In order to reduce greenhouse gas emissions in the transportation sector traditional combustionvehicles have to be replaced with low-emission alternatives, such as electric vehicles (EV)s andfuel cell (FC) vehicles. As (EV)s have a short driving range and a long recharging time and FCvehicles are limited by their slow power dynamics, the fuel cell hybrid vehicle (FCHV) is examinedas it retains the advantages of the FC vehicle and the EV.
However, FCHV are held back by their shorter lifespan compared to traditional combustionvehicles. The shortened lifespan of a FCHV is caused by degradation of the FC. Thus, this thesiswill focus on degradation-conscious control of the FCHV in an effort to pave the way for broadcommercial use of FCHVs.
One of the biggest causes of degradation occurs due to flooding and drying of the FC (improperwater management). Flooding lowers the FC effective power output while causing chemicaldegradation at the electrodes while drying lowers the membrane conductivity while causingcracking of the membrane. Furthermore, membrane degradation can also occur due to reactantstarvation. Safe and efficient air path control can prevent the occurrence of reactant starvation.Therefore, a degradation-conscious control strategy must take into account the proper watermanagement and air path control. In order to achieve proper water management, the humidifierand the water dynamics are modelled. Additionally, to address the real-life application of FCSs astate estimator is used to estimate the system states.
The controller is implemented as a hierarchical control strategy to account for the differenttime constants found in the FCHV. Lastly the developed control strategy is tested according tostandardised testing protocols. Furthermore, extreme scenarios are analysed to ensure degradationconsciouscontrol within the full scope of operation.