• 조명전기설비학회논문지
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• 제29권1호
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• pp.70-79
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• 2015

In this paper, enhanced stand-alone operation and development of Matlab/Simulink model of emergency diesel based hybrid energy system is presented. Simulations based on the remote community or islands were performed for PV-diesel-battery hybrid system. Modeling of PV-diesel-battery integrated system is done to perform under the solar radiation and load conditions on Matlab/Simulink platform. The models of diesel generator unit, battery energy storage system, PV and frequency-power control are developed and simulation studies have been carried out under various conditions using Matlab/Simulink and SimPowerSystem. It is demonstrated that the proposed system can provide reliable and good quality power to the customers in diesel synchronous generator-based hybrid energy systems.

• 조명전기설비학회논문지
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• 제27권11호
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• pp.57-68
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• 2013

The market for distributed power generation based on renewable energy is increasing, particularly for standalone mini-grid applications in developing countries with limited energy resources. Stand-alone power systems (SAPS) are of special interest combined with renewable energy design in areas not connected to the electric grid. Traditionally, such systems have been powered by diesel engine generator sets (DEGS), but also hybrid systems with photovoltaic and/or wind energy conversion systems (WECS) are becoming quite common nowadays. Hybrid energy systems can now be used to generate energy consumed in remote areas and stand-alone microgrids. This paper describes the design, simulation and feasibility study of a hybrid energy system for a stand-alone power system. A simulated model is developed to investigate the design and performance of stand-alone hydrogen renewable energy systems. The analysis presented here is based on transient system simulation program (TRNSYS) with realistic ventilation load of a large store. Design of a hybrid energy system is site specific and depends on the resources available and the load demand.

• Journal of Power Electronics
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• 제15권3호
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• pp.849-859
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• 2015

This paper proposes a novel compound-type hybrid energy storage system (HESS) that inherits the unique advantages of both battery/supercapacitor (SC) and the SC/battery HESSs for electric vehicles (EVs). Eight operation modes are designed to match this system. A mode control strategy is developed for this HESS on the basis of these modes, and five classes of operation modes are established to simplify this strategy. The mode control strategy focuses on high operating efficiency and high power output. Furthermore, the compound-type HESS is designed such that the SC is the main priority in braking energy absorption. Thus, this HESS can operate efficiently and extend battery life. Simulation results also show that the compound-type HESS can not only supply adequate power to the motor inverter but can also determine suitable operation modes in corresponding conditions. Experimental results demonstrate that this HESS can extend battery life as well. The overall efficiency of the compound-type HESS is higher than those of the battery/SC and the SC/battery HESSs.

• 전기학회논문지
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• 제61권12호
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• pp.1848-1856
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• 2012

This paper proposes a new grid-tied power conditioning system for battery energy storage, which is composed of a 2-stage DC-DC converter and a PWM inverter. The 2-stage DC-DC converter is composed of an LLC resonant converter connected in cascade with a 2-quadrant hybrid-switching chopper. The LLC resonant converter operates in constant duty ratio, while the 2-quadrant hybrid-switching chopper operates in variable duty ratio for voltage regulation. The operation of proposed system was verified through theoretical analysis and computer simulations. Based on computer simulations, a hardware prototype was built and tested to confirm the technical feasibility of proposed system. The proposed system could have relatively higher efficiency and smaller size than the existing system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.157-159
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• 2007

The conventional hard disk has been the dominant database storage system for over 25 years. Recently, hybrid systems which incorporate the advantages of flash memory into the conventional hard disks are considered to be the next dominant storage systems to support databases for desktops and server computers. Their features are satisfying the requirements like enhanced data I/O, energy consumption and reduced boot time, and they are sufficient to hybrid storage systems as major database storages. However, we need to improve traditional index node management schemes based on B-Tree due to the relatively slow characteristics of hard disk operations, as compared to flash memory. In order to achieve this goal, we propose a new index node management scheme called FNC-Tree. FNC-Tree-based index node management enhanced search and update performance by caching data objects in unused free area of flash leaf nodes to reduce slow hard disk I/Os in index access processes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집
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• pp.33-37
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• 2004

Photovoltaic energy and wind energy are highly dependent on the season, time and extremely intermittent energy sources. Because of these reasons, in view of the reliability the photovoltaic and the wind power generation system have many problems(energy conversion, energy storage, load control etc.) comparing with conventional power plant. In order to solve these existing problems, hybrid generation system composed of photovoltaic(500W) and wind power system(400W) was suggested But, hybrid generation system cannot always generate stable output due to the varying weather condition So, the auxiliary power compensation unit that uses elastic energy of spiral spring was added to hybrid generation system for the present study. It was partly confirmed that hybrid generation system was generated a stable outputs by spiral spring was continuously provided to load.

