An energy management strategy for an EV with two propulsion machines and a hybrid energy storage system

This manuscript presents a powertrain model with two propulsion machines and a battery-ultracapacitor based hybrid energy storage system (HESS). A two-propulsion machine powertrain can take the best advantage of the limited space under the hood of high performance electric vehicles. One of the major challenges in this architecture is to effectively split the load power demand between the two propulsion machines and the hybrid energy storage components. This manuscript presents a supervisory energy management strategy that optimizes the power split in order to improve the powertrain energy efficiency and also prolong the battery lifetime. It is estimated that the proposed two propulsion machines improves the powertrain efficiency by 5% in comparison to its counterpart with only one propulsion machine. In addition, the energy management control strategy improves the battery state-of-health by 15% in comparison to the battery-only energy storage system under the daily commute assumption based on standard urban drive cycles.