• 반도체디스플레이기술학회지
• /
• 제19권3호
• /
• pp.118-123
• /
• 2020

In this paper, the design method of asynchronous nonvolatile memory module that can efficiently process and store large amounts of data without loss when the power turned off is proposed and implemented. PSRAM, which takes advantage of DRAM and SRAM, was used for data processing, and NAND flash memory was used for data storage and backup. The problem of a lot of signal interference due to the characteristics of memory devices was solved through PCB design using high-density integration technology. In addition, a boost circuit using the super capacitor of 0.47F was designed to supply sufficient power to the system during the time to back up data when the power is off. As a result, an asynchronous nonvolatile memory module was designed and implemented that guarantees reliability and stability and can semi-permanently store data for about 10 years. The proposed method solved the problem of frequent data loss in industrial sites and presented the possibility of commercialization by providing convenience to users and managers.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2004년도 춘계학술대회
• /
• pp.247-257
• /
• 2004

Electrodes were fabricated based on activated carbon powder BP-20, conducting agent such as Super P, vapor grown carbon fiber (VGCF) and acetylene black (AB), and the mixed binders of flexible poly(vinylidenefluoridehexafluoropropylene) [P(VdF-co-HFP)] and cross linking dispersion agent of polyvinylpyrrolidone (PVP) to increase mechanical strength. According to impedance measurement of the electrode with the addition of conducting agent, we found that it was possible to charge rapidly by the fast steady-state current convergence due to low equivalent series resistance (AC-ESR, fast charge transfer rate at interface between electrode and electrolyte and low RC time constant. The self-discharge of unit cell showed that diffusion process was controlled by the ion concentration difference of initial electrolyte due to the characteristics of Electric Double Layer Capacitor (EDLC) charged by ion adsorption in the beginning, but this by current leakage through the double-layer at the electrode/electrolyte interface had a minor effect and voltages of curves were remained constant regardless of electrode material. We found that the 2.3V/230F grade EDLC would be applied to industrial safety usage such as uninterrupted power supply (UPS) because of the constant DC-ESR by IR drop regardless of discharge current.

• Journal of Electrochemical Science and Technology
• /
• 제10권2호
• /
• pp.159-169
• /
• 2019

The activated carbon materials were prepared from waste biomass by ultrasonic assisted chemical activation method (UCA), ultrasonic assisted physical activation method (UPA) and Manganese nitrogen doped carbon (Mn/N-C). The XRD result shows the turbostatic (fully disordered) structure. The cyclic voltammetry test was done at 50 mV/s using 1M sodium sulfate and the values of specific capacitance were found to be 93, 100 and 115 F/g for UCA, UPA and Mn/N-C respectively. The power density values for the samples UCA, UPA and Mn/N-C were found to be 46.04, 87.97 and 131.42 W/kg respectively. The electrochemical impedance spectroscopy was done at low frequency between 1 to 10 kHz. The Nyquist plot gives the resistant characteristics of the materials due to diffusional resistance at the electrode-electrolyte interface. The Energy Dispersive X-Ray Spectroscopyanalysis (EDAX) analysis showed that the percentage doping of nitrogen and manganese were 3.53 wt% and 9.44 wt% respectively. It is observed from the experiment Mn/N-C doped carbon show good physical and electrochemical properties.

• 전기화학회지
• /
• 제5권1호
• /
• pp.21-26
• /
• 2002

비정질 루테늄 산화물을 사용한 수퍼캐패시터를 개발하였다. 삼염화루테늄 수화물$(RuCl_3{\cdot}xH_2O)$로부터 제조한 비정질의 이산화루테늄 수화물$(RuO_2{\cdot}nH_2O)$을 사용하여 수퍼캐패시터 전극을 제조하였다. 집전체로는 티타늄 및 STS 304박막에 비해 보다 넓은 전위창을 가지는 탄탈륨 박막을 사용하였다. 제조한 전극과 4.8M 황산 전해액을 사용하여 수퍼캐패시터를 제조하였다. 전극의 비정전용량은 순환전위전류분석에서 미분 최대 값으로 산화 및 환원 과정 각각 710 및 $645\;F/g-RuO_2{\cdot}nH_2O$이었으며, 평균값은 $521\;F/g-RuO_2{\cdot}nH_2O$으로 나타났다. 수퍼캐패시터를 포화카로멜기준전극에 대하여 0.5 V로 protonation level을 조정하고, 충방전 시험한 바, $151\;F/g-RuO_2{\cdot}nH_2O$의 비정전용량을 나타내었다.

