• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1997.10a
• /
• pp.88-92
• /
• 1997

Power conversion system must be increased swiching frequency in order to achieve a small size, a light weight and a low noise, However, the swiches of converter are subjected to high switching power losses and switching stresses. As a result of those, the power system brings on a low efficiency. In this paper, the authors propose a DC-DC boost converter of high power by partial resonant switch method (PRSM). The switching devices in a proposed circuit are operated with soft swiching and the control technique of those is simplified for switch to drive in constant duty cycle. The partial resonant circuit makes use of a inductor suing step up and a condenser of loss-less snubber. Also the circuit has a merit which is taken to increase of efficiency, as if makes to a regeneration at input source of accumulated energy in snubber condenser without loss of snubber in conventional cirvuit. The result is the the switching loss is very low and the efficiency of system is high. The proposed converter is deemed the most suitable for high power applications where the power switching devices are used.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.12
• /
• pp.2190-2195
• /
• 2011

Due to enhanced demands on quality, security and reliability of the electric power energy system, a microgrid has become a subject of special interest. In this paper, output characteristics of energy storage system (ESS) with an electric double layer capacitor (EDLC) and battery energy storage system (BESS) of a renewable energy based microgrid were analyzed under grid-connected and islanded operation modes. The microgrid which consists of photovoltaic and wind power turbine generators, diesel generator, ESS with an EDLC, BESS and loads was modeled using real time digital simulator. The results present the effective control patterns of the microgrid system.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.10
• /
• pp.840-847
• /
• 2007

This Paper focuses on modeling and simulation to analyze the characteristic of hybrid vehicle. The system includes a proton exchange membrane fuel cell(PEMFC), photovoltaic generator(PV), lead-acid battery, motor, vehicle and controller. Main electricity is produced by the PEMFC and battery to meet the requirements of a user load. When vehicle is parked in a sunny place, extra power is generated by the photovotaics and is charged in a battery for next drive. Further we evaluate usefulness of this hybrid vehicle by using ADVISOR - the advanced vehicle simulator written in the Matlab/Simulink environment. According to simulation results, the extra power obtained by photovoltaics which have been explored in nature conditions can help to reduce the electrical load of PEMFC and increase the efficiency (over 21 %).

• Journal of the Korean Solar Energy Society
• /
• v.32 no.2
• /
• pp.11-18
• /
• 2012

Diesel fuel is expensive because transportation to remote areas adds extra cost, and it causes air pollution by engine exhaust. Providing a feasible economical and environmental solution to diesel generators is important. A hybrid system of renewable plants and diesel generators can benefit islands or other isolated communities and increase fuel savings. Renewable energy is, however, a natural source that produces a fluctuating power output. In this paper, hybrid power system of the marado lighthouse is proposed to supply stable power in the stand-alone hybrid power system. The proposed hybrid power system consists of the diesel generator, wind turbine, photovoltaic, fuel cell, and battery bank. To decrease the carbon emissions and find the optimization, the cost analysis of hybrid system is simulated using HOMER program and the optimized hybrid power system is designed.

• Proceedings of the KIEE Conference
• /
• 2002.04a
• /
• pp.133-138
• /
• 2002

The developments of the solar and the wind power energy are necessary since the future alternative energies that have no pollution and no limitation are restricted. Currently power generation system of MW scale has been developed, but it still has a few faults with the weather condition. In order to solve these existing problems, combined generation system of photovoltaic(400W) and wind power generation system(400W) was suggested. It combines wind power and solar energy to have the supporting effect from each other. However, since even combined generation system cannot always generate stable output with ever-changing weather condition, power compensation device that uses elastic energy of spiral spring to combined generation system was also added for the present study. In an experiment, when output of system gets lower than 12V(charging voltage), power was continuously supplied to load through the inverter by charging energy obtained from generating rotary energy of spiral spring operates in small scale generator.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.5
• /
• pp.760-768
• /
• 2016

