• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.105.2-105.2
• /
• 2013

배기속도 2500 L/s, 최고진공도 10-10 mbar의 구현을 목표로 하는 대용량 복합 분자펌프 설계를 위한 3차원 유동해석을 실시하였다. 진공도가 10-5 mbar 이상이 되는 고진공도에서는 Knudsen 수가 102 이상이 되어러 분자간 충돌을 거의 무시할 수 있게 되며, 이때의 유체해석 방법으로서는 통상 희박기체 해석법으로 많이 쓰이는 Direct simulation Monte Carlo 방법보다, 충돌이 없는 분자의 자유운동을 모사하는 Monte Carlo 방법이 더 적합할 수 있다. 본 연구에서는 다단계 rotor와 stator로 구성되는 복합분자 내 유동장에 Monte Carlo 해석법을 적용하여 유동해석을 실시하였다. 다양한 변수의 조합에 대한 수치적 해석에서, 복합분자펌프의 성능에 영향을 미치는 중요한 설계변수는 rotor-stator의 날개각, 유동방향 회전축의 두께 변화 등, 진행방향 분자의 모멘텀에 직접적인 영향을 미치는 변수들임이 확인되었다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
• /
• pp.267-274
• /
• 2009

To predict efficiency of Interior Permanent Magnet Synchronous Motors(IPMSM) and to cope with the demagnetization risk of permanent magnets used in the IPMSM, accurate iron analysis of the IPMSM is very important at the motor design stage. In the analysis, we calculate the operation condition such as rotor speed and current angle. and then, we analyzed the iron loss of the machine for electric vehicle according to its driving condition. From the analysis results, it was shown that the harmonic iron losses of stator are larger than before at field-weakening region. In addition, it was revealed that rotor iron loss mainly induced by stator slot-ripples is independent of current angle and only varied according to the speed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제51권8호
• /
• pp.425-433
• /
• 2002

This research investigates the electromechanical characteristics of a sing1e-phase squirrel cage induction motor due to broken rotor bars and rotor eccentricity. Numerical analysis is performed by solving the nonlinear time-stepping finite element equation coupled with the magnetic field equation, circuit equation and mechanical equation of motion. It shows that the asymmetry of magnetic flux due to the broken rotor bars and rotor eccentricity introduce a change in the stator current, torque, speed, magnetic force and vibration of a rotor at the same time. However, even in the existence of rotor eccentricity, 3 broken rotor bar introduces a dominant change in the magnetic force and rotor displacement, i.e., beating phenomenon in time domain and sideband frequencies in frequency spectra, respectively.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.693-696
• /
• 2011

The SRM (Switched Reluctance Motor) is composed of silicon steel plates where the rotor structure is simple and laminated without coil winding or permanent magnet, making it mechanically robust and its maintenance and repair excellent. Applying SRM as traction motor for railway vehicle is given consideration because of its ruggedness capability in severe loading condition and its compact structure. Optimal design of SRM is needed to reduce torque ripple to apply SRM for railway traction drive because SRM has high torque ripple. In this paper, switched reluctance motor with three different stator pole shapes is taken for magnetic analysis using 3d finite element method to apply SRM as traction drive for railway vehicle. It is observed that the model 3 added Tooth Tang Depth and Slot Round to stator shape gives the improved inductance and torque characteristic.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 A
• /
• pp.479-481
• /
• 1994

A direct vector control system of induction machine based determination of the spatial position of the airgap flux from the third harmonic component of the stator voltage is presented in this paper. The Rotor flux, necessary in direct vector control system, is estimated with the stator current and the airgap flux acquired from the third harmonic component of the stator voltage. And it will be used as an important information to implement the vector control system of the induction motor drive.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.104-106
• /
• 2003

In this paper, we study about the stator winding magnetization method and the magnetizing fixture magnetization method in post-assembly magnetization. Most of small electrical machine use the stator winding magnetization method but it is impossible to magnetize the permanent magnet by the stator winding magnetization method when the capacity of machine increases and the coercive force of magnet increases. And the eddy current disturbs the magnetization seriously in case of LSPM(Line Start Permanent magnet Motor) that have conductor bar in rotor. Hence, the magnetization fixture is required. So, in this paper we study about the post-assembly magnetization method that can use the stator winding magnetization method or must use the magnetization fixture magnetization method.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• 제12B권1호
• /
• pp.19-23
• /
• 2002

This paper investigates the influence of various stator pole shapes and yoke structures in Switched Reluctance Motors (SRM) on the mechanical behavior caused by the electromagnetic farce. The stator part in SRM produces most vibration. The geometric design of the stator is therefore necessary to reduce the vibration. Based on electromagnetic and structural Finite Element Method (FEM), the free and farced vibrations for the various structures of SRM with 6/4 poles are analyzed. Then a less vibration stator structure is proposed. Some of numerical computations for a prototype motor are verified by experimental results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제53권12호
• /
• pp.700-708
• /
• 2004

Flux-reversal machine (FRM) is a new doubly-salient stator-permanent magnet (PM) machine with flux linkage reversal in the stator concentrated windings. It can operate in both motoring and generating modes. In this paper, a novel design technique to improve the performance of FRM is proposed. Proposed techniques have a new stator winding and a magnet arrangement method. The stator and rotor shape with a concave type and a flux barrier are also proposed. According to the experimental results, it is shown that the proposed FRM have an improved performance.

• Journal of Electrical Engineering and Technology
• /
• 제6권3호
• /
• pp.350-355
• /
• 2011

This paper deals with the comparison of magnetic characteristics in transverse flux rotary machine according to different stator core composition with the same rotor. Three different stator designs are considered in the analysis according to the material composition of inner and outer stator cores. Electromotive force (EMF), inductance, torque, and core losses are calculated by threedimensional finite element analysis. Calculated and measured results of back-EMF according to the analysis models in dependency on speed are presented.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2005년도 전력전자학술대회 논문집
• /
• pp.30-32
• /
• 2005

In this paper, voltage control strategy for maximum torque operation of stator flux-oriented induction machine drive in the field-weakening region is proposed. In a conventional stator flux-oriented (SFO) induction machine drive system of the maximum torque capability cannot be obtained. The field-weakening method is used to vary the stator-flux reference in proportion to the inverse of the rotor speed. The proposed algorithm, based on the voltage control strategy, ensures the maximum torque operation over the field-weakening region. The proposed algorithm, voltage control strategy for maximum torque operation of capability, which is insensitive to the variation of machine parameters In the field-weakening region. The proposed algorithm is verified by simulation.