부산대학교 도서관

This thesis addresses the need to move to cleaner economic growth based and focuses on fuel cell electric vehicles (FCEVs) to help realised the move to zero carbon emissions by 2050. The review of the state of the art in Zero Emission Vehicle (ZEV), Energy Storage Source (ESS), fuel cell, hydrogen technologies and economy has confirmed the potential of FCEV. The review has also identified the need to reduce cost and improve efficiency to enable widespread market adoption. This thesis demonstrated the suitability of passive hybrid systems, where fuel cell and battery are directly connected without a DC-DC converter, to reduce the cost and increase the efficiency of FCEVs. An original passive hybrid powertrain model was developed and validated using experimental data to provide a realistic dynamic behaviour for the FCEV. An original fuzzy logic controller was designed using rules exploiting State of Charge (SoC) and fuel cell load power to determine the most appropriate fuel cell pressure to satisfy the load of the FCEV whist reducing the number of fuel cell start-stop times and extending the vehicle range. The system model was used to carry out simulation studies to demonstrate the advantages of passive hybrid systems compare to active hybrid systems in terms of reduced cost, complexity, weight, resulting in increased vehicle range. The simulation has highlighted the need to carefully design passive hybrid systems to minimise fuel cell power variation in response to load demand changes. An original set of rules was proposed to size fuel cell and battery and applied for different battery technologies whilst considering well-to-wheel for downsizing passive hybrid powertrain. Overall, this thesis has demonstrated through the use of surveys, modelling control systems design and component sizing that passive hybridization is a good alternative for Ultra-Low Emission Vehicle (ULEV).