• 마이크로전자및패키징학회지
• /
• 제23권2호
• /
• pp.1-10
• /
• 2016

This paper reports the trends of researches and technologies of electronic packaging using graphene. Electronic packaging is to provide the signal and electrical current among electronic components, to remove the heat in electronic systems or components, to protect and support the electronic components from external environment. As the required functions and performances of electronic systems or components increase, the electronic packaging has been intensively attracted attention. Therefore, technologies such as miniaturization, high density, Pb-free material, high reliability, heat dissipation and so on, are required in electronic packaging. Recently, graphene, which is a single two-dimensional layer of carbon atoms, has been extensively investigated because of its superior mechanical, electrical and thermal properties. Until now, many studies have been reported the applications using graphene such as flexible display, electrode, super capacitor, composite materials and so on. In this paper, we will introduce and discuss various studies on recent technologies of electronic packaging using graphene for solving the required issues.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.490-500
• /
• 2017

Fuel cell (FC) is a promising power supply in electric vehicles (EV); however, it has poor dynamic performance and short service life. To address these shortcomings, a super capacitor (SC) is adopted as an auxiliary power supply. In this study, the frequency decoupling control method is used in electric vehicle energy system. High-frequency and low-frequency demand power is provided by SC and FC, respectively, which makes full use of two power supplies. Simultaneously, the energy system still has rapidity and reliability. The distributed power system (DPS) of EV requires DC-DC converters to achieve the desired voltage. The stability of cascaded converters must be assessed. Impedance-based methods are effective in the stability analysis of DPS. In this study, closed-loop impedances of interleaved half-bridge DC-DC converter and phase-shifted full-bridge DC-DC converter based on the frequency decoupling control method are derived. The closed-loop impedance of an inverter for permanent magnet synchronous motor based on space vector modulation control method is also derived. An improved Middlebrook criterion is used to assess and adjust the stability of the energy system. A theoretical analysis and simulation test are provided to demonstrate the feasibility of the energy management system and the control method.

• 공업화학
• /
• 제27권4호
• /
• pp.449-454
• /
• 2016

본 연구에서는 구형의 폴리스티렌 구슬을 틀로 사용하여, 크기분포가 좁으면서 속은 비어있고 벽이 다공성인 구조의 탄소 마이크로 캡슐을 합성하였다. 폴리스티렌의 표면은 무기물인 실리카졸이 쉽게 입혀질 수 있도록 폴리비닐피롤리돈(PVP)을 코팅하여 변조하였다. PVP가 코팅된 PS 마이크로 입자표면에 SBA-16 졸을 부착시킨 다음, 실리카층에 존재하는 중간 크기의 세공 내에 탄소원을 채워 넣는 음각식 형뜨기법을 적용함으로써 속이 빈 구조의 탄소 마이크로캡슐을 제조하였다. 탄화과정을 거치고 틀로 사용한 다공성 실리카입자를 HF로 용해하면, 좁은 입자크기분포를 갖는 중간세공이 함유된 계란껍질형의 탄소입자를 얻을 수 있었다. 계란껍질형 탄소 마이크로캡슐 입자의 다공성과 전기화학적 특성은 XRD, SEM, TEM, 질소분자 흡/탈착분석법 및 cyclic voltammetry법으로 평가하였다. 이들 탄소입자는 슈퍼캐패시터와 같은 전자재료로서 유효하게 사용될 만한 높은 전기전도도와 용량을 나타내었다.

