• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.891-897
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• 2012

In this paper, the observer based nonlinear state feedback controller has been developed to control the pressures of the oxygen and the hydrogen in the PEM(Proton Exchange Membrane) fuel cell system. Nonlinear model of the PEM fuel cell system was introduced to study the design problems of the state observer and model based controller. A cascade observer using the filtering technique was used to estimate the pressure derivatives of the cathode and the anode in the system. In order to estimate the pressures of the cathode and the anode, the sliding mode observer was designed by using these pressure derivatives. To estimate the oxygen pressure and the hydrogen pressure in the system, the nonlinear state observer was designed by using the cathode pressure estimates and the anode it. These results will be very useful to design the state feedback controller. The validity of the proposed observers and the controller has been investigated by using the Lyapunov's stability analysis strategy.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.5
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• pp.428-435
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• 2005

In this paper a power controller is proposed to accurately control the commanded power for charge and discharge operation of a bidirectional DC-DC converter so that durability is improved in hybrid systems such as fuel cell vehicles. Also, a control algorithm for charge and discharge operation is proposed to improve fuel utilization and keep battery SOC constant so that energy is effectively utilized.

• Journal of Power Electronics
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• v.11 no.2
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• pp.194-201
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• 2011

The air flow supplied to a fuel cell system is one of the most significant factors in determining fuel efficiency. The conventional method of controlling the air flow is to fix the oxygen supply at an estimated constant rate for optimal efficiency. However, the actual optimal point can deviated from the pre-set value due to temperature, load conditions and so on. In this paper, the maximum efficiency point tracking (MEPT) algorithm is proposed for finding the optimal air supply rate in real time to maximize the net-power generation of fuel cell systems. The fixed step MEPT algorithm has slow dynamics, thus it affects the overall efficiency. As a result, the variable step MEPT algorithm is proposed to compensate for this problem instead of a fixed one. The complete small signal model of a PEM Fuel cell system is developed to perform a stability analysis and to present a design guideline. For a design example, a 1kW PEM fuel cell system with a DSP 56F807 (Motorola Inc) was built and tested using the proposed MEPT algorithm. This control algorithm is very effective for a soft current change load like a grid connected system or a hybrid electric vehicle system with a secondary energy source.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1038-1040
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• 1992

Booster is used widely as one of the step-up DC/DC power converter in power conversion process for fuel cell power plant which have the electrical characteristic of the high current density and low cell voltage. In view of control system, booster can be unstable when it is operated in broad operation range because the transfer function of booster has zero in right half plane of s-domain. So for reliable operation, controller must make the system stable in whole working range. In this paper, the two control method such as digital PID control and fuzzy control is studied for booster output voltage regulation in fuel cell plant. The design procedure of PID control and fuzzy control is described. And the experiment of designed controller action is performed in various operation points for controller performance test.

• 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.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1149-1150
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• 2006

This paper describes the development of software platform of embedded controller for Fuel Cell System. The fuel cell system is complex which needs an embedded controller to execute multiple tasks. The software organized by modualarization and layered architecture can perform complicated control algorithms. By development of the software platform with architectural software, the fuel cell system's embedded controller has a reusability and a scalability. And the developed software platform guarantees a execution of multiple tasks.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.772-777
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• 2009

The development of fuel cell hybrid power system, as a next generation power system to promote clean energy which will mitigate the continued global warming, has demonstratd a significant progress in passenger vehicle applications. Also, in case of railway vehicles in non-electrified railway lines, the adoption of fuel cell hybrid power system is being studied among well-known manufacturers. This paper introduces both the configuration and the control strategy of fuel cell hybrid power system to apply to a light electronic railway vehicle having a repeated driving pattern of acceleration, coasting and deceleration. The simulation results demonstrate the viability of the proposed power system design and its control strategy.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.304-315
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• 2013

In this paper, analysis of cascaded H-bridge multilevel inverter in DTC-SVM (Direct Torque Control-Space Vector Modulation) based induction motor drive for FCEV (Fuel Cell Electric Vehicle) is presented. Cascaded H-bridge multilevel inverter uses multiple series units of H-bridge power cells to achieve medium-voltage operation and low harmonic distortion. In FCEV, a fuel cell stack is used as the major source of electric power moreover the battery and/or ultra-capacitor is used to assist the fuel cell. These sources are suitable for utilizing in cascaded H-bridge multilevel inverter. The drive control strategy is based on DTC-SVM technique. In this scheme, first, stator voltage vector is calculated and then realized by SVM method. Contribution of multilevel inverter to the DTC-SVM scheme is led to achieve high performance motor drive. Simulations are carried out in Matlab-Simulink. Five-level and nine-level inverters are applied in 3hp FCEV induction motor drive for analysis the multilevel inverter. Each H-bridge is implemented using one fuel cell and battery. Good dynamic control and low ripple in the torque and the flux as well as distortion decrease in voltage and current profiles, demonstrate the great performance of multilevel inverter in DTC-SVM induction motor drive for vehicle application.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.241-246
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• 2023

Fuel cells are one of the renewable energy sources that have sparked a lot of scientific attention for solving problems related to the energy crisis and environmental pollution. One of the most crucial subjects concerning the utilization of fuel cells is modeling. Therefore, an analytical steady-state and dynamic fuel cell model was described in this study. The parameter for the identification process was investigated, and the MATLAB/Simulink implementation was demonstrated. A 15-W proton exchange membrane fuel cell was used to apply the suggested modeling methodology. Comparing experimental and simulation findings indicated that the model error was constrained to 3%. This study showed that temperature and humidity affect fuel cell performance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.154-161
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• 2009

A fuel cell power plant is a very complex system which has various control loops with some non-linearity. For control of a fuel cell power plant, dynamic models of fuel cell stacks have been developed and simplified process flow diagrams of a fuel cell power plant has been presented. Using such a model of a Molten Carbonate Fuel Cell (MCFC) power plant, this paper deals with development of an intelligent setpoint reference governor (I-SRG) to find the optimal setpoints and feed forward control inputs for the plant power demand. The I-SRG is implemented with neural network by using Particle Swarm Optimization (PSO) algorithm based on system constraints and performance objectives. The feasibility of the I-SRG is shown through simulation of an MCFC power plant for tracking control of its power demand.