Energy Management of an Hybrid Electric Vehicle in Degraded Operation

This paper studies the energy management of a hybrid electrical vehicle equipped with batteries, an ultracapacitor system (UCS) and a fuel cell system (FCS). The energy management strategy (EMS) is designed to enable degraded operation in case of failure of one of the energy sources. In the considered architecture, the vehicle is not operational without batteries because they impose the DC bus voltage, hence degraded operations are only considered for failures in the FCS or in the UCS. The objective is not to develop a new EMS for each degraded operation mode, but to slightly modify the global EMS developed for normal operation. The paper presents simulation and experimental validation results.