• Journal of Power Electronics
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• 제18권2호
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• pp.558-572
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• 2018

In addition to its modular nature, a Hybrid Modular Multilevel Converter (HMMC) assembled from half-bridge and full-bridge sub-modules, is able to block DC faults with a minimum number of switching devices, which makes it attractive for high power applications. This paper introduces a control strategy based on the Root-Least Square (RLS) algorithm to estimate the capacitor voltages instead of using direct measurements. This action eliminates the need for voltage transducers in the HMMC sub-modules and the associated communication link with the central controller. In addition to capacitor voltage balancing and suppression of circulating currents, a fault tolerant control unit (FTCU) is integrated into the proposed strategy to modify the parameters of the HMMC controller. On advantage of the proposed FTCU is that it does not need extra components. Furthermore, a fault detection unit is adapted by utilizing a hybrid estimation scheme to detect sub-module faults. The behavior of the suggested technique is assessed using PSCAD offline simulations. In addition, it is validated using a real-time digital simulator connected to a real time controller under various normal and fault conditions. The proposed strategy shows robust performance in terms of accuracy and time response since it succeeds in stabilizing the HMMC under faults.

• 한국융합학회논문지
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• 제9권3호
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• pp.31-37
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• 2018

에너지저장시스템(Energy Storage System)은 생산된 전력을 필요한 시기에 선택적으로 저장하고 사용함으로써 에너지 효율을 극대화 시키는 시스템이다. 따라서 언제든지 에너지를 충전하거나 공급할 수 있는 상태를 유지하여야 하며, 고장이나 유지보수 시에도 비운영 시간을 최소화하여야 한다. 하지만 현재 대용량 에너지저장시스템은 구조적 문제로 유지보수 시 반드시 운영을 정지하여야 한다. 본 논문에서는 대용량 에너지저장시스템용 모듈라(Modular)를 병렬 구성하여 1MW급 에너지저장시스템용 PCS를 제작하고, 시스템에서 동작 상태를 유지하면서 시스템을 구성하는 요소들의 교체, 변경, 수리가 가능한 핫스왑(Hot Swap) 기술을 실험을 통해 검증하였다.

• 전기학회논문지
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• 제57권10호
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• pp.1883-1887
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• 2008

Most of digital media contents are composed with video and audio, picture and animation informations. Sometime, there is some deviation of information recognition quality for the video and audio information according to information receiver's characteristics or the understanding. But visual information using the text provide most clear and accurate ways for information recognition to human being. In this paper, we propose a new broadcasting system(BSDMC) to transmit clear and accurate meaning of the digital media contents. We implement general-purpose components to display the video, picture, text and symbol simultaneously. Only plug-in and call these components with proper parameters on the application developing tool, we can easily develop the multimedia contents broadcasting system. These components are implemented based on the object-oriented framework and modular structure so that increase the reusability and can be develop other applications quick and reliable.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.435-440
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• 2005

This study describes a new method of constructing Reconfigurable machine tools configurations from a set of modules or components. This proposed method defines combinability vector for each module and mutual combinability coefficient matrix for adjacent two modules. All of machine configurations possible to be generated from any two adjacent modules can be determined by quadratic form of two associated combinability vectors. Furthermore, all of possible RMT configurations generating from a series of multiple modules also can be obtained by multiplying quadratic form of two adjacent conbinability vectors recursively. Our proposed RMT configuration generating method can be successfully applied to determining all of possible machine configurations from several modules or components at conceptual- or preliminary- design stage.

• 전자공학회지
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• 제42권7호
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• pp.45-53
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• 2015

Power 소자 기술은 digital & mixed signal device와 on-chip 구현을 위해서 CMOS 공정에 대한 기본 이해가 필요하다. CMOS 공정 기반 위에 power device 공정을 추가하면서 다양한 operation voltage의 power 소자를 구현하고, passive device 들을 동일 공정에서 구현하여 다양한 components 들로 power IC 제품을 design 할 수 있도록 modular process를 제공하는 것이 중요하다. 또한 power device로 주로 사용되는 LDMOS 소자에 대한 performance 개선을 위해 simulation을 통해 key device parameter들의 특성을 예측하고, 구조를 설계하는 것이 Si process 전에 중요한 일 중의 하나이다. 아울러 power management가 potable power, consumer electronics 및 green energy에서 가장 빠르게 성장하는 분야이므로, 차별화된 power 소자 기술을 확보하여 급변하는 시장 환경에 대응하는 것이 필요하다.

