• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.6
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• pp.419-427
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• 2019

Several multilevel converter topologies have been proposed and compared. The three-level (3L) neutral-point-clamped (NPC) topology is promising and widely accepted. However, this topology suffers from uneven loss distribution among switches due to its fixed switching strategy. The 3L active NPC (ANPC) topology, which exhibits improved loss distribution profile, was proposed to address this disadvantage. The 3L T-NPC topology, a hybrid configuration of 2L and 3L NPC topologies, was introduced to address not only the loss distribution problem but also the reduction in the number of switches. In the present research, the application of these three topologies in PMSG-based medium-voltage wind turbines was investigated. The power devices considered were 10 kV IGCTs. Performance was evaluated in terms of a power loss of 10 kV IGCT for each NPC topology, which is a crucial indicator of thermal behavior, reliability, cost, and lifetime of any converter. The comparison was performed using ABB make 10 kV IGCT 5SHY17L9000 and the simulation tool PLECS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1491-1496
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• 2014

VSC-HVDC system is vulnerable to a DC fault because the fault current can be injected from AC system to DC system during the fault. Therefore, DC circuit breaker is required to isolate faults in VSC-HVDC system. The inverse current injection method of circuit breaker has been considered as DC circuit breaker. However, the topology has drawback that the breaking time is longer than hybrid circuit breaker using semiconductor devices. In order to solve this problem, this paper proposes an improved topology of circuit breaker based on inverse current injection method. In addition, the proposed topology will be compared with the existing topology. And we will verify its effects by using the simulation results.

• Journal of Magnetics
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• v.21 no.3
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• pp.399-404
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• 2016

This paper presents a new permanent magnet (PM) assisted topology for a recently introduced brushless wound rotor synchronous machine (BL-WRSM) [1]. The BL-WRSM had a dual-inverter configuration for generating a composite magneto motive force (MMF) with a fundamental component and a subharmonic component. The subharmonic component of the MMF is used for brushless excitation of the rotor. In this paper, additional PMs were introduced on the rotor of the BL-WRSM, making it a hybrid BL-WRSM. We also discussed the flux weakening operation for the hybrid BL-WRSM. The hybrid BL-WRSM offered advantages for starting the machine and provided better performance under full-load conditions. The finite element method (FEM) was used to analyze the performance of the hybrid BL-WRSM, and we compared its performance with BL-WRSM. Finally, prototypes were built with and without the PM-assistance, and experiments were conducted to demonstrate their performance.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.113-116
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• 1988

In this paper, We Proposed a new Thyristor-FET hybrid type high-Frequency inverter circuit topology. Concerning the proposed high-frequency inverter. We applied the normalized parameters to the characteristic analysis of steady-state at the resistive load.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.315-316
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• 2019

This paper proposes the operation scheme and control method for a four-level hybrid half-bridge flying-capacitor inverter (4L-HHBFCI). With in-phase disposition level-shifted modulation (IPD), the flying capacitor voltage ripple is less than 1% of the reference value, while the line-to-line voltage total harmonic distortion is 23.27% at unity modulation index. The performance and effectiveness of the proposed inverter operation have been verified by simulation results.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.31-40
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• 1997

This paper presents a hybrid WDM/TDM channel acess protocol for high speed WDM networks based on passive double star topology. In the proposed scheme, all nodes in a network are splitted into groups forming passive double star topology and each node has a tunable transmitter and a fixed receiver. WDM channels are allocated to the groups, which are used as home channels to transmit or receive packets. TDM frames of the WDM channel are composed of the same number of slots as that of groups, and all nodes in a group transmit packets simultaneously at each slot. The proposed scheme reduces the system complexity and the number of the required WDM channels. It was proved that the proposed protocol is less sensitive to the propagation delay and maintaining its superior transmission performance by employing the efficient transmission schedule based on passive double star topology.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.70-71
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• 2017

This paper presents a new cascaded boost multilevel converter topology for distributed generation (DG) systems. Most of DG systems, such as photovoltaic (PV), wind turbine and fuel cells, normally require the complex structure power converters, which makes the system expensive, complex and hard to control. However, the proposed converter topology can generate a much higher output voltage just by using the standard low-voltage switch devices and low voltage DC-sources in a simplified structure, also enhancing the reliability of the switch devices. Simulation and experimental results with a 1.2kW system are presented to validate the proposed topology and control method.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.544-552
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• 2004

This paper deals with the hybrid active filter which can reduce the 11th/13th harmonics in AC network by using the single tuned filter. Since the proposed algorithm uses the detuning compensation capability of the filter, the output voltage of the proposed active power filter is changed according to the capacitance of capacitors, magnitude of harmonic current, resonance frequency and control mode. In this paper, the control characteristics and the design of hybrid active filter is investigated. A new hybrid active filter with new algorithm, which is an active filter with single tuned filter instead of double tuned filter, is proposed.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2644-2649
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• 2011

The purpose of this study is to propose the modular design of hybrid lightweight carbody structures made of sandwich composites and aluminum extrusion. The sandwich composites were used for secondary structures to minimize the weight of carbody, and the aluminum extrusions were applied to primary structures to improve the stiffness of carbody and manufacturability. Key requirements were defined for the modular design of hybrid carbody, and the applied parts of sandwich composites were determined through the topology optimization analysis. Consequently, feasibility of enhancing mass saving and maintainability in modular hybrid carbody design were presented, comparing with the carbody structures made of aluminum extrusion or sandwich composites only.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.5
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• pp.19-32
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• 1997

So far, the multiple path MINs to provide redundant paths in the traditional UPP MINs have been realized by adding additional hardware such as extra stages, duplicated data links, or multiple copies of sthe MIN. And the traditional MINs do not exploit locality: communication with all processor-memory paris takes the same amount of time. Also so far there has been little progress for exploiting locality of reference in MINs. In this paper, we present a new topology MIN, hybrid MIN that is constructed with 2N-3 SEs which is far fewer SEs than that of traditional MINs. Although the hybrid MIN is constructed with 2N-3 SEs, the hybrid MIN satisfies full access capability (FAC) and has redundant paths(but providing single path for 2 memory modules of each processor). Moreover the has redundant paths (but providing single path for 2 memory modules of each processor). Moreover the Hybrid MIN provides shortcut path between pairs which have frequent dat acommunication (locality of reference). Its performance under varing degrees of localized communication is analyzed.