Development of Next Generation Fuel Cell Bus: Investigation of Configuration Impact and Control Strategy Development

The emergence of fuel cell powertrains has opened up new pathways to net-zero greenhouse gas emissions across a number of sectors, including public transport. However, while these technologies are gaining momentum,
they are mostly still in their infancy with a range of fundamental challenges which still need to be addressed. The typical configuration deployed in bus applications requires integration with other fast-response power sources, e.g., battery and/or ultra-capacitor, to effectively manage power delivery. However, implementation of such hybrid energy storage systems (ESSs) complicates the design and control of the vehicle powertrains. In this work, a concept fuel cell bus vehicle powertrain configuration has been constructed first using Matlab/Simulink which can be used to explore the impact of various ESS hybridization strategies, and their effectiveness in power management. Three variants have been studied: [I] fuel cell + battery; [II] fuel cell + ultra-capacitor
and [III] fuel cell + battery + ultra-capacitor. A unified global energy management strategy (EMS) based on dynamic programming (DP) has been developed and deployed in the simulated bus powertrain models to understand the practicalities of the three EMS configurations, and the potential advantages and constraints associated with each, offering guide for practical EMS development. Using an explicit equivalent consumption minimization strategy (eECMS), tailored EMSs are developed for three configurations which optimize
the power split between the available power sources in real time, and the enhanced performance are achieved benchmarked against other energy management solutions in the compare study. Comparison of results manifests great advantage of the novel instant EMSs in energy consumption saving.