• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1759-1768
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• 2018

The energy density, power density and ohm resistance of battery change significantly as results of battery aging, which lead to decrease in the accuracy of the equivalent model. A parameter identification method of the equivale6nt circuit model with 3 R-C branches based on the test database of battery life cycle is proposed in this paper. This database is built on the basis of experiments such as updating of available capacity, charging and discharging tests at different rates and relaxation characteristics tests. It can realize regular update and calibration of key parameters like SOH, so as to ensure the reliability of parameters identified. Taking SOH, SOC and T as independent variables, lookup table method is adopted to set initial value for the parameter matrix. Meanwhile, in order to ensure the validity of the model, the least square method based on variable forgetting factor is adopted for optimizing to complete the identification of equivalent model parameters. By comparing the simulation data with measured data for charging and discharging experiments of Li-ion battery, the effectiveness of the full life cycle database and the model are verified.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.282-289
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• 2010

A Thomson coil type actuator is applied as the driving unit in an arc eliminator system. To eliminate the arc efficiently, the speed of the actuator is required as fast as possible with certain limit of the exciting current. Therefore, the dynamic characteristics of the Thomson coil type actuator should be analyzed in an effective way. In this paper, a novel solving technique has been developed based on the equivalent circuit model which is set up by dividing the conducting plate into multi segments. To guarantee the calculation accuracy and improve the calculation efficiency, an adaptive refinement algorithm is suggested based on the field continues condition. The proposed method has been verified by the FEM calculation and experiment. The influence of circuit and plate parameters to the performance of the actuator is also investigated, from which a reasonable set of parameters can be found.

• 한국정밀공학회지
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• 제22권4호
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• pp.99-106
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• 2005

In this study, the electromagnetic characteristics of a flat-type two-dimensional proportional solenoid were analyzed by the magnetic reluctance method. The equivalent magnetic circuit equation for the solenoid was derived by modeling the reluctance of air gaps and magnetic structural components such as pole core, armature and yoke. It was solved iteratively because of the nonlinear magnetization properties of the iron parts. The solutions showed good agreement with experimental data. Based on the equivalent magnetic circuit equation, the influence of design parameters on the force-to-armature displacement curves was mathematically derived and experimentally verified. In this way, dominant design parameters could be analytically determined.

• International Journal of Precision Engineering and Manufacturing
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• 제7권2호
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• pp.46-51
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• 2006

In this study, the electromagnetic characteristic of a flat-type two-dimensional proportional solenoid were analyzed by the magnetic reluctance method. The magnetic equivalent circuit equation for the solenoid was derived by modeling the reluctance of air gaps and magnetic structural components such as pole core, armature and yoke. It was solved iteratively because of the nonlinear magnetization properties of iron parts. The solutions showed good agreement with experimental data. Based on the magnetic equivalent circuit equation, the influence of design parameters on force-to-armature displacement curves was mathematically derived and experimentally verified. In this way, dominant design parameters could be analytically determined.

• 한국항행학회논문지
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• 제15권2호
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• pp.256-263
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• 2011

뉴런의 신경임펄스는 뉴런이나 축삭 자신의 자극에 의하여 유도되며, 이 자극전압이 임계치 이하이면 뉴런의 전도거리와 전도시간에 따라 지수함수적으로 감쇠된다. 이러한 현상은 전기회로에서의 전도현상과 매우 유사한 형태이므로 전기적인 등가회로를 이용하여 해석할 수 있다. 따라서 본 논문에서는 뉴런의 전기적인 각종 파라미터를 구한 후 전기회로의 분포정수회로 이론을 적용하여 자극전도 현상을 해석하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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• pp.470-477
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• 2002

