Functional Safety Development of E-motor Drive System for PHEV 2015-01-0261
The EMDS (E-motor Drive System), as the core powertrain system of the EV/HEVs, which safety is becoming more and more critical. Meanwhile, the newly released ISO26262 standard rules the functional safety for E/E systems in vehicles, and provides a framework for developing automotive products that are safe from E/E system malfunctions in passenger vehicles.
This paper mainly presents the functional safety concept development of the EMDS for a state-of-the-art P2 hybrid powertrain architecture according to the ISO26262 standard, including system architectures and item definition, hazard analysis and risk assessment, functional safety concept and technical safety concept.
In the development of functional safety concept, the ASIL decomposition is also applied between requirements regarding main functionality and monitoring process, and obtains functional safety requirements based on a preliminary architecture. Meanwhile, in order to avoid any potential harm or damages by any malfunction, the warning and degradation concept is also presented.
In addition, the technical safety requirements which refine the functional safety concept considering system architecture are developed. To develop the technical safety concept, the three-level monitoring safety architecture based on the 1oo1D concept is adopted. In the functional monitoring concept belonging to the second level, the paper primarily takes the typical example of the torque monitoring function to ensure the correctness of the functional level regarding violation of the defined safety goals.