Theoretical study of a power generation unit based on the hybridization of a fuel cell stack and ultra capacitors

• Main Author: Garcia Arregui, Marcos
• Format: Others
• Published: 2007
• Online Access: http://oatao.univ-toulouse.fr/7617/1/garcia_arregui.pdf

The presented work deals with the design and conception of an electrical network from a fuel cell stack and its associated storage device. The framework of this project is an aeronautical and transport application. Air pressurized fuel cell stacks need some auxiliary devices that permits a correct gas flow through the fuel cell stack. Due to the auxiliary devices, the fuel cell dynamics performances may be limited, and a power buffer is required to support power peaks. Furthermore, hybridization has a positive effect in the system size, and can lead to reduce the global system weight and volume. Ultracapacitors seem to be well adequate for this purpose. Nevertheless, the introduction of a storage device in the electrical network opens a wide range of possible architectures. Indeed, due to the important voltage variations of the supercapacitor bank and the fuel cell stack, some power electronics interfaces may be placed in order to assure the electrical network requirements. Thus, the system behaviour varies according to the position of the power converters and the storage device in the electrical network. Therefore, the power converter conception, the retained electrical architecture characteristics and its associated control laws are studied in this work. Due to the transport application, the system hydrogen consumption, volume, weight and cost are essential parameters, and become the key to choose one of the retained architectures. Furthermore, the system couplings and the important number of design variables makes impossible to design the system without the help of a software tool. Therefore, and in order to compare fairly all the proposed architectures, a multiobjective optimization tool is developed