• Title/Summary/Keyword: Coupling Matrix

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Hopf Bifurcation Study of Inductively Coupled Power Transfer Systems Based on SS-type Compensation

  • Xia, Chenyang;Yang, Ying;Peng, Yuxiang;Hu, Aiguo Patrick
    • Journal of Power Electronics
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    • v.19 no.3
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    • pp.655-664
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    • 2019
  • In order to analyze the nonlinear phenomena of the bifurcation and chaos caused by the switching of nonlinear switching devices in inductively coupled power transfer (ICPT) systems, a Jacobian matrix model, based on discrete mapping numerical modeling, is established to judge the system stability of the periodic closed orbit and to study the nonlinear behavior of Hopf bifurcation in a system under full resonance. The general flow of the parameter design, based on the stability principle for ICPT systems, is proposed to avoid the chaos and bifurcation phenomena caused by unreasonable parameter selection. Firstly, based on the state equation of SS-type compensation, a three-dimensional bifurcation diagram with the coupling coefficient as the bifurcation parameter is established with a numerical simulation to observe the nonlinear phenomena in the system. Then Filippov's method based on a Jacobian matrix model is adopted to deduce the boundary of stable operation and to judge the type of the bifurcation in the system. Then the general flow of the parameter design based on the stability principle for ICPT systems is proposed through the above analysis to realize stable operation under the conditions of weak coupling. Finally, an experimental platform is built to confirm the correctness of the numerical simulation and modeling.

Design rules of directional coupler optical switches in consideration of parasitic couplings in the input/output bending sections (Input/Output bending 영역에서의 parasitic coupling을 고려한 방향성 결합기 광 스위치의 설계 법칙)

  • 김동각;김창민
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.1
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    • pp.41-48
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    • 1997
  • Design rules of directional coupler optical switches are discussed in consideration of parasitic couplings in the bending section. The parasitic coupling phenomenon is analyzed based on the coupled-mode theory and the solutions are represented in the form of the transfer matrix. The modified switching conditions due to the parasitic coupling are derived and the resultant switching diagrams are illustrated. It is revealed that the parallel section's length needs to be adjustd less than the coupling length $l_c(=\pi/2\textsc{k}o)$ to obtain the desired crosstalk and that the adjustment depends on the strength of the parasitic coupling. However, it is discovered that, for weak parasitic coupling, the switching voltage does not need to be altered but may maintain the same value as if no parasitic coupling is taken into account.

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Closed-form and numerical solution of the static and dynamic analysis of coupled shear walls by the continuous method and the modified transfer matrix method

  • Mao C. Pinto
    • Structural Engineering and Mechanics
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    • v.86 no.1
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    • pp.49-68
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    • 2023
  • This study investigates the static and dynamic structural analysis of symmetrical and asymmetrical coupled shear walls using the continuous and modified transfer matrix methods by idealizing the coupled shear wall as a three-field CTB-type replacement beam. The coupled shear wall is modeled as a continuous structure consisting of the parallel coupling of a Timoshenko beam in tension (with axial extensibility in the shear walls) and a shear beam (replacing the beam coupling effect between the shear walls). The variational method using the Hamilton principle is used to obtain the coupled differential equations and the boundary conditions associated with the model. Using the continuous method, closed-form analytical solutions to the differential equation for the coupled shear wall with uniform properties along the height are derived and a numerical solution using the modified transfer matrix is proposed to overcome the difficulty of coupled shear walls with non-uniform properties along height. The computational advantage of the modified transfer matrix method compared to the classical method is shown. The results of the numerical examples and the parametric analysis show that the proposed analytical and numerical model and method is accurate, reliable and involves reduced processing time for generalized static and dynamic structural analysis of coupled shear walls at a preliminary stage and can used as a verification method in the final stage of the project.

GRADIENT PROJECTION METHODS FOR THE n-COUPLING PROBLEM

  • Kum, Sangho;Yun, Sangwoon
    • Journal of the Korean Mathematical Society
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    • v.56 no.4
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    • pp.1001-1016
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    • 2019
  • We are concerned with optimization methods for the $L^2$-Wasserstein least squares problem of Gaussian measures (alternatively the n-coupling problem). Based on its equivalent form on the convex cone of positive definite matrices of fixed size and the strict convexity of the variance function, we are able to present an implementable (accelerated) gradient method for finding the unique minimizer. Its global convergence rate analysis is provided according to the derived upper bound of Lipschitz constants of the gradient function.

Calculation of Coupling Loss in a HTS Tape by using Analytic Method and Numerical Method (해석적인 방법과 수치적인 방법에 의한 고온초전도테이프의 결합손실 계산)

  • Sim, Jeong-Uk;Lee, Hui-Jun;Cha, Gwi-Su;Lee, Ji-Gwang;Han, Song-Yeop
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.6
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    • pp.309-315
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    • 1999
  • Coupling loss is generated by the time-varying external magnetic field in the normal matrix of the multi-filamentary HTS tape. This paper calculates the coupling loss in the HTS tape. Analytic calculation of the coupling loss cannot consider the effect of the different shapes and the arrangement of the filaments. Numerical calculation by using finite element method and analytic calculation of the coupling loss have been done in this paper and results of two calculations have been compared. Transverse magnetic field and longitudinal magnetic field were considered as the external field.

