Battery aging conscious intelligent energy management strategy and sensitivity analysis of the critical factors for plug-in hybrid electric buses

The aim of this paper is to propose a battery aging conscious energy management strategy. The initial design of an energy management strategy is a significant point, in order to fulfill the efficiency goals in a short term. However, with the aging, the initial conditions vary. The new trend of digitalization allows to monitor the operation, having the possibility to update the developed first strategy in a long term. Therefore a methodology for updating the energy management strategy throughout the bus lifetime is proposed, in order to improve the operation costs and extend the battery lifetime. This update is based on a dynamic programming optimization, tuning the fuzzy logic membership functions and output. Operation costs improvements up to 32.5% are obtained beside a rule-based strategy and a BT lifetime extension of 5.64% is reached. A sensitivity analysis for identifying the critical factors affecting the plug-in hybrid electric bus energy management strategy has been carried out. Auxiliary consumption variation and battery lifetime throughout the bus lifetime have been identified as the most affecting factors.