Depth of discharge optimization for energy management of plug-in hybrid electric vehicles considering the social cost of carbon

The depth of discharge (DOD) determines the battery electricity and fuel usage, which is associated with the social cost of the equivalent carbon emission at the well-to-pump (WTP) and pump-to-wheel (PTW) in plug-in hybrid electric vehicles (PHEVs). Higher DOD leads to a significant increase in PHEV operational cost, causing higher energy consumption cost (ECC) and the equivalent cost of battery life loss (ECBLL) due to larger battery packs. Further, the social cost of carbon (SCC) plays a pivotal role in the PHEV energy management strategy (EMS) to maintain global fuel economy. This paper puts forward a multi-objective EMS solution to devise an optimal DOD strategy based on the minimization of the ECC, ECBLL, and SCC over the entire trip. To assess the proposed framework, two types of driving cycles including the developed city bus driving cycle and the standard driving cycle - China heavy-duty commercial vehicle test cycle-bus (CHTC-B) are both utilized for driving simulation studies. The influence of the mileage, power source of battery charge, and vehicular load on optimal DOD are concurrently discussed in the sequel. The results demonstrate that a lower DOD enhances global fuel economy due to the use of less electricity in the PHEV, incorporating the SCC. The results also suggest that the optimal DOD increases with the growing mileage, and the optimal DOD at full load is lower than that in the case of no load under the multi-objective optimization-driven EMS design. Compared with wind power, thermal power tends to choose a lower DOD in the optimal solution of the developed scheme.