• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.371-376
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• 2017

In this paper, we propose a magnetic resonant WPT(wireless power transfer) scenario using a large coil resonating at 6.78 MHz, and compare the characteristics through a three-dimensional electromagnetic field simulation and a magnetic resonant WPT equivalent circuit. The magnetic resonant WPT equivalent circuit proposed in this paper considers the parasitic capacitance generated between the coils in addition to the conventional equivalent circuit. Based on this analysis, we fabricated the magnetic resonant WPT coil and compared it with simulation prediction. As a result of comparison, the transfer characteristics and the resonance frequency shift can be predicted. Error proposed characteristics of equivalent circuit for the magnetic resonant WPT and the measured values are estimated to be ${\Delta}{\mid}S11{\mid}=1.31dB$ and ${\Delta}{\mid}S21{\mid}=1.21dB$, respectively.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.818-819
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• 2011

본 논문은 가변자속 기능을 가지는 Flux Switching Permanent Magnet (FSPM) 전동기의 전 자기적 등가회로를 이용한 특성해석방법을 다룬다. 우선 가변자속 기능을 갖는 FSPM 전동기의 구조와 동작원리를 설명하였다. 다음으로 오버행을 고려한 2-D유한요소 해석 모델을 이용하여 역기전력, 인덕턴스를 구하였다. 마지막으로 등가회로 해석을 통해 가변자속 운전 시 FSPM 전동기의 특성해석을 실시하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.245.1-245.1
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• 2014

교차하는 전기장과 자기장으로 플라즈마를 방전하고, 이온 빔을 효과적으로 가속하는 원형 이온 빔 소스를 개발하였다. 방위각 방향으로 비대칭적인 중성 가스와 전자 빔의 공급으로 이온 빔 소스에서 불안정하고 불균일한 플라즈마가 방전되어, 이온 소스의 효율을 저하시킨다. 본 연구에서는 플라즈마 이미지를 이용하여 이온 소스 내부에서의 중성입자 밀도 분포를 측정하는 방법을 개발하였다. 자기장의 방향이 서로 다른 방전조건에서 얻어지는 한 쌍의 플라즈마 이미지로부터 티코노프 정형화 기법을 이용하여 방위각에 대한 중성입자의 밀도 분포를 재구성한다. 본 재구성 기법을 이용하여 얻어진 밀도 분포는 유체흐름 등가회로 모델을 바탕으로 한 수치해석을 이용하여 분석하였다. 중성입자 밀도의 공간분포는 인가 전압, 자기장의 세기 및 유량과 같은 방전조건의 변화에 크게 영향을 받지 않고, 가스 공급부의 내부 구조에 의해 결정되는 것을 확인하였다. 또한, 등가회로 모델을 이용하여 균일한 공간분포를 얻기 위한 공급부 설계를 수행하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.568-569
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• 2005

한빛 자기거울 장치는 고온 플리즈마 물성을 연구하기 위한 장치로서 플러즈마 밀도 형성을 위한 slot 형 안테나 고주파 가열 시스템이 중앙 진공용기에 설치되어 있다. 본 연구에서는 이러한 고주파 전송선로, 임피던스 정합 network. 장치 임피던스를 포함하는 한빛 장치의 고주파 가열 시스템에 대하여 기존에 정립된 고주파 가열 이론[1]을 기반으로 하여 이론적인 해석만으로 구성된 회로모델을 완성하였다. 임피던스 정합 소자 값들은 임피던스 정합 조건으로 결정함으로써 다양한 장치 및 플라즈마 변수들의 함수로 표현하여 그 의존성을 조사하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1036-1043
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• 2003

In this paper, novel lumped equivalent circuits for a conventional parallel directional coupler are proposed. This novel equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of a parallel-coupled line. By using the derived design formula, we have designed the 3 dB and 10 dB lumped element directional couplers at the center frequency of 100 MHz and 2 GHz, respectively a chip type directional coupler has been designed with multilayer configurations by employing commercial EM simulator. Designed chip-type directional couplers have a 3 dB-coupling value at the center frequency of 2 GHz and fabricated lumped directional coupler on fr4 organic substrate has a 3 dB, 10 dB-coupling values at the center frequency of 100 MHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper. Furthermore, in order to adapt to multi-layer process such as Low Temperature Cofired Ceramic (LTCC), chip-type lumped element couplers have been designed by using this method.

• Journal of the Korean Magnetics Society
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• v.27 no.2
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• pp.54-62
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• 2017

This paper presents a design of the Interior Permanent Magnet Synchronous Motor (IPMSM). an initial design process is accomplished by using the parametric design. In the design process, motor characteristics of parameters is computed by the d-q axis equivalent circuit model. Then, an optimal design process is accomplished by combination the experimental design and the response surface method. Finally, the design and analysis results are verified with experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.537-543
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• 2010

This paper presents a slot-shaped defected ground structure(DGS) which has multi-band rejection property. The proposed structure, in which the spiral slot-shaped defects with different size are aligned in the transverse direction to the guiding direction of the coplanar waveguide(CPW), provides multiple resonance frequencies. Compared with the simulated results, the band rejection characteristic is in good agreement with the measurement. Also, an equivalent circuit model of the proposed structure is presented, where the DGS on the ground plane is modeled as LC-resonators. This resonators are inductively coupled to the signal line through mutual inductance. From the equivalent circuit model, multi-band rejection property was derived.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.137-144
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• 2011

A Simple equivalent circuit model is developed for a wireless energy transfer system via coupled magnetic resonances and a practical design method is also provided. Node equations for the resonance system are built with the method, expanding on the equations for a transformer, and the optimum distances of coils in the system are derived analytically for optimum coupling coefficients for high transfer efficiency. In order to calculate the frequency characteristics for a lossy system, the equivalent model is established at an electric design automation tool. The model parameters of the actual system are extracted and the modeling results are compared with measurements. Through the developed model, it is seen that the system can transfer power over a mid-range of a few meters and impedance matching is important to achieve high efficiency. This developed model can be used for a design and prediction on the similar systems such as increasing the number of receiving coils and receiving modules, etc.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.610-616
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• 2010

In this paper, particle swarm optimization(PSO) is applied for the design of frequency selective surface based artificial magnetic conductor. An equivalent circuit model for this artificial magnetic conductor(AMC) with Jerusalem Cross arrays was derived and then PSO was applied for obtaining the optimized geometrical parameters with desired resonant frequency. The resonant frequency and the reflection phase characteristics from the optimization were compared to the results from commercial software for verifying the validity of this paper. The procedure presented in this paper can be applied to design the AMC with different frequency selective surface and also can be used for the design of microwave circuits like the AMC ground planes.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.936-938
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• 2005

본 논문은 실제 단상유도전동기의 정확한 특성예측을 위해 각종 기생성분, 즉 자기회로 포화 및 고조파에 의한 영향을 분석하였다. 특히 기동특성에 큰 영향을 주는 공간고조파 성분의 영향을 고려하기 위해 슬롯과 권선분포에 대한 고조파분석 및 고조파 등가회로를 구현하였다. 이로부터 동특성해석을 시행함으로써 공간고조파에 의한 기동에서의 기생토크효과를 분석하였다.