Towards Vehicle-Level Simulator Aided Failure Mode, Effect, and Diagnostic Analysis of Automotive Power Electronics Items

The increasing demand for Electronic Control Units able to perform safety-relevant tasks leads the automotive industry to find novel verification methodologies, capable to decrease the time-to-market and, at the same time, to improve the quality of the assessment. The ISO26262:2018 automotive functional safety standard requires to follow a strict development process, compliant with its “safety lifecycle”. It includes all the phases of the item life, from the concept to the decommissioning. The phase that places most difficulties about its objectivity and repeatability is the hardware/software integration verification since, usually, the software is in charge to mitigate the effects of some possible hardware failures. This paper proposes a novel technique, based on a simulation-based approach, to aid the designers during the Failure Mode, Effect, and Diagnostic Analysis (FMEDA). We consider a power electronics module, to be embedded into electric vehicles powertrains, as a challenging practical example. We performed some tests on it, considering a rear traction car with two independent electric motors, one per each wheel. This system, to allow the vehicle to curve, has to act like a differential gear. Hence, it has a strong safety impact on the driveability of the car. All the involved components have been simulated propagating their behaviours up to the entire vehicle. Due the strong coupling between item failures and vehicle dynamics, a structured way based on coupling fault injection with vehicle dynamic simulation is desirable.