• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.523-531
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• 2012

This paper proposes a high efficiency power conversion system for battery-ultracapacitor hybrid energy storages. The proposed system has only one bidirectional dc-dc converter for hybrid power source with batteries and ultracapacitors. The hybrid power source has bidirectional switching circuits for selecting one energy storage device. Bidirectional power flow between the energy storage device and high voltage capacitor can be controlled by one bidirectional converter. An asymmetrical switching method is applied to the bidirectional converter for high power efficiency. Switching power losses are reduced by zero-voltage switching of power switches. System operation and design considerations are presented. The experimental results are provided to verify the performance of the proposed system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2103-2108
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• 2016

Energy saving is as important as developments of green energy and alternative energy. This paper describes design of hybrid type streetlight for railway station with renewable energy as photovoltaic, wind, secondary battery. In designing hybrid type streetlight for railway station, generation energy with renewable energy and reliability is strongly needed to meet the demand of railway station. In order to achieve the high performance of a streetlight, photovoltaic, wind and secondary battery system, PV tracker, monitoring and GUI system with logging function are designed. To verify of performance of hybrid type streetlight for railway station, we have demonstration test to get of generation energy and flow of energy and the results are present in this paper.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.4
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• pp.1-8
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• 2019

In this paper, we study the BESS of a standalone hybrid street light. The proposed BESS proposed a BESS with the function of efficiently charging irregularly generated power from two or more generators. AC generated by wind power is converted to DC using an AC / DC converter and then to a voltage that can charge the battery through the DC / DC converter. The lack of voltage and current, which is a disadvantage of the MPPT method used in solar power generation, is compensated by the DC value of wind power generation. The compensation method is to convert the DC generated from solar power into a voltage suitable for charging the battery through a DC / DC converter, and then connect the DC generated in wind power in parallel to compensate for the insufficient current to charge the battery in a short time. Allow this to begin. By securing the maximum charging time, the usage time of the stand-alone hybrid street light is huge. Experimental results show that the battery has a short charging time and can be efficiently applied to battery-dependent standalone hybrid street lights.

• Progress in Superconductivity and Cryogenics
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• v.24 no.2
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• pp.27-38
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• 2022

Urban air mobility (UAM) has recently attracted lots of attention as a solution to urban centralization and global warming. Electric vertical take-off and landing (eVTOL) is a concept that emerges as one of the promising and clean technologies for UAM. There are two difficult challenges for eVTOL aircraft to solve. One is how to improve the weight efficiency of aircraft, and the other is how to complete long-range missions for UAM's flight scenarios. To approach these challenges, we propose a consolidated concept design of battery-fuel cell hybrid tiltrotor aircraft with a liquid hydrogen (LH₂) fuel tank. The efficiency of a battery-fuel cell hybrid powertrain system on the designed eVTOL aircraft is compared to that of a battery-only powertrain system. This paper shows how much payload can increase and the flight scenario can be improved by hybridizing the battery and fuel cell and presenting a detailed concept of a cryogenic storage tank for LH₂.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.501-505
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• 2004

The study on the hybrid power source for the IMT2000 application has been presented. The hybrid power source is composed of solar cell, super-capacitor and battery. To compensate for the pulse loader of the IMT2000 application, the super-capacitor is connected through the Lithium-ion battery to absorb the pulse current. The solar cell provides the additional current to compensate for the depleted current. The controller design for the hybrid source has been presented and verified through experiment.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.320-325
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• 2005

Power of fuel cell tram is supplied by only fuel cell system or hybrid system of fuel cell and battery/super capacity. Fuel cell is operated by hydrogen, which is fed directly from hydrogen tank or by reforming gasoline or methanol into hydrogen. Power system is preferred with hybrid of fuel cell and battery/super capacity since it improves total energy efficiency through interaction of hybrid components and restores energy regenerated by braking. Also, power supply system by fuel cell hybrid should be designed to output optimum energy efficiency depending on driving mode of fuel cell tram.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2255-2260
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• 2007

This Paper focuses on modeling and simulation to analyze the characteristic of hybrid vehicle. The system includes 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 30%).

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.95-96
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• 2013

In this paper, an operation algorithm for the fuel cell-battery hybrid power system is proposed. As the output current slope of the fuel cell is normally limited to protect the fuel cells' defection, efficient power distribution algorithm between the fuel cell and battery is very important for the successful hybrid control operation. For the experimentation, a 1kW dc-dc converter with 500W fuel cell stack and 1kWh Li-polymer battery is implemented.

• Journal of Hydrogen and New Energy
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• v.34 no.5
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• pp.490-496
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• 2023

Unmanned aerial vehicles (UAVs) research is recently actively underway. Especially, fuel cell battery hybrid systems are widely used to overcome the limitations of continuous operation. However, fuel cell systems must be operated in combination with a battery due to their low specific output characteristics. Therefore, a hybrid power system model for UAVs is developed. The rule-based strategy is applied to the model to properly distribute power to batteries and fuel cells. As a result, the designed rule-based power distribution control operates UAVs while maintaining battery state of charge(SOC) at an appropriate level.

• Journal of Power Electronics
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• v.15 no.3
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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.