• Journal of international Conference on Electrical Machines and Systems
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• 제3권1호
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• pp.54-60
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• 2014

This paper shows a calculation method of several types of loss and the efficiency of brushless DC motors coupled with a load system by using a simple equivalent circuit, in which copper loss, eddy current loss, hysteresis loss, friction loss, viscous loss, and inverter loss are taken into account. We clarify each loss and motor efficiency at different motor speeds and different output torques by using the Microsoft-Excel. Moreover, the calculated results are in good agreement with the measured ones.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1901-1907
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• 2018

This paper is a study for accurate iron loss calculation of a cylindrical linear machine for free piston engine. This study presents that it is possible to accurately predict power loss in ferromagnetic laminations under magnetic flux by specially considering the dependence of hysteresis, classical, and excess loss components on the magnetic induction derivative. Significant iron loss in the armature core will not only compromise the machine efficiency, but may also result in excessive heating, which could lead to irreversible deterioration in the machine performance. Thus, correct prediction of power losses under a distorted flux waveform is therefore an important prerequisite to machine design, particularly when dealing with large apparatus where stringent efficiency standards are required. Finally, it will be discussed about the iron loss in various materials of cylindrical linear electric machine by geometric and electrical parameters. It will give elaborate information about the perfect design and design rules of cylindrical linear machine and in parallel tools for the calculation, simulation and design will be available.

• 한국초전도ㆍ저온공학회논문지
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• 제16권4호
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• pp.62-65
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• 2014

To minimize most heat loss of current lead for high-temperature superconducting (HTS) rotating machine, the choice of conductor properties and lead geometry - such as length, cross section, and cooling surface area - are one of the various significant factors must be selected. Therefore, an optimal lead for large scale of HTS rotating machine has presented before. Not let up with these trends, this paper continues to improve of diminishing heat loss for HTS part according to different model. It also determines the simplification conditions for an evaluation of the main flux flow loss and eddy current loss transient characteristics during charging and discharging period.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권3호
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• pp.224-228
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• 2005

In this paper, we investigate the main components of stray load loss of induction motors for ammonia compressors. The variations of the losses at each part of the motor due to load are calculated by the combined 3-D-2D finite element method formulated by the mixed moving coordinate systems. The stray load loss is calculated from these results due the definition of IEEE standard-112. It is clarified that the core loss and the eddy current loss of the can increase due to load, which can be considered as the main part of the stray load loss.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.723-724
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• 2008

The rotational loss is one of the most important problems for the practical applications of PM synchronous motor/generator. This rotational loss is divided as the mechanical loss by windage and bearing and iron loss by hysteresis loop and eddy current in the part of the magnetic field. So, In this paper, a double-sided PMSM/G without the iron loss is designed by analytical method of the magnetic field and estimation of the back-EMF constant represented as the design parameter. This design model consists of the double-sided PM rotor with Halbach magnetized array and coreless 3-phase winding stator. The results show that the double-sided PMSM/G without iron loss can be applicable to the required system without the rotational loss.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.86-88
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• 2008

The rotational loss is one of the most important problems for the practical use of the high power Flywheel Energy Storage System (FESS). This rotational loss is divided as the mechanical loss by windage and bearing and iron loss by hysteresis loop and eddy current in the part of the magnetic field. So, In this paper, a double-sided PMSM/G without the iron loss is designed by analytical method of the magnetic field and estimation of the back-EMF constant represented as the design parameter. This design model consists of the double-sided PM rotor with Halbach magnetized any and coreless 3-phase winding stator. The results show that the double-sided PMSM/G without iron loss can be applicable to the high power FESS.

• Journal of Welding and Joining
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• 제20권1호
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• pp.76-82
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• 2002

In these days, many advanced nations have enforced import restrictions against things emitting electromagnetic wave which has report that it is so harmful. In general, electromagnetic wave is composed of electric wave and magnetic wave. The reflection of electromagnetic wave is mainly reflected by conductive materials and the magnetism loss is generated by magnetic ferrite. The magnetism loss of ferrite is separated by eddy current loss, residual magnetism loss and hysteresis loss. Thermal sprayed coating is intended to manufacture because of simple processes and high efficient electromagnetic wave shielding. The high efficient thermal sprayed coatings were made from the magnetic ferrite materials that characterizes absorption of electromagnetic wave, and the electric conductive materials that characterize emitting of electromagnetic wave. This study was manufactured thermal sprayed coatings to improve absorption-efficiency, and measured the electromagnetic wave shielding efficiency. As the experimental results, high electromagnetic wave shield efficiency was obtained at wave frequency 2GHz to thermal sprayed ferrite coatings manufactured by size distribution range of spray powders, $38~88\mu\textrm{m}$.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.225-229
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• 2017

This paper describes the loss analysis based on load conditions of the air conditioning compressor motors using variable dc-link voltage. The losses of PMSM (Permanent Magnet Synchronous Motor) should be analyzed by the PWM (Pulse Width Modulation) output of inverter. The harmonic loss by the PWM cannot consider that using the current source analysis of the inverter. In addition, when the voltage of dc-link is variable with the condition of variable speed and load conditions in motor, the losses of motor are also changeable, however it is hard to analyze those losses by only electromagnetic finite element method (FEM). Therefore, this paper proposes the analysis method considering the carrier frequency of the inverter and the varying state of the dc-link voltage through the FEM-control coupled analysis. Using proposed analysis method, additional core loss and eddy current loss of permanent magnet caused by PWM could be analyzed. Finally, the validity of the proposed analysis method is verified through the comparison the result of coupled analysis with experiment.

• 조명전기설비학회논문지
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• 제12권4호
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• pp.128-135
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• 1998

돌극형 동기 릴럭턴스 전동기의 고속회전 영역에서, 철손의 영향은 무시할 수 없게 된다. 본 논문에서는 돌 극형 동기 릴럭턴스 전동기에 대하여 고정자 철손이 고정자 내의 둥가 와전류에 의해서 발생한다는 가정 하에서, 둥가 인덕턴스에 직렬로 등가 철손저항이 삽입된 모델을 이용하여 철손을 고려한 전압방정식을 유도하였다. 또, 동작 주파수의 증가에 따른 철손의 변동은 벡터제어계의 제어성능을 악화시키고,d 축과 q 축의 쇄교자속에 서로 간섭하여 벡터제어의 적용을 어렵게 한다. 따라서, d 축과 q 축을 비간섭화 하여 철손저항의 영향을 제거해서 비간섭 토크제어가 가능한 벡터제어법올 제안하였으며, 시뮬레이션올 통하여 이를 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.788-789
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• 2011

A comprehensive thermo-electromagnetic model has been developed to estimate temperature and electromagnetic distribution in an three-phase induction motor under steady state operation. Electromagnetic modeling enables us to predict thermal dissipation rates by eddy-current loss and copper loss in induction motors. Non-uniform temperature distributions are investigated to account for the strong effect of local temperature build-up on the motor performance and expected life-span. For more accurate thermal modeling purpose, Heat loss mapping method, which is matched up with electromagnetic losses and volumetric heat source, is developed and performed analysis. Heat loss mapping method can be greatly used as a design or diagnostic tool for three-phase induction motors with complex structural electromagnetic fields.