• 디지털융복합연구
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• 제14권7호
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• pp.193-200
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• 2016

최근 들어 가정 내 태양광과 에너지저장시스템을 도입하여 에너지 자립도를 높이고자 하는 기술 개발이 활발히 이루어지고 있다. 낮에 생산된 전기를 에너지 저장 시스템에 충전해 두고 전기요금이 높을 때 사용함으로써 효율적인 에너지 관리를 수행할 수 있다. 국내에서는 아직까지 가정용 실시간 요금제가 이루어지고 있지 않지만 누진제 상의 일정 목표까지 전기 사용량을 낮출 수 있다. 가정 내 태양광을 도입하기 위해서는 전력 변환장치인 PCS를 필요로 한다. PCS는 직류로 생산된 전력을 교류로 변환하여 사용하고 에너지 저장 시스템의 충방전을 수행하도록 한다. 에너지 자립형 스마트 홈 시스템은 태양광, 에너지저장시스템에 대한 일반인들의 관심이 높아지면서 해외를 중심으로 시장이 형성되는 단계이다. 본 논문의 결과물은 실환경에 설치되어 검증을 수행하였으며 실시간 요금제를 가정하여 에너지 절감 효과를 분석하였다.

• 디지털융복합연구
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• 제17권3호
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• pp.161-168
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• 2019

전자펜의 소비자 활용도 및 제품 개선점 분석을 위해 Davies(1989)의 TAM 모형을 적용하여 전자펜 사용자들의 지각된 유용성, 이용용이성 및 기대가치를 통한 기술수용의도를 분석하였다. 연구방법으로 기업 설문내용에 기반 한 내용분석법과 고객들의 참여도인 Activity 분석을 통해 전자펜 제품의 기술수용정도와 제품 전략의 개선점을 도출하였다. 연구결과 전자펜의 활용도를 보인 고객들은 30~49세의 남성과 사무직과 연구원으로 나타났으며, 개선사항에 대한 키워드 중심의 내용분석법의 분석결과 전원동작의 개선, App 연계 펜 기능의 확장성, 전자펜의 수정기능, 펜의 데이터인식 기능, 전자펜이 펜으로서의 필기감, 그립감, 펜 굵기 선택 등 세분화 기능의 개선, 타 스마트 기기와의 동기화 개선과 충전기능의 개선 필요성이 추출되었다. 본 연구는 전자펜에 TAM을 적용하여 전자펜이 초기시장에서 주류시장으로 확산되기 위한 제품속성 개선점을 제시하였고 향후 스마트폰이나 아이패드 등 스마트 디바이스와 연계된 전자펜 제품 확산과의 차이점 규명 통해 차별화 된 시사점을 제공할 수 있을 것이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3506-3511
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• 2007

The energy harvesting using smart materials has been extensively investigated to supply electric power to wireless sensor systems. In this paper, the energy harvesting using eddy current was studied with the integrated magnetic cantilever beam system. If a large conductive metal plate moves through a magnetic field which intersects perpendicularly to the sheet, the magnetic field will induce small rings of current which will actually create internal magnetic fields opposing the change. This eddy current that was induced in the coiled conductive sheet from the mechanical vibration was converted to chemical energy by charging batteries. The experimental results show that the eddy current generated the electric power up to max 31.2mW. Additionally the vibration reduction of the mechanical cantilever beam was observed by the energy dissipation in the electro-magnetic coupled system. The present result shows that the vibration level of the first natural frequency was reduced up to 7.7dB

• International journal of advanced smart convergence
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• 제8권4호
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• pp.138-146
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• 2019

In this paper, we proposed a soft-switched synchronous buck converter, which can perform charging the battery. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss, resulting in small conduction loss, also. In this reason, the efficiency of the converter can be greatly improved even in high frequency. The size and weight of the converter can be reduced by high frequency operation of the converter. In this paper, we designed a battery charger with a switching frequency of 100 kHz. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery charger had soft switching characteristics. The simulation results for transient response to charge current for the designed converter show that the converter responds to charge current commands quickly within 0.05 ms.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.275-277
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• 2005

In a lithium-ion battery which is being used in many portable electronic goods, electrolyte is disaggregated and then the gas is happened when electric charging volt is over the 4.5V. So, the pressure on the safety valve is increased and electrolyte is leaked out in the cell. It leads to the risk of explosion. On the other hand, in the case which the battery is discharged excessively, the negative pole is damaged and the performance of the battery is deteriorated. The protection module of a lithium-ion battery is used for preventing such risk and the inspection system is needed to check the performance of such protection module. In this research, a PC-based auto inspection system is developed for the inspection of a battery protection module using Dallas chipset. In the inspection system, AVRl28 chip is used as a controller and the communication protocol is developed for the data communication between the protection module and the AVR128 chip. And GPIB interface is used for the control of measuring devices. Also, MMI environment is developed using LabView for convenient monitoring by the tester.