• Journal of Electrical Engineering and information Science
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• 제3권3호
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• pp.336-341
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• 1998

We describe the architecture of an optical cross-connect (OXC) which is modular in structure and is able to be upgraded to a virtual wavelength path by adding wavelength converters. The additional feature of the OXC is the all-optical nature. It can be implemented with commercial components including mechanical optical switches. As a result of the test on the experimental OXC, it has been shown that 2.5 Gb/s signal can be transmitted via the OXC through 100 km length o an ordinary single mode fiber with 3 dB penalty.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2002년도 추계학술발표대회
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• pp.339-344
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• 2002

The Purpose of this study Is to investigate Open Housing design methods on multi-family housing in the Netherlands and Finland. This study is based on the several actual field survey through visiting eight sites in the netherlands and Finland. we found a lot of design items applied to the Holland and Finnish multi-family housing for Open Housing. Open Housing design items are user participation design, layout flexibility, finishes selection, flexible utilities, interior components and use of modular grid.

• BioChip Journal
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• 제12권4호
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• pp.280-286
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• 2018

Hydrogel scaffolds composed of multiple components are promising platform in tissue engineering as a transplantation materials or artificial organs. Here, we present a new fabrication method for implementing multi-layered macroscopic hydrogel scaffold composed of multiple components by controlling height of hydrogel layer through precise control of ultraviolet (UV) energy density. Through the repetition of the photolithography process with energy control, we can form several layers of hydrogel with different height. We characterized UV energy-dependent profiles with single-layered PEGDA posts photocrosslinked by the modular methodology and examined the optical effect on the fabrication of multi-layered, macroscopic hydrogel structure. Finally, we successfully demonstrated the potential applicability of our approach by fabricating various macroscopic hydrogel constructs composed of multiple hydrogel layers.

• 방사성폐기물학회지
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• 제18권4호
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• pp.481-496
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• 2020

After nuclear power plants are permanently shut down and decommissioned, the remaining irradiated metal components such as stainless steel, carbon steel, and Inconel can be used as neutron absorber. This study investigates the possibility of reusing these metal components as neutron absorber materials, that is burnable poison. The absorption cross section of the irradiated metals did not lose their chemical properties and performance even if they were irradiated over 40-50 years in the NPPs. To examine the absorption capability of the waste metals, the lattice calculations of WH 17×17 fuel assembly were analyzed. From the results, Inconel-718 significantly hold-down fuel assembly excess reactivity compared to stainless steel 304 and carbon steel because Inconel-718 contains a small amount of boron nuclide. From the results, a 20wt% impurity of boron in irradiated Inconel-718 enhances the excess reactivity suppression. The application of irradiated Inconel-718 as a burnable absorber for SMR core was investigated. The irradiated Inconel-718 impurity with 20wt% of boron content can maintain and suppress the whole core reactivity. We emphasize that the irradiated metal components can be used as burnable absorber materials to control the reactivity of commercial reactor power and small modular reactors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.748-751
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• 1997

The White Beamline of the Pohang Accelerator Laboratory(PAL) consists of main and second slits, a microprobe system, two ion chambers, a video-microscope, and a Si(Li) detector. These machine components must be controlled remotely through computer system to make user experiments precise and speedy. A real-time computer control system was developed to control and monitor these machine components. A VNIEbus computer with OS-9 real-time operating system was used for low-level data acquisition and control. VME I/O modules were used for step motor control and scaler control. The software has modular structure for maximum performance and easy maintenance. We developed database, I/O driver, and control software. We used PC/Window95 for data logging and operator interface. Visual C++ was used graphical user interface programming. RS232C was used for communication between VME and PC.