Adaptive Power Split Control for a Hybrid Electric Scooter

An adaptive power split control for a rear-wheel-driven hybrid electric scooter (HES) is proposed in this paper. It is designed using the concept of total equivalent fuel consumption. The equivalence factor is used to transform the electric energy into the equivalent fuel energy and is often selected to be a predetermined function of the state of charge (SOC) of the battery. However, the predetermined function might not be optimal for different driving cycles. An adaptive fuzzy sliding mode controller is used to adjust the equivalence factor according to the SOC deviation. An instantaneous cost function, which consists of the total equivalent fuel consumption, is then minimized to obtain the optimal power split between the internal combustion engine and the electric motor. Deterministic dynamic programming (DDP) is used to offer the performance upper bound to benchmark the proposed control strategy. Preliminary results show that suboptimal fuel economy, which is close to the DDP performance, can be achieved for various driving cycles.