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Design of Neuro-Fuzzy Controller using Relative Gain Matrix (상대 이득 행렬을 이용한 뉴로-퍼지 제어기의 설계)

  • Seo Sam-Jun;Kim Dongwon;Park Gwi-Tae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.15 no.1
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    • pp.24-29
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    • 2005
  • In the fuzzy control for the multi-variable system, it is difficult to obtain the fuzzy rule. Therefore, the parallel structure of the independent single input-single output fuzzy controller using a pairing between the input and output variable is applied to the multi-variable system. However, among the input/output variables which arc not paired the interactive effects should be taken into account. these mutual coupling of variables affect the control performance. Therefore, for the control system with a strong coupling property, the control performance is sometimes lowered. In this paper, the effect of mutual coupling of variables is considered by the introduction of a neuro-fuzzy controller using relative gain matrix. This proposed neuro-fuzzy controller automatically adjusts the mutual coupling weight between variables using a neural network which is realized by back-propagation algorithm. The good performance of the proposed nero-fuzzy controller is verified through computer simulations on 200MW boiler systems.

A Study on the Preparation ana Mechanical Properties of Composites Reinforced FRP Waste and Rock-Crush Sludge (폐 FRP/석분슬러지 충전 복합재의 제조 및 기계적 물성에 관한 연구)

  • 황택성;박진원;이철호
    • Polymer(Korea)
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    • v.24 no.6
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    • pp.829-836
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    • 2000
  • In order to recyle the FRP waste from SMC bathtubs and rock-crush sludge obtained as a byproduct of stones, the composite consisting of the FRP and rock-crush sludge and the unsaturated polyester matrix resin were prepared. To enhance the interfacial bonding force between the reinforcements and the matrix resin, the rock-crush sludge was treated with silane coupling agent, ${\gamma}$-methacryloxypropyltrimethoxysilane (${\gamma}$-MPS) and their mechanical properties and interface phenomena were examined. The flexural modulus of the composite containing 10 wt% rock-crush powder treated with 3 wt% silane coupling agent showed the maximum value. And also the initial thermal degradation temperature of composites were in the range of 352~359$^{\circ}C$. From these results, we observed that the weight loss of composites was almost constant regardless of the concentration of silane coupling agent. It is confirmed that the interface of the composites containing filler treated with ${\gamma}$-MPS was improved in that there were no pull-out phenomena between the reinforcement and matrix resin.

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Interface Characteristics of Epoxy Composite Treated with Silane Coupling Agent (실란 결합제 처리된 에폭시 수지 복합재료의 계면 특성)

  • Lee, Jae-Yeong;Lee, Hong-Gi;Sim, Mi-Ja;Kim, Sang-Uk
    • Korean Journal of Materials Research
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    • v.11 no.12
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    • pp.1009-1013
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    • 2001
  • The effects of coupling agent on the interface characteristics between epoxy resin and natural zeolite were studied by SEM, optical microscope and universal testing machine (UTM). Epoxy resin as a matrix was diglycidyl ether of bisphenol A (DGEBA)/4,4'-methylene dianiline (MDA)/malononitrile (MN) system and natural zeolite as an inorganic fillet was produced in Korea. With the increment of zeolite content, tensile strength decreased and it was due to the different elastic moduli of two materials. When external stress was loaded on the composites, the stress concentrated on the weakly bonded interface and crack grew easily. To improve the interface characteristics, the surface of the natural zeolite was treated with the silane coupling agent and it was found that the tensile strength was increased. The morphology of the interface showed that the bonding characteristics were modified by coupling agent.

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Influence of Frequency Separation on Modal Coupling in Nonclassically Damped Systems (비고전적 감쇠시스템에서 주파수분리의 모드연관에 대한 영향)

  • 김정수;최기흥;최기상
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2245-2250
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    • 1994
  • The normal coordinates of a nonclassically damped systems are coupled by nonzero off-diagonal elements of modal damping matrix. The relationship between modal coupling and the frequency separation of the natural modes is presented in this paper. Contrary to widely accepted beliefs, increasing the frequency separation of the natural modes does not neccessarily diminish the effect of modal coupling. Consequently, in the pratical engineering applications, wide frequency separation of the natural modes would not be sufficient for neglecting modal coupling.

Surface Modification of Glass Fiber for Polymer Insulator by Plasma Surface Treatment (플라즈마 표면처리에 따른 고분자절연재료용 유리섬유의 표면개질)

  • 임경범;이덕출
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.5
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    • pp.206-206
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    • 2003
  • It is hard to expect excellent electrical, mechanical and chemical properties from most of the composite materials presently used as insulators due to insufficient wettability property caused by the difference of interfacial properties between the matrix material and the reinforcer. Therefore, various interfacial coupling agents have been developed to improve the interfacial properties of composite materials. But if the wettable coupling agents are used outdoor for a long time, change in quality takes place in the coupling agents themselves, bringing about deterioration of the properties of the composite materials. In this study, glass surface was treated by plasma to examine the effect of dry interface treatment without coupling agent. It was identified that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system pressure, 100 W of discharge power, and 3 minutes of discharge time. Also, the surface resistance rate and dielectric property were improved.