• 한국전기전자재료학회논문지
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• 제26권7호
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• pp.515-521
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• 2013

Magnetoelectric(ME) bulk composites with PZT-PNN-PZN/$Fe_2O_4$ were prepared by using a conventional ceramic methods and investigated on the ME voltage vs frequency of ac magnetic fields. We made the electric equivalent circuits by using the Maxwell-Wagner model and simulated the frequency dependence of ME voltage in low frequency region. ME devices were described by a series of two equivalent circuits of piezoelectric and magnetic, which have the relaxation time ${\tau}$ due to the interaction between ME device and load resistor. Equivalent circuit of piezoelectric material is independent of frequency. However ferrite magnetic materials have Debye absorption and dipolar dispersion, whose equivalent circuit is a function of frequency. Therefore we suggest the resistance in the equivalent circuit is proportion to $1+{\omega}^2{\tau}^2$ and the capacitance is in inverse proportion to $1+{\omega}^2{\tau}^2$ in the magnetic materials.

• Journal of Magnetics
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• 제19권4호
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• pp.404-410
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• 2014

This paper considers the design and performance evaluation of interior permanent magnet synchronous motors (IPMSMs). The initial design such as the sizing and shape design of the stator and rotor is performed for a given load condition. In particular, the equivalent magnetic circuit (EMC) is employed both to design the mechanical parameters of the rotor while considering nonlinear magnetic saturation effect and to analyze the magnetic characteristics of the air-gap of the motor. The designed motor is manufactured and tested to confirm the validity of the design processes and simulated results.

• 전기학회논문지P
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• 제66권1호
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• pp.1-6
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• 2017

Recently, many motor analysis methods have been developed and studied. Among these methods, the finite element method(FEM) and the analytic method are most popular in field engineers because of the accuracy of FEM and the convenience and rapid analysis time of the analytic method. Contrary, the finite element method has a weakness in calculation time and it is not easy to obtain the instantaneous characteristics value of motor with the analytic method. In this paper, the authors proposes a novel method for calculating the instantaneous characteristics of motors with the magnetic slot equivalent circuit.

• Journal of Magnetics
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• 제16권1호
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• pp.58-63
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• 2011

This paper presents design procedures of a transverse flux linear motor (TFLM). The minimum and maximum flux linkage was determined by the simplified equivalent magnetic circuit and estimated average magnetic flux density at the air gap region by considering the shape of applied magnetomotive force (MMF). With this information, the number of turns of each phase winding was calculated based on the amplitude of applied voltage and speed of a mover. The rated current, coil diameter, and winding area were obtained with the aid of an empirical formula for determining the required MMF. The usefulness of the proposed design method for TFLM is verified by the three-dimensional equivalent magnetic circuit network (EMCN) method and the experimental results of prototyped machine.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권8호
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• pp.449-456
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• 2002

3D Equivalent magnetic Circuit Network Method (EMCNM) is comparatively the easy way that analyzes 3D models of Electric Machine by using permeance as a distributive magnetic circuit parameter under the existing magnetic equivalent circuit method and Numerical Method. The existing 3D EMCNM could not correctly describe the shape of an analysis target when using rectangular shape element or fan shape element, so it made errors when calculating permeance. Therefore, this paper proposes the trapezoidal element contained rectangular element, fan-shape element, and quadrilateral element to express a shape. The proposed method in this research was confirmed as a useful and an accurate method through comparing with the analysis result of SRM model that is sufficiently guaranteed by 2D-Analysis.

• 한국수소및신에너지학회논문집
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• 제33권3호
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• pp.226-231
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• 2022

Power converter are usually equipped for fuel cell power generation system to connect alternating current (AC) electric power grid. When converting direct current (DC) of fuel cell power source into AC, the power converter has a frequency ripple, which affects the fuel cell and the grid. Therefore, an equivalent circuit having dynamic characteristics of fuel cell power, for example, impedance, is useful for designing an inverter circuit. In this study, the current, voltage and impedance characteristics were calculated through fuel cell modeling and validated by comparing them with experiments. The equivalent circuit element values according to the current density were formulated into equations so that it could be applied to the circuit design. It is expected that the process of the equivalent circuit modeling will be applied to the actual inverter circuit design and simulated fuel cell power sources.

• 한국산학기술학회논문지
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• 제10권6호
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• pp.1180-1185
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• 2009

본 논문에서는 T-접합선로의 집중소자 등가회로를 고려한 저역통과 여파기를 제안하였다. 일반적인 저역통과 여파기 설계 시 발생하는 T-접합선로의 특성에 따른 주파수 변이 특성을 해결하기 위해 T-접합선로 등가회로의 소자 값을 구하는 수식을 유도 하였다. 또한, 전자장 시뮬레이터(HFSS)를 이용하여 T-접합선로를 디임베딩하였다. 이로써 선로의 임피던스 허수값들이 일치되게 하여 T-접합선로 등가회로에서 집중소자의 정확한 값을 구하였다. 그리고 이 값들을 이용하여 저역통과 여파기를 설계한 결과, 집중소자 여파기의 주파수 특성과 분포소자 여파기의 주파수 특성이 매우 잘 일치함을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.330-332
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• 2000

To analyze the transient state of an induction motor, there have been studies for using the magnetic equivalent circuit method(MECD) instead of the time differential finite-element method. MECD which analyzes magnetic equivalent circuits after converting each part of an electric machine into the magnetic circuit elements, has the merits of short calculation-time and comparatively accurate results. To analyze an electric machine with MECM, we have to replace stator and rotor with the magnetic elements and express the air gap, where electromechanical energy conversion takes place, with the permeance. So in this study, to analyze an Induction Motor with HECM, we express the magnetic equivalent circuit as algebraic equations and then as the matrix for solving easily them. In particular, all relations are formed with matrixes to solve Mathematically them in the programming process later. As a result, this theory will be the basis on the static and dynamic analysis of an Induction Motor.

• 전력전자학회논문지
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• 제26권3호
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• pp.167-175
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• 2021

Reusing electric vehicle batteries after they have been retired from mobile applications is considered a feasible solution to reduce the demand for new material and electric vehicle costs. However, the evaluation of the value and the performance of second-life batteries remain a problem that should be solved for the successful application of such batteries. The present work aims to estimate the remaining useful life of Li-ion batteries through the neuro-fuzzy system with the equivalent circuit parameters obtained by Electrochemical Impedance Spectroscopy (EIS). To obtain the impedance spectra of the Li-ion battery over the life, a 18650 cylindrical cell has been aged by 1035 charge/discharge cycles. Moreover, the capacity and the parameters of the equivalent circuit of a Li-ion battery have been recorded. Then, the data are used to establish a neuro-fuzzy system to estimate the remaining useful life of the battery. The experimental results show that the developed algorithm can estimate the remaining capacity of the battery with an RMSE error of 0.841%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.32-35
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• 1996

This paper analyzes characteristics of PMLSM using 3 dimensional equivalent magnetic circuit network method (3-D EMC). PMLSM of which the effective electric-airgap is not only very large, but also the width is finite width lateral edges has much leakage flux. Therefore, 2-D analysis method cannot consider it so carefully that 3-D analysis method must required. 3-D EMC which will be used for analysis of PMLSM performs modeling of it including solt and teeth structure, uses the magnetic motive force of stator winding and permanent magnet as source. and calculates magnetic flux density and force considering nonlinear characteristics of materials. we verified analysis validity by comparing simulation results with expermental results.