• 한국산학기술학회논문지
• /
• 제12권3호
• /
• pp.1289-1301
• /
• 2011

본 논문에서는 전 속도 영역에서 안정적인 자속추정이 가능한 유도전동기 자속추정방법을 제안 하였다. 제안된 방법은 전압, 전류, 속도 등의 정보를 통하여 자속각을 연산하는 유도전동기 직접벡터제어방식을 이용하였다. 유도전동기 벡터제어에 있어서 자속정보는 필수적이기 때문에 정확한 자속을 추정하기 위한 방법으로 저속영역에서 는 전류모델 자속 추정기를, 고속영역에서는 전압모델 자속 추정기를 각각 이용함으로써 전 속도영역에서 정확한 자속을 추정할 수 있었다. 또한 기본적인 속도, 전류, 자속제어기는 PI제어기를 이용하였으며, 각각의 적분에 의한 오차를 보상하기 위하여 Anti-windup PI 제어기를 추가하였다. 제시한 제어기의 타당성을 알아보고자 Matlab / simulink를 이용하여 전류모델, 전압모델 자속 추정기를 설계하여 정확한 자속추정이 이루어짐을 확인하였으며, 유도 전동기 벡터제어 시 간접벡터와 직접벡터방식의 파라미터 영향에 따른 분석을 통해 보다 정밀한 제어가 이루어짐을 확인하였다. 이와 같은 시뮬레이션 결과를 분석 하여 제시한 알고리즘의 타당성을 입증하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.65-67
• /
• 2007

This paper proposes a novel flux barrier in q-axis of rotor in IPM type BLDC motor, The proposed flux barrier can reduce cogging torqeu and diminisg torque ripple by sinusoidal waveform distribution of flux generated in the permanent magnet. To determine the optimal shape of the novel flux barrier, we also propose a modified Taguchi method which considering multiple quality characteristics, such as cogging torque, average torque, and efficiency. The proposed design and method were analyzed by using the 2D finite element method (FEM). Results of the proposed model were compared with initial model.

• 한국전산유체공학회지
• /
• 제11권1호
• /
• pp.8-15
• /
• 2006

The existing approximations of diffusion flux in unstructured cell-centered finite volume methods are examined in detail with each other and clarified to have indefinite expressions in several respects. A new numerical approximation of diffusion flux at cell face center is then proposed, which is second-order accurate even on irregular grids and may be easily implemented in CFD code using cell-centered finite volume method with unstructured grids composed of arbitrary convex polyhedral shape.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.402-402
• /
• 2000

MFL(Magnetic Flux Leakage) methods are used extensively for inspection of ferromagnetic materials. As an example, pipelines that are buried underground are inspected using MFL methods. By the MFL methods, ferromagnetic pipelines are magnetized by a permanent magnet or an electromagnet and then flux leakage is detected at the defection position. In this paper, we perform modeling of the magnetized pipelines. Also we propose the method localization of th defected areas. The effectiveness of the proposed method is verified experimentally.

• 한국CDE학회논문집
• /
• 제13권4호
• /
• pp.296-304
• /
• 2008

Recently, various attempts are being done to apply off-line programming system to field of paint robot. But most commercial simulation softwares have problems that are slow simulation speed and not support various painting paramenters on simulation. This paper proposes enhanced paint simulation method for off-line programming system. For these, this method used the mathematical model of flux field from a previous research. The flux field has the flux distribution function, which reflects on the feature of paint spray. A previous research derived this flux distribution function for an integral function and calculated paint thickness function for an integral function. But if flux distribution function is defined as an integral function, it is inadequate to use for real-time simulation because a number of calculation is needed for estimation of paint thickness distribution. Therefore, we defined the flux distribution function by numerical method for reducing a mount of calculation for estimation of paint thickness. We derived the equation of paint thickness function analytically for reducing a mount of calculation from the paint distribution function defined by numerical method. In order to prove proposed paint simulation method this paper compares the simulated and measured thickness. From this comparison this paper show that paint thickness distribution is predicted precisely by proposed spray paint simulation process.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
• /
• pp.268-272
• /
• 1989

To avoid the use of position sensor or flux sensor in a field oriented induction machine drive system, the terminal quantities are often used to estimate the rotor flux. Since the estimation involves the leakage inductance of the machine, the performance of such systems is sensitive to the variations of leakage. Since estimation of the stator flux is independent of the leakage, the steady state performance of the stator flux oriented system is insensitive to the leakage inductance. In this paper, the torque response of stator flux oriented system is compared to that of rotor flux oriented system by digital simulation. And induction motor sensor less speed control by stator flux oriented method is developed. The performance of the speed estimation is showed by digital simulation.

• Journal of Magnetics
• /
• 제18권2호
• /
• pp.111-116
• /
• 2013

This paper presents a characteristic analysis method of a permanent magnet type transverse flux linear motor (TFLM) with spiral cores. The spiral cores are used as the mover cores in order to make 3-dimensional (3-D) magnetic flux paths at the TFLM which have 3-D magnetic flux flows. The 3-D Equivalent Magnetic Circuit Network Method is used to analyse the magnetic characteristics of the machine, and an imaginary part, 'flux barrier,' is introduced to consider the spiral core characteristic. Magnetic parameters such as flux, inductance, and thrust are calculated from the analysis results. The computed thrust forces are compared to measured values to confirm the accuracy of the analysis.

• Journal of applied mathematics & informatics
• /
• 제32권5_6호
• /
• pp.761-781
• /
• 2014

An exponentially accurate nonconforming spectral element method for elasticity systems with discontinuities in the coefficients and the flux across the interface is proposed in this paper. The method is least-squares spectral element method. The jump in the flux across the interface is incorporated (in appropriate Sobolev norm) in the functional to be minimized. The interface is resolved exactly using blending elements. The solution is obtained by the preconditioned conjugate gradient method. The numerical solution for different examples with discontinuous coefficients and non-homogeneous jump in the flux across the interface are presented to show the efficiency of the proposed method.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• 제12B권1호
• /
• pp.13-18
• /
• 2002

Novel method to calculate flux linkage for 3-D finite element analysis is proposed. It does not require any integral path if the current direction in a coil is known. The flux linkage can be calculated very easily using simple volume based integration. The current direction is calculated based on the recently developed technique by the authors. The novel method for flux linkage calculation is verified by applying to a very complicated deflection yoke coil. The simulation result is compared to the experimental one. From the simulation, it is shown that the proposed method is very accurate and effective to calculate the flux linkage of a coil.

• 천문학회지
• /
• 제39권4호
• /
• pp.151-155
• /
• 2006

Long slit spectrometers are widely used in optical and infrared bands in astronomy. Absolute flux calibration for extended sources, however, is not straightforward, because a portion of the radiation energy from a flux calibration star is blocked by the narrow slit width. Assuming that the point spread function(PSF) of the star is circularly symmetric, we develop a robust method to extrapolate the detected stellar flux to the unobscured flux using the measured PSF along the slit-length direction. We apply this method to our long slit data and prove that the uncertainty of the absolute flux calibration is less than a few percents.