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정은수,이학준,설승기 전력전자학회 2007 전력전자학회 논문지 Vol.12 No.4
본 논문에서는 FPGA(Field Programmable Gate Array) 기반의 전류 제어기를 설계하고 구현하였다. 기존의 DSP (Digital Signal Processor) 기반의 전류 제어기는 알고리즘 연산으로 인해 일반적으로 한 샘플링의 디지털 시지연 이 발생한다. 반면에, FPGA 기반의 전류제어기는 FPGA의 높은 연산 능력을 이용하여, 알고리즘 연산에 필요한 시지연을 감소시킬 수 있다. 이로 인해 시지연이 물리적으로 줄기 때문에, 어떠한 시지연 보상 알고리즘 없이 전류 제어기의 대역폭을 향상시킬 수 있다. 구현된 FPGA 기반 전류 제어기의 성능은 실험을 통해 검증되었다. This paper presents a design of an FPGA (Field Programmable Gate Array) -based currentcontroller. Using the nature of the high computational capability of FPGA, the digital delay due to the algorithm execution can be reduced. The control performance can be better than the conventional DSP (Digital Signal Processor)-based current controller. Moreover, this method does not need any delay compensationalgorithm because the digital delay is physically diminished. Therefore, the bandwidth of the current controller can be extended by this method. The feasibility of this method is verified by several experimental results under the various conditions.
샌드위치패널 화재 시 내장재(스티로폼, 그라스울)에 따른 위험도에 관한 고찰
정은수,정병운 한국화재감식학회 2022 한국화재감식학회 학회지 Vol.13 No.1
Recently, many large-scale fires have occurred due to problems such as performance tests of sandwich panel finishing materials and insulation materials.. In the case of a large fire, combustible materials are burnt out before the fire brigade's golden time (7 minutes) and the fire pattern and evidence are lost, making it difficult to identify the cause and point of ignition. In order to point out these problems, the risk of combustible insulating material (Expandable Polystyrene Foam) was revealed and non-combustible material (Glass wool), a study was conducted to recommend it.
정은수,정성구 한국화재감식학회 2020 한국화재감식학회 학회지 Vol.11 No.3
Determining the short circuit of molten rock found at the site when determining the cause of the fire is a very important clue to estimate an electrical fire or ignition point. Characteristics such as pores, metal structures, and boundary surfaces, which are the determining factors of short circuit wounds, are quantified with objective numerical data. As a result, the difference by the thickness of the boundary surface is analyzed as the most suitable criterion for determining whether the melt is shorted or not, and the cause of the difference is due to the difference in the occurrence time of the shorting wound due to the coating melt.
정은수 대한설비공학회 2005 설비공학 논문집 Vol.17 No.8
A theoretical investigation for optimization of conduction-cooled Peltier current leads is undertaken. A Peltier current lead(PCL) is composed of a thermoelectric element(TE), a metallic lead and a high TC superconductor(HTS) lead in the order of decreasing temperature. Mathematical expression for the minimum heat flow per unit current crossing the TE- metal interface and that flowing from the metal lead to the joint of the metal and the HTS leads are obtained. It is shown that the temperature at the TE-metal interface possesses a unique optimal value that minimizes the heat flow to the joint and that this optimal value depends on the material properties of the TE and the metallic lead but not the joint temperature nor electric current. It is also shown that there exists a unique optimal value for the joint temperature between the metal and the HTS leads that minimizes the sum of the power dissipated by ohmic heating in current leads and the refrigerator power consumed to cool the lead, for a given length of the HTS.
정은수 대한설비공학회 2000 설비저널 Vol.29 No.1
최신의 암모니아의 냉동시스템들은 효율이 더 높고 더 안전하게 제작될 수 있다. 또한, 현재의 표준인 고충전 펌프순환 시스템들을 펌프를 사용하지 않고 증발기에 냉매를 과공급하도록 설계된 저충전 시스템들로 대체함으로써 기존의 암모니아 시스템들을 성능과 안전성을 향상시킬 수 있다.
암모니아/물 흡수식 열펌프의 흡수기의 흡수과정에 대한 수치적 해석
鄭恩洙,許其俊 弘益大學校 科學技術硏究所 2000 科學技術硏究論文集 Vol.11 No.-
A numerical model which simulates the simultaneous heat and mass transfer within a vertical tube absorber of an ammonia/water absorption heat pump was developed. The flow of the liquid film was assumed to be laminar. The film thickness and the velocity distribution of the liquid film were obtained by matching the shear stress at the liquid-vapor interface. A modified Colburn-Drew analysis was used for the vapor phase to determine the heat and mass fluxes at the liquid-vapor interface. The model was used to investigate the effects of the vapor mass flow rate, the diameter and the length of the absorber, and the mass fractions of the vapor and the liquid at inlet on the absorption rates of water and ammonia. It was shown that both ammonia absorption rate and water desorption rate increase near the inlet of the absorber as the mass flow rate of the vapor increases. Absorption rate increases as the diameter of the absorber decreases since heat and mass transfer coefficients increase as the vapor flow rate increases. The effects of the ammonia mass fractions of liquid and vapor on absorption rate were negligible.
鄭恩洙 弘益大學校 科學技術硏究所 2002 科學技術硏究論文集 Vol.13 No.-
A quasi one-dimensional analytic model for the pulse tubes of pulse tube refrigerators was proposed. In this model the heat transfer rate between the wall and the gas is expressed in terms of the wall to mean-gas temperature difference and the time rate of change of pressure. The temperature distribution normal to the wall is expressed in terms of a pressure dependent boundary layer thickness. The model can be used as a one-dimensional model but has characteristics of two-dimensional model since it can take the temperature variation normal to the wall.