• 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.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권4호
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• pp.299-305
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• 2005

The work described in this paper is to investigate the additional iron losses and consequent temperatures in core ends of a turbo-generator wound with high voltage cables. Electromagnetic calculations are made with 3D FE models, which include the lamination material with anisotropic properties both in magnetic permeability and electric conductivity. The models also include the geometry of the stator teeth and eventually the axial steps designated to reduce the core end losses. The 3D model of the rotor consists of field windings with straight in-slot parts and end windings. The thermal models are simplified into two dimensions and include the heat sources dumped from the 3D electromagnetic solutions. The influences of power factor on additional iron losses are studied for this cable wound machine and conventional machines. The calculation results show that the additional iron losses can be reduced to about $15\%$ by introducing some small steps around the airgap corner of core ends.

• Journal of Magnetics
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• 제16권1호
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• pp.64-70
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• 2011

Surface-mounted permanent magnet (PM) machines were examined experimentally and theoretically, through power loss measurements and calculations. Windage, friction and copper losses were calculated using simple analytical equations and finite element (FE) analyses. Stator core losses were calculated by determining core loss coefficients through curve-fitting and magnetic behavior analysis through non-linear FE calculations. Rotor eddy current losses were calculated using FE analyses that considered the time harmonics of phase current according to load. Core, windage and friction open-circuit losses and copper loss were determined experimentally to test the validity of the analyses.

• Journal of Magnetics
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• 제19권2호
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• pp.146-150
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• 2014

The objective of this paper is to provide a comparison between two transverse flux rotary machines (TFRM) with different topologies of stator cores. Depending on how to make stator core with laminated steel sheets, the one topology is 'perpendicular stacking core' and the other is 'separated core'. Both of the two cores have been designed considering 3-dimensional (3-D) magnetic flux path with the same output power conditions, but the core losses are quite different and it causes different magnetic and thermal characteristics. For comparison of these two topologies of stator cores, therefore, core losses have been calculated and used as a heat source in no-load conditions, and the thermal stress has been also calculated. 3-D finite element method has been used for the magnetic field, thermal, and stress analysis to consider the 3-D flux path of the TFRM. After comparing the analysis results of the two topologies, experimental results are also presented and discussed.

• Journal of Electrical Engineering and Technology
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• 제6권4호
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• pp.527-534
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• 2011

In the present paper, the characteristics of Mega-Flux$^{(R)}$, JNEX-Core$^{(R)}$, amorphous and ferrite cores are compared to the inductor of buck-boost converters for Hybrid Electric Vehicles. Core losses are analyzed at the condition of 10 kHz sine wave excitations, and permeability fluctuations vs. temperature and magnetizing force will be analyzed and discussed. Under the specifications of the buck-boost converter for 20 kW THS-II, the power inductor will be designed with Mega-Flux$^{(R)}$ and JNEX-Core$^{(R)}$, and informative simulation results will be provided with respect to dc bias characteristics, core and copper losses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.93-95
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• 2008

Nowadays more attention is paid to the developing high efficiency electrical machines for energy saving and protection of natural resources. In general, the electromagnetic losses appearing in electrical machines are widely classified into copper loss, core loss and rotor loss. Particularly, in permanent magnet (PM) machines, core loss forms a larger portion of the total losses than in another machine. So, satisfactory prediction of core loss at the design or analysis stage of PM machines is essential to active high efficiency and high performance. This paper deals with analysis of magnetic field distribution due to geometry of stator core for magnetic core loss calculation of multi-pole PM synchronous machine.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권10호
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• pp.511-520
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• 2006

Recently, more attention has been paid to the development of high-speed permanent magnet (PM) synchronous motors, since they are conductive to high efficiency, high power density, small size, and low weight. In high-speed PM machines, core loss and windage loss form a larger proportion of the total losses than usual in conventional mid- or low speed machines. This article deals with the analysis on the core loss and windage loss in PM synchronous motor for high-speed application. Using the data information from a manufacturer and non-linear curve fitting, this paper investigates the magnetic behavior and its core losses in the stator core using the electrical steels. And, the windage loss is calculated according to the variation of the rotational speed, motor inner pressure and temperature.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권1호
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• pp.16-22
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• 2013

This paper presents the analysis and optimization of air-core permanent magnet linear synchronous motor with overlapping concentrated windings to achieve high thrust density, high thrust per copper losses and low thrust ripple. For the motor design, we adopt equivalent magnetizing current (EMC) method to analyze the magnetic field and give analytical formulae for calculation of motor parameters such as no-load back EMF, dynamic force, thrust density and thrust per copper losses. Further, we proposed a multi-objective optimization by genetic algorithm to search for the optimum parameters. The design optimization is verified by 2-D Finite Element analysis (FEA).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.86-88
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• 2004

In this paper, optimal stator slot shape of 3-phase inverter-fed induction motor is designed to reduce stator core and winding losses. For the analysis, the F.E.M on 1 phase band periodic condition in stator is coupled with harmonic equivalent circuit. For the optimal design, the conjugate gradient method is used as an optimizing algorithm. The stator core and winding losses are reduced by the design method. The results are verified by those of the time-step finite element analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.881-883
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• 2004

The high efficiency for motors has been continuously required for energy saving. The iron losses occurring in motor cores account for high percentage in the energy losses of motors, so that electrical steels with lower iron losses have been desired as core materials. It is necessary to understand the basic charecteristic of the electrical steel to design motors and establish manufacturing process for the loss reduction. Therefore, this paper deal with the basic characteristic related with the magnetic properties of electrical steels and descibes the cause of core loss in electrical machines.