• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.103-108
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• 2012

Fuel economy is an important factor in a vehicle owing to recent energy supply and environmental problems. This paper deals with fuel cell hybrid vehicles (FCHVs) and introduces a fuel economy evaluation method. The fuel economy of an FCHV depends on its power management strategy. Two rule-based power management strategies are applied to this paper and their fuel economy is evaluated based on the optimal control theory. The concept of the optimal line is also applied to this paper, which is used to compare the fuel consumption of a power management strategy to the optimal result. The two rule-based strategies are also compared to each other.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.631-640
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• 2016

A dual-mode power management for a hybrid-electric UAV with a cruise power of 200W is proposed and empirically verified. The subject vehicle is a low-speed long-endurance UAV powered by a solar cell, a fuel cell, and a battery pack, which operate in the same voltage bounds. These power sources of different operational characteristics can be managed in two different methods: passive management and active management. This study proposes a new power management system named PMS2, which employs a bypass circuit to control the individual power sources. The PMS2 normally operates in active mode, and the bypass circuit converts the system into passive mode when necessary. The output characteristics of the hybrid system with the PMS2 are investigated under simulated failures in the power sources and the conversion of the power management methods. The investigation also provides quantitative comparisons of efficiencies of the system under the two distinct power management modes. In the case of the solar cell, the efficiency difference between the active and the passive management is shown to be 0.34% when the SOC of the battery is between 25-65%. However, if the SOC is out of this given range, i.e. when the SOC is at 90%, using active management displays an improved efficiency of 6.9%. In the case of the fuel cell, the efficiency of 55% is shown for both active and passive managements, indicating negligible differences.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1038-1039
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• 2008

This paper proposes a base models of Hybrid railway vehicle power system. A powered system with fuel cell is regarded as a high current and low voltage source. The design parameters of the system should be chosen by taking into account the characteristics of the fuel cell, so the costs of the power system at given operating conditions can be reduced. Currently, no integrated simulation has been approached to analyze interrelated effects. Therefore, the base models of power conversion system with a PEM fuel cell/IPT system for hybrid powered system that includes the PEM fuel cell stack, DC/DC converter are developed. Concept of bidirectional converter for super capacitor charging system is presented.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.355-358
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• 2005

This paper describes an simulation method to utilize the hybrid system with fuel cell and battery. The hybrid system has unique advantage to manage energy state between high energy system (fuel cell) and high power system (battery) according to various type of load. For proper design, the hybrid system is modelled and simulated. Especially, battery SOC is used as an important control parameter to decide the energy control.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.7
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• pp.615-622
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• 2004

Recently, the hybrid system combining fuel cell and gas turbine has drawn much attention owing to its high efficiency and ultra low emission. It is now on the verge of world wide development and various system configurations have been proposed. A national project funded by Korean government has also been initiated to develop a pressurized hybrid system. This work aims at presenting design performance analysis for various possible system configurations as an initial step for the system development. Study focuses are given to major design options including the power ratio between gas turbine and fuel cell, reforming method (internal or external), reforming heat source (reforming burner, cathode hot air, fuel cell heat release) and steam supply method for reformer (anode gas recirculation, external steam generator). A wide variation in performance among different configurations has been predicted.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1605-1612
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• 2002

Thermodynamic performance analysis has been carried out for a hybrid electric power generation system combining a gas turbine and a solid oxide fuel cell and operating at over-atmospheric pressure. Performance characteristics with respect to main design parameters such as maximum temperature and pressure ratio are examined in detail. Effects of other important design parameters are investigated including fuel cell internal parameters such as fuel utilization factor, steam/carbon ratio and current density, and system parameters such as recuperator efficiency and compressor inlet temperature.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.198-200
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• 2006

In this paper, three types of power control strategies for controlling a Fuel Cell Hybrid Electric Vehicle(FCHEV) are studied in view of fuel economy. The FCHEV has become one of alternatives for future vehicles since it does emit water only without any exhaust gas while it has a high well-to-wheel efficiency together with an energy saving due to regenerative braking. However, it has also several disadvantages such as the complexity of vehicle system, the increased weight and the extra battery cost. Among various power control strategies, a static power control strategy, a power assist control strategy and a fuzzy logic-based power control strategy are simulated and compared to show the effectiveness of each method.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.67-75
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• 2013

In this paper, parallel input/serial output dual converter is designed appropriately for fuel cell hybrid power system. In case of proposed converter, zero voltage switching condition is designed without additional resonance device using leakage inductance of transformer and output capacitance of switch, and zero voltage switching method is used. Also, the system method is for increasing power by connecting half-bridge in parallel and increasing output voltage by connecting secondary output of transformer in serial. Through this method we can increase power and decrease volume of system. So in this paper, dual converter is designed. 1.5kW fuel cell hybrid power system was implemented, and system operation and stability was verified through experiment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2235-2242
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• 2016

The electric power system based on fuel cell is applied in various forms to the ship and offshore plants. In particular, a research on the hybrid power system of the fuel cell combined with battery in connection topology has been researched actively. Fuel cell-based hybrid ship has not been carried out research, it is not carried out research in the integrated monitoring system. In this paper, we developed an integrated monitoring system to increase the convenience and stability for the hybrid fuel-cell ship operator. Research into integrated monitoring system based on GUI (Graphic User Interface), in consideration of the stability of the user convenience and ship operations, and developed communication and hardwired signal with the main equipment of the ship, to see in realtime state of the ship. The collected ship operation data is stored and it can be seen after the ship operating.