• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.9
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• pp.833-841
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• 2016

The 200 W electrically powered unmanned aerial vehicle, which is studied in this research, uses solar cells, a fuel cell and batteries as the main power source simultaneously. The output of each power source performs power control for each power source by the active power control method so that an adequate capacity of the battery could be maintained while limiting the maximum output of the fuel cell. The output variation for each power source under the active power control method was identified through an integrated ground test. In addition, the effect of limiting the maximum output of the fuel cell on the output variation of the entire system was experimentally identified, and it was confirmed that the adequate maximum output value of the fuel cell for preventing the overdischarge of six series-connected, small size batteries for fuel cell systems is 150 W.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.176-179
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• 2009

The performance of direct methanol fuel cells is affected by operating conditions such as, methanol feeding temperatures, methanol concentrations, and methanol flow rates during the operation in different environmental conditions. In this study, effects of the environmental temperature on performance of direct methanol fuel cells have been investigated in order to test a applicability of direct methanol fuel cell to the vehicle. The environmental temperature (ET) was varied from $-20^{\circ}C$ to $+30^{\circ}C$. The inside fuel cell temperature (CT) during test at various operating conditions was monitored and the performance of fuel cell was measured in the I-V polarization curve. With increasing the ET, the performance of the fuel cell was significantly improved and the CT also almost linearly increased. However, at below $0^{\circ}C$ ET, the DMFC showed very poor performance and needed to control CT or methanol feeding temperature (MFT), methanol flow rate(MFR) to obtain enough power of the vehicle.

• Journal of Power Electronics
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• v.11 no.2
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• pp.202-210
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• 2011

Polymer electrolyte membrane (PEM) fuel cell is one of the popular renewable energy sources and widely used in commercial medium power areas from portable electronic devices to electric vehicles. In addition, the increased integration of the PEM fuel cell with power electronics, dynamic loads, and control systems requires accurate electrical models and simulation methods to emulate their electrical behaviors. Advancement in parallel computation techniques, various real-time simulation tools, and smart power hardware have allowed the prototyping of novel apparatus to be investigated in a virtual system under a wide range of realistic conditions repeatedly, safely, and economically. This paper builds up advancements of optimized model constructions for a fuel cell stack system on a real-time simulator in the view points of improving dynamic model accuracy and boosting computation speed. In addition, several considerations for a power hardware-in-the-loop (PHIL) simulation are provided to electrically emulate the PEM fuel cell stack system with power facilities. The effectiveness of the proposed PHIL simulation method developed on Opal RT's RT-Lab Matlab/Simulink based real-time engineering simulator and a programmable power supply is verified using experimental results of the proposed PHIL simulation system with a Ballard Nexa fuel cell stack.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2367-2369
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• 2004

It is well known that an indirect methanol based fuel cell system imposes a performance limitation on the fuel cell electric vehicle (FCEV) due to the reformer lag. An optional battery system can be used together with fuel cell to improve this performance limitation and it is called a fuel cell hybrid electric vehicle (FCHEV) this paper first describes the configuration of FCHEV with explanation of the energy flow between subsystems. Mathematical modeling of each subsystem such as a fuel cell system, a battery system, a driving motor with the transmission are formulated and coded using Matlab/simulink software. It is illustrated by simulation results that fuel cell modeling yields appropriate stack voltage in order to get the required current quantity with varying hydrogen flow.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1792-1797
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• 2013

Recently, due to the excessive use of fossil fuels, many studies about the fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be reason of power quality in the power system. In this paper, we constructed the system for an assessment on Islanding. The system is composed with power source, Impedance coordination load and linear load, fuel cell system. we are performed assessment on voltage and power quality in customer and the distributed power system during the Islanding of residential fuel cell system. In addition, no change in the impedance of power system, we made a islanding condition only using the actual load, As a variation of generation and load current under islanding, an analysis results based on assessment system showed that the power qualities of distribution system became more aggravation as effect of voltage sag and voltage swell phenomena.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.49-52
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• 2008

The present study conducts a series of experiments to develop a novel air supplying module for a micro fuel cell using piezoelectric linear actuator. An intermittently and operating air breathing module with reciprocating motion of the linear actuator has been suggested in the present study. A test bench for a micro fuel cell system has been constructed to estimate performance of the active fuel cell system using the air supplying module. With the stroke and operating duty as main control parameters, the optimal operating method of the air supplying module has been discussed.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.93-96
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• 2006

PEMFC(proton exchange membrane fuel cell) is most applicable to automobile in various types of fuel cell. However, to improve system dynamics and logn term Performance fuel cell is supported by auxiliary power unit forming hybrid system. The operating strategy of hybrid system influences on efficiency and stability. In this paper the proper strategies are compared each other considering power distribution and stable system operation. The chosen strategy is simulated by MATLAB simulink to forecast realization of fuel cell hybrid vehicle

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.61-72
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• 2007

This study proposed a high efficiency DC-DC converter with a new current doubler rectifier for fuel-cell systems for use with the Nexa(310-0027) PEMFC from the Ballard Co. The proposed high efficiency DC-DC converter for the fuel-cell system generated ZVS by applying partial resonance and using a phase shift PWM control method. Constantly switching frequency, loss of switching, peak current, and peak voltage were reduced by this system. In addition to this system, two inductors were attached to a rectifier circuit allowing it to be able to provide the direct current(DC) and DC voltage safely to a load with reduced ripple components. Also, by using the newly proposed current doubler rectifier, the high frequency DC-DC converter for the fuel cell system was capable of reaching a highest efficiency of 92[%] as compared to 88.3[%] efficiency in previous results, which means that efficiency increased 3.7[%]. The overall results were confirmed by a simulation and laboratory experiment.

• Journal of Power Electronics
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• v.6 no.2
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• pp.172-177
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• 2006

This paper presents the sliding mode observer of an induction motor for the fuel cell electric vehicles. The exact rotor flux estimation of the induction motor is important for achieving the best performance from the fuel cell electric vehicle system. However, the flux estimator of the induction motor control is highly sensitive to the voltage sensor output characteristics and system parameter variation influenced by external factors. In order to eliminate these problems, this paper investigates the electric vehicle performance due to parameter variation of the induction motor. A new method to estimate the fuel cell electric vehicle system is proposed based on the sliding mode observer.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.867-869
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• 1993

In generally Boost Converter is used for Fuel Cell System. Because the output voltage of fuel cell is too small and greatly depends on the load condition, Boost Converter are required to boost and regulate the Fuel Cell voltage for per conversion efficiency. In this Paper, 6-phase Boost Converter is used to boost the Fuel Cell Voltage and regulate the output voltage. Multi phase converter hag some advantages such as low ripple and filter sine. About the Peak Current Control and compare of the Ripple Current of Boost Converter, we have studied.