Investigation of real-time adaptive energy management strategy for a series-parallel hybrid electric bus

Abstract

To improve fuel economy of a novel series-parallel hybrid electric bus (SPHEB) further, the control rule of battery power distribution is derived from the offline optimisation algorithm based on Pontryagin's minimum principle, internal relationship between the equivalence fuel factor λ and trend of state of charge (SOC) with different driving condition is established and calculation model of SOC is formed. On the basis of the above, according to the feature of the city bus driving cycle, the algorithm of adaptive fuzzy sliding-mode control (AFSMC) is introduced to periodically update the equivalence fuel factor, and then the power-balancing adaptive control strategy is developed. To validate the proposed strategy rationality, the hardware in-the-loop integrated with bench test is applied to compare the proposed control strategy with the previous optimal control strategy. The results indicate that the efficiency of SPHEB system is improved by the proposed control strategy.