SDP-Based Battery Charging Controller for Hybrid Electric Vehicles in Preparation for Zero-Emission Zone Drives

The zero-emission zone (ZEZ) is a recent environmental regulation that restricts the entry of internal combustion engine vehicles. In a ZEZ, hybrid electric vehicles (HEVs) are allowed but must operate in full-electric mode. Therefore, it is important for HEVs entering a ZEZ to have a sufficiently charged battery. This study presents a stochastic dynamic programming-based power management strategy for optimizing HEV charging in preparation for ZEZ drives. Stochastic dynamic programming models the driver's intentions as a Markov chain and designs optimal controllers by incorporating future probabilistic information up to an infinite time horizon. Furthermore, the proposed controller takes into account the remaining distance to the zero-emission zone, enabling efficient charging. Compared to stochastic dynamic programming strategies that do not consider the remaining distance, the proposed power management strategy improves the equivalent fuel efficiency by up to about 21%.