• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.283-287
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• 2013

This paper presents a method for calculating iron losses in three-phase induction motors under the inverter supply through the field-circuit coupled time-stepping finite element method (FEM). Iron losses are calculated by using the three-term iron losses separated model and modifying the loss coefficients obtained by the iron losses curves which are provided by the manufacturer under the sinusoidal supply. Simulation results by the presented method are verified by the measured results with an error lower than 5%, confirming the validity of the proposed method. Finally, iron losses distribution of the inverter-fed three-phase induction prototype motor is shown.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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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.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.55-57
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• 1998

A finite element analysis for a synchronous reluctance motor (SynRM) is presented with emphasis on the effect of saturation and iron losses. Preisachs model, which allows accurate prediction of iron losses, is adopted in this procedure to provide a nonlinear solution. This technique provide significant properties of proposed SynRM under the magnetic saturation and iron losses effect.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.152-160
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• 1999

A high speed motor has been generating a lot of attention due to its performance-more light, thin, short, compact than ordinary motors. But they have low efficiency with high frequency power source because of the iron losses which may produce too much heat as well as the copper losses occurred in the rotor windings. The Halbach array can generate the strong magnetic field systems without additional magnetic materials, therefore the iron losses can be removed. In this paper, the Halbach array is applied to the field system for the high speed motor, and three dimensional FEM is used to analyze the field of the Halbach array considering with the leakage flux. The measured values of flux density are also compared with the FEM analysis. And the magnetic characteristics of the Halbach array field system are compared with those of the conventional field systems such as slot-iron type, PM-iron type. Consequently, it is confirmed that the Halbach array field system is more suitable to the high speed motor because it has high flux density, sinusoidal flux distribution than others.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.758_759
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• 2009

In the design and analysis of electric machines the precise calculation of iron loss has incredible significance. It is tough to foresee iron losses precisely in machines due to distribution of non sinusoidal flux density. It is necessary to approximate the iron losses for the precise computation of efficiency. This paper presents a novel approach for the prediction of iron losses of the brushless dc (BLDC) motors by considering the effects of minor hysteresis loops in the simplified model. The novel iron loss model results are compared with the simplified model and with finite element method (FEM).

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1604-1613
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• 2018

The paper presents the equivalent circuit of an induction machine (IM) model which includes fundamental stray load and iron losses. The corresponding equivalent resistances are introduced and modeled as variable with respect to the stator frequency and flux. Their computation does not require any tests apart from those imposed by international standards, nor does it involve IM constructional details. In addition, by the convenient positioning of these resistances within the proposed equivalent circuit, the order of the conventional IM model is preserved, thus restraining the inevitable increase of the computational complexity. In this way, a compromise is achieved between the complexity of the analyzed phenomena on the one hand and the model's practicability on the other. The proposed model has been experimentally verified using four IMs of different efficiency class and rotor cage material, all rated 1.5 kW. Besides enabling a quantitative insight into the impact of the stray load and iron losses on the operation of mains-supplied and vector-controlled IMs, the proposed model offers an opportunity to develop advanced vector control algorithms since vector control is based on the fundamental harmonic component of IM variables.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.604-606
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• 2002

Air-cored machines have a higher efficiency with high frequency. speed than iron-cored machine because of the iron losses which may produce too much heat as well as the copper losses occurred in the rotor winding. But air-cored machine is lower flux than iron machine. The nature of the machine from 'iron-cored' to 'air-cored' is a progressive feature in the machines. A general analysis of the fields that is applicable to all configurations is presented. Slotless machines have been applied for no ripple induced voltage. In this paper, slotless mahcines equipped with internal 4-pole amature winding. This paper pay attention to analyze flux density of air-cored and iron-cored synchrous machine analytically and compare flux density of aired-cored machine to iron-cored machine.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.2
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• pp.76-82
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• 2006

This paper investigates the magnetic field behavior and its iron losses in the stator core using electrical steels. The analysis model is a brushless motor with the permanent magnet. The elliptical rotating and alternating flux distributions with non-sinusoidal waveform are obtained by Finite Element Method and then their harmonic components are extracted. Based on these results, the local iron losses in the stator core caused by the harmonic flux are calculated. And then this paper explains the relation between flux waveform and iron loss produced in each part of the stator core. Furthermore, the iron loss at no load condition is measured and compared with the analysis results.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.699-703
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• 2018

Flux-switching permanent magnet machines (FSPMM) have doubly-salient and simple structures making it cost effective and suitable for mass production. In addition, it is possible to increase the rotor rotating speed and concentrate the flux of the permanent magnet on the air-gap. Due to these merits, the FSPMM can be applied to the various industry applications. To improve the performance, various design variables need to be studied in terms of design techniques. In this paper, we especially concentrate on the distribution of iron losses using a two-dimensional finite-element method (2D FEM). As a result, we can get an information for high efficiency FSPMM design.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1281-1282
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• 2007

Effect of tension coating on reducing iron losses of thin grain-oriented 3% Si-Fe steel sheets was investigated. Conventional grain-oriented electrical steel sheets have a forsterite coating layer and a tension coating layer in order to apply tensile stress to the rolling direction of the sheets. However the proposed coating method in this paper is to form only a tension coating layer on the both surfaces of the sheets. Iron losses with the tension coating were reduced by 8% under the condition of 1.7 T and 60 Hz. Consequently the proposed tension coating is applicable to $80{\mu}m$-thick 3% Si-Fe steel sheets.