Modeling of a fuel cell/battery hybrid powertrain 2008-36-0142
In order to develop a control strategy for hydrogen fuel cell based powertrain, the dynamic models of the fuel cell stack and its auxiliary components must be devised. All The mathematical models currently available are able to estimate the polarization curve of the fuel cell at steady state condition, based on input variables like cathode and anode pressures and cell temperature. For automotive applications, the transient behavior of the fuel cell must be considered, since the powertrain is submitted to severe variations on the electrical power consumption during normal vehicle operation.
Lumped models of the air and hydrogen supply systems, as well as other subcomponents like air compressor, coolers and humidifiers allow one to have a better understanding of the fuel cell behavior during transients and steady-state operation. By simulating the state variables of the system, including the mass if oxygen and hydrogen on the cathode and anode, as well as the membrane humidification, undesirable conditions at the fuel cell system can be predicted and taken into account on developing the controller: membrane de-hydration and oxygen starvation at the cathode during transients.
The strategy developed on the presented model is to use the fuel cell to charge a battery pack that will be responsible for powering the vehicle's electric motor. The mathematical model of the DC electric engine, the power electronics and the fuel cell itself were developed in Matlab® Simulink®.