• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.85-88
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• 2007

This paper describes various FTTH topology such as FTTH-R, Hybrid-FTTH etc. Especially, we focus on GW-PON based Hybrid-FTTH topology. Furthermore, the optical link technology and the features of the developed GW-PON system were explained in detail.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.3
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• pp.312-319
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• 2012

The operation principle of an axial flux-switching hybrid excitation synchronous machine (AFHESM) is analyzed and its topology structures are proposed in this paper. After some comprehensive analysis of the operation principle to axial flux electrical machine, flux-switching electrical machine and hybrid excitation electrical machine, the operation principle of AFHESM is given. Combined with some typical topological structures of hybrid excitation electrical machine, some possible topological structures are proposed and some comprehensive comparisons are carried out. The analysis results show that the stator-separated AFHESM has some advantages such as less AM turns, less impact on the demagnetization of PM, less magnetic flux-leakage and higher efficiency compared to other topologies.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2200-2208
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• 2009

This paper presents a novel single converter and single inverter (1Con-1Inv) topology for photovoltaic (PV)-fuel cell (FC) hybrid system and a new control scheme for the PV-FC hybrid system is then proposed. The new topology and the unique algorithm can minimize volume and production cost of the hybrid system. Moreover, system efficiency can improve due to reduction of losses of hardware components and other control factors are well regulated using just 1Con-1Inv with the help of the proposed control algorithm. The validity of proposed algorithm is verified both computer simulation using PSIM and Matlab/Simulink program and experimental with 700W of PV and 600W of FC system.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.27-34
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• 2016

In the train system, railway vehicles are connected in a line. Therefore, this feature should be considered in composing network topology in a train system. Besides, inter-car communication should be distinguished from in-car communication. As for the inter-car communication, the hybrid topology was proposed to use rather than the conventional ring, star, daisy-chain, and bus topologies. In the hybrid topology, a number of cars are bound to be a group. Then star topology is used for the communication in a group and daisy-chain topology is used for the communication between groups. Hybrid topology takes the virtue of both star and daisy-chain topologies. Hence it maintains communication speed with reducing the number of connecting cables between cars. Therefore, it is important to choose the number of cars in a group to obtain higher performance. In this paper, we focus on the optimization of hybrid topology for railway cars. We first assume that the size of data and the frequency of data production for each car is identical. We also assume that the importance for the maximum number of cables to connect cars is variable as well as the importance of the communication speed. Separated weights are granted to both importance and we derive the optimum number of cars in a group for various number of cars and weights.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1389-1410
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• 2016

This paper proposes a hybrid of topological derivative-based level set method (LSM) and isogeometric analysis (IGA) for structural topology optimization. In topology optimization a significant drawback of the conventional LSM is that it cannot create new holes in the design domain. In this study, the topological derivative approach is used to create new holes in appropriate places of the design domain, and alleviate the strong dependency of the optimal topology on the initial design. Furthermore, the values of the gradient vector in Hamilton-Jacobi equation in the conventional LSM are replaced with a Delta function. In the topology optimization procedure IGA based on Non-Uniform Rational B-Spline (NURBS) functions is utilized to overcome the drawbacks in the conventional finite element method (FEM) based topology optimization approaches. Several numerical examples are provided to confirm the computational efficiency and robustness of the proposed method in comparison with derivative-based LSM and FEM.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1311-1318
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• 2015

This paper introduces a novel topology and an effective control strategy for a shunt hybrid power filter (SHPF) to simultaneously compensate harmonic currents and reactive power. The proposed SHPF topology is composed of an LC passive filter tuned to the 7^th harmonic frequency and a small-rated active filter connected in parallel with the inductor L_pf of the LC passive filter. Together with the SHPF topology, we also propose a control strategy, which consists of a proportional-integral (PI) controller for DC-link voltage regulation and a PI plus repetitive current controller, in order to compensate both the harmonic current and the reactive power without the need for additional hardware. Thanks to the effectiveness of the proposed control scheme, the supply current is sufficiently compensated to be sinusoidal and in-phase with the supply voltage, regardless of the distorted and phase lagging of the load current. The effectiveness of the proposed SHPF topology and control strategy is verified by simulated and experimental results.

• Journal of Korean Association for Spatial Structures
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• v.21 no.2
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• pp.89-97
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• 2021

This paper describes an adaptive hybrid evolutionary firefly algorithm for a topology optimization of truss structures. The truss topology optimization problems begins with a ground structure which is composed of all possible nodes and members. The optimization process aims to find the optimum layout of the truss members. The hybrid metaheuristics are then used to minimize the objective functions subjected to static or dynamic constraints. Several numerical examples are examined for the validity of the present method. The performance results are compared with those of other metaheuristic algorithms.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.485-486
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• 2016

This paper proposes a new hybrid five-level voltage-source inverter topology, based on the conventional five-level active neutral-point-clamped topology (5L-ANPC), where the lower number of switching devices is required, resulting in saving the cost. The operating principle and control method of the proposed topology is described. The comparison of THD, power losses, loss distribution, and cost of components are evaluated among the proposed topology, the 5L-ANPC and 5L-DCI (diode-clamped inverters) topology.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.498-502
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• 1999

Harmonics and the reactive power related problems in the supply and demand side are increasing with the proliferation of nonlinear loads such as power converters in industrial applications. Filtering options such as passive, active and hybrid filters are countermeasures against these problems. In this study, a novel hybrid active filter topology with a new approach to enhance the system performance is presented. In this study, a novel hybrid active filter topology with a new approach to enhance the system performance is presented. The proposed topology comprised a parallel inverter and a hybrid active filter. It improves the system efficiency and reduces VA ratings, hence, overall filtering cost. The system operation, control and experimental verification on three phase rectifier and/or capacitor loads are presented.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.106-113
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• 2017

In this paper, we propose a suitable network topology for the Ethernet based Train Communication Network (TCN) for control system in a autonomous multi-articulated vehicle. We propose a network topology considering the structural constraints such as the number of cables and ports, and the performance constraints such as network response time and maximum throughput. We compare the network performances of star topology and daisy chain topology as well as hybrid topology, which is proposed in previous studies and a compromise between daisy chain and star topology. Here, the appropriate number of nodes in a group is obtained for the configuration of the hybrid topology. We first derive estimates of the network performance through simulation with different topologies, and then, implement the network by connecting the actual devices with each network topology. The performance of each topology is measured using various network performance measurement programs and the superiority of the proposed topology is described through comparison.