• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.553-561
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• 2012

Existing energy sources convert chemical energy into mechanical energy, while fuel cell directly generates electricity through an electrochemical reaction between hydrogen and oxygen. Therefore, it has a lot of strong points such as high efficiency, zero emission, and etc. In addition, with the development of hydrogen preservation technique, some companies have been researching and releasing portable fuel cell power packs for specific applications like military equipment, automobile, and so on. However, there are some drawbacks to the fuel cell, high cost and slow dynamic response. In order to compensate these weak points, auxiliary energy storages could be applied to the fuel cell system. In this paper, the optimum structure for a 150W portable fuel cell power pack with a battery pack is selected considering the specification of the system, and the design process of main parts is described in detail. Here, main objectives are compact size, simple control, high efficiency, and low cost. Then, an automatic mode change algorithm, which converts the operating mode depending on the states of fuel cell stack, battery pack, and load, is introduced. Finally, performance of the designed prototype using the automatic mode change control is verified through experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1629-1633
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• 2004

In this paper, we first implement the simulation environment to investigate the efficient control method of a Fuel Cell Electric Vehicle (FCEV) system with battery. The subsystems of a FCEV including the fuel cell system, the electric motor (including the power electronics) and the tansmission (reduction gear), and the auxiliary power source (battery) are mathematically fomulated and coded using the Matlab/Simulink software. Some examples are given to show the capabilities of the modeled system and d a basic control strategy is examined for the economic energy distribution between the fuel cell and the auxiliary power source. It is illustrated by simulations that the actual vehicle velocity follows the given desired velocity pattern while both SOC control and power distribution control are being performed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.143-148
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• 2018

In this paper, the optimal fuzzy logic controller(FLC) for a hybrid renewable energy system(HRES) is proposed. Generally, hybrid renewable energy systems can consist of wind power, solar power, fuel cells and storage devices. The proposed FLC can effectively control the entire HRES by determining the output power of the fuel cell or the absorption power of the electrolyzer. In general, fuzzy logic controllers can be optimized by classical optimization algorithms such as genetic algorithms(GA) or particle swarm optimization(PSO). However, these FLC have a disadvantage in that their performance varies greatly depending on the control parameters of the optimization algorithms. Therefore, we propose a method to optimize the fuzzy logic controller using the teaching-learning based optimization(TLBO) algorithm which does not have the control parameters of the algorithm. The TLBO algorithm is an optimization algorithm that mimics the knowledge transfer mechanism in a class. To verify the performance of the proposed algorithm, we modeled the hybrid system using Matlab Tool and compare and analyze the performance with other classical optimization algorithms. The simulation results show that the proposed method shows better performance than the other methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.139-139
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• 2009

As ideal new energy, solar cell has renewable and inexhaustible characteristics and the fuel cell only needs low maintenance and low operating cost. This paper introduces hybrid system of solar cell and fuel cell considering the advantages of stable and sustainable energy from the economic point of view. Then the paper shows the I-V characteristics of the solar module which are dependent on the power of the halogen lamp and the P-I and I-V characteristics of fuel cells which are connected in parallel and series.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.357-363
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• 2021

Eco-friendly hybrid railroad propulsion system with fuel-cell and battery was suggested to reduce carbon dioxide gas and replace retired diesel railroads. Lithium-ion battery with high energy/power density and long lifetime is selected as the energy source at the battery side due to its excellent performance. However, the performance of lithium-ion batteries was affected by temperature, current rate, and operating condition. Temperature is known to be the most influential factor in changing battery parameters. In addition, appropriate thermal management is required to ensure the safe and effective operation of lithium-ion battery. Electro-thermal coupled model with varying parameter depends on temperature, and state-of-charge (SOC) is suggested to estimate battery temperature. The electric-thermal coupled model contains diffusion current using parameter identification by adaptive control algorithm when considering thermal diffusion effect. An experiment under forced convection was conducted using cylindrical cell and 18 parallel-connected battery module to demonstrate the method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.8 s.251
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• pp.756-763
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• 2006

PEMFC has several technical problems such as water management, long term stability and performance degradation as. PEMFC has been studied not only to solve water management, but also to generate power in stable manner to system by using a hybrid system with auxiliary energy storage device. The purpose of this study is to couple PEMFC with supercapacitor to make a hybrid system and to design and test control strategies for stable power generation in case of changing output power. The polarization curve and dynamic behaviors while changing power were investigated to find out characteristics of PEMFC stack. A DC/DC converter was fabricated in order to increase fuel cell and supercapacitor voltage and to charge supercapacitor. We found that the operation strategy 2 was recommended to the system because of solving water management problem and increasing the dynamic behavior.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.377-377
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• 2009

Currently, new and renewable energy come into the spotlight, such as solar energy, wind power, fuel cell, hybrid car etc., due to the energy resources is being depleted. In order to solve like this problem, we addressed the roll to roll printing machine for the thin film solar cell by using printing technology. For the this research, we archived concept design and verified propriety.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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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.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.112-116
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• 2010

Fuel cell as a renewable energy source is clean and has a lot of advantages. The source can solve energy crisis and environmental problems such as greenhouse effect, air pollution and the ozone layer destruction. This paper introduces hybrid system(hydro-Genius Professional, heliocentris) of solar cell and fuel cell. Also, this paper shows the I-P, V-I characteristics of fuel cells which are connected in parallel and series. From these results, we also found the maximum power was transferred at 0.5[${\Omega}$]. The terminal voltage was also decreased according to the current because of the internal resistance. The power transfer in series was two times than that in parallel.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.133-133
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• 2009

연료전지는 연료의 화학적 에너지를 전기화학 반응을 통하여 직접 전기로 변환하기 때문에 에너지 전환효율이 높고 공해물질을 배출하지 않는 환경친화적인 고효율 발전방식으로, 특히 용융탄산염 연료전지(MCFC) 및 고체산화물 연료전지(SOFC)같은 고온형 연료전지의 경우 분산전원이나 중앙집중발전 같은 발전용에 적합한 연료전지로 평가받고 있다. 현재 MCFC 및 SOFC등의 발전용 연료전지 시스템의 효율은 약 50% 정도이며, 시스템의 발전효율을 높이기 위한 여러 연구가 진행되고 있다. 그 중에서 고온의 배열을 이용하여 연료전지 발전시스템의 효율을 향상시키기 위해 FuelCell Energy, Ansaldo Fuel Cells 및 Simens Westinghouse 등에서 수백 kW급의 fuel cell - gas turbine hybrid system에 대한 상용화 수준의 실증연구가 진행되었다. 본 연구에서는 발전용 연료전지 시스템의 발전효율을 높이기 위한 방안 중 하나로 배열을 이용하여 steam을 발생시켜 air amplifier에 사용함으로써 연료전지 시스템의 MBOP(Mechanical Balance of Plant)중 전력을 소비하는 air blower를 대체하여, 시스템 효율을 향상시키고 시스템의 가용성을 높일 수 있는 설계안에 대하여 논하고자 한다.