Optimal energy management strategy for a range-extended electric bus under consideration of battery health

The fuel economy performance of hybrid electric vehicles is highly dependent on the energy management strategy. Additionally, the strategy which determines the power split between different power resources has an impact on the battery life. In this paper, a dynamic programming (DP) based control strategy including battery state-of-health (SOH) restrictions is proposed for a range-extended electric bus. The DP-based controllers are evaluated in a high-fidelity vehicle model built in Matlab, and compared to a fuzzy logic based energy management controller. Simulation results show that the DP-based controllers are superior in fuel economy to the fuzzy logic based controller under the same battery capacity degradation. In addition, with different weighting factors of SOH in the cost function, the different trade-off between fuel consumption and SOH is achieved, which can be provided as a benchmark for the fuzzy logic based energy management controller to modify the fuzzy logic rules.