Scalable Electric-Motor-In-The-Loop Testing For Vehicle Powertrains

Model-Based System Testing (MBST) combines physical testing and simulation models to enable the validation of complex systems early-on in their design cycle. Therefore, it shows great potential for the validation of increasingly complex Electric Vehicle (EV) powertrains. In this work, the MBST methodology is applied to a downscaled powertrain, including a Permanent-Magnet Synchronous Machine (PMSM) and a 3-phase switch-mode inverter. This System-under-Test (SuT) is integrated into an X-in-the-Loop (XiL) test bench, where real-time simulation models of the rest of the vehicle are used to impose realistic boundary conditions to the SuT. These include the emulation of the vehicle inertia, its friction losses and the regenerative braking controller. Both hardware and software architectures required to achieve this setup are presented. Subsequently, a methodology used for computing scaling factors that match the power levels of the full vehicle to the miniature test bench is proposed. Finally, the combined physical-virtual system is evaluated on a driving cycle to validate its behaviour. The usage of a downscaled SuT constitutes the first step towards full-scale E-powertrain-in-the-loop testing, as well as a valuable multi-purpose didactical XiL setup.