Adaptive and Non-Adaptive Strategies for Optimal Energy Management and Sizing of a Dual Storage System in a Hybrid Electric Bus

In this paper, a non-adaptive and a novel adaptive energy management strategy (EMS) are proposed for a series hybrid electric bus with a dual energy storage system (ESS) combining batteries and supercapacitors. The scenario considers the hybrid (genset+dual ESS) and full-electric (only dual ESS) operation during the daily journey. The main goal of this paper is to highlight the improvements that can be achieved either with an enhanced adaptive EMS (fuzzy-based) compared with the non-adaptive (rule-based) approach as well as with the co-optimization of ESS sizing and operation targets in economic, fuel saving, and efficiency terms. To do so, a multi-objective optimization methodology is proposed (considering economic and ageing models) to minimize the operation cost (cycling cost) of the dual ESS and its replacements along the vehicle lifetime as well as the fuel consumption, while fulfilling the performance of the bus in its daily journey. The simulation results showed that the adaptive EMS can reduce both the operation cost of the vehicle and the average fuel consumption (up to 15% and 19%, respectively) compared with the optimal solution obtained with the non-adaptive EMS.