• 한국태양에너지학회 논문집
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• 제24권3호
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• pp.47-54
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• 2004

Photovoltaic energy and wind energy are highly dependent on the season, time and extremely intermittent energy sources. Because of these reasons, in view of the reliability the photovoltaic and the wind power generation system have many problems(energy conversion, energy storage, load control etc.) comparing with conventional power plant. In order to solve these existing problems, hybrid generation system composed of photovoltaic(500W) and wind power system(400W) was suggested. But, hybrid generation system cannot always generate stable output due to the varying weather condition. So, the auxiliary power compensation unit that uses elastic energy of spiral spring was added to hybrid generation system for the present study. It was partly confirmed that hybrid generation system was generated a stable outputs by spiral spring was continuously provided to load.

• 한국태양에너지학회 논문집
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• 제32권6호
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• pp.53-59
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• 2012

This study was carried out to evaluate thermal performance of the renewable hybrid heat supply system with solar thermal system and wood pellet boiler for Zero Carbon Green home of apartment houses. The hybrid heat supply system was set up at Korea Institute Energy Research in 2011. The system was comprised of the wood pellet boiler unit with heat capacity designed as 20,000kcal/hr, a $0.15m^3$ hot water storage tank for space heating, a evacuated tubular solar collector $3.74m^2$ of aperture area at the $20^{\circ}$ install angle, a $0.3m^3$ hot water storage tank. Thermal performance tests for one-house of apartment house were carried out by hot water load and heating load in winter season through the hybrid heat supply system. As a result, hot water energy supplied by the hybrid heat supply system was 11kWh in a day. Solar thermal energy portion was 2.99kWh which is 27% of the total hot water energy supply. wood pellet boiler supply portion was 8.017kWh which is 73% of the total hot water energy supply.

• 조명전기설비학회논문지
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• 제28권12호
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• pp.18-29
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• 2014

This paper proposes the integration of photovoltaic (PV) and energy storage systems for sustained power generation. In this proposed system, whenever the PV system cannot completely meet load demands, the super capacitor provides power to meet the remaining load. A power management strategy is designed for the proposed system to manage power flows between PV array systems and supercapacitors (SC). The main task of this study was to design PV systems with storage strategies including MPPT with direct control and an advanced DC-link controller and to analyze dynamic model proposed for a PV-SC hybrid power generation system. In this paper, the simulation models for the hybrid energy system are developed using Matlab/Simulink, SimPowerSystems and Matlab/Stateflow tool. This is the key innovative contribution of the research paper. The system performances are verified by carrying out simulation studies using practical load demand profile and real weather data.

• 한국태양에너지학회 논문집
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• 제33권4호
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• pp.23-30
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• 2013

This paper presents the determination method of the hybrid energy storage capacity for compensating the output of wind power when disconnecting from the grid. In the wind power output compensation, a lot of charging and discharging time with lithium-ion battery will be deteriorated the life time. And also, this fluctuation will cause some problems of the power quality and power system stability. To solve these kind of problems, many researchers in the world have been studied with BESS(Battery Energy Storage System) in the wind farm. But, BESS has the limitation of its output during very short term period, this means that it is difficult to compensate the very short term output of wind farm. Using the EDLC (Electric Double Layer Capacitor), it is possible to solve the problem. Installing the battery system in the wind farm, it will be possible to decrease the total capacity of BESS consisting of HESS (Hybrid Energy Storage System). This paper shows simulation results when not only BESS is connected to wind farm but also to HESS. To verify the proposed system, results of computer simulation using PSCAD/EMTDC program with actual output data of wind farms of Jeju Island will be presented.