• 전력전자학회논문지
• /
• 제18권1호
• /
• pp.45-53
• /
• 2013

Fuel cell power system is one of the most promising energy source for the alternative energy because it has unique advantages such as high energy density, no power drop during operation, and feasible to make compact size. However, due to very low response time, fuel cell is difficult to correspond to drastic load changes and start-up operation. For solving these problem, fuel cell power system must include energy storage device such as Li-Poly battery or super capacitor. Therefore, bi-directional DC-DC converter must be required for this storage device and fuel cell-PCS control. This paper presents a design and modeling of the bi-directional DC/DC converter. Firstly, we present modeling the boost and buck mode of the bi-directional converter through both PWM switch model and state space averaging technique. Secondly, in order to minimize output ripple and transient response overshoot, we have two identical DC-DC converters interleaved and adopt two-loop voltage-current controller. The proposed bi-directional DC-DC converter's modeling method and control design have been verified with computer simulation and experimentation.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 1996년도 춘계학술발표회 초록집
• /
• pp.161-161
• /
• 1996

본 연구에서는 차량(승용차) 시동용 수퍼캐패시터-밧데리 조합시스템에 적용할 시작품 전기이중층 수퍼캐패시터(super-capacitor:SC)를 설계 제작 개발하고 그 성능 특성을 확인하였다. 재래식의 차량용 밧데리의 비동력(specific power)이 100~200 W/kg에 비하여 전기이중층 SC의 경우는 1,000~3,000 W/kg으로 단위 총량당의 동력이 매우 크다. 또한 충방전시의 화학반응이 없는 관계로 인하여 충전식 2차 전지에 비하여 사용수명이 매우 길다. 이러한 SC를 기존의 밧데리와 함께 조합하여 차량 시동용으로 사용하게 되면 밧데리의 사용수명을 2~3배 길게 할 수 있으며 밧데리는 시동에 필요한 큰 전류의 방전이 요구되지 않으므로 그 용량과 크기가 대체로 절반이상 줄어든다. 또한 매우 낮은 온도의 기후조건에서는 밧데리의 방전효율이 급격히 저하되므로 이를 대비하여 필요 이상의 과용량, 과중량 밧데리의 사용이 실제로 행해지고 있으나 조합시스템의 차량 시동시에는 SC가 갖는 특성상 -5$0^{\circ}C$까지의 기후조건에서도 방전효율이 크게 저하되지 않은 채 시동전류를 공급해주므로 혹한지역이나 혹한시의 차량시동에도 탁월한 시동성능을 갖는다. 설계 제작된 SC는 저장에너지 6KJ, 정격전압 12Volt, 설계축전용량 70F 그리고 사용은 도 범위가 섭씨 영하 25도에서 영상 50도이며 무공해성 수용성 전해질을 사용하였으며, 제작된 CS는 사용온도 범위에서 축전용량 65F - 85F, 내부저항 1.8mOhm - 5.2mOhm의 변화를 보였으며, 정상시동에 필요한 방전전류 300Amp의 경우 2.6초의 방전시간, 약 89%의 방전효율을 보였다. 현재까지 상온하에서 30.000회의 충방전 시험결과로서는 방전효율의 저하가 없는 양호한 성능을 보였으며, SC의 시범 작동시험을 실차(소나타 1800cc)에 장착하여 수행한 결과 20회 이상의 연속시동에서도 아무런 문제점 없이 잘 동작하였다.

• 한국태양에너지학회 논문집
• /
• 제29권2호
• /
• pp.1-7
• /
• 2009

Use of the PV(photovoltaic) generation system is increased in such areas as remote mountain places or islands at which electrical energy is not serviced. The stand alone PV system is required the power storage products such as battery, fly wheel and super capacitor. Several lead storage batteries are connected in series to get high voltages. The life of lead storage battery is shortened when over charge or over discharge takes place. So, it is needed to control batteries not to be overcharged or be discharged deeply. Voltage of each battery was ignored in former control methods in which overall voltage was used to control charge or discharge battery. In this study, the charging and discharging voltage variations of sealed lead storage batteries with l2V/l.2A were investigated step by step experiments. The results of the test show that one should consider and specify the state of each battery to prevent overcharge or deep discharge. With the basis of the experiments, we designed a monitoring unit to monitor battery voltages simultaneously using micro-controller. The unit measures voltage of 20 batteries simultaneously and displays data on the color LCD monitor with curved line graph. It also sends data to PC using the RS232C communication port. The designed unit was adapted to stand alone PV system with 1kW capacity and lead storage batteries are connected to the PV generation system. The number of lead storage batteries was 10 in series and 12V/250Ah each. Resistive load with 3kW was used for discharging.