Recently, as one of the policies for carbon free operation method of independent power system replacing diesel generator with renewable energy such as wind power and photovoltaic(PV) system has been presented. Therefore, this paper proposes an operation algorithm and modeling of independent power system by considering CVCF(constant voltage constant frequency) ESS(energy storage system) for constant frequency and voltage, LC(load control) ESS for demand and supply balancing and SVC(static var compensator) for reactive power compensation. From the simulation results based on the various operation scenario, it is confirmed that proposed operation algorithm and modeling may contribute stable operation and carbon free in independent power system.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.60 no.2
• /
• pp.194-206
• /
• 2024

This study focuses on analyzing the energy-saving effects of the recirculation aquaculture system using seawater source heat pumps and solar power generation. Based on the thermal load analysis conducted using the transient system simulation tool, the annual energy consumption of the recirculation aquaculture system was analyzed and the energy-saving effects of utilizing the photovoltaic system was evaluated. When analyzing the heat load, the sea areas where the fish farms are located, the type of breeding tank, and the circulation rate of breeding water were taken into consideration. In addition, a method for determining the appropriate capacity for each operation time was examined when applying the energy storage system instead of the existing diesel generator as an emergency power, which is required to maintain the water temperature of breeding water during power outage. The results suggest that, among the four seas considered, Jeju should be estimated to achieve the highest energy-saving performance using the solar power generation, with approximately 45% energy savings.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.114-123
• /
• 2018

Recently, as one of the countermeasures to reduce carbon dioxide($CO_2$) for global warming problems, operation methods in micro-grid systems replacing diesel generator with renewable energy sources including wind power(WP) and photovoltaic(PV) system have been studied and presented in energetic manners. However, it is reported that some operation problems in micro-grid systems without diesel generator for carbon-free island are being occurred when large scaled WP systems are at start-up. To overcome these problems, this paper proposes an operation strategy in micro-grid systems by adapting control devices such as CVCF(constant voltage constant frequency) ESS(energy storage system) for constant frequency and voltage regulation, load control ESS for balancing demand and supply and SVC(static-var compensator) for reactive power compensation. From the simulation results based on the various operation scenarios, it is confirmed that the proposed operation strategy in micro-grid systems without diesel generators is a useful tool to perform a stable operation in micro-grid systems without diesel generator and also make a contribution to reduce carbon dioxide in micro-grid systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.3
• /
• pp.16-23
• /
• 2012

This paper relates to a study on the economic of electrical storage device for supplying power in sunless days, in the stand alone PV/Wind hybrid system, which it is applied to separate houses. In a photovoltaic/wind hybrid power system used in a separate house, when only the battery is used in sunless days, the capacity of the battery is become larger. For example, as in recent days, if cloudy days are frequent due to anomaly climate, it is difficult to supply power stably by only the battery based upon pre-estimated sunless days. Accordingly, in order to supply stably power of new renewable energy such as solar to any separate houses, it is preferable to reduce the capacity of battery by decreasing the number of sunless days when estimating the capacity of battery and to drive the small generator for compensation of the power shortage.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.5
• /
• pp.583-591
• /
• 2007

This paper reports the performance of a 150W PV-wave hybrid system with battery storage in buoy. This system was originally designed to meet a new hybrid ower system for buoy in Korea. In the case or lighted buoys and lighthouses, a light failure alarm system of wireless radio is attached so that light failures are immediately notified to the office. At lighthouse offshore fixed lights and light buoys where commercial electricity is not available, the power source depends on solar system and batteries. This power system has a various problems. Therefore energy derived from the sunshine, wind and waves has been used as the energy source lot aids to navigation. Recently a hybrid system of combining the solar, wind and the wave generator is a favorable system lot the ocean facilities like lighthouse and buoy. The hybrid system in this paper is intended for variable DC load like light, communication system in the buoy and includes a PV-wane generation system and battery. This is composed a high efficiency charging algorithm, switching converter and controller. This paper includes discussion on system reliability, power quality, and effects of hybrid system in the buoy. Simulation and experimental results show excellent performance.