. The proposed algorithm was tested by using collected current signals on PSCAD/EMTDC considering a hydro turbine based generator control system. It can be seen that the proposed relaying by negative sequence current is useful for detection of unbalanced state of large generator.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1942-1944
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• 2000

On-line diagnosis system has been developed and is now applied the detection of shorted-turn in the field winding of large generator. This system consists of data aquisition system and display PC. The data aquisition system detects voltage waveform from flux probe sensor installed in the stator slot. The display PC shows the shorted-turn situation of generator rotor winding.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.567-573
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• 2012

Outer rotor type in-wheel Blushless DC Motor(BLDCM) for three-wheeled electric vehicle is researched. In-wheel system is to drive the electric vehicle without mechanical transmission, shaft, differential gears or other mechanical system. The motor is designed considering the performance requirements and drive modes of the vehicle. The determined dimensions as well as the slot and rotor pole are simulated by magnetic and thermal finite element analysis and ansys workbench to analyze the performance and heating of the motor. In order to verify the performance characteristics of the proposed motor, the experiment tests are executed and satisfy well the requirements.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2035-2042
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• 2011

In this paper, we proposed the outer-rotor type of FSPM motor for high speed operation and optimized motor shape. First of all, combinations of pole and slot numbers are examined for the optimal back-EMF and cogging torque, then optimizes the better shape design of the permanent magnet, rotor pole width. Further, The winding turns are obtained by circle of the voltage limit equation and motor parameters to minimize the current and to improve the efficiency. As a result, the performance of the designed model is satisfied, and it is verified through a two-dimensional finite element method (2D-FEA).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1846-1857
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• 2011

This paper deals with design and analysis of surface-mounted PM (SPM) motor for compressor of air-conditioning system for electric vehicle applications according to slot/pole combination. First, required torque-speed curve characteristics are determined from operating conditions of the compressor. Restricted conditions such as motor size limit and current density are also determined. And then, under same rated and restricted conditions, twelve models which have different slot/pole combinations each other are designed for various pole arc/pitch ratio using simple equations and 2-d finite element (FE) analyses. Designed models are analyzed and compared in terms of back-emf THD, cogging torque, torque ripple, power losses, efficiency, etc. On the basis of analysis results, it is found that the motor with a 6-pole PM rotor and a 27-slot stator has most outstanding performances in electromagnetic aspects. Finally, through the mechanical modal analysis and demagnetization analysis, it is concluded that the determined motor is most suitable for the compressor of air-conditioning system for electric vehicles.