• IEIE Transactions on Smart Processing and Computing
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• 제2권4호
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• pp.248-254
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• 2013

The size and power consumption of digital circuits including the dimming circuit part will increase for high-performance solid state lighting (SSL) systems in the future. This study examined the low-power consumption of adiabatic dynamic CMOS logic (ADCL) due to the principles of adiabatic charging. Furthermore, the designed low-power ADCL digital pulse width modulation (PWM) was optimized for SSL dimming systems. For this purpose, an ADCL digital 3-bit PWM was optimized in two steps. In the first step, the architecture of the ADCL digital 3-bit PWM was miniaturized. In the second step, the clock cut-off circuit was designed and added to the ADCL PWM. As a result, compared to the original configuration, 60 transistors and 15 capacitors of ADCL digital 3-bit PWM were reduced for miniaturization. Moreover, the clock cut-off circuit, which controls wake-up and sleep mode of ADCL D-FFs, was designed. The power consumption of an optimized ADCL digital PWM for all bit patterns decreased by 54 %.

• JSTS:Journal of Semiconductor Technology and Science
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• 제10권1호
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• pp.1-10
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• 2010

This paper proposes a two-phase clocked adiabatic static CMOS logic (2PASCL) circuit that utilizes the principles of adiabatic switching and energy recovery. The low-power 2PASCL circuit uses two complementary split-level sinusoidal power supply clocks whose height is equal to $V_{dd}$. It can be directly derived from static CMOS circuits. By removing the diode from the charging path, higher output amplitude is achieved and the power consumption of the diode is eliminated. 2PASCL has switching activity that is lower than dynamic logic. We also design and simulate NOT, NAND, NOR, and XOR logic gates on the basis of the 2PASCL topology. From the simulation results, we find that 2PASCL 4-inverter chain logic can save up to 79% of dissipated energy as compared to that with a static CMOS logic at transition frequencies of 1 to 100 MHz. The results indicate that 2PASCL technology can be advantageously applied to low power digital devices operated at low frequencies, such as radio-frequency identifications (RFIDs), smart cards, and sensors.

• 전기학회논문지
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• 제62권1호
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• pp.63-69
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• 2013

In recent years, technology for storing a preliminary power or a surplus of photovoltaic energy is required. This technique, as well as store a preliminary energy and improve the reliability of the gird safety. This system can plan a efficient power generation through the flexibility of the power supply from the perspective of not only provider but also user. Accordingly, the realization of the smart grid can be expected. This paper proposes a hybrid PCS using a photovoltaic and a lithium-polymer battery with the characteristics of high density energy. The main energy source of a hybrid PCS is a photovoltaic, grid and the auxiliary energy source is a lithium-polymer battery. The operation of a proposed system in this paper is verified with simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1125-1131
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• 2014

Application of residential demand response (DR) programs are currently realized up to a limited extent due to customers' difficulty in manually responding to the time-differentiated prices. As a solution, this paper proposes an automatic home load management (HLM) framework to achieve the household minimum payment as well as meet the operational constraints to provide customer's comfort. The projected HLM method controls on/off statuses of responsive appliances and the charging/discharging periods of plug-in hybrid electric vehicle (PHEV) and battery storage at home. This paper also studies the impacts of different time-varying tariffs, i.e., time of use (TOU), real time pricing (RTP), and inclining block rate (IBR), on the home load management (HLM). The study is effectuated in a smart home with electrical appliances, a PHEV, and a storage system. The simulation results are presented to demonstrate the effectiveness of the proposed HLM program. Peak of household load demand along with the customer payment costs are reported as the consequence of applying different pricings models in HLM.

• 전기학회논문지
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• 제65권2호
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• pp.264-268
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• 2016

Recently, various energy efficiency optimization activities are ongoing globally by integrating conventional grids with ICT (Information and Communication Technology). In this sense, various smart grid projects, which power suppliers and consumers exchange useful informations bilaterally in real time, have been being carried out. The electric vehicle diffusion program is one of the projects and it has been spotlighted because it could resolve green gas problem, fuel economy and tightening environmental regulations. In this paper, the economics of V2G system which consists of electric vehicles and the charging infrastructure is evaluated comparing electric vehicles for V2G with common electric vehicles. Additional benefits of V2G are analyzed in the viewpoint of load leveling, frequency regulation and operation reserve. To find this benefit, electricity sales is modeled mathematically considering depth of discharge, maximum capacity reduction, etc. Benefit and cost analysis methods with the modeling are proposed to decide whether the introduction of V2G systems. Additionally, the methods will contribute to derive the future production and the unit cost of electric vehicle and battery and to get the technical and economic analysis.