• International Journal of Precision Engineering and Manufacturing
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• 제9권2호
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• pp.23-27
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• 2008

As a biofuel source, direct photosynthetic/metabolic biofuel cells (DPBFC) use cyanobacteria whose photosynthesis and metabolization reactions can convert light energy to electricity, In our previous work, we fabricated a prototype micro-DPBFC that could generate a peak current density of $36{\mu}A/cm^{2}$ and a maximum power density of $270nW/cm^{2}$. In this study, we improve on the previous results by using carbon micro electromechanical systems (C-MEMS), formed from the pyrolysis of patterned photoresist, to fabricate carbon electrodes of an arbitrary shape and controlled porosity to increase the surface area. With these new C-MEMS electrodes, the maximum power density of the micro-DPBFC was $516nW/cm^{2}$, a performance twice as good as the results of our previous work.

• Journal of Power Electronics
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• 제8권2호
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• pp.156-162
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• 2008

This paper proposes a low-cost power converter for micro wind turbine systems using permanent magnet synchronous generators (PMSG). The proposed converter consists of a two-leg three-phase PWM inverter for the generator control and a single-phase half-bridge PWM converter which is connected to the utility grid. For the two separate DC-link voltages, a balancing control is added and the adverse effect of the DC-link voltage ripples on the inverter output voltage is compensated. The control performance of the proposed converter topology for the micro wind turbine system is shown by the simulation results using PSIM software.

• 전기전자학회논문지
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• 제18권1호
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• pp.159-164
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• 2014

본 논문에서는 하나의 태양광 모듈에 대한 전력 변환기인 마이크로 컨버터의 개발을 목표로 하고 있다. 중앙집중형 태양광발전시스템이 부분적인 음영에 의해서 성능저하가 발생하는데 반해 단일 태양광모듈의 전력변환기는 태양광모듈의 발전량을 최대화 할 수 있다. 전력 변환기는 지속적으로 각 모듈의 최대 전력 점을 추적하여 태양 광 발전 시스템의 에너지 출력을 증가시킨다. 태양광 전력 변환기의 반도체 스위치 및 외부 장치의 수를 최소화하고, 또한 동기 정류기를 사용하여, 320W급의 태양광 마이크로 컨버터를 개발하였으며, 시뮬레이션과 실험에 적용하여 효율성을 검증하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.611-616
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• 2004

In this study, microfabrication of a micro-arcjet nozzle with Fifth-harmonic generation Nd：YAG pulses (wavelength 213 nm) and its thrust performance tests were conducted. A micro-arcjet nozzle was machined in a 1.2 mm thick quartz plate. Sizes of the nozzle were 0.44 mm in width of the nozzle exit and constrictor diameter of 0.1 mm. For an anode, a thin film of Au (~100 nm thick) was deposited by DC discharge PVD in vacuum on divergent part of the nozzle. As for a cathode, an Au film was also coated on inner wall surface. In operational tests, a stable discharge was observed for mass flow of 1.0mg/sec, discharge current of 6 ㎃, discharge voltage of 600 V, or 3.6 W input power (specific power of 3.6 MW/kg). In this case, plenum pressure of the discharge chamber was 80 ㎪. With 3.6 W input power, thrust obtained was 1.4 mN giving specific impulse of 138 sec with thrust efficiency of 24 %.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1112-1118
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• 2014

In island and backcountry areas, electrical power is usually supplied by diesel generators. It is difficult for small scale diesel generators to have an economy of scale owing to the usage of fossil fuels to produce electricity. Also, there is a problem of carbon dioxide emissions that brings some environmental pollution to the entire region of the area. For solving those, this paper proposes a design method of autonomous micro-grid to minimize the fossil fuels of diesel generator, which is composed of diesel generator, wind turbine, battery energy storage system and photovoltaic generation system. The proposed method was verified through computer simulation and micro-grid operation system.

• 세라미스트
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• 제7권3호
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• pp.38-47
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• 2004

최근 micro structure, micro sensor, micro actuator 및 microelectronics 등을 활용하는 microelectromecha-nical systems (MEMS) 기술은 마이크로 로봇, micro manipulation, 광학 소자 및 시스템, 유체, 열, 바이오 및 화학공정 등을 위한 시스템 그리고 atomic force와 scanning tunneling microscope 등에 사용되는 다양한 소자 등 많은 잠재력을 가지고 있다. 이들 응용 분야 들은 micro actuator와 같은 mechanical power source가 요구되는 경우가 있다. 압전 특성을 포함하는 강유전체 재료는 이러한 micro actuator를 위해 여러 가지 다양한 장점을 지니고 있는데, 이들을 정리하면 다음과 같다. (중략)

• Journal of Power Electronics
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• 제15권6호
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• pp.1601-1608
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• 2015

This paper presents a PQ control strategy for micro grid inverters with axial voltage regulators. The inverter works in the voltage-controlled mode and can help improve the terminal power quality. The inverter has two axial voltage regulators. The 1st regulator involves the output voltage amplitude and output impedance, while the 2nd regulator controls the output frequency. The inverter system is equivalent to a controllable voltage source with a controllable inner output impedance. The basic PQ control for micro grid inverters is easy to accomplish. The output active and reactive powers can be decoupled well by controlling the two axial voltages. The 1st axial voltage regulator controls the reactive power, while the 2nd regulator controls the active power. The paper analyses the axial voltage regulation mechanism, and evaluates the PQ decoupling effect mathematically. The effectiveness of the proposed control strategy is validated by simulation and experimental results.

• 한국군사과학기술학회지
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• 제14권6호
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• pp.1192-1197
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• 2011

Recent developments of small-size unmanned or manned mobile systems such as autonomous robots, exoskeleton or armored suits, micro air vehicles, and unmanned armored vehicles require long-lasting independent power sources of high energy and power density to support the systems' operation for up to 72 hours in the fields. Chemical batteries such as Ni-MH, Li-Ion, the current primary power sources for mobile devices, however, are not capable of providing enough power and energy density for the next generation high power mobile machines. For this reason, KIMM along with KERI and KIMS has been carrying out a 500W MTG development project under the DAPA's "Next generation military power source R&D program" since 2009. In this paper, a design process for a 500W MTG system currently being developed at KIMM is briefly described and the technical issues related to its development are addressed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.56-59
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• 1996

In this paper, we developed a micro-stepping drive circuit of step motor and proposed software algorithm for parallel operation of step motors drived by micro-stepping circuit. Also, we implemented a parallel operation controller with a 16-bit micro-controller.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.318-321
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• 1997

This paper is about improving characteristic of plant by using micro-step driver method in 5 phase step motor for satisfying the condition of low oscillation and high accuracy in soldering machine. We choose open loop control method for minimizing hardware system and use one chip microprocessor, power MOSFET nd some device to realize accurate micro-step driver system.