Comparison of energy and exergy analysis of fuzzy logic and power follower control strategies in fuel cell electric vehicles

Abstract

With the increasing importance of green energy, traditional vehicles are being gradually replaced by hybrid electric vehicles, electric vehicles, and fuel cell electric vehicles (FCEVs), all of which emit minimal to no CO2. The popularity of FCEVs is on the rise due to their lower emissions compared to hybrid electric vehicles and their ability to address the range limitations of electric vehicles. These vehicles utilize fuel cells in conjunction with supercapacitors and batteries to enable rapid acceleration. An energy management system (EMS) facilitates the distribution of power from multiple sources. Fuzzy logic control (FLC), among various EMS approaches, emerges as a favorable option for vehicle applications due to its adaptability to nonlinear systems and tolerance for uncertainties. This study undertakes the analysis of FCEVs with fuel cell + battery (FC + B) and fuel cell + supercapacitor (FC + SC) configurations across various driving cycles such as the Federal Test Procedure (FTP), Urban Dynamometer Driving Schedule (UDDS), Worldwide Harmonised Light Vehicle Test Procedure (WLTP), and Highway Fuel Economy Test (HWFET). The comparison between power follower control (PFC) and FLC is conducted based on fuel consumption and energy efficiency. Moreover, exergy efficiency, alongside energy efficiency, holds significant importance. Through exergy analysis, losses that cannot be identified solely through energy analysis are determined. Hence, both energy and exergy analyses are conducted in this study. Exergy efficiencies and losses in FC + B and FC + SC configurations under FLC strategy and PFC strategy are thoroughly examined. The energy analysis results of this study show that the FLC reduced hydrogen consumption and increased energy efficiency in all driving cycles and different topologies compared to the PFC strategy. Exergy analysis showed that the FLC increased energy efficiency and reduced exergy loss. Small-scale decreases in exergy efficiency were observed in UDDS and HWFET driving cycles in FC + B topology. These findings indicate that optimization should continue under certain driving conditions. In other driving cycles, an increase in exergy analysis was observed. These results support that the FLC is more efficient in terms of both energy and exergy.