Real-time battery state of charge based power-split adaptation to different driving conditions for range extender fuel cell hybrid vehicles

摘要

A real-time applicable adaptive power split controller for fuel cell hybrid vehicles is proposed. Simulation analyses were carried-out on a high degree of hybridization (i.e., with small fuel cell size) vehicle configuration, whose design and control strategies were simultaneously optimized by exploiting a specification-independent power-split controller. The goal was to upgrade the original thermostatic controller by letting the fuel cell system increase its power share whenever the battery state of charge falls below a critical value, so as to ensure both proper functioning and adequate lifetime for the hybridizing device. This way, it was possible to adapt the optimized vehicle configuration and control strategy to different driving cycles with respect to the one considered in the design phase, also including extra-urban segments. The research outcomes confirm how the previously designed range extender fuel cell vehicle configuration can be safely used onto a variety of driving cycles, including those exhibiting more frequent high power requests. The adaptive control strategy is able to intervene avoiding that the state of charge level goes below the minimum threshold, set to 0.25 after a trial and error analysis. This will allow keeping the benefits associated to limiting fuel cell system size, which also reflects into reduced costs and solves mass production related bottlenecks. The latter aspect is of paramount importance, especially when aiming at supporting short-term market penetration of fuel cell vehicles.