Comparison of two control strategies for range extender hybrid electric vehicles

Drivetrain electrification is widely used as a main solution for road transport carbon emission reduction. Due to range limitation of battery electric vehicles and high cost of batteries, the plug-in and range extender hybrid electric vehicles are seen as an intermediate step in full transition to battery electric vehicles. These vehicles have onboard charging capability using internal combustion engine to generate energy and extend the driving range of the vehicle charging the battery. There is substantial influence of how the power demand is split between battery and generator. This article compares the rule- and optimal operating point-based control strategies applied to range extender hybrid electric vehicles. Results of the developed simulation model in MATLAB/Simulink environment are compared to the experimental results of a 2014 BMW i3 RexHEV, that are available online. The comparison between rule- and optimal operating point-based control strategies highlight that there is still room for improvement for the former one in certain conditions, whereas the use of the latter one gives a clear advantage in some other.