Performance Simulation for Energy Management Considering Derating Effects of Electrified Vehicles 2019-01-0351

One scope of work for energy management of electrified vehicles is the powertrain dimensioning in early development phases. In current development processes only dynamic short term or stationary long term maneuvers for powertrain dimensioning are considered. Therefore, requirements can be already defined for peak and continuous operation for electric motors and the traction battery, but not for the transition in-between. Based on analysis of benchmark vehicles and the driving of more realistic load cases, it is noticeable that also dynamic long term maneuvers become interesting for the end customer. The derating behavior of the electric powertrain components must be considered, especially for such maneuvers. This means in detail the transition between peak and continuous operation. Therefore, this aspect requires a simulation model considering dynamic derating effects for early development phases.

Initially, benchmark vehicles are equipped with measurement devices and standardized maneuvers are driven with the vehicles on a chassis dynamometer to bring the vehicle into derating status. The derating behavior on system level describing the transition from peak to continuous operation is derived based on the measurements. Next, a new simulation model for the simulation of the derating behavior is developed and calibrated to provide the same derating behavior comparable to the measurements. Using this simulation model, also dynamic long term maneuvers can be simulated considering the transition between peak and continuous operation. Such a simulation model can improve the development process to derive requirements for powertrain dimensioning.

By applying this model on a fictional vehicle in the simulation, standard maneuvers and also new dynamic long term maneuvers are simulated and the effect on the powertrain dimensioning is shown. Using such a simulation model in early development phases improves the definition of powertrain requirements for providing more driveable vehicles under realistic conditions and improves the acceptance to the end customer.