Possibility of passive piezoelectric damping based on a new shunting parameter estimation method is studied using finite element analysis. The adopted tuning method is based electrical impedance that is found at piezoelectric device and the optimal criterion for maximizing dissipated energy at the shunt circuit. Full three dimensional finite element model is used for piezoelectric devices with cantilever plate structure and shunt electronic circuit is taken into account in the model. Electrical impedance is calculated at the piezoelectric device, which represents the structural behavior in terms of electrical field, and equivalent electrical circuit parameters for the first mode are extracted using PRAP (Piezoelectric Resonance Analysis Program). After the shunt circuit is connected to the equivalent circuit for the first mode, the shunt parameters are optimally decided based on the maximizing dissipated energy criterion. Since this tuning method is based on electrical impedance calculated at piezoelectric device, multi-mode passive piezoelectric damping can be implemented for arbitrary shaped structures.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.130-133
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• 2004

The characterization of interdigitated capacitors was investigated. The test structures are manufactured by low temperature co-fired ceramic(LTCC) process and their s-parameters were measured. The optimized equivalent circuit models for test structures were obtained using the partial element equivalent circuit(PEEC) method. Predictive modeling was performed on different test structures using optimized parameters to verify the circuit models. From this result, the manufacturability on the process can be improved through the predictive modeling for the characteristics of interdigitated capacitors.

• 대한전자공학회논문지SD
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• 제41권12호
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• pp.21-26
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• 2004

본 논문에서는 package된 BJT의 RF 등가회로 모델을 optimization과정 없이 직접 추출하는 방법을 개발하였다. 먼저, open 과 short package 구조를 사용하여 plastic package의 기생성분을 측정된 S-파라미터로부터 정확히 제거하였다. 이와 같이 package do-embedding된 S-파라미터로부터 package lead와 chip pad 사이의 bonding wire 인덕턴스와 chip pad 캐패시턴스를 직접 추출하는 간단한 방법을 구축하였다. 그 후에 내부 BJT소자의 소신호 모델변수들은 RF 등가회로로부터 유도된 Z나 Y-파라미터 방정식을 이용하여 결정하였다. 이 방법으로 모델화된 packaged BJT의 S-파라미터는 측정 데이터와 아주 잘 일치하였으며 이는 새로운 추출방법의 정확성을 증명한다.

• Journal of electromagnetic engineering and science
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• 제11권2호
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• pp.122-127
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• 2011

A general analysis of an aperture-coupled vertically mounted strip antenna is presented to examine its circuit characteristics. Based on the present analysis, an equivalent circuit model is developed, and an analytic or semi-analytic evaluation of the related circuit element values is described. The effects of structure parameters on the antenna characteristics were studied with the developed equivalent circuit, and the design curves were obtained. To check the validity of the proposed analysis and design theory, two C-band antennas (5.0 GHz and 4.5 GHz) were designed and fabricated. Their computed characteristics, derived from the proposed network analysis, were compared with the measurement and simulation results. The error of the current model in predicting the operating center frequency was less than 0.50 %. In addition, the observed bandwidth was found to be comparable to the conventional microstrip antennas. All the results fully validated the efficiency and accuracy of the proposed analysis and network model.

• 한국음향학회지
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• 제28권4호
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• pp.363-369
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• 2009

본 논문에서는 인접된 다중모드 공진점을 갖는 수중 음향 압전 트랜스듀서의 전기적 등가회로 모델을 추정하는 방법을 제안하였다. 트랜스듀서의 실측된 임피던스와 추정된 등가모델의 임피던스 오차가 최소가 되도록 공진모드간 결합 영향을 고려한 적합도 함수를 제안하고, 미립자 집단 최적화 (PSO:Particle Swarm Optimization) 알고리즘을 이용하여 등가회로의 미지상수를 추정하였다. 3개의 공진점을 갖는 샌드위치형 예제 트랜스듀서에 대하여 제안된 방법을 적용하여 등가회로를 모델링하고, 수중에서의 임피던스 측정치와 추정된 등가모델의 임피던스를 비교함으로써 제안된 기법의 타당성을 검증하였다.